Eradicating Scrapie: Finding the Last Cases
By Mary Jane Lis, MS, DVM, PhD, State Veterinarian
Scrapie is a fatal, degenerative disease affecting the central nervous system (brain and spinal cord) of sheep and goats.
The infectious agent is smaller than a virus and may take two to five years before presenting noticeable signs of disease in an animal. It damages the neural tissue, leaving holes that look like Swiss cheese or a sponge when examined under the microscope, giving this class of diseases the name Transmissible Spongiform Encephalopathy (TSE).
Bovine Spongiform Encephalopathy (BSE, “Mad Cow” Disease) in cattle and Chronic Wasting Disease in deer and elk are also TSEs.
There is no cure or treatment for these diseases. Transmission of Scrapie occurs primarily from an infected dam to her offspring and other lambs or kids exposed to the birth fluids, placenta, or bedding soiled by the birth fluids.
It can take several years for an infected sheep or goat to show signs such as the following:
· subtle changes in behavior or temperament;
· intense, frequent rubbing against objects to relieve itching;
· gait abnormalities—incoordination, stumbling, high stepping of forelegs, hopping like a rabbit, and swaying of
the back end;
· weight loss despite a normal appetite;
· weakness—difficulty getting up or falling down;
· biting at legs and feet;
· lip smacking; or
· normal behavior at rest, but if stimulated with sudden noises or excessive movement, trembling or falling down.
After the onset of clinical signs, death occurs within a few weeks to several months.
Live animal testing for Scrapie is difficult and at best 87% accurate in finding positive animals. Testing is performed on biopsies of lymphoid tissue from the third eyelid or rectal mucosa. The procedure requires topical anesthetic, restraint, and light sedation to collect the tissue. The most accurate and reliable Scrapie testing is done on brain tissue of dead animals.
In 2001 the U.S. Department of Agriculture (USDA) initiated an accelerated program to eradicate Scrapie from the nation’s sheep flocks and goat herds. The National Scrapie Eradication Program (NSEP) coordinated by the USDA is a joint effort that includes participation by state governments and industry.
NSEP has reduced the prevalence of Scrapie by over 85%, but to find and eliminate the last few cases, greater awareness, cooperation and compliance with state and federal regulations by sheep and goat producers and livestock dealers is essential.
Producers can contribute significantly to the success of the NSEP through the following:
1. officially identifying their sheep and goats according to state and federal regulations;
2. complying with movement requirements for import permits and health certificates;
3. reporting suspect sheep and goats to a state, federal, or accredited veterinarian;
4. using the diagnostic services available at the Connecticut Veterinary Medical Diagnostic Laboratory at the University of Connecticut’s Storrs campus to determine causes of animal mortality; and
5. participating in the Connecticut Department of Agriculture Scrapie Surveillance Program.
Mandatory identification requirements enable trace-back of Scrapie infected animals to their flock/herd of origin.
Since September 5, 2007, Connecticut sheep and goats moving interstate, intrastate, and to any shows/exhibitions are required to be officially identified. All sheep, lambs, goats, and kids within the state require official identification to move off the farm. Connecticut sheep and goat owners are also required to maintain identification and change-of-ownership records on their animals for five years.
USDA has approved several methods of identification. They are premises (location) based and producer applied. Producers can use official USDA ear tags or approved breed-registry tattoos (with current registration papers) for official identification. Ear tags, tattoos, or microchips used by producers on the Voluntary Scrapie Flock Certification Program are also acceptable.
Whichever method is used, identification records must be maintained by the producers for five years. For an example of a producer identification record, see http://www.ct.gov/doag/lib/doag/pdf/scrapieproducer1.pdf.
USDA is providing plastic or metal ear tags in lots of 20 or 100, with an applicator, at no charge, and the option to order custom tags from an approved manufacturer at the owner’s expense.
Connecticut sheep and goat producers can obtain their premises identification numbers and order their free tags and applicators through the office of the Connecticut State Veterinarian by phone (860-713-2505), or by written application (see http://www.ct.gov/doag/lib/doag/pdf/scrapietag.pdf), returned by mail or fax (860-713-2548). Tags will be shipped directly to the producer from the manufacturer and will take three to four weeks to arrive.
Connecticut accredited veterinarians working with sheep and goats will also have USDA tags assigned to them to use in small hobby flocks or herds that do not have a premises identification number, approved-breed registry tattoos (with current registration papers), or other acceptable identification and that require official identification for health certificates and/or interstate movement.
The producer should make his veterinarian aware prior to the farm visit that his animals will need official USDA tags, so that the veterinarian will have the correct ear tags on hand.
We encourage all producers with sheep and/or goats to examine the options available to them, to choose the best one for their operation, and to follow through, so when enforcement occurs at livestock venues they will be in compliance.
Sheep and goats moving across state lines and to fairs and shows require health certificates written by a licensed and accredited veterinarian. An import permit is also required to bring animals into the state. Call 860-713-2504 for import permits and travel requirements prior to moving any animals.
Producers should report any suspicious diseases and high animal-mortality events to the Connecticut State Veterinarian at
860-713-2505, or to the USDA’s APHIS Veterinary Services, New England Area Veterinarian-in-Charge at 508-363-2290, and should call their local accredited veterinarian for diagnosis and treatment assistance.
Animal disease diagnostic services are also available at the Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL). With financial support from the Connecticut Department of Agriculture and USDA’s APHIS Veterinary Services, CVMDL is able to offer subsidized necropsy services for sheep and goats 14 months of age and older as part of the Connecticut Scrapie Surveillance Program.
Currently, the program will pay the first $100 of the total service cost and the animal owner is responsible for the remainder. Funds are available through March 2013 or until exhausted. If strong producer participation continues as in previous years, additional funds may be available for 2013-2014.
The CVMDL courier service is available during the work week to transport animals to the laboratory from any town in Connecticut. For questions on the program parameters and for courier service appointments, please contact the laboratory at 860-486-3738.
For more information about Scrapie disease, fact sheets, brochures, video clips, and all the aspects of the National Scrapie Eradication Program, see www.aphis.usda.gov/animal_health/animal_diseases/scrapie/.
For Connecticut Department of Agriculture information, state regulations, ordering ear tags, and record sheets, see http://www.ct.gov/doag/cwp/view.asp?a=1367&q=259122&doagPNavCtr=|44678|#44684.