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Conservation > Fish & Wildlife Diseases Contagious ecthyma

For questions/concerns about this disease in humans, please call your doctor or the Montana Department of Public Health and Human Services  (DPHHS).


For questions about this disease/parasite in wildlife, please call the FWP Wildlife Health Lab at 406-577-7882.


Contagious ecthyma is caused by a large double stranded DNA virus that is a member of the parapox group of viruses (Adrian, 1981).


Contagious ecthyma (CE) is found worldwide wherever sheep and goat species are concentrated in large numbers (Adrian, 1981). CE is usually reported during the rut when these species are in close association and during the winter when they are using road salt or salt blocks. CE is also likely to be reported during the hunting season when humans see animals more closely (Miller et al, 2003).

Species affected

Contagious ecthyma affects domestic and wild sheep and goats as well as humans (Adrian, 1981). The disease is endemic in some populations of bighorn sheep and mountain goats. Experimental infection has been observed in moose, white-tailed deer, and elk but the effects were considered mild. The disease not appear to affect these species in the wild (Miller et al, 2003). Young animals are more likely to be affected and may have difficulty nursing (Stitt, 2011).


Transmission occurs as a result of direct contact with infected animals or from cuts and abrasions that contaminated objects such as salt blocks. The virus can survive outside of the host for extended periods. Contagious ecthyma virus is highly resistant to normal environmental extremes and has been known to survive in scab material for over 20 years. Scab material lying in places of habitual use may serve as recurring “reservoirs of infection” (Miller et al, 2003).


Clinical contagious ecthyma (CE) is characterized by proliferative, cauliflower-like, scab covered areas of the lips, nostrils, eyelids, and coronary bands above the hooves. Lesions easily bleed when the scab is disturbed or removed. Occasionally lesions are found on the teats, udder and exposed genitalia. Lesions range in size from tiny crusts to large merging scabs that may cover the lips. Within the mouth, cauliflower shaped growths may be present around the incisor teeth and scattered over the hard palate. If mouth lesions are severe enough, animals will not feed and lameness may ensue due to lesions on the foot. In bighorn sheep, ulceration and abscess formation of the tongue has been seen (Lance et al., 1981). Lesions of the eyelids may produce blindness through dried scab material producing mechanical damage to the cornea (Stitt, 2011; Adrian, 1981). Painful lesions around the mouth of lambs, or around the teats of the ewe may prevent nursing and lead to loss of condition or death from starvation. Animals may appear restless or nervous, or may excessively lick their lips and nostrils and scratch the head. Affected animals usually recover uneventfully; however, bighorn sheep sometimes develop a severe clinical form of disease, and in severe outbreaks, death may occur in younger animals.

Scabs typically develop about 7 days after infection. Lesions generally persist for 3-5 weeks and heal leaving de-pigmented areas around the mouth and muzzle. These areas persist for at least 6 months and can be used as a field aid to determine whether or not CE has been present in a band of sheep (Adrian, 1981). Short-term immunity (up to 5 months) is thought to occur following an infection (Miller et al, 2003).

Public Health Concerns

he contagious ecthyma (CE) virus is transmissible to man and produces a locally painful, persistent skin condition known as Orf (Adrian, 1981). Orf is an occupational hazard of those who handle domestic and wild goats and sheep. CE may also be contracted by hunters during the hunting season when they come into direct contact with lesions of infected animals. Skin lesions usually subside within 6 weeks without scarring. Appropriate precautions should be taken when handling an animal suspected of having CE (Miller et al, 2003). Wear gloves, practice good hygiene, trim away affected tissue, and avoid contact between affected tissue and edible meat (Stitt, 2011).

Is it safe to eat the meat?

Meat from an infected animal is suitable for consumption, however, trim off affected parts (Miller et al, 2003). If you harvest an animal and are unsure whether it is safe to eat, contact your local FWP staff for guidance soon after the animal is harvested.


Adrian, W.J., editor. 1981. Manual of Common Wildlife Diseases in Colorado. Denver: Colorado Division of Wildlife.

Lance W, Adrian W, Widhalm B. An epizootic of contagious ecthyma in rocky mountain bighorn sheep in Colorado. J Wildl Dis. 1981 Oct;17(4):601–603. [PubMed]

Miller, M.J.R., R.D. Dawson, and H. Schwantje. 2003. Manual of Common Diseases and Parasites of Wildlife in Northern British Columbia. University of Northern British Columbia.

Stitt, Tyler. 2011. Diseases You Can Get From Wildlife - A Field-guide for Hunters, Trappers, Anglers and Biologists. British Columbia Ministry of the Environment.