"Most populations of Dall sheep, mountain goat and musk ox in Alaska have never been exposed to the infectious diseases and parasites of domestic animals," said Wildlife Veterinarian Dr. Kimberlee Beckmen. "They will likely have little resistance if exposed to domestic animal diseases."
Domestic goats are known to have exposed wild sheep to diseases and parasites in other states. In Arizona, for example, domestic goats introduced a virus that caused blindness as well as contagious ecthyma to a desert bighorn sheep herd that led to deaths and a decline in the population. In other cases, the introduction of domestic animal diseases has resulted in the loss of entire wild populations of sheep.
"Domestic animals are not intended to interact with wildlife species. They are fenced and intensively managed for food and fiber production," said Dr. Bob Gerlach, state veterinarian. "Domestic animals, especially sheep and goats, are adapted to several diseases and usually appear healthy even when they are carrying infections that can be deadly to wildlife."
Diseases can be passed though feces, urine, saliva, respiratory aerosol or exudates like crusts from skin or pus. These tissues, fluids or excrement can contaminate the environment and still remain infective for years.
"Domestic animal diseases could become introduced to Dall sheep and established before we even detect the introduction," Beckmen said. "This could lead to population declines and would be extremely difficult, if not impossible to eradicate."
Llamas and goats can be carriers of Johne's disease, as well as contagious ecthyma. Contagious ecthyma can be transmitted to humans and is then called "Orf." Llamas may have just one or two tiny scabs in the nose, but in Dall sheep it causes severe lesions all over the face. In musk ox calves it is highly fatal and killed almost all the wild musk ox calves in an entire calf cohort in Norway last year. Contagious ecthyma can also be very serious or even fatal to Dall sheep lambs.
The best approach is to prevent the introduction of diseases and parasites of domestic goats, sheep, or llamas into habitat used by Dall sheep or musk ox, Beckmen said. The use of goats or llamas as pack animals on Dall sheep hunts presents a significant risk to wild populations. By using llamas and domestic goats in Dall sheep habitat, guides may be jeopardizing the very resource they depend on for a livelihood.