Infectious Diseases: Soundness of World Health Organization Estimates for
Eradication or Elimination (Letter Report, 04/23/1998, GAO/NSIAD-98-114).

Infectious diseases place an enormous burden on the developing world,
killing more than 17 million people a year and afflicting hundreds of
millions of others. If polio, measles, and other infectious diseases
were eliminated, the United States could save hundreds of millions of
dollars, primarily because it would no longer need to vaccinate U.S.
schoolchildren against polio and measles. Although the cost estimates
and time frames developed by the World Health Organization (WHO) for
eradicating some infectious diseases are based on firm information,
others are more speculative because complete data are unavailable on
target populations, disease prevalence, and other factors. Other
diseases also pose health threats to the United States and could be
potential candidates for eradication. Four diseases were frequently
mentioned in the literature and by experts whom GAO interviewed:
rubella, mumps, hepatitis B, and Hemophilus influenzae type b. WHO
officials said that although it is technically possible to eliminate
these diseases with existing vaccines, it is unlikely that other
diseases will be considered for eradication before success is achieved
with currently targeted diseases. GAO estimates that the United States
has saved nearly $17 billion so far from the eradication of smallpox in
1977. Experts agree that several lessons can be learned from the
smallpox effort, but the main lesson is that a disease can actually be
eradicated. However, they caution that smallpox has limitations as a
model for other diseases because it has characteristics that are
uniquely amenable to eradication. GAO summarized this report in
testimony before Congress; see: Infectious Diseases: Analysis of
Eradication or Elimination Estimates, by Benjamin F. Nelson, Director of
International Relations and Trade Issues, before the House Committee on
International Relations. GAO/T-NSIAD-98-183, May 20 (13 pages).

--------------------------- Indexing Terms -----------------------------

 REPORTNUM:  NSIAD-98-114
     TITLE:  Infectious Diseases: Soundness of World Health
	     Organization Estimates for Eradication or Elimination
      DATE:  04/23/1998
   SUBJECT:  Infectious diseases
	     Medical research
	     Disease detection or diagnosis
	     Immunization programs
	     Health care cost control
	     Cost analysis
	     Developing countries
	     Immunization services
	     Health care services
	     International cooperation

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Cover
================================================================ COVER

Report to the Chairman, Committee on International Relations, House
of Representatives

April 1998

INFECTIOUS DISEASES - SOUNDNESS OF
WORLD HEALTH ORGANIZATION
ESTIMATES FOR ERADICATION OR
ELIMINATION

GAO/NSIAD-98-114

Infectious Diseases

(711258)

Abbreviations
=============================================================== ABBREV

  AIDS - acquired immunodeficiency syndrome
  APOC - African Programme for Onchocerciasis Control
  CDC - Centers for Disease Control and Prevention
  DEC - Diethylcarbamizine
  HIV - human immunodeficiency virus
  ITFDE - International Task Force on Disease Eradication
  PAHO - Pan American Health Organization
  UNICEF - United Nations Children's Fund
  USAID - U.S.  Agency for International Development
  WHO - World Health Organization

Letter
=============================================================== LETTER

B-279440

April 23, 1998

The Honorable Benjamin A.  Gilman
Chairman, Committee on International Relations
House of Representatives

Dear Mr.  Chairman:

Infectious diseases place an enormous burden on the developing world,
killing more than 17 million people a year and afflicting hundreds of
millions of others.  The World Health Organization (WHO) has
identified seven diseases--dracunculiasis, polio, leprosy, measles,
onchocerciasis, Chagas' disease, and lymphatic filariasis--as
candidates for global eradication or elimination\1 and estimated the
costs and time frames for achieving these goals.  Appendix I provides
a table summarizing some of the characteristics of each disease, and
appendixes II through VIII provide descriptions of each disease and
WHO's strategies to address them.

As you requested, we examined

  -- the soundness of the cost and time frame estimates developed by
     WHO for eradicating or eliminating these diseases,

  -- U.S.  spending related to the seven diseases in fiscal year 1997
     and any potential cost savings to the United States as a result
     of eradication or elimination,

  -- other diseases that international health experts believe pose a
     risk to Americans and could be candidates for eradication, and

  -- historical information on U.S.  costs and savings from smallpox
     eradication and whether experts view smallpox eradication as a
     model for other diseases.

--------------------
\1 Eradication reduces worldwide incidence of a disease to zero and
obviates the need for further control measures.  Elimination reduces
the number of cases to zero in a defined geographic area and/or
reduces morbidity to a level that does not constitute a major public
health problem.  Elimination still requires a basic level of control
and surveillance.

   BACKGROUND
------------------------------------------------------------ Letter :1

Global disease eradication and elimination campaigns are initiated,
primarily by WHO, to concentrate and mobilize resources from both
affected and donor countries.  WHO provides recommendations for
disease eradication and elimination to its governing body, the World
Health Assembly, based on two general criteria--scientific
feasibility and the level of political support by endemic and donor
countries.  Formal campaigns were initiated against dracunculiasis
and leprosy in 1991, and against polio and lymphatic filariasis in
1988 and 1997, respectively.  Regional or subregional campaigns are
also underway against measles, onchocerciasis, and Chagas' disease.
Disease eradication and elimination efforts are normally implemented
by national governments of the affected countries.  Developing
countries typically receive assistance for these efforts from
bilateral and multilateral donors, nongovernmental organizations, and
the private sector.

In April 1997, WHO provided the House International Relations
Committee with estimated costs and target dates for eradicating or
eliminating the seven diseases.  Subsequently, WHO revised some of
the costs and time frames based on more recent information.  We also
made some adjustments for consistency among the figures.  Our review
focuses on the estimates that WHO provided to us as of December 1997.
WHO officials estimated that about $7.5 billion would be needed to
eradicate or eliminate the seven targeted diseases.  Developing costs
and time frames for these efforts is difficult due to challenges in
gathering and verifying data from countries with minimal health
infrastructure.  Unpredictable and unstable country conditions, such
as civil unrest, further complicate efforts to project how much these
efforts will cost and how much time is needed.  Table 1 provides a
breakdown of costs and time frames for eradicating or eliminating
each disease.

                                Table 1

                WHO Estimated Target Dates and Costs for
                  Eradicating or Eliminating Selected
                      Diseases as of December 1997

                         (Dollars in millions)

                                                             Estimated
                                                                cost\a
                                                                 (1997
Disease                    Goal             Target date       dollars)
-------------------------  -------------  -------------  -------------
Dracunculiasis             Eradication           2011\b            $40
Polio                      Eradication           2000\c         $1,600
Leprosy                    Elimination             2000           $225
Measles                    Eradication             2010         $4,900
Onchocerciasis             Elimination             2010           $143
Chagas' disease            Elimination             2010           $391
Lymphatic filariasis       Elimination             2030           $228
----------------------------------------------------------------------
\a These costs represent projected public expenditures by national
governments and donor countries for eradication or elimination
campaigns.

\b WHO expects that all but two countries will be free of
dracunculiasis by 2005.

\c Certification is expected by 2005.

To assess the soundness of WHO's estimated costs and time frames, we
met with the WHO officials responsible for preparing them and with
other international health experts who discussed the factors that
should be considered when estimating how much disease eradication or
elimination will cost and how time frames are established.  Following
consultation with WHO and other experts, we determined five overall
factors to be considered for estimating costs.  These experts also
provided information on how targets are developed and the variable
circumstances that may affect time frames.  We used this information
to assess whether the data underlying WHO's estimates were sound.  In
addition to WHO, the experts we consulted included officials from the
Pan American Health Organization (PAHO), the U.S.  Agency for
International Development (USAID), the U.S.  Centers for Disease
Control and Prevention (CDC), the Carter Center's Global 2000 health
program, the Johns Hopkins University, and Emory University to obtain
their views on WHO's estimates.  Appendix IX contains a detailed
description of our scope and methodology.

   RESULTS IN BRIEF
------------------------------------------------------------ Letter :2

The soundness of WHO's cost and time frame estimates for eradicating
or eliminating the seven diseases varied for each disease.  Cost and
time frame estimates for dracunculiasis, polio, and leprosy were the
most sound because campaigns against them have been underway for
several years and are largely based on firm data about target
populations and intervention costs from ongoing initiatives.  For the
other diseases, WHO's estimates are more speculative because data
underlying the cost and time frame estimates are incomplete or
unavailable.  WHO officials acknowledge that the costs and time
frames provided to the House Committee on International Relations are
not exact and that they must continually be refined as new
information becomes available.

The United States spent about $391 million in 1997 on programs to
combat these diseases.  Potential savings to the United States if
eradication or elimination of these diseases were achieved could be
substantial.  Most of the savings would result from eliminating the
need to vaccinate U.S.  children against polio and measles.

The experts we interviewed and our review of the literature
identified several other diseases that pose health threats to the
United States and that meet the scientific criteria for eradication
used by health experts.  Four diseases were frequently mentioned:
rubella, mumps, hepatitis B, and Hemophilus influenzae type b (Hib).
WHO officials stated that while it is technically possible to
eradicate these diseases with existing vaccines, it is unlikely that
other diseases will be considered for eradication before achieving
success with currently targeted diseases.

Using CDC data, we estimated that the United States has saved almost
$17 billion to date from the eradication of smallpox in 1977.  The
savings are due to the cessation of vaccinations and related
expenditures such as surveillance, treatment, and loss of
productivity.  Experts agree that several lessons can be learned from
the smallpox effort, but the primary lesson is that a disease can
actually be eradicated.  However, they also suggested that smallpox
has limitations as a model for other diseases because it had
characteristics that were uniquely amenable to eradication.

   SOUNDNESS OF ESTIMATES VARIES
   BY DISEASE
------------------------------------------------------------ Letter :3

WHO officials and other experts identified the following as the key
factors to consider in estimating direct costs for eradicating or
eliminating diseases:  (1) the funds needed to purchase the required
intervention products, such as vaccines, drugs, insecticides, or
water filters; (2) the prevalence and incidence of the disease and
the population targeted for intervention;\2 (3) the administrative
costs for delivering products to the target population (for example,
transportation, setting up local infrastructure, administering
vaccines or treatment, spraying, and technical assistance); (4) the
costs for surveillance activities, such as diagnosing the disease,
testing blood or other specimens at laboratories, and monitoring and
reporting disease incidence; and (5) for eradication, the costs of
certifying that each country is free of the disease.  We focused our
assessment primarily on these five factors.

WHO addressed all five factors in developing its cost estimates,
except for the measles estimate, which did not include certification
costs.  The completeness of the data underlying the estimates varies
by disease.  Estimates for those diseases with long-standing
campaigns that are closest to eradication or
elimination--dracunculiasis, polio, and leprosy--are more complete,
and costs are based on actual experience in endemic countries.  For
the other diseases, WHO is still gathering data and refining its
assumptions.  For several diseases, products are donated and are not
included in projected costs.  Examples include nylon filters donated
by Dupont Corporation and Precision Fabrics Group for controlling
dracunculiasis, donations of ivermectin by the Merck Company for the
onchocerciasis program, and donations of albendazole by SmithKline
Beecham for treating lymphatic filariasis.  The Nippon Foundation of
Japan also funds the drugs used for leprosy treatment.

WHO establishes time frames primarily to gain commitment and mobilize
resources from endemic and donor countries.  WHO bases time frame
estimates on the technical feasibility of reaching target populations
over a period of time and an assessment of the commitment of endemic
and donor countries.  As part of that assessment WHO considers the
economic and political conditions in endemic countries that could
affect their ability to carry out disease campaigns.  As with costs,
time frames for diseases expected to be eradicated or eliminated
within 5 to 10 years are considered more accurate than for those with
later target dates because of the unavailability of data and the
difficulty of predicting commitment levels and country conditions
over time.

The following sections describe in more detail WHO's cost and time
frame estimates for eradicating or eliminating each of the seven
diseases.

--------------------
\2 "Prevalence" is the number or percentage of existing cases of a
disease, and "incidence" is the number of new cases in a defined
period of time.

      DRACUNCULIASIS (GUINEA WORM
      DISEASE)
---------------------------------------------------------- Letter :3.1

WHO's cost estimate for eradicating dracunculiasis included data on
each of the five key factors and appears to be sound.  The cost data
associated with each element are based on historical data from
community-based control programs underway since 1980.  WHO had
previously set target dates of 1995 and the year 2000 for
eradication, but continuing civil unrest in some endemic areas
precluded meeting those dates.  WHO now expects that all countries
except Nigeria and Sudan will be free of dracunculiasis by 2005 at
the latest; assuming safe access to endemic areas and appropriate
funding, WHO officials said this goal could be reached by 2002.  WHO
expects that transmission of the disease will be interrupted in
Nigeria and Sudan by 2010, provided that safe access and funding
conditions can be met.  WHO has prepared a biennial estimate of the
funds needed through 2011, including certification costs.

Experts we interviewed agreed that eradicating dracunculiasis is
generally feasible within the time frame and cost estimate
established by WHO.  In fact, officials from CDC and the Carter
Center's Global 2000 program believe that dracunculiasis will be
eradicated in some countries even sooner than WHO estimated and costs
will therefore be lower than WHO's projections.  However, one expert
cautioned that continuing instability in the region could extend the
projected time frame.

      POLIO
---------------------------------------------------------- Letter :3.2

WHO's cost estimate for eradicating polio is generally sound and
included well-developed cost data on each of the five key factors
based on historical experience in controlling the disease.  The
global effort to eradicate polio was formally launched in 1988,\3
although many countries began polio vaccinations as part of the
Expanded Programme on Immunization during the 1970s and 1980s.\4 WHO
relies on UNICEF for estimates of vaccine costs and uses its own
estimates for the cost of vaccine delivery based on actual experience
in countries around the world.

While the World Health Assembly originally targeted polio for
eradication by the year 2000, most experts we consulted said that
polio is on track for eradication by 2002 and certification by 2005.
However, some experts raised concern about whether less developed
countries will maintain the required level of commitment to polio
vaccinations and surveillance until eradication is achieved.  In
addition, a 1997 WHO report raised concerns about some countries'
progress in meeting performance indicators for detecting and
reporting acute flaccid paralysis, a key component of polio
surveillance.\5 According to WHO, unless sufficient resources are
mobilized to improve detection capability, eradication cannot be
certified.

--------------------
\3 In 1985, PAHO launched a campaign to eradicate polio from the
Western Hemisphere.  The last indigenous case of polio was reported
in Peru in 1991, and PAHO certified the eradication of polio from the
Americas in 1994.

\4 The Expanded Programme on Immunization, launched by WHO in 1974
and jointly carried out with the United Nations Children's Fund
(UNICEF), aims to increase global vaccination coverage against
childhood diseases through donor and technical assistance to national
governments.  The standard immunizations include polio, measles,
diphtheria, neonatal tetanus, pertussis, and tuberculosis;
immunizations against hepatitis B and yellow fever have been added in
some countries.

\5 See Polio:  The Beginning of the End, WHO, Global Programme for
Vaccines and Immunizations (Geneva, Switzerland:  WHO, 1997), p.  22.

      LEPROSY
---------------------------------------------------------- Letter :3.3

WHO's cost estimate for eliminating leprosy as a public health
problem included well-defined data on all key cost elements and
appears to be sound.  The current elimination strategy is based on
the multidrug therapy program begun in 1981, so cost information is
well developed.  Endemic countries have made significant progress
toward eliminating leprosy since the 1980s.  However, WHO officials
noted that it is possible that some countries with concentrated
pockets of leprosy might need to continue campaigns beyond the target
date of the year 2000 to reach the global leprosy elimination target
of less than 1 case per 10,000 people.  Despite this caution, experts
generally agreed that WHO's cost and time frame estimates for leprosy
are reasonable.

      MEASLES
---------------------------------------------------------- Letter :3.4

WHO's measles eradication estimates are speculative.  While vaccine
costs are well known and based on UNICEF data, WHO officials told us
that their estimates did not include the costs of certifying measles
eradication and that cost estimates for other factors were low or
incomplete.  Specifically, WHO officials noted that

  -- information on the number of children to be vaccinated is
     incomplete;

  -- administrative costs may be underestimated and are in need of
     further refinement, and assumptions regarding the efficacy of
     mass campaigns may be overstated; and

  -- assumptions regarding the costs of surveillance and monitoring
     are low because WHO did not account for inadequate health
     systems in some countries.

Despite these limitations, WHO noted that the measles eradication
estimates benefit from the experience of previous eradication
efforts.  The vaccine administration, surveillance, and certification
costs utilize estimates from the polio eradication experience and are
adjusted upward to account for difficulties in administering an
injectable rather than an oral vaccine.

Experts we consulted, including WHO officials, noted that there are
unique challenges to eradicating measles within the estimated time
frames.  Measles is highly contagious, requiring even higher routine
vaccination coverage than smallpox and polio.  Special campaigns in
varying age groups are also necessary to catch those still
susceptible after vaccination because the vaccine is not 100 percent
effective.  Outbreaks can occur even in areas with high routine
vaccination coverage.  Injection safety is also a concern in the
large-scale campaigns required for eradication, particularly in areas
where the risk of infection with human immunodeficiency virus and
hepatitis is high.  In addition, diagnosis is difficult because the
symptoms can mimic other, less severe infections, and surveillance is
difficult because the disease can spread rapidly while laboratory
analysis and confirmation are undertaken.  Finally, while measles is
a major cause of mortality and morbidity for children in poorer
countries, according to some experts we consulted, it is not
perceived to be a major public health problem by some industrialized
countries.  As a result, unlike polio, some developed countries have
not initiated the measles elimination efforts necessary to prepare
for global eradication.  More than half of the estimated cost of
measles eradication is expected to be incurred by developed
countries.  WHO estimates that the lowest income countries will
require up to $1.8 billion in external funding for measles
eradication.

At a February 1998 meeting in Atlanta, Georgia, over 200 disease
eradication experts concluded that it is biologically plausible to
eradicate measles with the current vaccine, noting that measles
transmission appears to have been interrupted for variable time
intervals in the Americas.  According to a CDC summary of the
meeting, participants recommended, among other things, that (1)
developed countries proceed with measles elimination efforts as a
step toward eradication; (2) less developed countries accelerate
control efforts, particularly in areas with high mortality; and (3)
experience from regional and country level interventions be used to
refine the strategies for eventual eradication.  Participants ranked
measles as the disease most likely to be the next candidate for a
global eradication effort.  USAID officials told us that many
participants, while agreeing on the technical feasibility of
eradicating measles, also cautioned that further study should be
undertaken to fully understand the magnitude of the effort and
resources required for eradication.

According to WHO and CDC, some areas are beginning to set regional
elimination goals.  In addition to the PAHO elimination goal for the
year 2000, over 50 countries encompassing Europe and the Newly
Independent States are in the final stages of adopting a goal of
regional elimination by 2007, and the Eastern Mediterranean region
has adopted an elimination goal of 2010.

      ONCHOCERCIASIS (RIVER
      BLINDNESS)
---------------------------------------------------------- Letter :3.5

WHO's estimate for eliminating onchocerciasis is somewhat
speculative.  It incorporates data on all key cost
elements--including the costs for larvicides and drug treatment,
delivery, and surveillance--but data on the size of the target
population are incomplete, which could affect the cost and time frame
estimates.  A control program covering 11 countries in West Africa
has been in place for 24 years and has almost reached its elimination
goal,\6 and a program covering 6 countries in Latin America has been
ongoing since 1991.\7 Thus, the costs for these countries are well
defined.  However, WHO officials told us that the amount estimated
for the other 19 endemic African countries of the African Programme
for Onchocerciasis Control (APOC) is more speculative because WHO is
still mapping the prevalence of the disease in this area.\8 WHO's
early estimates of the population eligible for treatment, upon which
the APOC cost estimate was based, are low for some areas.  The latest
estimate for the population eligible for treatment in the APOC
program is 42 million compared to the original estimate of 35
million.  Due to the political unrest in the Democratic Republic of
the Congo (formerly Zaire), WHO does not have a reliable estimate of
the number of people to be treated.  However, according to WHO
officials, this region is probably the first or second most infected
area in the world.  Experts generally agreed that the ongoing West
Africa and Latin America programs are on schedule and onchocerciasis
is likely to be eliminated as a public health problem within the cost
and time frames estimated by WHO.  The APOC program started its
operations in 1996 and, according to WHO, it is too early to judge
whether it will achieve elimination goals within the set time frame.

--------------------
\6 The Onchocerciasis Control Programme in West Africa includes
Burkina Faso, Benin, Cote d'Ivoire, Ghana, Guinea, Guinea-Bissau,
Mali, Niger, Senegal, Sierra Leone, and Togo.

\7 The Onchocerciasis Elimination Programme in the Americas includes
Brazil, Colombia, Ecuador, Guatemala, Mexico, and Venezuela.

\8 The APOC area includes Angola, Burundi, Cameroon, Central African
Republic, Chad, Congo, Democratic Republic of the Congo (formerly
Zaire), Ethiopia, Equatorial Guinea, Gabon, Kenya, Liberia, Malawi,
Mozambique, Nigeria, Rwanda, Sudan, Tanzania, and Uganda.

      CHAGAS' DISEASE
---------------------------------------------------------- Letter :3.6

Although WHO included data on all five cost factors, the estimates
for eliminating Chagas' disease are understated because (1) not all
countries have submitted estimates and (2) countries that are
targeted for elimination of Chagas' disease by 2010 only submitted
estimates through 2005.  Like onchocerciasis, the cost and time frame
estimates vary among several regional efforts.  The program for the
southern portion of South America\9 has been underway since 1991, so
data from this region are more complete and based on actual
experience.  However, the efforts in the Central American and Andean
countries only began in 1997.\10 Costs and time frames in these
countries are less certain because three countries have not submitted
cost estimates, and three countries have not submitted prevalence and
incidence data.  Experts generally agreed that the first program in
South America is on track and will probably meet elimination goals by
the target date of 2005.  However, they believed that the estimates
for some of the other countries are likely to increase.

--------------------
\9 Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay.

\10 The Andean Countries Initiative includes Colombia, Ecuador, Peru,
and Venezuela.  The Central American Initiative includes Belize,
Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, and
Panama.

      LYMPHATIC FILARIASIS
---------------------------------------------------------- Letter :3.7

Costs for eliminating lymphatic filariasis are very speculative.
While all five direct cost factors were addressed in the estimates,
WHO officials said that the data are very preliminary.  Unlike its
information for some of the other diseases, WHO has limited
historical data on costs because formal campaigns have only recently
begun in some of the 73 countries in which lymphatic filariasis is
known to be present.  WHO extrapolated actual program costs from the
first four country programs to other countries and is continuing to
develop more accurate estimates of costs based on further experience.
In addition, WHO officials said that they have not completed country
assessments to establish the number of people who must be treated in
identified countries and to determine whether there are other endemic
countries.  Quantitative targets for defining elimination have not
yet been established, but WHO plans to prepare a draft document with
elimination definitions to be reviewed by an expert working group by
the end of 1998.  According to WHO, initial control programs show
such dramatic results in reducing disease transmission that WHO
believes that elimination may occur in a number of endemic areas
(particularly island populations) after 5 to 6 years of effective
control efforts.  Experts generally agreed that the disease was a
good candidate for elimination but that the costs and time frames
were speculative at best.

   U.S.  SPENDING ON THESE
   DISEASES AND POTENTIAL U.S.
   SAVINGS ASSOCIATED WITH THEIR
   ERADICATION OR ELIMINATION
------------------------------------------------------------ Letter :4

The United States currently spends about $391 million a year on these
diseases.  This amount includes $300 million a year on polio and
measles prevention programs and leprosy treatment in the United
States, and about another $91 million abroad for all seven diseases
(see table 2).  Most of this amount would be saved if eradication and
elimination goals were met and efforts to combat them ceased or were
reduced.  The United States does not currently track domestic costs
related to Chagas' disease, but there have been discussions about
implementing routine blood screening for it.  An American Red Cross
official estimated this screening could cost $25 million a year.

                                Table 2

                    U.S. Spending on Diseases to Be
                 Eradicated or Eliminated, Fiscal Year
                1997 (excluding research spending by the
                     National Institutes of Health)

                         (Dollars in millions)

                                Domestic       Overseas
Disease                         programs       programs          Total
-------------------------  -------------  -------------  -------------
Dracunculiasis                         0           $0.7           $0.7
Polio                               $230           74.2          304.2
Leprosy                               20              0           20.0
Measles                               50           11.7           61.7
Onchocerciasis                         0            3.5            3.5
Chagas' disease                        0            0.4            0.4
Lymphatic filariasis                   0            0.6            0.6
======================================================================
Total                               $300          $91.1         $391.1
----------------------------------------------------------------------
Sources:  USAID; CDC; and the U.S.  Department of Health and Human
Services, National Hansen's Disease Program.

      POTENTIAL COST SAVINGS FOR
      POLIO AND MEASLES
---------------------------------------------------------- Letter :4.1

         POLIO
-------------------------------------------------------- Letter :4.1.1

The overall savings to the United States as a result of polio
eradication are estimated to be at least $304 million a year,
including about $230 million in public and private expenditures for
controlling polio within U.S.  borders and about $74 million for the
global eradication effort.  This estimate does not include the costs
of caring for about eight or nine vaccine-associated polio cases that
occur in the United States each year.  As a donor, the United States
currently funds the global polio eradication effort through CDC and
USAID and indirectly through support of the Expanded Programme on
Immunization.

According to CDC, about 48 percent of domestic expenditures is for
the cost of the oral polio vaccine and about 52 percent is for
administrative costs.  The U.S.  polio schedule is four vaccine
doses; until recently, most children received only the oral vaccine.
For purposes of estimating savings to the United States with
eradication, CDC estimates an additional $20 million a year may be
incurred due to a 1996 CDC recommendation to administer two doses of
the more expensive injectable vaccine before administering two doses
of oral vaccine.  Unlike the injectable polio vaccine, the oral
vaccine is a live, attenuated vaccine that causes disease in several
people each year in the United States.  Providing the injectable
vaccine first in the vaccine schedule will lessen the possibility of
provoking disease from the oral vaccine.  However, the oral vaccine
is the vaccine of choice for eradication because, unlike the
injectable vaccine, it prevents the wild poliovirus from readily
multiplying in the gut and thus stops person-to-person transmission.

         MEASLES
-------------------------------------------------------- Letter :4.1.2

The overall savings to the United States as a result of eradicating
measles are estimated at a minimum of $61.7 million a year, including
about $50 million for domestic vaccine costs and about $11.7 million
for global measles control efforts.  CDC estimates that it spent an
additional $1.3 million on domestic measles research in 1997.  The
$50 million spent in the United States only includes the cost of the
vaccine and not administration costs because immunization against
measles is included in the vaccine for mumps and rubella, and the
United States would continue administering mumps and rubella vaccines
even if measles were eradicated.  Therefore, projected savings are
not as large as for the eradication of polio.  Additional savings
would be realized from preventing periodic measles epidemics in the
United States; the last measles epidemic of 1989-91 cost $150
million, not including costs associated with lost productivity.

      U.S.  SAVINGS ASSOCIATED
      WITH ACHIEVING WHO'S GOALS
      ON OTHER DISEASES ARE
      LIMITED
---------------------------------------------------------- Letter :4.2

For the other tropical diseases we reviewed, U.S.  savings from
eradication or elimination are estimated at about $25 million.  The
U.S.  Department of Health and Human Services spends approximately
$20 million a year to treat a small number of leprosy patients in the
United States.  However, without eradication of the disease, it is
likely that the United States would continue to have a small number
of cases.  USAID funds the dracunculiasis eradication effort at
$500,000 a year and the onchocerciasis effort at $3.5 million a year.
CDC spends about $1 million for overseas efforts against
dracunculiasis, Chagas' disease, and onchocerciasis.  Eradicating
dracunculiasis and eliminating onchocerciasis, Chagas' disease, and
lymphatic filariasis will remove or reduce the need for U.S.
assistance.  In addition, as previously discussed, U.S.  blood banks
may begin screening donated blood for Chagas' disease due to a
significant number of infected Latin American immigrants in certain
areas of the United States.  Screening requirements might be reduced
or unnecessary at some point if a successful elimination effort
diminished the threat to the U.S.  blood supply.

   EXPERTS SUGGEST OTHER DISEASES
   AS POSSIBLE CANDIDATES FOR
   ERADICATION
------------------------------------------------------------ Letter :5

International public health experts at CDC and Johns Hopkins
University and a 1993 report by the International Task Force for
Disease Eradication (ITFDE) revealed a number of diseases that pose
threats to the United States and that are technically possible to
eradicate.\11 Diseases commonly mentioned include rubella, mumps,
hepatitis B, and Hib.  The ITFDE concluded that mumps and rubella
could probably be eradicated and that the transmission of hepatitis B
could be eliminated by universal vaccination.\12 While these diseases
generally meet the technical criteria for eradication, we discuss in
the following paragraphs some of the challenges to initiating
campaigns at this time and WHO's position on eradicating these
diseases.

CDC officials suggested that rubella and mumps could be considered
candidates for eradication as part of a measles eradication effort,
since they are often included as part of a trivalent vaccine against
measles, mumps, and rubella.  Their inclusion would result in
significant increased savings to the United States because, without
the eradication of rubella and mumps, most of the cost of the measles
vaccination--vaccine administration--would continue to be incurred
after measles eradication.  CDC estimated U.S.  savings from
eradicating measles, mumps, and rubella at about $255.5 million a
year.  According to WHO and CDC officials, rubella constitutes a
significant health burden in the form of birth defects and is being
discussed as an elimination initiative for the Americas.  As with
polio and measles, a successful strategy in the Western Hemisphere
would likely be a model for global eradication.  Challenges to
eradication are difficulties in diagnosis and the additional costs,
particularly for developing countries.  WHO said that, because the
global burden of mumps is relatively low or unknown in some areas,
the costs of an eradication effort would be difficult to justify.

According to WHO and CDC officials, the viral disease hepatitis B may
be a candidate for eventual eradication because the vaccine is
effective and relatively inexpensive--about 50 to 75 cents per dose.
In addition, a good diagnostic tool is available and it appears that
humans are the only reservoir for the disease.  Hepatitis B is
considered a major public health threat because it often progresses
to cancer.  Almost 1.2 million deaths result each year from hepatitis
B, usually from liver cancer or chronic liver disease.  The National
Science and Technology Council and the National Institutes of Health
estimate that the United States spends about $720 million each year
in direct and indirect costs related to hepatitis B.  CDC estimates
that U.S.  public and private sectors spend from $308 million to $383
million a year for hepatitis B vaccines alone.  According to CDC
officials and the ITFDE report, the major barrier to eradication is
that it would take decades to achieve because some people are chronic
carriers and would have to die before the disease could be considered
eradicated.

Hib is a bacterial infection that is the most common cause of
childhood meningitis and, like hepatitis B, poses a serious global
disease burden, including 400,000 to 700,000 deaths each year among
children in developing countries.  The U.S.  public and private
sectors spend about $162 million a year on Hib vaccines.  According
to CDC officials, this disease has potential for eradication but more
needs to be known about the vaccine before it could be an eradication
candidate.  WHO has made Hib a priority for introduction to routine
childhood immunization, but cost is a barrier.  The vaccine costs $1
to $2 per dose, which would substantially increase the vaccine costs
of the Expanded Programme on Immunization.

According to WHO officials, due to the public health burden
associated with rubella, hepatitis B, and Hib and the success in
controlling the diseases in some parts of the world, these three
diseases could be eventual candidates for eradication.  However, WHO
officials noted that, due to the high costs associated with
eradication efforts, political will and popular support are as
critical to any eradication effort as the technical ability to
achieve success.  As a result, they said that it is important to
limit the number of ongoing efforts and that they do not support
adding campaigns at this time.  They noted that other diseases could
be considered as eradication candidates after success with the
currently targeted diseases is achieved.

Other infectious diseases pose a growing threat to the United States
but do not have characteristics that make them amenable to
eradication.  During congressional testimony last year, a WHO
official noted several other diseases--in addition to human
immunodeficiency virus (HIV)/acquired immunodeficiency syndrome
(AIDS)--that continue to be major public health problems, globally
and in the United States.\13 For example, malaria, which results in
about 500 million infections and 2 million to 3 million deaths
outside the United States each year, is being imported into the
United States about 1,000 times each year.  In some instances,
malaria is then transmitted locally by mosquitoes present in the
United States.  During 1996, a tourist to Latin America returned to
Tennessee with yellow fever.  According to the WHO witness, if
mosquitoes in Tennessee had become infected with yellow fever from
this patient, they could have caused an epidemic in the United States
similar to the one that caused high mortality in the southern United
States at the beginning of the 20th century.  Outbreaks of dengue
fever, another mosquito-borne disease, have occurred in more than 100
tropical and subtropical countries, including recent epidemics in
Central America.  WHO reported 138,000 deaths from dengue in 1996.
There are about 8 million new cases worldwide of tuberculosis each
year, a new infection every second, and 3 million deaths in 1996.
Finally, influenza, a viral disease, causes between 10,000 and 40,000
deaths each year in the United States alone.

These diseases are not likely candidates for eradication over the
next generation for a variety of reasons, although it is possible to
control disease transmission in some instances.  According to the
ITFDE, eradicating malaria has proven difficult due to the lack of an
effective vaccine, resistance of some mosquitoes to insecticides, and
resistance of some malaria parasites to treatment.  Although an
effective vaccine for yellow fever has been available for more than
50 years, it has only recently been standardized in freeze-dried form
so that its stability, both in the freeze-dried and reconstituted
form, resembles measles vaccine.  According to WHO officials, the
additional cost is proving a major constraint to having endemic
countries include it in their routine childhood immunization
programs.  Yellow fever cannot be eradicated because humans are not
the only reservoir for infection--an animal reservoir also exists.
No effective treatment is available for dengue fever; the primary
intervention is mosquito control--and a possible monkey reservoir for
dengue infection is suspected.  The need for improved diagnostic
tests, chemotherapy, and vaccines is cited as obstacles to
eradicating tuberculosis; emerging drug-resistant strains of the
bacterium causing tuberculosis have complicated control programs.
Finally, influenza reemerges worldwide each year in a new form and is
highly infectious; the yearly vaccines are only partially effective.
The ITFDE reported that an animal reservoir is also suspected for
influenza.

--------------------
\11 The ITFDE was a group of scientists from WHO, CDC, other health
and development agencies, and academia.  It was convened by the
Carter Center of Emory University during 1989-92 to establish
criteria for eradication and to use them to evaluate the potential
for eradicating other diseases in the aftermath of the smallpox
eradication campaign.

\12 Centers for Disease Control and Prevention:  Recommendations of
the International Task Force for Disease Eradication.  MMWR 1993; 42
(No.  RR-16) (Atlanta, Ga.:  U.S.  Department of Health and Human
Services, Public Health Service), pp.  11-13.

\13 Statement by David L.  Heymann, M.D., Director, Emerging and
Other Communicable Diseases Surveillance and Control, WHO, before the
Committee on International Relations, House of Representatives, 105th
Cong., 1st session, July 30, 1997.

   SMALLPOX ERADICATION SHOWED
   THAT SUCCESS WAS POSSIBLE
------------------------------------------------------------ Letter :6

According to the literature and experts with whom we met, the primary
lesson learned from the smallpox initiative was that disease
eradication can be technically feasible.  The smallpox campaign
provided valuable institutional knowledge on the role of community,
national, and international mobilization.  Eradicating smallpox also
meant that costly programs for immunizations and treatment of
infected cases were no longer needed.  However, unlike most of the
diseases that are currently candidates for eradication, smallpox had
unique characteristics that made it particularly vulnerable to
eradication and therefore has limitations as a model for current
efforts.

As the first and only disease to be eradicated through human
intervention, smallpox is used as evidence that disease eradication
is technically feasible.  According to some experts, the smallpox
effort yielded lessons that have since been applied to other disease
control and health care efforts, such as the role of surveillance and
the ability to garner resources for massive campaigns.

The considerable amounts spent on smallpox prevention and treatment
ceased after eradication, resulting in considerable savings.  Using
1967 estimated smallpox costs\14 as a baseline measure for savings
from smallpox eradication and adjusting for annual birth rates, we
estimated the cumulative present value global savings in 1997 dollars
for the post-eradication period 1978-97 at $168 billion.  This amount
included vaccinations, treatment, and loss of economic productivity
for developing countries.\15 For the United States, cumulative
savings from smallpox eradication are estimated at $17 billion.  The
United States spent about $610 million in 1997 dollars for domestic
smallpox control in 1968 and about $130 million in 1997 dollars
during 1968-77 on the overseas eradication effort.  We estimated the
annual real rate of return for the United States at about 46 percent
per year since smallpox was eradicated.

Smallpox had the characteristics that experts consider desirable for
eradication.  The disease was easily diagnosed, and all infections
resulted in visible symptoms.  The smallpox vaccine was effective
with only one dose, stable in heat, and inexpensive.  Polio and
measles share many of the desirable eradication characteristics of
smallpox, including being viral agents with human-only reservoirs,
having effective interventions available to interrupt transmission,
and providing long-lasting immunity after vaccination.  However,
certain differences exist.  For example, smallpox was less infectious
than either polio or measles.  Polio is difficult to diagnose without
laboratory confirmation because the vast majority of infections show
no symptoms, and the paralytic manifestations of polio can be due to
other causes.  In addition, while the oral vaccine is easy to
administer and does not always require trained health workers, up to
four doses are recommended, and the vaccine is sensitive to heat,
requiring refrigeration until administered.

Similarly, measles is not as easily diagnosed as smallpox and is much
more infectious.  Because the measles virus spreads so easily and the
diagnosis may present difficulties, the surveillance and containment
strategies used for the smallpox eradication campaign are not as
effective for measles, and a surveillance strategy uniquely tailored
to measles is required.  Even in the United States, where
transmission of the measles virus has essentially been interrupted
since 1993, occasional outbreaks still occur due to imported virus.

Dracunculiasis is very different from smallpox since it is a
parasitic disease and not vaccine preventable.  However, like
smallpox, it is vulnerable to eradication efforts primarily because
the interventions are inexpensive and effective, and the infection is
easily diagnosed.  Simply using a water filter and keeping infected
persons out of the water supply can stop transmission of the disease.
The main barriers to eradication within the time frames set by WHO
are ongoing civil strife in the endemic regions of Africa and a
potential lag in national and donor support for a disease that is
found mostly in isolated rural areas.

--------------------
\14 F.  Fenner, et al., Smallpox and Its Eradication (Geneva,
Switzerland:  WHO, 1988), pp.  1364-65.

\15 If cost savings are limited to vaccinations and their related
costs, the cumulative global savings are estimated at $41 billion.

   CONCLUSIONS
------------------------------------------------------------ Letter :7

The soundness of WHO's cost and time frame estimates for eradicating
and eliminating these seven diseases varies for each disease.  The
estimates are most sound for diseases where eradication or
elimination campaigns have been underway for several years.  For the
other diseases, complete data are unavailable so the estimates are
more speculative.  WHO officials acknowledge their estimates are a
snapshot in time, based on the information then available.  They also
pointed out that they are continuously revising their assumptions and
the data underlying cost factors to refine the estimates.

For some of the diseases, WHO indicated that obtaining good data will
be difficult because many developing countries do not have good
disease surveillance systems or the health infrastructure to collect
and report the information.  Moreover, WHO indicated that external
factors, such as civil strife and government commitment to disease
eradication and elimination, can influence the cost and time frame
estimates.

The United States is spending a significant amount to combat these
diseases domestically and overseas, most of which could be saved if
eradication and elimination efforts are successful.  In addition,
other diseases posing significant public health problems and costs
for the United States may be potential candidates for eradication and
possible U.S.  savings if the current strategies prove successful.

   AGENCY COMMENTS
------------------------------------------------------------ Letter :8

WHO, the State Department, CDC, and USAID provided written comments
on a draft of this report.  Their responses and our evaluation, where
appropriate, are printed in appendixes X through XIII.  WHO, CDC, and
USAID also provided technical comments, which we incorporated as
appropriate.

WHO stated that the report fairly reflects the processes it is using
to estimate the costs and time frames associated with global
eradication or elimination of the seven diseases.  WHO pointed out
that, as we state in our report, such estimates are most complete for
those diseases with long-standing campaigns and closer target dates
and that all estimates are refined as new information becomes
available.  WHO noted that successful campaigns against a disease
must build on and build up strong national and international health
infrastructure, such as routine immunization, disease reporting
systems, trained health workers, and laboratory capacity.  WHO stated
that the explanations in the report appendixes about the unique
challenges faced by each campaign should prove useful to
decisionmakers in focusing on these important contextual dimensions.

The State Department stated that our report provides a comprehensive
analysis of WHO's estimates.  State noted that estimates are inexact
and should not become an unrealistic yardstick for measuring costs.
State also said that the value of investments in eradication and
control should provide support for U.S.  investment in bilateral and
multilateral programs associated with campaigns against diseases.
However, State pointed out that it is important to maintain a balance
between eradication and elimination programs and other vital health
care programs.  State indicated that resources should not necessarily
be diverted to eradication programs from other important health
activities because, while the results may not be as dramatic, they
are nonetheless essential.

CDC discussed the benefits of eradication programs, citing the 46
percent annual return on investment we estimated for smallpox and the
$300 million that could be saved by the United States as a result of
polio eradication.  CDC added that these costs will be saved in
perpetuity.  CDC also noted that it appreciated our "recognition of
the value of disease eradication and elimination programs." However,
we did not assess the value of eradication or elimination programs.
Rather, our work focused on WHO's estimates of program costs and
potential U.S.  savings based on current expenditures.

USAID commented that in general our report was comprehensive and
informative.  However, USAID expressed concern that we did not fully
consider the costs and concerns regarding disease eradication and as
a result we imply that there is global consensus on the eradication
potential of the seven diseases reviewed.  In particular, USAID said
that we did not consider the financial and opportunity costs to
health systems of eradication campaigns and that we implied a
consensus on the feasibility and soundness of measles eradication.
USAID said that eradication campaigns can be disruptive to primary
health care systems and may result in an unfortunate reduction in
efforts to prevent other diseases.  As recognized by USAID, our
report clearly states that our objective was to assess the soundness
of WHO's estimates.  We did not assess the potential impacts of
eradication or elimination campaigns on national health care systems.
In addition, we do not imply that there is a global consensus on
measles.  In fact, our report specifically discusses many of the
experts' views and the challenges facing eradication and elimination
campaigns, particularly for measles.

---------------------------------------------------------- Letter :8.1

Unless you publicly announce its contents earlier, we plan no further
distribution of this report until 30 days after its issue date.  At
that time, we will send copies of this report to the Director General
of WHO, the Secretary of State, the Director of CDC, the
Administrator of USAID, and other interested congressional
committees.  Copies will be provided to others upon request.

Please contact me at (202) 512-4128 if you or your staff have any
questions concerning this report.  Major contributors to this report
are Lynne Holloway, Audrey Solis, Ann Baker, and Bruce Kutnick.

Sincerely yours,

Benjamin F.  Nelson
Director, International Relations
 and Trade Issues

SUMMARY DESCRIPTIONS OF SEVEN
DISEASES PROPOSED FOR ERADICATION
OR ELIMINATION
=========================================================== Appendix I

                                                                        Endemic           Estimated number  Estimated global                                      Challenges to
                  Type of           Mode of                             countries/        of new cases per  health burden     Primary                             eradication or
Disease           infection         transmission      Characteristics   regions           year              (selected data)   interventions     Progress          elimination
----------------  ----------------  ----------------  ----------------  ----------------  ----------------  ----------------  ----------------  ----------------  ----------------
Dracunculiasis    Parasitic         Drinking water    Adult worm (up    16 countries in   152,814           Temporary         Water filters or  Global            Civil unrest in
(guinea worm                        contaminated      to 1 meter in     Africa, plus      reported          illness and       other water       prevalence        Sudan, where
disease)                            with              length)           Yemen             cases\a (1996)    incapacitation    safety measures   reduced by 97%    about 75% of
                                    water fleas that  migrates                                              in every case.    to prevent        between 1986      cases now occur.
                                    carry             through                                                                 ingestion of      and
                                    the larvae of     the body,                                                               parasite;         1996.
                                    the               usually                                                                 prevention of     Eradication
                                    parasite.         emerging                                                                persons with      certified in
                                                      painfully                                                               emerging worms    Pakistan
                                                      through                                                                 from entering     in 1997.
                                                      the foot and                                                            drinking water
                                                      causing                                                                 supply.
                                                      illness and
                                                      incapacitation
                                                      for weeks or
                                                      months.

Polio             Viral             Human to human,   Usually no or     Originally        35,000            Deaths: 1,750     Vaccine           Elimination of    Need to maintain
                                    via contact with  mild symptoms;    throughout the    (1997)            (1997).                             the wild virus    vaccination
                                    feces of an       attacks the       world; still                        Paralysis:                          in the Americas   coverage of 90%
                                    infected person.  central nervous   endemic in 61                       10 million-20                       certified in      in all countries
                                                      system and may    countries in                        million                             1994. Global      until
                                                      cause aseptic     Africa, Asia,                       total cases.                        prevalence        eradication
                                                      meningitis (in    and Europe                                                              reduced by over   effort is
                                                      5%-10%                                                                                    90% since 1988.   complete.
                                                      of cases),                                                                                                  Inadequate
                                                      paralysis or                                                                                                surveillance of
                                                      reduced                                                                                                     acute flaccid
                                                      breathing                                                                                                   paralysis in
                                                      capacity (in                                                                                                some countries.
                                                      less than
                                                      1% of cases), or
                                                      death.

Leprosy           Bacterial         Believed to be    Slowly affects    55 countries      566,604           Deaths: 2,000     Drug treatment    Global            Need to detect
                                    primarily human   skin, nerves,     throughout the    (1997)            (1996).                             prevalence        hidden cases and
                                    to human, via     and mucous        world, with most                    Disabilities:                       reduced by 84%    reach patients
                                    droplets from     membranes; can    cases in                            1 million-2                         since 1985 with   in remote and
                                    respiratory       lead              Southeast Asia                      million                             the introduction  underserved
                                    tract of a        to permanent                                          total cases.                        of                areas.
                                    severely          damage                                                                                    multidrug
                                    infected          to nerves,                                                                                therapy.
                                    person, but       bones, eyes,
                                    exact             and other organs
                                    mode of           and deformities
                                    transmission      of face and
                                    is not fully      extremities
                                    understood.       after many
                                                      years.

Measles           Viral             Human to human,   High fever,       Throughout the    31.077 million    Deaths: 961,000   Vaccine           Incidence         High
                                    via droplets      malaise,          world             (1997)            children (1997).                    reduced           infectiousness
                                    from              conjunctivitis,                                                                           99% since 1990    requires very
                                    respiratory       congestion, and                                                                           in the Americas.  high vaccination
                                    tract of an       cough, followed                                                                           Transmission      coverage (95% or
                                    infected person.  by rash; may                                                                              interrupted       higher). Measles
                                                      lead to serious                                                                           briefly in some   is not perceived
                                                      complications or                                                                          countries,        as a major
                                                      death,                                                                                    including the     burden by many
                                                      especially from                                                                           United States.    developed
                                                      secondary                                                                                                   countries, which
                                                      infections.                                                                                                 results in poor
                                                                                                                                                                  surveillance and
                                                                                                                                                                  lack of
                                                                                                                                                                  willingness to
                                                                                                                                                                  improve control.

Onchocerciasis    Parasitic         Bite of           Adult worms       36 countries in   Data not          Deaths: 47,000    Drug treatment;   In West Africa,   Need to sustain
(river                              blackflies that   lodge in nodules  Africa and the    available         (1996).           insecticide       near elimination  implementation
blindness)                          carry the larvae  under the skin;   Americas, plus                      Blindness:        spraying          in original       of long-term,
                                    from human to     immature worms    Yemen (99% of                       270,000 cases.    to control        program area      community-based
                                    human.            move through the  cases are in                        Other visual      blackflies.       (seven            drug treatment.
                                                      body, causing     Africa)                             impairment:                         countries), 1.5   Possibility of
                                                      intense itching,                                      500,000 cases.                      million cured,    development of
                                                      skin disease,                                         Skin disease: 6                     and blindness     resistance to
                                                      swollen                                               million cases.                      prevented in      drug.
                                                      genitals, and                                         (Above are                          185,000.
                                                      visual                                                totals.)
                                                      impairment or
                                                      blindness.

Chagas' disease   Parasitic         Contact with      Initial acute     18 countries in   500,000           Deaths: 45,000    Insecticide       Transmission      Insect carriers
                                    feces of certain  phase may cause   Central and       (1997)            per year.         treatment of      interrupted in    in Andean and
                                    parasite-         illness or,       South America                       Chronic           houses to         Uruguay in 1997.  Central American
                                    carrying insects  rarely, death;                                        complications:    control insects;  Significant       countries cannot
                                    that bite         possibly fatal                                        2 million-3       blood screening   reductions in     be controlled by
                                    humans; also      damage to heart                                       million total     to prevent        house             household
                                    transmitted       and digestive                                         cases.            transmission      infestation and   insecticides and
                                    through blood     tract may                                                               through blood     prevalence of     will require
                                    transfusions and  occur in chronic                                                        supply; drug      human infection   development of
                                    congenitally.     phase                                                                   treatment for     in Argentina,     new strategies.
                                                      many years                                                              acute and         Brazil, and
                                                      after                                                                   congenital        Chile.
                                                      infection.                                                              cases.

Lymphatic         Parasitic         Bite of           Adult and         At least 73       Data not          Swollen limbs     Drug treatment    A few national    National and
filariasis                          mosquitoes that   immature worms    countries in      available         and genitals and  or regular use    control programs  international
                                    carry the larvae  damage the        Africa, Asia,                       lung disease: 44  of drug-          are underway.     funding
                                    from human to     lymphatic         South and                           million           fortified table   SmithKline        commitments are
                                    human.            ducts,            Central America,                    total cases.      salt to kill      Beecham recently  uncertain.
                                                      causing gross     and the Pacific                     Preclinical       immature worms;   agreed to donate
                                                      swelling and      islands                             damage            limited control   one drug
                                                      sores on                                              to organs: 76     of mosquito       (albendazole) to
                                                      limbs, genital                                        million           populations;      all endemic
                                                      areas,                                                total cases.      hygiene           countries.
                                                      and breasts and                                                         measures,
                                                      damage to                                                               antibiotics, and
                                                      lymphatic                                                               antifungal
                                                      and renal                                                               agents to
                                                      systems.                                                                treat effects of
                                                                                                                              the
                                                                                                                              disease.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\a The number of reported disease cases is generally less than the
number of actual cases.  For dracunculiasis, the World Bank estimated
that the total number of cases in 1996 was 330,000.

Sources:  WHO and other data sources.

DRACUNCULIASIS (GUINEA WORM
DISEASE)
========================================================== Appendix II

DISEASE CHARACTERISTICS

Dracunculiasis is caused by the parasite Dracunculus medinensis, or
guinea worm.  Infection occurs by drinking water contaminated with
the intermediate hosts (water fleas) of the parasite.  Once a person
is infected, the worm migrates throughout the body, growing to a
length of up to
1 meter.  About a year after infection, the worm emerges from the
body, normally through the foot, causing an intensely painful
swelling and blister.  Perforation of the skin is accompanied by
fever, nausea, and vomiting.  Secondary infections are common and can
cause permanent deformity of the joints.  Although the infection
rarely kills, it inflicts intense suffering and sickness for at least
several months, and a small percentage of victims may become
permanently disabled.  The diagnostic tools for dracunculiasis are
visual and testimonial.  Health workers and trained villagers can see
the emerging worms or the scars from previous infection and take the
testimony of the victim.

In endemic countries, the disease typically appears during the
agricultural season, with farmers in particular being affected.  A
United Nations Children's Fund (UNICEF) study of an area in Nigeria
with 1.6 million people found that rice farmers lost about $20
million a year due to the effects of the disease on their ability to
harvest.  A World Bank study showed an economic rate of return of 29
percent for the eradication program for 1987-98, acknowledging a
conservative assumption of 5 weeks for the average disability period
caused by infection.\1 According to the World Bank study and a Carter
Center expert on dracunculiasis, the average period of disability is
about 8 weeks.

Dracunculiasis is present in Yemen and 16 countries in Africa, 10 of
which are considered least developed countries.  Last year, Pakistan
was the first endemic country to be certified free of dracunculiasis;
India and Kenya recently reached zero cases.  The number of endemic
villages decreased from about 23,000 in 1992 to 9,900 in 1996;
reported cases during the same period fell from 422,555 to 152,814,
according to the World Health Organization (WHO).

STRATEGY FOR ERADICATION

Dracunculiasis eradication has been divided into three major
phases--interruption of transmission in endemic countries,
surveillance in formerly endemic countries, and certification that
countries are free of the disease.  Because no vaccine or drugs exist
to prevent dracunculiasis or to kill the worm inside the body,
interrupting transmission of the disease is the basis of eradication.
The strategy promoted in endemic countries combines several
approaches, including community-based surveillance, case containment
measures, and targeted interventions such as provision of safe water,
health education, community mobilization, distribution of filters,
and treatment of selected water sources.

According to WHO, the most powerful tools in monitoring eradication
of dracunculiasis are village-based surveillance and case containment
strategies.  For effective surveillance, cases should be identified
prior to worm emergence or within 24 hours after the worm appears.
Due to the intense pain as the worm emerges, victims often put their
foot in the nearest water source, thereby releasing the larvae back
into the water to reproduce and continue the contamination.  Once a
case is identified, containment measures are initiated, the wound is
bandaged to help prevent further transmission, and the patient is
advised to avoid contact with stagnant water.  The community is
educated regarding prevention and containment and encouraged to
filter or boil drinking water.  According to WHO, this strategy has
proven very effective and has been implemented in almost all endemic
villages, except in Sudan.  Other methods to provide safe drinking
water include digging bore-hole wells and treating water sources with
larvicide.  Wells are considered the best option because they provide
protection against diarrheal diseases.  However, such interventions
are more expensive.

CHALLENGES TO ERADICATION

Experts agree that eradication of dracunculiasis is feasible and no
technical obstacles exist.  The relatively simple interventions for
interrupting transmission and the community-based surveillance
network are effective.  Potential obstacles to achieving eradication
within the time frames set by WHO include ongoing civil unrest and
unanticipated upheavals in health, communications, and transportation
infrastructure.  Some experts are concerned about sustaining donor
and national support for eradicating a disease rarely seen outside
rural and often remote areas; they caution that such support must be
maintained to achieve eradication.

--------------------
\1 Cost-Benefit Analysis of the Global Dracunculiasis Eradication
Campaign, The World Bank, Africa Human Development Department
(Washington, D.C.:  Oct.  1997).

POLIO
========================================================= Appendix III

DISEASE CHARACTERISTICS

Polio is an infectious disease caused by any of three related types
of poliovirus that mostly affect children under three.  The virus
usually enters through the nose or mouth and multiplies in the throat
and intestines.  Poliovirus can enter the bloodstream and invade the
central nervous system.  As it multiplies, the virus destroys the
motor neurons that activate muscles.  These nerve cells cannot be
regenerated, and the affected muscles no longer function.  Muscle
pain, spasms, and fever are associated with the rapid onset of acute
flaccid paralysis.  In the most severe cases, poliovirus attacks the
motor neurons of the brain stem, reducing breathing capacity and
causing difficulty in swallowing and speaking.  Without adequate
respiratory support, this type of polio can result in death by
asphyxiation.

Although paralysis is the most visible sign of polio infection, less
than 1 percent of polio infections result in paralysis.  About 90
percent of cases produce either no or mild symptoms and usually go
unrecognized.  The remaining cases involve mild, flu-like symptoms
common to other viral infections but do not result in paralysis.
About 5 to 10 percent of all polio infections result in aseptic
meningitis, a viral inflammation of the outer covering of the brain.
There are no animal or insect reservoirs or long-term human carriers.
Once deprived of its human host, poliovirus will rapidly die out.

While most people are unaware of their infection, they can shed the
virus intermittently in feces for several weeks.  This enables the
rapid spread of poliovirus, especially in areas with poor sanitation
and hygiene, but also in any environment in which young children, not
yet fully toilet trained, are a ready source of poliovirus
transmission.  Poliovirus circulates "silently" at first--possibly
infecting up to 200 people before the first case of polio paralysis
emerges.  Due to this silent transmission and the rapid spread of the
virus, WHO considers a single confirmed case of polio paralysis to be
evidence of an outbreak.

Protective immunity against polio is established through immunization
or as a result of natural infection with the virus.  Polio infection
provides lifelong immunity to the disease but the protection is
largely limited to the particular type of poliovirus involved and may
fail to protect against the other two types.  Immunization provides
protection against all three types of poliovirus.

The last case of indigenous polio in the Western Hemisphere was
reported in Peru in August 1991; the Pan American Health Organization
(PAHO) certified the eradication of polio from the Americas in 1994.
In 1996, 155 countries and territories reported zero cases of polio.
Polio is still considered endemic in 61 countries, mostly in Africa
and Asia.  Before 1996, India accounted for over half the world's
polio cases every year; however, India's polio eradication strategy
has recently decreased this portion to about 25 percent of worldwide
polio cases.

It is estimated that about 10 million to 20 million people of all
ages are living with paralysis due to polio.  The number of reported
cases was 4,074 in 1996--a decline from 35,251 reported in 1988.
However, due to incomplete epidemiological surveillance in many
countries, WHO estimates that approximately 35,000 to 40,000 cases of
paralytic polio occurred in 1996.  Before the development of polio
vaccines, it is estimated that about 500,000 people a year were
paralyzed or died after contracting the disease.

STRATEGY FOR ERADICATION

WHO's strategy for polio eradication has four components:  routine
immunization coverage, supplemental immunization in the form of mass
campaigns or national immunization days, effective surveillance, and
door-to-door campaigns ("mop-ups") in the final stages in areas where
the virus persists.

According to WHO, routine coverage with four doses of oral vaccine is
needed among infants to reduce the incidence of polio and make
eradication feasible.  Unless high routine coverage is maintained,
pockets of nonimmunized children accumulate, creating ideal
conditions for the spread of the virus.  National immunization days
are intended to supplement routine immunization.  In polio endemic
countries, this usually means organizing two rounds of national
immunization days a year,
1 month apart, over at least 3 years or until circulation of the
virus is interrupted in the country.  For the poorest endemic
countries, where health, communications, and transportation systems
are most deficient, WHO estimates that 5 years of national
immunization days may be necessary.

Surveillance is needed to pinpoint where and how the wild poliovirus
is still circulating and to verify when it has been eradicated.
Health care workers are asked to report every case of acute flaccid
paralysis in any child under 15.  The number of cases reported each
year is used as an indicator of the effectiveness of a country's
surveillance system.  Because it is often difficult to tell whether a
case of acute flaccid paralysis is caused by polio, WHO recommends
laboratory-based surveillance in addition to collecting clinical and
epidemiological information.  Early detection and testing are
essential because the highest concentrations of the virus are found
during the first 2 weeks after the onset of paralysis.  Precise
information on the patterns of poliovirus spread is considered
essential in developing strategies for global eradication.  Finally,
following up on surveillance data, mop-up campaigns are conducted
door to door to provide two doses at 1-month intervals to immunize
all children under 5 in high-risk districts regardless of the child's
immunization status.

CHALLENGES TO ERADICATION

As the more developed countries reach eradication goals, the least
developed countries are just beginning to conduct national
immunization days and increase routine coverage.  The poorest
countries are least able to support vaccine programs.  In the
countries of the Americas, national funding averaged 80 percent of
the costs, and campaigns were started in countries with generally
higher routine vaccine coverage than in most African countries.  WHO
estimates that the poorest countries fund about 25 to 75 percent of
the costs and, in countries affected by conflict, 100 percent of the
costs may need to be funded from external resources.  Many of the
least developed and most unstable countries are unable to reach the
majority of their population with even the most basic health
services.  Some academic experts also state that, while local
mobilization for supplemental campaigns can be sustained for 2 or 3
years, the volunteer spirit dissipates as the disease appears to be
under control.  At that point, supplemental campaigns tend to become
more expensive.

At the same time, WHO fears that "donor fatigue" may set in and the
competing needs for funds to combat other infectious diseases--some
more widespread and life-threatening than polio--will slow the
eradication momentum.  According to the U.S.  Agency for
International Development (USAID) officials and several academic
experts, eradicating polio is not a priority for developing countries
compared to controlling malaria, tuberculosis, acquired
immunodeficiency syndrome (AIDS), and diarrheal and respiratory
diseases.  These experts assert that, if eradication is to be
achieved, industrialized countries, which will enjoy greater benefits
from eradication, need to assume a substantial part of the cost.

Developing a surveillance system is a long-term process that must be
maintained until eradication is certified.  Surveillance of acute
flaccid paralysis poses special difficulties in countries with
inadequate health, transportation, and communication infrastructures.
According to WHO, of the 61 countries where polio is endemic, less
than 10 percent are meeting the essential criterion of reporting at
least 1 case of acute flaccid paralysis for every 100,000 children
under 15.  Moreover, by the end of 1996,
25 polio-endemic countries had not officially established a
surveillance system for acute flaccid paralysis, a crucial
requirement for certifying eradication.

In some countries, infrastructures have been destroyed by war and
neglect, vaccine supply lines cut off, and immunization programs
suspended, setting the stage for an upsurge in polio and other
vaccine-preventable diseases.  War-related outbreaks of polio
occurred in Chechnya in the Russian Federation in 1995, in Iraq
during 1992 and 1993, and in Sudan in 1993.  Today, emerging
polio-free areas are threatened by continuing unrest in Afghanistan,
Angola, Iraq, Liberia, Somalia, Sudan, and the Democratic Republic of
the Congo (formerly Zaire).  However, as some officials have pointed
out, unrest existed in several countries near the end of the smallpox
eradication effort, yet political pressure and massive,
military-style campaigns allowed health workers to deliver the
vaccine.

LEPROSY
========================================================== Appendix IV

DISEASE CHARACTERISTICS

Leprosy is a chronic infection caused by a bacillus that multiplies
very slowly and mainly affects the skin, nerves, and mucous membrane;
infection may lead to permanent disfigurement, disability, and
deformity.  Humans are the primary reservoir for leprosy, although
some wild animals, such as the armadillo in the southwestern United
States, may also serve as reservoirs.  The transmission cycle of the
disease is not fully defined, but it is generally accepted that
infected humans serve as the source for all human infections, most
likely through droplets spread from more severe cases.  Leprosy cases
are diagnosed through existing health facilities.  Minimum diagnostic
procedures include clinical examination and a skin smear.  Detection
of leprosy remains a challenge because leprosy patients are often
ostracized from society or they are ashamed of the disease and hide
themselves from public view.

Leprosy remains a public health problem in 55 countries, but only 16
of these are considered seriously endemic, accounting for 91 percent
of the cases.\1 At the beginning of 1997, there were about 1.15
million leprosy cases, a significant decrease from the 10 million to
12 million estimated cases in 122 countries in 1985.

STRATEGY FOR ELIMINATION

The overall strategy for eliminating leprosy is to ensure cases are
identified and patients have access to treatment.  Leprosy cases are
divided into two general categories.  Paucibacillary cases are those
that have fewer bacteria--normally less than 1 million bacilli in a
gram of skin tissue.  Multibacillary cases--the most serious and
infectious cases--may have more than 100 billion bacilli.  Leprosy is
curable with a combination of drugs--dapsone, rifampin, and
clofazimine--known as multidrug therapy.  This combination has
prevented the bacillus from becoming resistant to any one of the
three drugs.  According to the Centers for Disease Control and
Prevention (CDC), for paucibacillary patients, the treatment is six
doses of rifampin within a 6-month period plus daily dapsone.  Until
recently, multibacillary patients received 24 doses within a 24 to 36
month period.  In June 1997, however, the Expert Committee on Leprosy
recommended reducing treatment for multibacillary patients to monthly
doses of rifampin for 12 to 18 months plus daily dapsone.

In most countries, multidrug therapy services have reached patients
who have easy access to the health care system.  However, certain
areas in some endemic countries have patients who have not been
reached because there is no health infrastructure to deliver
multidrug therapy, the present geographical coverage is poor, or the
health services for delivering multidrug therapy are not operating
properly.  To reach these patients, leprosy elimination campaigns and
special action projects have been established so that elimination
goals can be achieved.  Campaigns are based on three elements:
diagnosing and treating patients, increasing community awareness and
participation, and establishing capacity-building measures for health
workers.

CHALLENGES TO ELIMINATION

While WHO and other experts agreed that the elimination program has
been largely successful, they noted several factors that may affect
achieving elimination by the year 2000.  In densely populated
countries with significant numbers of infected people, large declines
in cases, even as much as 95 percent, may not be enough to reach the
elimination target.  Civil unrest and difficult conditions in
countries such as Sudan, Nigeria, Sierra Leone, and the Democratic
Republic of the Congo (formerly Zaire) may delay detection,
treatment, and surveillance.  Complacency may also become a problem
as some countries believe they have done a good job and cease
conducting campaigns.  Finally, leprosy patients are often ostracized
and hidden, making case identification difficult and possibly slowing
progress toward elimination of leprosy.

--------------------
\1 These countries, in order of number of estimated cases, are India,
Brazil, Indonesia, Bangladesh, Myanmar, Nigeria, Nepal, Democratic
Republic of Congo (formerly Zaire), Mozambique, Ethiopia, Madagascar,
Sudan, Philippines, Cambodia, Tanzania, and Guinea.

MEASLES
=========================================================== Appendix V

DISEASE CHARACTERISTICS

Measles is a highly contagious viral disease that mostly affects
children.  Before vaccines were available, almost everyone eventually
acquired measles, usually as a young child.  The virus is transmitted
by droplets or airborne spray from the respiratory tract of infected
individuals to mucous membranes in the upper respiratory tract or
eyes of susceptible persons.  Secondary attack rates among
susceptible household members are reported to be more than 80
percent.  Humans are the only known reservoir for measles infection,
although some primates can be infected.  Protective immunity against
measles is established either through immunization or as a result of
natural infection with the virus.  Global immunization coverage of
infants is estimated at about 80 percent; in WHO's Africa region, the
rate is only about 56 percent.  The virus is not expected to develop
a resistance to the vaccine.

The clinical diagnosis of measles can be difficult, particularly as
incidence decreases, making surveillance a challenge.  Measles
symptoms develop approximately 10 days after exposure.  The early
symptoms of high fever, malaise, conjunctivitis, upper respiratory
congestion, and cough are followed after 2 to 4 days by a rash that
lasts several days.  The patient is most infectious during the
earlier phase but can transmit the virus during the first 3 to 4 days
after the rash appears.  Communicability generally decreases rapidly
after the appearance of the rash.  Rashes due to other causes, such
as other viruses and drug reactions, and accompanied by similar
symptoms, are easily confused with measles.

About 1 million deaths each year are attributed to measles, the vast
majority of them children under age 5 in developing countries.  About
another 30 million cases survived the illness in 1997.
Complications, such as ear infections, pneumonia, croup, and diarrhea
are common in young children, and acute encephalitis occurs in about
1 of every 1,000 cases.  Measles is more severe among malnourished
children in developing countries.  For the most part, measles
transmission has been interrupted in the Americas and the United
Kingdom.  According to CDC, measles reached record low levels in the
United States during 1997, with a provisional total of 135 cases
reported.  However, measles outbreaks may still occur in the United
States and other developed countries that have maintained high
immunization coverage.

STRATEGY FOR ELIMINATION AND
EVENTUAL ERADICATION

Measles elimination refers to the interruption of transmission of the
virus in a sizable geographic area in which vaccination would
nevertheless need to continue because reintroduction of the virus is
an ongoing threat.  Eradication is the global interruption of measles
transmission, representing the sum of successful elimination efforts
in all countries.  Once eradication is achieved, vaccinations could
be stopped without risk of future measles outbreaks.

Estimates of the appropriate level of population immunity needed to
stop transmission of the virus vary.  Many variables affect
transmission, such as population density, living patterns, and
temperature and humidity, but the consensus is that transmission is
very efficient.  Outbreaks have been reported in populations in which
as few as 3 to 7 percent of individuals were susceptible.  Current
estimates of the routine coverage needed range from 90 to 95 percent
or higher, and some experts suggest that 97 percent may not be enough
under certain conditions.

WHO is using PAHO's measles elimination strategy as guidance in
developing a possible global measles eradication initiative.  This
strategy aims to (1) rapidly interrupt measles transmission by
initially conducting mass campaigns and (2) maintain interruption of
transmission by sustaining high population immunity through
vaccination of infants at routine health services facilities
supplemented by periodic mass campaigns.  Surveillance of both
symptoms and virus transmission is to be a key part of this strategy.

CHALLENGES TO ERADICATION

Many countries have made significant progress in decreasing the
transmission of the measles virus; in the Americas, measles incidence
decreased by 99 percent from 1990 to 2,109 cases in 1996.  However,
the nature of measles presents several challenges to an elimination
or eradication campaign.  It is highly contagious and requires high
immunization coverage rates that are difficult to achieve, even in
the most developed countries.  The accumulation of susceptible
persons over time is considered the most serious impediment to the
elimination or eradication of measles.  However, experts at WHO,
PAHO, and CDC believe that strategies that provide at least two doses
of vaccine to each child can overcome this challenge.

The timing of immunization also presents special difficulties.
Vaccinating infants under 12 months is less effective due to the
presence of maternal antibodies and hastens the accumulation of
susceptible preschool aged children.  The PAHO strategy and
experience in the United States demonstrate that vaccinating at 12 to
15 months or switching to a two-dose schedule provides immunity more
effectively.  However, vaccinating those under 12 months has
substantially reduced measles incidence in this group, in which
mortality from this disease is the highest.

Some experts express concern that use of the PAHO strategy as a model
may not work globally or will require modifications to allow for less
favorable country conditions.  They point out that high immunization
coverage and surveillance have been successful in the Americas due to
the relatively advanced state of the health, transportation, and
communications infrastructure in these countries compared with the
infrastructure of the least developed countries.  Good surveillance
systems allow PAHO countries to calculate the number of susceptible
children and target campaigns accordingly.  Some experts remain
doubtful that such high coverage and good surveillance can be
achieved in the least developed countries with much weaker
infrastructure.  WHO officials agreed that sustaining a measles
eradication campaign in the poorest countries will be a challenge.

In addition to technical challenges, political commitment in selected
industrialized countries and adequate donor support for low-income
countries remain uncertain.  While measles is a major childhood
killer among the poor, it is often perceived as a mild illness, and
many industrialized countries do not consider the disease a major
public health threat.  This perception can inhibit the public and
political support for allocating the resources needed for a
successful eradication effort.  Accordingly, immunization coverage
and surveillance systems in many areas, including industrialized
countries, are inadequate to interrupt transmission.  The measles
strains that enter the United States, for example, largely do not
originate in less developed countries.  Most measles strains imported
into the United States come from France, Germany, Japan, and Italy,
according to CDC.  However, according to WHO and CDC officials,
support for measles eradication is increasing.  For example, the more
than 50 countries encompassing WHO's region for Europe and the former
Soviet Union are in the final stages of adopting a goal of regional
elimination by 2007, and WHO's Eastern Mediterranean region has
adopted an elimination goal by 2010.

Despite the challenges to measles eradication, WHO and CDC officials
believe that a global measles eradication strategy should be pursued
based on the burden of the disease and the technical feasibility of
eradication.  They point out that similar skepticism existed before
and during the early years of the smallpox and polio eradication
initiatives.  Several global meetings on measles, sponsored primarily
by WHO, PAHO, UNICEF, and CDC, have been held in recent years to
discuss challenges and build consensus on eradication.  At the most
recent meeting of about 200 public health experts in February 1998,
measles was identified as the leading candidate for the next global
eradication initiative due to its biological feasibility, high
mortality and complications among children, effective interventions,
demonstrated feasibility in the Americas, increasing global support,
and potential cost benefits.  According to USAID, participants also
agreed that further study should be undertaken regarding operational
feasibility and possible costs to the development of sustainable
primary health care systems before a global campaign is launched.

ONCHOCERCIASIS
========================================================== Appendix VI

DISEASE CHARACTERISTICS

Onchocerciasis, also known as river blindness, is a chronic parasitic
disease that causes blindness and severe skin conditions.  The
clinical manifestations of the disease include formation of nodules
under the skin, changes in skin pigmentation, loss of skin
elasticity, debilitation, severe itching, visual loss, and blindness.
A World Bank study for calculating the net benefits of the
Onchocerciasis Control Programme in West Africa assumed that people
who become blind due to the disease live another
8 years with blindness and die 12 years prematurely, thus indicating
that preventing one case of blindness can add 20 years of productive
life.\1

Humans are the only known host for the disease.  The parasite is
transmitted between humans by the bite of blackflies, which breed in
streams and rivers.  When a fly bites an infected human host, the fly
becomes infected with the larvae of Onchocerca volvulus.  When the
infected fly bites another human, the larvae may develop into adult
worms (macrofilariae) in the human, producing offspring, or
microfilariae.  These microfilariae may in turn be ingested by other
blackflies, thus continuing the transmission.  A human is infectious
to the blackfly only when microfilariae are present; the adult worm
is not transmitted.  However, the adult worms usually live about 12
to 15 years inside the body and generally keep reproducing
microfilariae for much of that time if not treated.

Although onchocerciasis is considered nonfatal, it is the second
leading cause of infectious blindness and the source of enormously
debilitating skin disease.  WHO estimates that 120 million people are
at risk and that 18 million are infected.  Blindness afflicts about
270,000 persons, and about 500,000 suffer visual impairment.  Severe
itching and dermatitis affect about 6 million.  Onchocerciasis is
suspected to be endemic in 30 countries of sub-Saharan Africa, in
Yemen, and in 6 countries in Latin America.  Because the disease is
endemic in fertile river valleys, it has had significant
socioeconomic impact over the years as residents have abandoned
villages with arable land and moved to more arid areas.  The first
onchocerciasis control program in West Africa has resulted in people
beginning to resettle in lands that have been deserted for as long as
50 to 100 years, resulting in increased income levels.  Twenty-five
million hectares have been opened for resettlement and cultivation,
an area that can feed a population of about 17 million people.

STRATEGY FOR ELIMINATION

Two specific elimination strategies have been implemented:
controlling the vector (blackfly) in endemic areas and treating
infected persons with ivermectin.  Vector control is accomplished
through the use of larvicide in rivers and streams, mostly by
helicopter spraying, and aims at interrupting disease transmission.
The drug ivermectin kills the microfilariae, thus arresting further
development of the disease.  It has a very limited effect, if any, on
killing the adult worms.  Treatment with ivermectin once a year is
considered sufficient to prevent blindness.  Ivermectin treatment
reduces transmission of the parasite but does not appear to halt it.
Annual, large-scale treatment will therefore have to continue for a
long time.  Current predictions based on a simulation model indicate
that annual treatment at the current level of coverage may have to
continue for about 1-1/2 to 2 decades, although elimination of the
disease as a public health problem is likely to occur before the full
treatment regimen is complete.  A third treatment option, not widely
used, is removing the nodules under the skin in which the
microfilariae are lodged.

CHALLENGES TO ELIMINATION

Sustainability of community-directed ivermectin distribution systems
is a potential concern.  Cost estimates assume that community-based
programs will be independent within 5 years, but this may be modified
as these systems are evaluated.  One issue is whether community
volunteers will continue to work without compensation.  Another
unknown is whether people will continue to come for treatment after
their condition improves, but WHO officials do not see this as a
problem at this time.  It is also uncertain whether the parasite will
develop resistance to ivermectin.  A final challenge to eliminating
onchocerciasis within estimated costs and time frames is the fact
that WHO is still mapping the prevalence of the disease in the area
of the African Programme for Onchocerciasis Control, where the
population to be treated appears to be greater than originally
estimated.

--------------------
\1 Aehyung Kim and Bruce Benton, Cost-Benefits Analysis of the
Onchocerciasis Control Programme, World Bank (Washington, D.C.:  Nov.
1994).

CHAGAS' DISEASE
========================================================= Appendix VII

DISEASE CHARACTERISTICS

Chagas' disease is a parasitic disease with both acute and chronic
complications.  It is caused by a parasite, Trypanosoma cruzi,
contained in the feces of reduviid insects.  More than 100 species of
mammals have been found infected.  Normally, humans become infected
following the insect's bite, but the contaminated feces may also
enter through the mucous membrane when a child rubs or scratches a
bite then touches his or her eyes or mouth.  The parasite may also be
transmitted from human to human through transfusions of contaminated
blood or through congenital transmission from an infected mother to
the fetus.  The insect favors poverty conditions, normally living in
the cracks of poorly built or decaying housing.

The acute phase of Chagas' disease appears shortly after infection
and often has no distinctive symptoms.  It can be characterized by
inflammation at the site of the infection and flu-like symptoms.  If
the parasite is introduced into the eye, conjunctivitis and swelling
of the eye area develops.  A characteristic lesion may also develop,
but often the disease goes unnoticed and undiagnosed during this
period.  However, it is during the early phase of the
infection--lasting only a few weeks--that the parasite can be seen in
the blood and that the disease may be curable with the drugs
nifurtimox or benznidazole.  Once the acute phase has passed, the
parasite moves into tissue and cannot be treated.  About one-third of
those infected will develop chronic conditions, especially heart
disease.  Chronic cardiopathy occurs in 27 percent of those infected,
chronic digestive lesions in 6 percent, and neurological disorders in
3 percent.  Patients with severe chronic disease become progressively
sick and ultimately die, usually from heart failure.

Prevalence of Chagas' disease is limited to the Americas.  WHO
estimates that about 100 million people in 18 countries are at risk
in Latin America.  The Caribbean region has not reported any cases.
Up to 18 million are currently infected, with about 2 million to 3
million of these suffering from chronic complications.  Various
estimates place the number of infected persons in the United States
at up to 100,000, due mostly to immigration.  The World Bank has
characterized Chagas' disease as a major public health burden in
Latin America.

STRATEGY FOR ELIMINATION

Control and eventual elimination of Chagas' disease centers on two
overall strategies to interrupt transmission of the parasite--vector
control and blood bank screening.  Vector control includes
insecticide spraying, insecticidal paints, fumigant canisters,
housing improvement, and health education.  The blood screening
strategy aims to screen all blood donors in and from endemic
countries for antibodies and to strengthen existing health service
infrastructure for multiple blood screening.  Serological testing is
also conducted to treat the disease in its acute phase and for
surveillance purposes.

Distribution of Chagas' disease may be divided into two areas:  the
Southern Cone countries of Argentina, Bolivia, Brazil, Chile,
Paraguay, and Uruguay; and the areas of northern South America and
Central America.  The insects that transmit Chagas' disease differ in
these two areas; this has implications for disease control
strategies.  In the Southern Cone countries, the insect mainly lives
in the cracks of poorly constructed housing and not outside the home.
In these countries, the use of insecticides and other vector control
measures are reducing infection significantly.  In northern South
America and in Central America, the insect can live in housing and
outside in other diverse habitats.  Because vector control measures
have limited effectiveness, the initial strategy in these countries
is to interrupt transmission through blood screening measures.

CHALLENGES TO ELIMINATION

As noted, the vectors carrying the parasite that transmits Chagas'
disease differ between the Southern Cone countries and the endemic
areas in the Andes and Central America.  Because the vector in the
latter areas is less easily controlled, the elimination strategy
currently relies on blood screening to interrupt transmission.  The
Andean and Central American elimination initiatives were launched
only last year, and serological testing for donated contaminated
blood has not yet been undertaken in all countries.  Moreover, it is
not yet clear that this strategy will eliminate Chagas' disease as a
public health problem because humans will still be vulnerable to
being bitten by the vector.

LYMPHATIC FILARIASIS
======================================================== Appendix VIII

DISEASE CHARACTERISTICS

Lymphatic filariasis, a parasitic disease transmitted by mosquitoes,
is the world's second leading cause of permanent and long-term
disability.  Like onchocerciasis, the infected vector takes blood
from a human and passes on the infection.  The adult worms, or
macrofilariae, settle into the lymphatic system and mature over a
period of 3 to 15 months.  When fertilized, female adults produce
large numbers of larvae known as microfilariae, which invade the
blood stream.  Mosquitoes can then ingest them when they bite an
infected human and transmit the microfilariae to other people, in
whom they pass through a larval sequence to become new adults.  The
vast majority of microfilariae remain in the body as immature forms
for 6 months to 2 years, growing up to a third of a millimeter in
length and doing immense damage.  The adult macrofilariae can grow to
several centimeters long, damaging the lymphatic ducts.  Humans are
the only hosts of the most common forms of filariasis.

The infection causes a very severe pathology of the lymph system.
This can result in elephantiasis, a condition in which one or more
limbs becomes grossly swollen and covered with sores; in hydrocele, a
grotesque enlargement of the male scrotum; or in lymphoedema in
women, in which their breasts or genitals are grossly swollen.  Other
internal damage and related infections can also occur, but the
effects are often hidden.  The disease can have serious social and
psychological consequences, including sexual dysfunction and social
exclusion.

Diagnosis of lymphatic filariasis used to be difficult--blood samples
had to be taken between 9:00 p.m.  and 3:00 a.m.  because the
parasite remained in the organs during the day and entered the
bloodstream at night.  Diagnostic tools were improved, and now a test
of a drop of blood on cardboard can detect the infection from blood
taken at any hour because the test detects a specific antigen, not
the parasite itself.  Another new diagnostic tool detects
deoxyribonucleic acid of the parasite in infected mosquitoes or in
human blood.

WHO estimates that at least 120 million people in 73 endemic
countries worldwide are infected with filarial parasites.  The
percentage infected is about 49 percent in Southeast Asia, 34 percent
in Africa, and 16 percent in the western Pacific.  There is some, but
very little, incidence of the disease in Europe and the Americas.
The prevalence of the disease is growing in some endemic areas, due
in large part to rapid unplanned urbanization.  The mosquitoes
carrying this parasite tend to breed in dirty urban water, making
this disease more prevalent in dense urban slums.

STRATEGY FOR ELIMINATION

The strategy for eliminating lymphatic filariasis is to interrupt the
transmission between mosquitoes and humans.  In the past, the
strategy was to control the mosquito population, but this proved
difficult, expensive, and ineffective, according to WHO.  While
limited vector control activities may continue, the recent
development of treatment options based on drugs that are inexpensive
(diethylcarbamazine, or DEC) or donated (ivermectin and albendazole),
safe, easily administered, and broadly effective has changed the
strategy to mass distribution of medication to entire at-risk
populations.  The optimal treatment regimens that result in almost
complete elimination of microfilaria-stage parasites from the blood
(thus blocking transmission by vector mosquitoes) involve two drugs
administered concurrently (either albendazole or DEC plus ivermectin)
given once yearly over a period of 4 to 6 years.  According to WHO,
experimental observations in the field indicate that such yearly
regimens are effective in interrupting transmission.  An alternative
treatment is the substitution of regular table salt with
DEC-fortified salt for 1 to 2 years.  This strategy also decreases
blood microfilaria numbers to very low levels and has been shown in
large-scale control programs to be effective in interrupting
transmission.

The treatment programs are largely community based.  Techniques for
identifying communities in need of treatment include estimating
infection rates from existing health records, assessing the presence
of hydrocele in adult men, examining mosquito vectors for infection,
and evaluating daytime finger-prick blood samples from selected
groups.  Geographical information systems for mapping public health
resources and disease patterns are now available for use in planning
and monitoring lymphatic filariasis control programs.

CHALLENGES TO ELIMINATION

National and international funding commitments through 2030 are
uncertain.  Although there is some possibility that the parasites
will develop resistance to the drugs, this is less likely because the
drugs are being used in combination and taken only once a year,
according to WHO officials.

OBJECTIVES, SCOPE, AND METHODOLOGY
========================================================== Appendix IX

Our objectives were to examine (1) the soundness of WHO's cost and
time frame estimates for eradicating or eliminating seven infectious
diseases, (2) U.S.  spending related to these diseases in fiscal year
1997 and any potential U.S.  savings as a result of eradication or
elimination, (3) other diseases that may pose a risk to Americans and
that could be candidates for eradication, and (4) historical
information on U.S.  costs and savings from smallpox eradication and
whether experts view smallpox eradication as a model for other
diseases.

To assess the soundness of the WHO's cost and time frame estimates
for the seven diseases, we met with epidemiologists and health
economists to understand the key elements of estimates and with
cognizant WHO officials to understand the information on which their
estimates were based.  We also reviewed the criteria that WHO set
forth to identify candidates for eradication or elimination and
assessed how the diseases fit the criteria.  We conducted a search of
the medical and scientific literature on these diseases to identify
studies and research by other experts on the costs and time frames
associated with disease control efforts and other factors relevant to
eradication or elimination.  We also met with epidemiologists at the
PAHO, CDC, and the Carter Center and with epidemiologists,
economists, and other experts at the Johns Hopkins University, Emory
University, USAID, and Abt Associates (a USAID health project
contractor that conducted a cost study for child survival
initiatives) to discuss the characteristics of the diseases and the
bases for cost and time frame estimates developed by WHO.  We used
the information to assess whether the data underlying WHO's estimates
were sound.

We did not develop independent estimates of the costs and time frames
for eradicating or eliminating these diseases nor did we verify the
accuracy of the data underlying the estimates.  However, we adjusted
some of the numbers to ensure consistency across diseases,
particularly to express all estimates as cumulative totals in 1997
dollars.  For dracunculiasis, measles, and Chagas' disease, no
adjustments were necessary because WHO's estimates had been
calculated in 1997 dollars with no annual inflation adjustments.  For
polio and onchocerciasis, we took out WHO's inflation adjustments.
Because WHO's leprosy estimate covered 2 years prior to this review,
we recalculated for the period 1998-2000.  We subtracted $72 million
from the lymphatic filariasis estimate for the cost of treating
symptoms for infected cases since treatment was not included in the
other estimates.

To determine past and current U.S.  spending on these diseases and
any likely savings that may be gained by the United States as a
result of reaching these goals, we obtained public and private
expenditure data and projections from CDC and USAID, including
information on U.S.  contributions to WHO.  We discussed the
incidence of the diseases and their potential threat to the United
States.  We also spoke with an official of the American Red Cross to
determine projected spending for screening donated blood for Chagas'
disease.

To identify other diseases that pose threats to the United States and
that could be candidates for eradication, we reviewed the medical and
scientific literature and consulted experts in epidemiology and
international public health at WHO, CDC, and USAID.  Finally, we
obtained information from CDC on global and U.S.  spending for
smallpox; adjusted estimated savings to reflect inflation, birth
rates, and present value in 1997 dollars; and estimated the annual
real rate of return on the U.S.  investment in smallpox eradication.
We discussed with public health officials and epidemiologists at WHO,
CDC, USAID, and the Johns Hopkins University how that undertaking
could be applied for ongoing efforts.

We conducted our review from August 1997 to December 1997 in
accordance with generally accepted government auditing standards.

(See figure in printed edition.)Appendix X
COMMENTS FROM THE WORLD HEALTH
ORGANIZATION
========================================================== Appendix IX

(See figure in printed edition.)Appendix XI
COMMENTS FROM THE DEPARTMENT OF
STATE
========================================================== Appendix IX

(See figure in printed edition.)Appendix XII
COMMENTS FROM THE CENTERS FOR
DISEASE CONTROL AND PREVENTION
========================================================== Appendix IX

(See figure in printed edition.)

(See figure in printed edition.)

(See figure in printed edition.)Appendix XIII
COMMENTS FROM THE U.S.  AGENCY FOR
INTERNATIONAL DEVELOPMENT
========================================================== Appendix IX

(See figure in printed edition.)

(See figure in printed edition.)

The following are GAO's comments on USAID's letter dated April 1,
1998.

GAO COMMENTS

1.  We do not imply global consensus on the eradication of all seven
diseases.  As we noted in our draft report, the World Health
Assembly, which is composed of health ministers from WHO member
countries, voted to initiate formal eradication campaigns against
dracunculiasis and polio in 1988 and 1991, respectively.  The only
other disease being discussed for possible eradication is measles,
for which we outline the challenges to eradication.

2.  We discuss many of the operational challenges facing measles
eradication raised by USAID.  We have clarified the text to reflect
USAID's concern about injection safety.

3.  The basis for our estimates of cost savings to the United States
is the current level of U.S.  spending on those diseases.  It is not
based on WHO's cost estimates for disease eradication and
elimination.  Thus, the fact that some of the estimates are
speculative does not affect the potential U.S.  cost savings, only
whether or when they might be forthcoming.

*** End of document. ***