Sheep and goat producers advised to watch for scrapie disease signs

By MANDY JOHN | Central Texas Edition

Dr. Jody Hall of the Texas Animal Health Commission addresses how scrapie disease is transmitted. Hall was a featured speaker at the Fall-Limestone County Meat Goat Production Seminar in Marlin last week. -Staff photo by Mandy John

August 8, 2002 -- Farmers today have a lot of things to consider when it comes to the safety and health of their sheep and goats. These things include the size of the pen these animals will be placed in, how much feed they are given, and how to keep them safe from diseases. One of the most deadly diseases a farmer must watch for is scrapie.

Scrapie is a fatal, degenerative disease affecting the central nervous system of sheep and goats. There is no cure and there is no treatment. This disease became known as scrapie because individual sheep or goats that had it would often rub on objects and scrape off their wool or hair.

The first case of scrapie in the United States was diagnosed in 1947 in a Michigan flock. From this first case through today, it has been diagnosed in about 1,600 sheep and goats.

"Scrapie is thought to be spread most commonly from the ewe to her offspring through contact with the placenta and placental fluids", stated Dr. Jody Hall of the Texas Animal Health Commission. Hall spoke July 31, 2002 during the Fall-Limestone County Meat Goat Production Seminar held in Marlin.

Signs of the disease vary widely among individual animals and develop very slowly. Due to damage to nerve cells, affected animals usually show behavioral changes. 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. Signs or effects ususally appear two to five months after the animal is infected but may be longer. Sheep may live one to six months or longer after the onset of the clinical signs, but death is inevitable.

Scrapie research efforts are currently focused on developing a practical live animal test to diagnose infected sheep before they show signs, investigating transmissibility, identifying scrapies 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 scrapie. Research studies using experimentally infected sheep suggest that embryos may play a role in the spread of scrapie.

The United States Department of Agriculture (USDA) has initiated an accelerated scrapie eradication program. The program is based on the following key concepts:

• The ability to detect pre-clinical sheep through live animal testing and active slaughter surveillance.

• The ability to trace infected animals to their flock/herd of origin as a result of the new identification requirements.

• Providing effective clean-up strategies that will allow producers to stay in business, preserve breeding stock, and remain economically viable. USDA will do this by providing the following to exposed and infected flocks/herd that participate in cleanup plans:

- Indemnity for high risk, suspect, and scrapie positive sheep and goats , which owners agree to destroy,

- Live-animal testing, and

- Genetic testing,

• Testing of exposed animals that have been sold out of infected and source flocks/herds.

The key requirements of the new program are that most breeding animals and all sheep 18 months of age and older be officially identified in order to be moved in interstate commerce and that states meet minimum standards for state scrapie control in order to move breeding sheep and goats freely, interstate.

Animals that need to have the required official scrapie ID prior to leaving the farmer's premises are:

* All breeding sheep

* All sheep over 18 months of age

* All scrapie exposed, suspect, test positive and high-risk animals

* Breeding goats excet low-risk commercial goats

* Animals for exhibition

Goats are included in the program because infected goats must be traceable in order to identify exposed, infected or source herds and to provide indemnity to affected goat producers.

A registration tattoo can be used in place of the official scrapie ID tags when the animal is accompanied by its registration paper or a photocopy or a completed application for registration.

Current information on scrapie is also available on the Internet at USDA's official scrapie Website, www.aphis.usda.gov/vs/scrapie.htm. To get official identification tags and/or more information, simply call 1-866-873-2824. That number will put you in touch with animal health officials in your state who are responsible for the scrapie eradication program.