Interstate Movement of Sheep and Goats From States That Do Not Quarantine Scrapie Infected and Source Flocks

DEPARTMENT OF AGRICULTURE

Animal and Plant Health Inspection Service

9 CFR Parts 54 and 79

[Docket No. 97-093-1]

RIN 0579-AA90

Interstate Movement of Sheep and Goats From States That Do Not

Quarantine Scrapie Infected and Source Flocks

AGENCY: Animal and Plant Health Inspection Service, USDA.

ACTION: Advance notice of proposed rulemaking.

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SUMMARY: We are soliciting public comment to help us develop options

for potential changes to our regulations for the interstate movement of

sheep and goats. We believe changes may be necessary to improve control

and limit the spread of scrapie, a serious disease of sheep and goats.

After evaluating public comment on the issues presented in this notice,

we will determine whether proposing changes to our regulations is

necessary.

DATES: Consideration will be given only to comments received on or

before March 27, 1998.

ADDRESSES: Comments may be submitted as paper copies or through the

World Wide Web. If you submit paper copies, please send an original and

three copies of your comments to Docket No. 97-093-1, Regulatory

Analysis and Development, PPD, APHIS, suite 3C03, 4700 River Road Unit

118, Riverdale, MD 20737-1238. Please state that your comments refer to

Docket No. 97-093-1. We encourage the submission of copies through the

World Wide Web, since this both facilitates our analysis of the

comments and allows us to make the text of comments available to the

public via the Internet. The Web page address for comments on this

proposed rule is http://www.aphis.usda.gov/ppd/scrapie. This Web page

also contains copies of the proposed rule in several formats and links

to related information. Please be sure to include your full name and

organization in any comments you submit via the Web. If your Web

comment is a duplicate of a paper copy you have submitted, please state

this in the first line of your Web message. Both paper and Web comments

received may be inspected at USDA, room 1141, South Building, 14th

Street and Independence Avenue SW., Washington, DC, between 8 a.m. and

4:30 p.m., Monday through Friday, except holidays. Persons wishing to

inspect comments are requested to call ahead on (202) 690-2817 to

facilitate entry into the comment reading room.

FOR FURTHER INFORMATION CONTACT: Dr. Joseph VanTiem, Senior Staff

Veterinarian, National Animal Health Programs, VS, APHIS, 4700 River

Road Unit 46, Riverdale, MD 20737-1231, (301) 734-7716.

SUPPLEMENTARY INFORMATION:

Background

Scrapie is a degenerative and eventually fatal disease affecting

the central nervous systems of sheep and goats. Its control is

complicated because the disease often has an extremely long incubation

period without clinical signs of disease, and because there is no

validated live-animal test for the disease.

Scrapie is the prototype of the group of diseases known as the

transmissible spongiform encephalopathies (TSEs). These diseases are

caused by a transmissible agent which is yet to be fully characterized.

TSEs share the following common characteristics:

A prolonged incubation period of months or years;

A progressive debilitating neurological illness that is

always fatal;

When examined by electron microscopy, detergent treated

extracts of brain tissue from animals or humans affected by these

diseases reveal the presence of scrapie associated fibrils;

Pathological changes are confined to the central nervous

system and include vacuolation, astrocytosis, and glyosis. Amyloid

plaques may be seen, especially in mice and hamsters; and

The transmissible agent elicits no detectable specific

immune response in the host.

Several recent scientific findings are relevant to the

understanding and control of scrapie. While there is still no validated

live animal test for scrapie, a recent study conducted in The

Netherlands (Schreuder et al., 1996) indicates that immunohistochemical

analysis of tonsil samples may be useful in detecting scrapie in sheep

prior to the onset of clinical signs. The Animal and Plant Health

Inspection Service (APHIS) is currently completing a pilot study to

harvest various tissues (tonsil, head lymph nodes, and brain) from

mature sheep at slaughter and then test them using immunohistochemistry

to ascertain if the partially protease-resistant form of the prion

protein (PrPsc--the protein associated with scrapie) may be routinely

detected in the preclinical animal. If this proves to be an effective

method of surveillance, it may prove useful as a screening tool and

facilitate tracebacks to infected flocks.

In addition to the possibility that a validated live-animal test

for scrapie may be developed, genetic studies have yielded a greater

understanding of the role of specific genes in determining the

incubation period of scrapie in sheep. However, there is still much to

be determined about the role of genetics in scrapie susceptibility. A

key question is whether certain genotypes fully prevent scrapie

infection, or merely protect against clinical manifestation in an

animal while possibly allowing the animal to serve as a carrier of

scrapie.

While these advances may come to significantly affect the control

of scrapie, current control programs rely largely on postmortem

diagnosis of scrapie, traceback of animal movements, and certification

of flocks' scrapie status based on monitoring the flock for scrapie

over a period of years.

Current APHIS initiatives concerning scrapie include interstate

movement regulations in 9 CFR part 79, which restrict the interstate

movement of certain sheep and goats in order to help control the spread

of scrapie, and the Voluntary Scrapie Flock Certification Program (the

Voluntary Program), described in regulations in 9 CFR part 54 and in a

program standards document entitled ``Uniform Methods and Rules--

Voluntary Scrapie Flock Certification'' (UM&R), which is available at

http://www.aphis.usda.gov/vs/scrapie/umr. A hard-copy of the UM&R may

be obtained by contacting the individual listed under FOR FURTHER

INFORMATION CONTACT.

APHIS worked with industry to develop the Voluntary Program, under

which participating flocks follow strict identification, recordkeeping

and other requirements and may eventually be certified free from

scrapie. If a flock that is participating in the Voluntary Program is

identified as an infected flock or source flock, it is removed from the

program until the flock completes a flock plan. The flock plan calls

for an epidemiologic investigation to remove high-risk animals from the

flock and includes other conditions, such as cleaning and disinfection

of flock premises, educating flock personnel in techniques to recognize

clinical signs of scrapie and control its spread, and maintaining

records of animals in the flock.

The regulations in part 79 also restrict the interstate movement of

scrapie-positive sheep and goats, and sheep and goats from scrapie

infected and source flocks. The regulations impose minimal restrictions

on the interstate movement

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of animals \1\ under 1 year of age destined for slaughter and animals

marked on the jaw with a 1-inch letter ``S.'' Other animals from

scrapie infected and source flocks may be moved interstate under

requirements that limit the further spread of scrapie and make it

feasible to trace back the movements of animals that are later

diagnosed with scrapie. These requirements include:

\1\ Throughout this document, when the term ``animals'' is used,

it refers only to sheep and goats.

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The owner of the flock or his or her agent has signed

an agreement with the Administrator in which the owner of the flock

or his or her agent agrees to comply with the requirements of 9 CFR

79.2 until the time the flock is no longer an infected flock or

source flock.

The owner of the flock or his or her agent shall

immediately report to a State representative, APHIS representative,

or an accredited veterinarian any animals in the flock exhibiting

the following: weight loss despite retention of appetite; behavioral

abnormalities; pruritus (itching); wool pulling; biting at legs or

side; lip smacking; motor abnormalities such as incoordination, high

stepping gait of forelimbs, bunny hop movement of rear legs, swaying

of back end; increased sensitivity to noise and sudden movement;

tremor, ``star gazing,'' head pressing, recumbency, or other signs

of neurological disease or chronic wasting illness. Such animals

must not be removed from the flock without written permission of an

APHIS representative or State representative.

The owner of the flock or his or her agent shall

identify all animals 1 year of age or over within the flock. All

animals less than 1 year of age will be identified when a change of

ownership occurs, with the exception of those moving within

slaughter channels. The form of identification shall be an

electronic implant, flank tattoo, or ear tattoo, providing a unique

identification number that may be applied by the owner of the flock

or his or her agent in accordance with instructions by an APHIS

representative, State representative, or an accredited veterinarian.

The owner of the flock or his or her agent shall

maintain, and keep for a minimum of 5 years after an animal dies or

is otherwise removed from a flock, the following records for each

animal in the flock: The animal's individual identification number

from its electronic implant, flank tattoo, or ear tattoo, and any

secondary form of identification the owner of the flock may choose

to maintain; sex; breed; date of acquisition and source (previous

flock), if the animal was not born in the flock; and disposition,

including the date and cause of death, if known, or date of removal

from the flock.

The owner of the flock or his or her agent shall allow

breed associations and registries, livestock markets, and packers to

disclose records to APHIS representatives or State representatives,

to be used to trace source flocks and expose animals.

The owner of the flock or his or her agent shall make

animals in the flock and records required to be kept under paragraph

(a)(2)(iv) of 9 CFR 79.2 available for inspection by APHIS

representatives and State representatives, given reasonable prior

notice.

Upon request of an APHIS representative, the owner of

the flock or his or her agent will have an accredited veterinarian

collect and submit tissues from animals reported in accordance with

paragraph (a)(2)(ii) of 9 CFR 79.2 to a laboratory designated by an

APHIS representative.

However, part 79 applies only when flock owners wish to move sheep

interstate. Part 79 does not restrict the intrastate movement of

animals from infected and source flocks, and such movement may spread

scrapie to other animals in a State. If these other animals, which are

not subject to the restrictions in part 79, then move interstate,

scrapie could be spread interstate.

Therefore, there is a risk that scrapie infection that originated

in an infected or source flock could spread interstate despite part 79.

This risk is very low where State authorities have imposed quarantines

on infected and source flocks that keep animals in these flocks from

contact with other animals. The risk is higher in States that do not

quarantine scrapie infected and source flocks.

APHIS does not have statutory authority to require intrastate

movement restrictions for sheep and goats (unless the Secretary has

declared an extraordinary emergency). However, APHIS does have

statutory authority to restrict the interstate movement of animals from

a State if intrastate movement practices result in a threat of

spreading disease interstate. We are seeking public input on whether

and how APHIS should restrict the interstate movement of animals from

States that do not quarantine infected and source flocks.

We are examining current interstate movement restrictions both to

ensure effective domestic control of scrapie and to ensure that our

domestic interstate restrictions are consistent with our requirements

for importing sheep and goats. The World Trade Organization principles

of ``national treatment'' and ``transparency'' state that regulations

shall be applied without discrimination between domestic and imported

consignments, and that countries shall make available to trading

partners the rationale of their requirements. Our current regulations

for importing sheep and goats use equivalency with the Voluntary

Program to qualify certain animals for import (see 9 CFR 93.435), and

we wish to ensure consistency between our import requirements and our

interstate movement requirements.

We believe the interstate movement restrictions and the definition

of ``flock plan'' in part 79 provide a good model for how an infected

or source flock may be effectively quarantined and managed until

release from quarantine is justified. One possible approach to

controlling the intrastate contact risks described above would be to

amend part 79 to prohibit or restrict movement of animals from a State

unless the State quarantines infected and source flocks in a manner

that is equivalent to the methods employed by part 79. However,

commenters may well suggest other approaches to revising part 79 to

address the risks of intrastate movements from infected and source

flocks.

In particular, we ask commenters to address the following areas

that apply to possible State quarantine standards, the alignment of

Federal interstate movement restrictions with State standards, and

Voluntary Program standards:

Should APHIS further restrict interstate movement of

animals from States that do not consider scrapie a reportable

disease or do not quarantine infected flocks or source flocks? If

so, should restrictions focus on high-risk animals or on broader

classes of animals? (A high-risk animal is defined in 9 CFR 79.1. In

short, a high-risk animal is: (1) An animal that is the progeny of a

scrapie-positive dam; (2) an animal born in the same flock during

the same lambing season as progeny of a scrapie-positive dam, with

certain exceptions outlined in the definition; or (3) an animal born

during the same lambing season as a scrapie-positive ewe or ram in a

source flock or trace flock.)

Currently, part 79 does not restrict interstate

movement of high-risk animals from flocks that are not infected

flocks or are not source flocks. Should APHIS restrict such

movements, and if so, how?

Should APHIS define how a State must conduct a

quarantine in order to avoid further restrictions on interstate

movement of animals from that State? If so, how should APHIS

describe the necessary quarantine conditions (e.g., imposition of

the quarantine; movement of animals into and from quarantined

flocks; duration of the quarantine; identification requirements for

quarantined animals, development and use of a flock plan; procedures

for release from quarantine and follow-up monitoring)?

Should any of the definitions in the interstate

movement regulations in part 79 or the Voluntary Program in part 54

be revised to better address this problem (e.g., the definitions of

source flock, trace flock, and high-risk animal)?

Should there be additional permit or official

identification requirements for the interstate movement of any

classes of sheep and goats to allow for a more effective national

program for surveillance for scrapie and traceback of scrapie-

positive animals?

Currently APHIS makes the following information

available on its World Wide Web

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site: The identity of scrapie infected flocks and source flocks

designated under part 79, and the identity and certification status

of flocks participating in the Voluntary Program. Should APHIS

continue to provide this information on the Web?

To assess the impacts of options regarding the

interstate movement of sheep and goats, baseline estimates of costs

and benefits are needed. What are the costs and benefits of the

current system of part 79, State quarantine standards, and the

Voluntary Program? For example, what costs are involved in complying

with State quarantine programs and how large are these costs?

Similarly, what are the costs to a flock owner who participates in

the Voluntary Program?

We invite comments on these topics. We also welcome ideas as to

different approaches we might take to improve our scrapie programs. In

responding to the questions posed in this notice, commenters are urged

to include economic reasons and data supporting their positions.

Whenever possible, please refer to specific terms, definitions, or

procedures contained in the current regulations in 9 CFR parts 54 and

79, and in the program standards UM&R (available at http://

www.aphis.usda.gov/vs/scrapie/umr). A hard-copy of the program

standards UM&R may be obtained by contacting the individual listed

under FOR FURTHER INFORMATION CONTACT. These resources should provide a

common context for discussing suggested changes. You may also wish to

refer to the Scrapie Flock Status Report on the APHIS Web, which lists

the certification status of flocks in the Voluntary Program and

identifies known infected and source flocks nationwide. This report is

at http://www.aphis.usda.gov/vs/scrapie/status.html.

Authority: 21 U.S.C. 111-114, 114a, 115, 117, 120, 121, 123-126,

134a-134h; 7 CFR 2.22, 2.80, and 371.2(d).

Done in Washington, DC, this 21st day of January 1998.

Thomas E. Walton,

Acting Administrator, Animal and Plant Health Inspection Service.

[FR Doc. 98-1810 Filed 1-21-98; 4:40 pm]

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