Scrapie Veterinary Services February 2002

Scrapie is a fatal, degenerative disease affecting the central nervous system of sheep and goats. It is among a number of diseases classified as transmissible spongiform encephalopathies (TSE). Infected flocks that contain a high percentage of susceptible animals can experience significant production losses. Over a period of several years the number of infected animals increases, and the age at onset of clinical signs decreases making these flocks economically unviable. Animals sold from infected flocks spread scrapie to other flocks. The presence of scrapie in the United States also prevents the export of breeding stock, semen, and embryos to many other countries. TSEs are the subject of increased attention and concern because of the discovery of bovine spongiform encephalopathy (BSE) in cattle, the link between BSE and variant Creutzfeldt-Jakob disease (vCJD) in people, and feline spongiform encephalopathy (FSE) in cats in Europe.

This increased concern has led to the following:

• Packers and producers have had difficulty finding options for disposal of sheep offal and dead sheep causing packers and producers to incur significant increases in disposal costs,
• Other countries have expressed concerns and have indicated that they may prohibit or restrict certain ruminant products because the United States has scrapie, and
• Domestic and international markets for U.S. sheep-derived meat and bone meal have been adversely affected.

The combination of all of these factors has led to the decision to develop a strong scrapie eradication program in the United States. Epidemiology and Transmission The agent responsible for scrapie and other TSEs is smaller than the smallest known virus and has not been completely characterized. There are three main theories on the nature of the scrapie agent: (1) the agent is a virus with unusual characteristics, (2) the agent is a prion, which is a malformed protein in the brain, and (3) the agent is a virino, a very small piece of DNA that acts like a virus. The scrapie agent is extremely resistant to heat and to normal sterilization processes. It does not evoke any detectable immune response or inflammatory reaction in host animals. The scrapie agent is thought to be spread most commonly from the ewe to her offspring and to other lambs through contact with the placenta and placental fluids. Signs or effects of the disease usually appear 2 to 5 years after the animal is infected but may not appear until much later. Sheep may live 1 to 6 months or longer after the onset of clinical signs, but death is inevitable. The genetics of the sheep affects their susceptibility to scrapie.

In the laboratory, the scrapie agent has been transmitted to hamsters, mice, rats, voles, gerbils, mink, cattle, and some species of monkeys by inoculation. There is no scientific evidence to indicate that scrapie poses a risk to human health. There is no epidemiologic evidence that scrapie of sheep and goats is transmitted to humans, such as through contact on the farm, at slaughter plants, or butcher shops.

Clinical Signs

Signs of scrapie vary widely among individual animals and develop very slowly. Due to damage to nerve cells, affected animals usually show behavioral changes, tremor (especially of head and neck), pruritus, and locomotor incoordination that progresses to recumbency and death. Early signs include subtle changes in behavior or temperament. These changes may be followed by scratching and rubbing against fixed objects, apparently to relieve itching. Other signs are loss of coordination, weight loss despite retention of appetite, biting of feet and limbs, lip smacking, and gait abnormalities, including high-stepping of the forelegs, hopping like a rabbit, and swaying of the back end. An infected animal may appear normal if left undisturbed at rest. However, when stimulated by a sudden noise, excessive movement, or the stress of handling, the animal may tremble or fall down in a convulsive-like state. Several other problems can cause clinical signs similar to scrapie in sheep, including the diseases ovine progressive pneumonia, listeriosis, and rabies; the presence of external parasites (lice and mites); pregnancy toxemia; and toxins.

On the farm, veterinarians diagnose scrapie based on the appearance of its signs combined with knowledge of the animal's history. There is a test currently undergoing evaluation by the U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) for scrapie detection in live animals. Scrapie can currently only be confirmed by microscopic examinations of brain tissue at necropsy or by procedures that detect the presence of the abnormal prion protein.

Research

Scrapie research efforts are currently focused on developing a practical live-animal test to diagnose infected sheep before they show signs, investigating transmissibility of the agent, identifying the scrapie agent and its different strains, identifying genes that influence scrapie infection and evaluating genetic selection as a tool for scrapie control, and examining the role of artificial insemination and embryo transfer in the transmissibility of the scrapie agent. Research studies using experimentally infected sheep suggest that embryos may play a role in the spread of scrapie.

Related Diseases

The TSE family of diseases includes BSE: transmissible mink encephalopathy; FSE; chronic wasting disease of deer and elk; kuru; both classical and variant Creutzfeldt-Jakob disease; Gerstmann-Straussler-Scheinker syndrome; and fatal familial insomnia. TSEs have also been reported in Europe in captive wild ruminants in the bovid family, cats, and monkeys. The occurrence of TSEs in captive wild animals is believed to have resulted from BSE-contaminated feed. Control Program USDA has initiated an accelerated scrapie eradication program. The program is based on the following key concepts:

• Identification of preclinical infected sheep through live animal testing and active slaughter,
• surveillance,
• Effective tracing of infected animals to their flock/herd of origin made possible as a result of the new identification requirements, and
• Providing effective cleanup strategies that will allow producers to stay in business, preserve breeding stock, and remain economically viable.

APHIS will do this by providing the following to exposed and infected flocks/herds that participate in cleanup plans:

• Indemnity for high-risk, suspect, and scrapie positive sheep and goats, which owners agree to destroy,
• Scrapie live-animal testing,
• Genetic testing, and
• testing of exposed animals that have been sold out of infected and source flocks/herds.

Operating an effective program to deal with this insidious disease requires cooperation among producer organizations, allied industries, and governmental agencies. History First recognized as a disease of sheep in Great Britain and other countries of Western Europe more than 250 years ago, scrapie has been reported throughout the world. Only two countries are recognized by the United States as being free of scrapie: Australia and New Zealand. The first case of scrapie in the United States was diagnosed in 1947 in a Michigan flock. The flock owner had imported sheep of British origin through Canada for several years. From this first case through July 2001, scrapie has been diagnosed in more than 1,000 flocks in this country. In the United States, scrapie has primarily been reported in the Suffolk breed. It also has been diagnosed in a Border Leicester, Cheviots, Corriedales, a Cotswold, Dorsets, Finn sheep, Hampshires, Merinos, Montadales, Rambouillets, Shropshires, Southdowns, and a number of crossbreeds. Through August 2001, approximately 1,600 cases in sheep and 7 cases in goats have been reported.

Additional Information For more information about scrapie, contact your local APHIS, Veterinary Services, Area Office or contact: USDA, APHIS, Veterinary Services National Animal Health Programs 4700 River Road, Unit 43 Riverdale, MD 20737-1231 Telephone (301) 734-6954 Fax (301) 734-7964

Q: What is scrapie? A: Scrapie is a disease of sheep and goats that attacks their brains.

Q: Where did scrapie in the United States come from? A: Scrapie came from sheep imported from England into the United States in 1947.

Q: What kinds of animals get scrapie? A: Sheep and goats get scrapie. Mice and hamsters can be given the disease in the laboratory.

Q: How did the disease get its name? A: Animals that have scrapie will rub on things and scrape off their wool or hair. This scraping is what gives the disease its name.

Q: What do sheep look like when they get sick? A: Sheep that get sick with scrapie will do different things. Here is a list of symptoms to look for when sheep are sick with scrapie:

• Eat and eat and still get thin
• Itch all the time
• Pull out their wool
• Bunny hop
• Step high with their front feet
• Sway in back
• Rub on things a lot
• Bite at their legs
• Smack their lips
• Wobble or stumble
• Shake
• Jump at normal sounds
• Press their head on things for a long time
• Stare up at the sky
• Can't get up

Q: Is there any cure for scrapie? A: No, there is not. Sheep that get sick with scrapie always die.

Q: Can you tell if an animal has the disease right away, or do you have to wait awhile? A: Sheep that get scrapie are sick a long time. You have to watch them closely because they don't show many signs at first. You have to wait to see if they get worse. You used to have to wait for them to die and test their brains to tell if they had scrapie. Today, scientists are working on a new test so that you do not have to wait that long. Veterinarians can take a small part of the third eyelid and test it for scrapie. This new test, when validated, will give sheep owners help in finding and stopping the spread of the disease.

Q: How do sheep get scrapie? A: Sheep get scrapie from other sheep or from where they have given birth. Scientists think that it is passed mostly during the birthing process. It takes from 2 to 5 years for scrapie to make sheep sick.

Q: What happens inside the animal? A: The disease can get inside through the mouth or broken skin. It then goes to the lymph tissues and to the brain.

Q: What does scrapie do to the brain? A: Under a microscope, the brains of sheep with scrapie look as if they have "holes" in them, sort of like a sponge. Scientists call these "spongiform" changes.

Q: How does scrapie make sheep die? A: Scrapie kills the sheep's brain cells so that the sheep cannot get up and eat and drink. Since the animal cannot do any of these things, it dies. Scrapie Program Veterinary Services February 2002 Since 1952, the United States Department of Agriculture (USDA) has worked to control scrapie, which entered the United States in 1947 from sheep imported from England. Additional information on scrapie can be found at http://www.aphis.usda.gov/vs/scrapie.

Today, USDA uses two approaches to control scrapie, flock certification and restriction on the interstate movement of high-risk and affected animals. The Scrapie Flock Certification Program (SFCP) has been in place since October 1992. The latest addition to the overall scrapie program is an initiative to accelerate the eradication of scrapie from the United States. Through this initiative, the Animal and Plant Health Inspection Service's (APHIS) Veterinary Services (VS) program has received $10 million in emergency funding to conduct the following activities in fiscal year (FY) 2000 and FY 2001: sheep and goat identification; slaughter surveillance; a scrapie live animal test validation project; scrapie control pilot projects; data collection; and increased and improved diagnostic capacity.

Scrapie Summary — Fiscal Year 2000

As of October 2, 2000, there were 6 scrapie source flocks and 44 scrapie-infected flocks. The number of scrapie cases confirmed by USDA's National Veterinary Services Laboratories (NVSL) was 57. Scrapie Flock Certification Program As of October 2, 2000, 617 flocks were enrolled in the Voluntary Scrapie Flock Certification Program (VSFCP). Of these, 50 flocks are certified as being free of scrapie, 558 are completely monitored, and 8 are selectively monitored. National Scrapie Oversight Committee (NSOC) The NSOC has added three additional VSFCP-enrolled sheep producers to the committee, Richard Hamilton, Steven Cloud, and Barbara Burrows. The NSOC has also added two goat producers to the committee to represent the interests of meat and dairy goat producers. Tom Boyer, International Boer Goat Association, and Dr. Joan Rowe, American Dairy Goat Association, have been selected. Individuals on the committee participate in conference calls and meetings to provide information to APHIS on issues that affect the VSFCP, particularly changes to the standards. Committee members are expected to participate in conference calls on an as-needed basis, usually 4 to 5 times a year. Members are also expected to advocate for the program. The term is for one year but may be renewed.

Accelerated Scrapie Eradication Initiative Proposed Rule Provides Framework for Scrapie Eradication

The proposed rule, Scrapie in Sheep and Goats: Interstate Movement Restriction and Indemnity Program, which was published in the Federal Register on November 30, 1999, resulted in 171 comments. In preparation for finalizing the interstate movement rule, APHIS published a proposed list of consistent States on August 15, 2000. All 50 States were listed as consistent States. In order to be listed as consistent States, the States had to agree to meet the minimum standards set by APHIS for scrapie control. The proposed rules can be found at http://www.aphis.usda.gov/ppd/rad/webrepor.html.

Sheep Identification

Sheep and goat identification allows APHIS to trace scrapie-infected and scrapie-exposed animals. APHIS will inform producers, marketers, dealers, and slaughter establishments about any new identification methods required by the final rule. Ongoing information and any necessary enforcement activities will follow. The proposed rule allows for the use of either premise-based identification in limited circumstances, premise-based individual animal identification, or individual animal identification. This means that, if the rule is finalized, either standard USDA metal eartags or, in the case of animals moving directly to slaughter, backtags could be used by accredited veterinarians, markets, dealers, or producers as long as the tag numbers have been assigned by a State or APHIS representative and recorded in the scrapie database.

Owners of registered animals may also use registration tattoos. Alternatively, producers could elect to either apply an assigned premise-based identification tattoo number or purchase eartags or backtags that are imprinted with an assigned premise identification number that either contains, or is used in association with, a unique production number. APHIS would approve tag companies to make eartags and backtags for this purpose. The cost of the premise eartags is expected to range from 6 cents for metal tags to $1 for tamper-resistant flap tags. Tags already approved for use in the VSFCP may be used for this purpose.

Slaughter Surveillance

Initially, the purpose of slaughter surveillance will be to determine the prevalence of scrapie in the United States based on immunohistochemistry on the brainstem. Once the prevalence work is completed, slaughter surveillance will be used to identify infected flocks. Slaughter surveillance will be initiated on a limited basis in 2001 to test the procedures for sample collection and handling, and to ensure a smooth start. Full implementation of the procedures will begin as soon as the sheep are adequately identified. Work will then continue for 12 months and will include sampling of 11,300 sheep. The sheep will be traced to their State of origin so that the prevalence of scrapie can be calculated on a regional basis. No individual animal results will be provided to the area offices or to owners, and no regulatory action will be taken unless the owner requests the results for his or her sheep.

APHIS' Centers for Epidemiology and Animal Health (CEAH) has developed a preliminary sampling plan. Twenty-five plants in 14 States have been included in the plan. This accounts for 122,755 head or 58 percent of the published number of mature sheep slaughtered in the United States. Funding is expected in FY 2001 and 2002 to maintain slaughter surveillance at the level of 1,000 samples per month through FY 2002. After the initial prevalence determination is completed, only scrapie-positive animals will be traced. The slaughter surveillance is expected to yield between 50 and 300 infected animals per year; this would necessitate subsequent traces, epidemiologic investigations, flock testing, and flock cleanup planning.

Scrapie Test Validation Project

The primary purpose of the Scrapie Test Validation Project is to determine the reliability and best regulatory and diagnostic uses of the third eyelid test. APHIS also intends to assess the role of genetics and the validity of the capillary immunoelectrophoresis (CIE) test. APHIS and USDA's Agricultural Research Service (ARS) began the Scrapie Test Validation Project in May 2000. Sheep in scrapie-affected flocks whose owners volunteer to participate in the project will be tested by third eyelid and genotype methods. Owners of source flocks, infected flocks, trace flocks, and high-risk sheep will be contacted and asked to participate as space is available at the lab for testing. APHIS will purchase all test-positive animals. High-risk animals acquired by flocks not designated infected, source, or trace will be tested and purchased whenever possible. Sheep for which the third eyelid test is positive will be shipped to an ARS or APHIS holding facility. A matched test-negative control group will be maintained at a separate facility, for a total of at least 600 sheep. All remaining high-risk sheep that have been tested will be purchased, euthanized, and necropsied by State or Federal personnel or an accredited veterinarian.

Scrapie Control Pilot Projects

In States that sign Scrapie Control Pilot Project agreements, APHIS will offer an option to purchase only test-positive sheep from those owners who are interested in participating in scrapie control pilot projects for flock cleanup and who have flocks that are suitable based on the epidemiology of the flock and the availability of required records. The final rule, Scrapie Pilot Projects, which allows APHIS to conduct pilot projects to evaluate flock cleanup plans based on testing was published June 27, 2000, in the Federal Register.

To qualify for a pilot project, a flock must be in a State that has signed an agreement with APHIS to conduct a scrapie control pilot project. As of November 2000, only Idaho and Kentucky had signed such an agreement, but three States have provided draft pilot project agreements and several others have expressed interest in conducting pilot projects. To qualify, a pilot project must advance knowledge about scrapie control and must provide adequate safeguards to prevent the spread of scrapie that are at least as effective as those that are currently required for flock clean up plans. These must include: the restriction of all high-risk animals to the premises except for movement to slaughter; necropsy and testing of all animals that die, particularly high-risk animals, if they are over 14 months of age; third eyelid testing of all animals over 14 months of age or when they reach 14 months of age with a retest 18 months after the last known exposure to scrapie; removal of all test-positive animals; and restrictions on the movements of other animals out of the flock except to slaughter unless testing or other methods have been used to ensure that they are at low risk for spreading scrapie. The pilot may include genotyping as a selection criteria.

Data Collection

The Scrapie National Generic Database (GDB) is operational and is being used to generate the web page. An individual animal information form has been developed and is being tested. This form will facilitate tracing and tracking of test-positive sheep as well as exposed animals. It is now possible to list up to three breeds and to list flock identification numbers on the web page.

Increased and Improved Diagnostic Capacity

NVSL has leased additional space to accommodate the increased testing. To handle the formic acid treatment of third eyelid tissues, the laboratory is upgrading the ventilation system; the need to replace the inadequate system delayed the start of third eyelid testing. Two hoods are now functioning at a safe level and are being used to test samples from ARS. NVSL and ARS will be running third eyelid slides in parallel using the protocol that was provided to NVSL by ARS in October. This work should be the final step needed to gather data for approval of the test. APHIS will enter into contracts for immunohistochemistry on brain, third eyelid, and genotype testing at approved laboratories. APHIS has contracted with two laboratories to test slaughter samples.

Conclusion

The effectiveness of the Scrapie Eradication Program will depend largely on the thought, effort, and care given to program implementation by everyone involved and will need the continued support of the industry. APHIS looks forward to working with industry, individual producers, accredited veterinarians, and approved laboratories to make these projects a success. Contact Information If you have any questions or concerns, please contact your local Veterinary Services area office or Diane Sutton, the national scrapie program coordinator, or her program assistant, Lisa Jackson, at 301-734-6954. Dr. Sutton can also be reached via e-mail at Diane.L.Sutton@USDA.GOV and Ms. Jackson can be reached at Lisa.L.Jackson@USDA.GOV.

Frequently Asked Questions About New Identification Requirements for Sheep and Goats Veterinary Services February 2002

Q. When does this regulation go into effect? A. The regulation went into effect on November 19, 2001, for sheep and goats not known to be exposed to scrapie.

Q. Why do I have to do this? A. It is the U.S. Department of Agriculture's (USDA) goal to eradicate scrapie in the United States to minimize ongoing losses to the sheep industry. To eradicate scrapie, USDA's Animal and Plant Health Inspection Service must be able to trace scrapie-infected animals back to their flock of birth or origin.

Q. What is scrapie? A. Scrapie is a fatal degenerative disease affecting the central nervous system of sheep and goats. Clinical signs include changes in behavior or temperament, scratching and rubbing against fixed objects, weight loss, loss of coordination, lip smacking, and gait abnormalities. The presence of scrapie in the United States is a major obstacle to establishing new export markets for sheep and sheep products.

Q. Which animals will need identification (ID) tags? A. All breeding sheep and sheep over 18 months of age need to be officially identified before they enter into interstate commerce. Additional situations requiring official ID are as follows: Cull ewes and rams sold to livestock markets or dealers are considered to be in interstate commerce. USDA recommends owners place official ID on these animals before they leave the farm so that animals can be traced back to a specific farm if needed. Additionally, markets may charge for their time to keep additional records and to apply ID if sheep are not properly identified when received. All sexually intact sheep of any age going to any show, demonstration, or exhibition "out-of- State," or any "in-State" show, demonstration, or exhibition where sheep from another State might be on site. Breeding animals sold "out-of-State" or sold at sales/markets/auctions "in-State" that handle animals in interstate commerce. It is even a good idea to identify breeding animals sold "in- State," as the purchaser will not be able to sell the animal "out-of-State" if it was born after January 1, 2002, if it was not identified to the flock of birth. Goats that must be identified for interstate sale or show or movement are as follows: Sexually intact registered goats and goats used primarily for milk production or sold for breeding or exhibition.

Note: Legible registration tattoos are acceptable for ID when the goats are accompanied by their registration certificate or the registration numbers and registry are listed on a certificate of veterinary inspection. Any other sexually intact goats that have resided on the same premises as sheep. There are additional identification requirements for animals exposed to scrapie. These "exposed" sheep must be officially identified by September 20, 2001.

Q. Where do you get the official ID tags? A. First, call APHIS" Veterinary Services (VS) office at this toll free number 1–866–873–2824 (1–866–USDA–TAG). This office will assign you an official flock ID and provide USDA tags.

Q. What is the cost of the tags and what do they look like? A. USDA provides two types of official tags free of charge. There is a white metal tag and a white plastic tag. Producers that order these free tags during the next year will also receive one pair of tag pliers free of charge with their first order. Additional pliers may be purchased directly from the company if desired. If you do not care for either of these, additional official tags can be ordered at a cost to you. Please ask for information on these tags when you call USDA. You need an official flock ID, issued by the USDA, prior to ordering these tags.

Q. How many tags should I order? A. You should order enough tags to identify any breeding sheep or cull sheep that will be sold over the next 2 to 3 years.

Q. Can registered tattoos be used to meet USDA's identification requirements? A. Yes, legible individual registry tattoos issued by breed associations may also be used as official identification. Your assigned tattoo prefix should be registered with your local USDA, APHIS, VS office using the enclosed form.

Q. What do I do when selling an animal that is required to be identified? A. When selling a sheep or goat that is required to be identified, the animal must be identified to the flock in which they were last used for breeding or were born. You can do this by applying your USDA-assigned tags to the animals and providing the purchaser with an owner statement and retaining a copy for yourself. You may use the enclosed owner statement for this purpose. If you are selling animals for slaughter only, be sure to tell the market and write "for slaughter only," on the owner statement. Animals sold for breeding must have a certificate of veterinary inspection from an accredited veterinarian. Animals born after January 1, 2002, must be identified to their flock of birth. If the animal is identified with flock-of-origin assigned ID you may use the premises identification number; however, when it is practical to do so, recording their full ID (flock number plus individual animal number) is recommended. A copy of this record should always go with each animal and you should keep a copy. Remember, the goal is to know both the flock into which an animal was born and any flocks in which the animal resided after birth. This is to determine the origin of scrapie and eradicate it if an infected animal is found.

Q. What if I buy sheep or goats that are required to be identified? A. The easiest thing to do is to request that the seller identify the animals and provide an owner statement (see attached sample). The owner statement has all the information you are required to keep. If the seller does not provide an owner statement, you will need to read and record all the tags, the number of animals purchased, the breeds, the date purchased, and the name, address and phone number of the person who sold them to you.

Q. What do I do when I sell one of these "purchased animals"? A. If the animal was not used for breeding purposes while in your ownership, you should provide a copy of the owner statement you received when you purchased the animal to the new buyer. If you used the animal for breeding purposes, you should provide the purchaser with your own owner statement.

Q. How long do I need to keep records? A. Records must be kept for at least 5 years from the date the animal was transported or sold.

Q. I purchased an animal with an official ID already on it, do I need to retag it? A. Never remove any official ID. You can add your own official ID if you wish. Again, there must be a combination of ID and records that will allow USDA to trace a scrapie-infected animal to the flock of birth and any flock(s) in which the animal has resided for breeding purposes.

Q. My neighbor needs to ID some sheep and has no tags. Should I lend her/him some of mine? A. No. USDA assigns flock numbers to each flock. Unique flock ID ensures that any traces involving flock ID will be traced to a single flock.

Q. Is this part of USDA's Scrapie Flock Certification Program? A. No. The Scrapie Flock Certification Program is a different program available to producers who wish to take additional actions that will allow their flocks to be certified as being free of scrapie.

Q. Will the ID tags used in Scrapie Flock Certification Program satisfy the requirements of this new regulation? A. Yes.

Q. What is the Scrapie Flock Certification Program? A. The Scrapie Flock Certification Program is a voluntary USDA program to identify flocks that are free of scrapie. The purpose of the certification program is to provide producers a source of replacement animals from flocks which are monitored for signs of scrapie. Owners of participating flocks must officially identify all animals over 1 year of age with an official tamperproof eartag, maintain required records, and agree to immediately report animals suspected of having scrapie.

Please contact the USDA, APHIS, VS office for more information or check out the web site (http://www.aphis.usda.gov/vs). Call 515-284-4140 if you have any questions or go to the Internet at http://www.aphis.usda.gov/vs/scrapie/ or http://www.animalagriculture.org/scrapie.

Voluntary Scrapie Flock Certification Program Veterinary Services July 1998

History

Since 1952, the U.S. Department of Agriculture (USDA) and the sheep industry have made numerous attempts to eradicate scrapie through various programs. The purpose of all previous USDA programs was to identify scrapie and eradicate it. That approach changed with the implementation of the Voluntary Scrapie Flock Certification Program on October 1, 1992. This program is a voluntary, cooperative effort among producers, allied industry representatives, accredited veterinarians, State animal health officials, and USDA's Animal and Plant Health Inspection Service (APHIS). The program provides participating producers with the opportunity to protect their sheep from scrapie and to enhance the marketability of their animals through certifying their origin in scrapie-free flocks. In addition, APHIS regulations restrict the interstate movement of sheep from scrapie-infected and source flocks. The program was modified in October 1997 to make it more practical for producers. This factsheet describes the new Voluntary Scrapie Flock Certification Program.

Program Purpose and Benefits

The intent of the program is to monitor flocks over a period of 5 years or more to identify flocks that are free of scrapie. Because there is no validated live-animal test for this disease and scrapie has a long incubation period, a flock is considered free of the disease if no sheep have been diagnosed with scrapie and there is no clinical evidence of it over a period of time. The longer a flock is enrolled and following the requirements of the program, the more likely the sheep in the flock are free of scrapie. The economic value of animals in enrolled flocks increases the longer they are in the program, especially once the flock is certified. Animals from certified flocks are a valuable source for replacement of breeding animals in other flocks. The program receives producer input at the national and State levels through the National Oversight Committee and the State Certification Board. These groups include producers, accredited veterinarians, allied industry representatives, State animal health officials, and APHIS officials.

Sign Up!

All flock owners may apply to enter the Voluntary Scrapie Flock Certification Program by contacting the APHIS Veterinary Services office for their area. The State Certification Board reviews applications and approves or disapproves admission to the program. The application package includes:

• A list of animals in the flock, including breed, gender, and official program identification (tattoo, microchip, or APHIS-approved, tamper-resistant ear tag);
• A statement by the flock's accredited veterinarian declaring the flock free of scrapie; and
• An inspection report authorized by a State or Federal regulatory official verifying official identification and other application information.

Program Requirements

When participating in the program, flock owners must:

• Agree to immediately report scrapie-suspect animals to the proper animal health official.
• Officially identify all animals within a flock that are 1 year of age or older. Animals less than 1 year old must be identified whenever a change of ownership occurs, except for those in slaughter channels.
• Maintain required records as specified by the program. Owners must account for all acquisitions, departures, births, and deaths. Records must be retained for a minimum of 5 years after an animal dies or is removed from the flock.
• Allow breed associations and registries, livestock markets, and packers to disclose records to APHIS and/or State animal health officials and State Scrapie Certification Board members.
• Provide necessary facilities and personnel to assist in inspections, including:
checking animals for official identification and signs of scrapie, and checking records for completeness and accuracy.
Submit to an official laboratory tissues from scrapie-suspect animals and from animals suspected of having other neurologic or chronic, debilitating illnesses.
Report to the State Certification Board acquisitions of sheep from flocks with lower status or from flocks not participating in the program.

Program Categories

Complete Monitored Category

This category means that a flock is approved to participate in the program. Flocks in this category have either enrolled or certified status.

Complete Monitored Enrolled Flock

When a flock enters the program, it is assigned enrolled status, becoming a "complete monitored enrolled flock." These flocks are assigned an enrollment date (the date the State Certification Board approves admission to the program) and a status date. The status date is the best risk indicator for scrapie in an enrolled flock. Initially, the status date is the same as the enrollment date and will be maintained if a flock continues to meet program requirements. However, if a flock acquires animals or commingles with animals that do not meet the program standards, the status date changes to reflect the date of this occurrence. The older the date, the longer the flock has been meeting program standards. Rams may be acquired from any flock (other than source or infected flocks), including those not enrolled in the program.

Presently, there is no scientific evidence that supports rams as a risk for spreading scrapie. However, producers increase the risk that scrapie will be diagnosed in their flock when purchasing rams from nonenrolled flocks. Ewes have been found to spread the disease. Therefore, to maintain scrapie-free status, flock owners may obtain ewes only from other enrolled flocks with an equal or older status date. Owners acquiring ewes from flocks not participating in the program or from flocks of lower scrapie status will have their flock's status date adjusted to reflect the addition of the lowest category animal.

Complete Monitored Certified Flock

When an enrolled flock has met program standards for 5 consecutive years, it advances to certified status. Sheep from these flocks are unlikely to be infected with scrapie. Flocks in this status may be augmented with rams from other certified flocks or enrolled flocks. However, APHIS recommends that producers consider the risk of scrapie infection when purchasing rams from lesser status flocks. Ewes may be purchased only from other certified flocks. Both enrolled and certified flocks are inspected annually by State or Federal regulatory personnel. Flocks of both statuses also may loan out rams for breeding without jeopardizing their status date. The ram must reside in the program flock other than for breeding purposes and cannot be with ewes 30 days prior to and 60 days following lambing.

Selective Monitored Category

Selective Monitored Category is open to any flock and was designed for slaughter lamb producers to allow for scrapie surveillance in large production flocks. Only male animals over 1 year of age must be officially identified. Producers agree to submit for scrapie diagnosis animals that are culled from the flock or that die. (The number of animals to submit per year depends on the flock size.) Additionally, an accredited veterinarian must inspect all cull ewes for clinical signs of scrapie prior to slaughter. Selective status is maintained indefinitely, as long as the flock meets the category requirements.

Epidemiologic Investigations

If scrapie is diagnosed in a flock in any program category, animal health officials will conduct an epidemiologic investigation. The investigation will identify and trace back the source of the disease and identify exposed animals. These officials will work with the flock owner to develop and implement a flock plan. The flock plan will include depopulation of high-risk animals, reduction of risk associated with spread of infection, and facility cleanup and disinfection.

Exhibition and Transportation Guidelines

The program standards also give guidelines for reducing the risk of scrapie exposure when sheep are at shows or are being transported. Guidelines include separating enrolled sheep from nonenrolled sheep by a vacant pen, barn alley, or solid barrier sufficient to prevent physical contact. Limited contact in show rings minimizes the risk of disease transmission. Enrolled sheep should not commingle with lambing ewes at exhibits or sales.

Additional Information

For more information about the Voluntary Scrapie Flock Certification Program, contact USDA, APHIS, Veterinary Services National Animal Health Programs 4700 River Road, Unit 43 Riverdale, MD 20737-1231 Telephone (301) 734-6954 Fax (301) 734-7964 Current information on enrolled, certified, source, and infected flocks is also available 24 a day hours every day through a toll-free automated telephone voice response service at (800) 545-USDA (8732). To reach APHIS' scrapie information on the World Wide Web, point your Web browser to http://www.aphis.usda.gov and type the word "scrapie" (minus the quotation marks) in the search engine.