[Federal Register Volume 72, Number 20 (Wednesday, January 31, 2007)]
[Proposed Rules]
[Pages 4467-4470]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-1528]


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DEPARTMENT OF AGRICULTURE

Animal and Plant Health Inspection Service

9 CFR Part 113

[Docket No. APHIS-2007-0001]
RIN 0579-AC28


Viruses, Serums, Toxins, and Analogous Products; Detection of 
Avian Lymphoid Leukosis Virus

AGENCY: Animal and Plant Health Inspection Service, USDA.

ACTION: Proposed rule.

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SUMMARY: We are proposing to amend the Virus-Serum-Toxin Act 
regulations concerning testing for avian lymphoid leukosis in 
veterinary biologics to specify that the test is for the detection of 
extraneous replicating avian leukosis virus; require such testing to be 
conducted using a procedure that will detect extraneous replicating 
avian leukosis virus and that is acceptable to the Animal and Plant 
Health Inspection Service; require firms to develop a procedure to test 
for lymphoid leukosis virus contamination in the case of vaccine virus 
cytopathic to chick embryo cell cultures; and specify the equivalent 
inoculum dose of vaccine to be used when testing certain specified 
chicken vaccines for lymphoid leukosis virus. These proposed changes 
would update the testing for lymphoid leukosis virus contamination by 
prescribing a test procedure that increases the probability of 
detecting atypical lymphoid leukosis viruses such as those recently 
found in a contaminated vaccine.

DATES: We will consider all comments that we receive on or before April 
2, 2007.

ADDRESSES: You may submit comments by either of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov, select ``Animal and Plant Health Inspection 
Service'' from the agency drop-down menu, then click ``Submit.'' In the 
Docket ID column, select APHIS-2007-0001 to submit or view public 
comments and to view supporting and related materials available 
electronically. Information on using Regulations.gov, including 
instructions for accessing documents, submitting comments, and viewing 
the docket after the close of the comment period, is available through 
the site's ``User Tips'' link.
     Postal Mail/Commercial Delivery: Please send four copies 
of your

[[Page 4468]]

comment (an original and three copies) to Docket No. APHIS-2007-0001, 
Regulatory Analysis and Development, PPD, APHIS, Station 3A-03.8, 4700 
River Road Unit 118, Riverdale, MD 20737-1238. Please state that your 
comment refers to Docket No. APHIS-2007-0001.
    Reading Room: You may read any comments that we receive on this 
docket in our reading room. The reading room is located in room 1141 of 
the USDA South Building, 14th Street and Independence Avenue, SW., 
Washington, DC. Normal reading room hours are 8 a.m. to 4:30 p.m., 
Monday through Friday, except holidays. To be sure someone is there to 
help you, please call (202) 690-2817 before coming.
    Other Information: Additional information about APHIS and its 
programs is available on the Internet at http://www.aphis.usda.gov.

FOR FURTHER INFORMATION CONTACT: Dr. Albert P. Morgan, Chief Staff 
Officer, Operational Support Section, Center for Veterinary Biologics, 
Licensing and Policy Development, APHIS, 4700 River Road Unit 148, 
Riverdale, MD 20737-1228; (301) 734-8245.

SUPPLEMENTARY INFORMATION: 

Background

    The Virus-Serum-Toxin Act regulations in 9 CFR part 113 (referred 
to below as the regulations) contain standard procedures and 
requirements that are used to establish the purity, safety, potency, 
and efficacy of veterinary biological products. The regulations in 
Sec. Sec.  113.200 and 113.300 specify general requirements for killed 
virus vaccine and live virus vaccine, respectively. The purity 
requirements for avian origin vaccine prescribed under these 
regulations specify that bulk or final container samples from each 
serial of avian origin vaccine must be tested for lymphoid leukosis 
virus contamination. Lymphoid leukosis viruses are ubiquitous in 
chickens, causing the disease lymphoid leukosis, and are considered to 
be potential contaminants of all biological products propagated in 
substrates of chicken origin. Inoculation of chickens and, possibly, 
other animals with veterinary biologics contaminated with lymphoid 
leukosis viruses may cause neoplastic diseases. Six subgroups (A, B, C, 
D, E, and J) of lymphoid leukosis viruses have been identified in 
chickens, with subgroups A (most often) and B (less frequently) being 
associated with disease. In order to ensure that biological products 
propagated in substrates of chicken origin are not contaminated with 
lymphoid leukosis viruses, veterinary biologics licensees and 
permittees are required to test such products for contaminating 
lymphoid leukosis viruses in accordance with the test procedure 
specified in Sec.  113.31 of the regulations. The test procedure 
specified in Sec.  113.31 is designed to detect contamination due to 
extraneous replicating subgroup A and B lymphoid leukosis viruses which 
are most often associated with disease in chickens. Biological products 
found contaminated with lymphoid leukosis viruses are unsatisfactory.
    Currently, the standard test procedure in Sec.  113.31 of the 
regulations prescribes the complement-fixation (CF) test for detecting 
lymphoid leukosis viruses in bulk pooled material or final container 
samples of biological products propagated in substrates of chicken 
origin. A negative CF test is considered evidence that the product is 
free of contaminating lymphoid leukosis viruses.
    Recently, however, in response to a reported finding of lymphoid 
leukosis virus contaminated vaccine, the Center for Veterinary 
Biologics and other laboratories, using an enzyme-linked immunosorbent 
assay (ELISA), detected lymphoid leukosis virus in 7 out of 129 serials 
of a commonly used chicken vaccine. The lymphoid leukosis virus 
contaminant had not been detected when the serials were tested using 
the CF test procedure specified in Sec.  113.31 of the regulations. 
Prior to the reported finding, and confirmation of lymphoid leukosis 
virus contamination in the seven serials mentioned above, the CF test 
procedure prescribed in Sec.  113.31 had been considered suitable for 
detecting previously known and/or classified lymphoid leukosis viruses. 
However, the failure of the CF test to detect lymphoid leukosis virus 
contamination in the vaccine suggests that the contaminant most likely 
is a previously unknown and unclassified subgroup A-like (atypical) 
lymphoid leukosis virus that cannot be detected using the standard CF 
test procedure prescribed in Sec.  113.31, but can be detected using an 
ELISA for the detection of avian leukosis virus. The inability of the 
CF test to detect the lymphoid leukosis virus contamination that was 
later found using an ELISA test procedure indicates that the ELISA has 
a broader spectrum of specificity as compared to the CF test, and may 
be more suitable for detecting previously unclassified atypical 
lymphoid leukosis viruses.
    The requirement to use the CF test procedure specified in Sec.  
113.31 of the regulations to test for contaminating lymphoid leukosis 
viruses was promulgated prior to the development of ELISA methodology. 
Subsequent to the development of ELISA methodology and the licensing of 
ELISA based avian leukosis virus test kits, APHIS has approved the use 
of licensed ELISA kits to test for contaminating lymphoid leukosis 
viruses in place of the CF test procedure. Such approvals were based on 
side-by-side testing of the two methods that found the licensed ELISA 
kits to be equivalent to the CF test procedure for detecting lymphoid 
leukosis virus contamination in biological products.
    However, because the contaminated vaccine test results indicate 
that an ELISA will detect lymphoid leukosis virus contamination that 
cannot be detected using the CF test procedure, APHIS has concluded 
that the CF test procedure should no longer be specified for the 
detection of lymphoid leukosis viruses in Sec.  113.31. In place of the 
CF test procedure, veterinary biologics licensees and permittees would 
be required to conduct a test that will detect extraneous replicating 
avian leukosis virus and that is acceptable to APHIS as specified in 
the product's filed Outline of Production.
    We are proposing to change the title of Sec.  113.31 from 
``Detection of avian lymphoid leukosis'' to ``Detection of extraneous 
replicating avian leukosis virus'' to clarify the fact that the test is 
for the detection of ``extraneous replicating'' avian leukosis virus 
that causes the disease ``lymphoid leukosis'' in chickens. We would 
also amend the introductory text of the section, where the current 
regulations specify that the CF test shall be conducted, to state 
simply that a test that will detect extraneous replicating avian 
leukosis virus and that is acceptable to APHIS shall be conducted. We 
expect that most manufacturers would specify a licensed ELISA kit for 
such testing, but other methods may be available and could be used 
provided they are acceptable to APHIS.
    In the case of biological product containing virus that has been 
propagated in substrates of chicken origin that cannot be tested for 
lymphoid leukosis virus contamination because the vaccine virus is 
cytopathic to chick embryo fibroblast cells, we would amend the 
regulations to require the individual firm(s) to specify a procedure to 
test such product for contaminating lymphoid leukosis viruses in the 
filed Outline of Production.
    Currently, Sec.  113.31 of the regulations provides that in the 
case of cytopathic vaccine virus, the test for contaminating

[[Page 4469]]

lymphoid leukosis viruses may be performed using a sample of another 
(alternative) vaccine prepared the same week from material harvested 
from each source flock used for the preparation of the product that 
contains the cytopathic (questionable) vaccine virus. Because both the 
questionable vaccine and the alternative vaccine would have been 
prepared using common-source avian origin substrate, the expectation 
was that if contaminating lymphoid leukosis viruses are not detected in 
the alternative vaccine, there is a strong probability that the 
questionable vaccine also is free of contaminating lymphoid leukosis 
viruses. However, as we sought to determine the source of the lymphoid 
leukosis virus found in the contaminated vaccine, we tested samples of 
another vaccine prepared the same week from material harvested from the 
same source flock(s) that provided the substrate used in the 
preparation of the contaminated vaccine. Because the substrate used to 
prepare both the contaminated vaccine and the vaccine used for the 
alternative test were derived from a common source, we expected the 
alternative vaccine to test positive for contaminating lymphoid 
leukosis viruses; however, none of the alternative vaccine samples 
tested positive for lymphoid leukosis viruses. These results indicate 
that testing an alternative vaccine for contaminating lymphoid leukosis 
viruses in place of a questionable vaccine does not ensure that a 
contaminant, if present, will be detected and, thus, should be 
discontinued. Therefore, when a vaccine cannot be tested for 
contaminating lymphoid leukosis viruses because the vaccine virus is 
cytopathic to the cells used for viral propagation, we are proposing to 
require veterinary biologics manufacturers to specify a procedure to 
test such vaccine for contaminating lymphoid leukosis viruses in the 
product's filed Outline of Production. The specified procedure would 
have to be acceptable to APHIS.
    In addition, we propose to specify that the equivalent of 200 doses 
of vaccine must be used as inoculum when testing bursal disease 
vaccine, tenosynovitis vaccine, and reovirus vaccine for contaminating 
lymphoid leukosis viruses. The current standard requirement specifies 
that when vaccines are tested for lymphoid leukosis virus 
contamination, the equivalent of 200 doses of Newcastle disease vaccine 
or 500 doses of other vaccine for use in poultry, or 1 dose of vaccine 
for use in other animals, shall be used as inoculum. Subsequent to 
codifying the requirement to use the equivalent of 200 doses as 
inoculum when testing Newcastle disease vaccine for contaminating 
lymphoid leukosis viruses, we have identified additional poultry 
vaccines for which the equivalent of 200 doses should be used as 
inoculum when testing for contaminating lymphoid leukosis viruses. 
APHIS now proposes to amend Sec.  113.31 by specifying that the 
equivalent of 200 doses also shall be used as inoculum when testing 
bursal disease vaccine, tenosynovitis vaccine, and reovirus vaccine for 
contaminating lymphoid leukosis viruses.
    These amendments are being proposed in order to update the 
procedure used to detect lymphoid leukosis virus contamination in 
biological products and ensure that such products are free of material 
that adversely affects their safe use in animals.

Executive Order 12866 and Regulatory Flexibility Act

    This proposed rule has been determined to be not significant for 
the purposes of Executive Order 12866 and, therefore, has not been 
reviewed by the Office of Management and Budget.
    We are proposing to amend the regulations for detection of avian 
lymphoid leukosis to require that a test that will detect extraneous 
replicating avian leukosis virus and that is acceptable to APHIS shall 
be conducted on all biological products containing virus that has been 
propagated in substrates (starting material) of chicken origin. 
Lymphoid leukosis is a disease of chickens caused by avian leukosis 
viruses. Veterinary biologics containing virus that has been grown in 
substrates of chicken origin are at risk for contamination with avian 
leukosis viruses which, if present, are referred to as extraneous 
replicating avian leukosis virus. Inoculation of chickens, and possibly 
other animals, with vaccine contaminated with avian leukosis virus may 
cause neoplastic disease. This proposed rule, if adopted, would allow 
any valid method to be used for testing veterinary biologics for 
extraneous replicating avian leukosis virus, provided that it is 
acceptable to APHIS.
    The proposed changes would affect all licensed manufacturers of 
veterinary biologics who are required to test for the detection of 
extraneous replicating avian leukosis virus. There are approximately 
125 veterinary biologics establishments, and approximately 15 of these 
establishments produce product that would be affected by this proposed 
rule. According to the standards of the Small Business Administration, 
most veterinary biologics establishments would be classified as small 
entities. The proposed changes, however, would not impose any 
additional economic burden since the regulations already require 
vaccine propagated in substrates of chicken origin to be tested for 
extraneous replicating avian leukosis virus; currently, the regulations 
require firms to use the CF test procedure for such testing. This 
proposed rule would discontinue required use of the CF test and instead 
require a test that will detect extraneous replicating avian leukosis 
virus and that is acceptable to APHIS to be conducted. In addition, the 
proposed rule would require firms to specify a procedure to test for 
extraneous replicating avian leukosis virus when questionable vaccine 
cannot be tested because the vaccine virus is cytopathic to chick 
embryo fibroblast cells; and would specify using the equivalent of 200 
doses as inoculum when testing bursal disease, tenosynovitis, and 
reovirus vaccines for contaminating lymphoid leukosis viruses. The 
overall effect of this action would be to update the standard procedure 
for detecting extraneous replicating avian leukosis virus in biological 
products by prescribing a test procedure that has a greater probability 
of detecting an atypical lymphoid leukosis virus such as was recently 
found in contaminated vaccine.
    Under these circumstances, the Administrator of the Animal and 
Plant Health Inspection Service has determined that this action would 
not have a significant economic impact on a substantial number of small 
entities.

Executive Order 12372

    This program/activity is listed in the Catalog of Federal Domestic 
Assistance under No. 10.025 and is subject to Executive Order 12372, 
which requires intergovernmental consultation with State and local 
officials. (See 7 CFR part 3015, subpart V.)

Executive Order 12988

    This proposed rule has been reviewed under Executive Order 12988, 
Civil Justice Reform. It is not intended to have retroactive effect. 
This rule would not preempt any State or local laws, regulations, or 
policies unless they present an irreconcilable conflict with this rule. 
The Virus-Serum-Toxin Act does not provide administrative procedures 
which must be exhausted prior to a judicial challenge to the provisions 
of this rule.

Paperwork Reduction Act

    This proposed rule contains no new information collection or 
recordkeeping requirements under the Paperwork

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Reduction Act of 1995 (44 U.S.C. 3501 et seq.).

List of Subjects in 9 CFR Part 113

    Animal biologics, Exports, Imports, Reporting and recordkeeping 
requirements.

    Accordingly, we propose to amend 9 CFR part 113 as follows:

PART 113--STANDARD REQUIREMENTS

    1. The authority citation for part 113 would continue to read as 
follows:

    Authority: 21 U.S.C. 151-159; 7 CFR 2.22, 2.80, and 371.4.

    2. Section 113.31 would be revised to read as follows:


Sec.  113.31  Detection of extraneous replicating avian leukosis virus.

    A test that will detect extraneous replicating avian leukosis virus 
and that is acceptable to the Animal and Plant Health Inspection 
Service (APHIS) shall be conducted on all biological products 
containing virus that has been propagated in substrates of chicken 
origin: Provided, An inactivated viral product will be exempt from this 
requirement if the licensee can provide data that demonstrates to APHIS 
that the agent used to inactivate the vaccine virus would also 
inactivate lymphoid leukosis virus.
    (a) Propagation of extraneous lymphoid leukosis viruses shall be 
done in chick embryo cell cultures or other substrate acceptable to 
APHIS.
    (1) Each vaccine virus cytopathic to the cell culture being used 
shall be effectively neutralized, inactivated, or separated so that 
minimal amounts of extraneous replicating lymphoid leukosis virus can 
be propagated during the specified growth period. If the product cannot 
be tested for extraneous replicating lymphoid leukosis virus because 
the vaccine virus cannot be effectively neutralized, inactivated, or 
separated, an alternative procedure acceptable to APHIS shall be 
specified in the filed Outline of Production.
    (2) When cell cultures are tested, 5 mL of the final cell 
suspension as prepared for seeding of production cell cultures shall be 
used as inoculum. When vaccines are tested, the equivalent of 200 doses 
of cytopathic vaccine viruses, including Newcastle disease vaccine, 
bursal disease vaccine, tenosynovitis vaccine, and reovirus vaccine, or 
500 doses of other vaccines for use in poultry, or 1 dose of vaccine 
for use in other animals shall be used as inoculum. Control cultures 
shall be prepared from the same cell suspension as the cultures for 
testing the vaccine.
    (3) Uninoculated chick embryo fibroblast cell cultures shall act as 
negative controls. One set of chick fibroblast cultures inoculated with 
subgroup A virus and one set of chick fibroblast cultures inoculated 
with subgroup B virus shall act as positive controls A and B, 
respectively.
    (4) The cell cultures shall be passed when necessary to maintain 
viability, and samples harvested from each passage shall be tested for 
group-specific antigen.
    (b) A test that will detect extraneous replicating lymphoid 
leukosis virus and that is acceptable to APHIS shall be used.
    (1) All test materials, including positive and negative controls, 
shall be stored at -60 [deg]C or colder until used in the test.
    (2) The test procedure, including the cutoff value indicative of a 
positive test for extraneous replicating lymphoid leukosis virus, shall 
be specified in a filed Outline of Production or Special Outline.
    (3) The detection of extraneous replicating lymphoid leukosis virus 
at the first passage shall be considered suspicious and the sample 
shall be further subcultured and tested to determine the presence of 
extraneous replicating lymphoid leukosis virus.
    (4) Biological products or primary cells that are found 
contaminated with lymphoid leukosis viruses are unsatisfactory. Source 
flocks from which contaminated material was obtained are also 
unsatisfactory.

    Done in Washington, DC this 25th day of January 2007.
Kevin Shea,
Acting Administrator, Animal and Plant Health Inspection Service.
 [FR Doc. E7-1528 Filed 1-30-07; 8:45 am]
BILLING CODE 3410-34-P