Scrapie

What are those little metal tags my sheep and goats wear from the time they are a few days old?  Those are identification tags that are part of the USDA Scrapie Eradication Program.  When I first learned about it, my veterinarian required I have my animals tagged prior to drawing labs that allowed me to sell milk.  If this disease has drawn that much interest in monitoring, I was curious to learn more.  I am in no way a scrapie expert, but there is a little of what I learned.

First of all, I believe the name comes from a commonly exhibited clinical sign of infection, which entails compulsive scraping on things in their environment to the point of losing hair and wool.  My animals like to rub, but this is beyond that.  It is suspected the disease gives the afflicted an itching sensation.  They also smack their lips excessively (especially if rubbed on the right spot of their rump), walk differently, and will suddenly collapse.  Advanced symptoms include weight loss, going off feed, lethargy, and death.

Scrapie is a transmissible spongiform encelphalopathy (related to mad cow disease and chronic wasting in deer).  It is not a virus or bacteria, but a prion, which is a type of protein.  So far, it does not appear transmissible to humans, but its transmission among sheep and goats is poorly understood.  It is possible that they can survive in the environment for decades, so a previously clean flock or herd and seem to spontaneously get sick.  Positive diagnosis of a carcass occurs when an accumulation of the prions are identified in the central nervous system.

Because of the contagious nature of the disease, sheep or goats can be introduced into a new flock or herd and spread the disease after a reasonable quarantine waiting period.  The ear tags we place in our animals are supposed to remain their and are part of a surveillance program.  If there is a case of scrapie that shows up on a farm, the tags assist in tracing the animals back to farms of origin and other possible exposed animals.  This helps prevent or limit the impact of an outbreak.

​If keeping sheep or goats, I recommend knowing about scrapie.  Odds are you'll never see it.  There is no cost-effective test or vaccine, so knowing what to watch for may mean saving your animals that aren't affected.