Sore mouth disease has recently been observed in Yellowstone National Park’s bighorn sheep population.
In particular, it’s been observed in the park’s bighorn ram population.
According to a Yellowstone press release, sore mouth, also called contagious ecthyma, is caused by the parapoxvirus. As such, it is transmittable people to people through contact.
If you see a bighorn sheep with sore mouth disease, do not approach it. In fact, don’t approach bighorn sheep at all; park rules mandate you stay at least 25 yards away from wildlife like sheep, deer, and elk. From the press release:
Sore mouth disease is common in farmed sheep and goats and widespread in wild bighorn sheep in the Rocky Mountains from Alaska to California. Typically spread from ewes to lambs, the disease can manifest itself as scabby sores around the mouth and face. Lesions disappear in 2-4 weeks and animals typically heal without scarring. Generally, affected animals recover but deaths can occur in severe outbreaks, especially with young animals who cannot feed. The virus has the greatest effect on lambs that refuse to nurse because of sore mouths.
According to Yellowstone officials, only breeding age rams seem to be affected, although it’s possible they contracted the virus from ewes during breeding season. Male rams typically live in “bachelor herds” of two to five.
Yellowstone biologists will continue to monitor the situation and its impact on the bighorn sheep population.