What is Scrapie?

What is scrapie?

Scrapie is a fatal, degenerative disease that affects the nervous systems of sheep and goats. Scrapie is slow to develop, usually takes more than a year and a half for clinical signs to appear in an infected animal, although it has been known to take up to eight years to develop. Typically, cases occur in animals between two and five years of age. Symptoms include apprehension, tremors, incoordination or abnormal gaits, extreme weight loss and poor wool coat. Once an animal appears ill it will generally die in one to two months.

While the exact cause of scrapie is not certain, the disease is associated with the presence of an abnormal form of a protein called a prion. A sheep with a QQ genotype is believed to be more susceptible to scrapie if it is exposed to the disease, but could not develop scrapie without becoming in contact with the disease, and even then may not (see below re birthing).

Scrapie is typically spread through fluid and tissue from the placentas of infected females. It can be transmitted from an infected female to her offspring at birth, or to other animals exposed to the same birth environment. Males can contract scrapie, but they do not transmit the disease to other animals. So why did CFIA kill all the Wholearth rams?

Is scrapie a human health risk?

NO. According to Health Canada, scrapie is not a human health risk.

Did any of the Shropshire sheep test positive for scrapie when CFIA did a live test?

NO. All were found negative for scrapie in the live rectal biopsy tissue testing which has 88% accuracy. Repeated testing would have raised the percentile. Even the dead testing of the brain obex is not 100% accurate.

Have any Wholearth Shropshire sheep ever shown symptoms or signs of scrapie?

NO. Symptoms include apprehension, tremors, incoordination or abnormal gaits, extreme weight loss and poor wool coat. Once an animal appears ill it will generally die in one to two months. The Wholearth flock did not exhibit any symptoms whatsoever.

How long  does the average sheep in the Wholearth flock live for?

Most commercial sheep live about 6 or 7 years until they are culled. Heritage Shropshires are known for their longevity and many of the Wholearth ewes have lived to 10, 11, 12 years of age while still producing healthy lambs. The original foundation Miller ram lived to be 14 years of age and even sired 12 healthy lambs that year. He was healthy, had all his teeth, was eating well, became arthritic in his front legs so he was euthanized in a quiet ceremony in April 2010 and buried in a hilltop plot overlooking his flock and pasture.

The Alberta sheep Wholearth Alder WHE24S that tested positive was born at the Wholearth farm five years ago. Is it possible that sheep contracted the disease from another source, enroute to Alberta or at the Alberta farm?

Yes.  CFIA has thus far been unable to determine how the sheep in the Alberta case was infected and have decided that since they do not know they determined to destroy all the QQ genotype sheep in the Wholearth flock, despite the absence of any signs of scrapie in the flock, and despite the fact that all have live tested negative.

** Wholearth Alder WHE24S ewe gave birth to two lambs . How come both of them tested negative for scrapie?

CFIA has indicated to us that they believe scrapie is passed on to the offspring by an infected via birthing (but not necessarily). They also state that a QQ genotype is susceptible so it would be almost certain that a QQ offpspring of an infected scrapie positive mother such as WHE 24S ewe would pass scrapie on to one or both of her offpspring lambs PDN84W ( ARQ/ARQ) and PDN96U (ARR/ARQ) .  However, CFIA reported that both of the offspring  tested negative.  How is this possible? This raises even more questions surrounding the possible misidentification of WHE 24S or the possiblility she contracted it on the Alberta farm after birthing.

 

If you have any questions about this case please email us and we will post here.