Contagious Ecthyma (Orf) Transmissable To Humans
Causative Agent
  • A viral disease of sheep and goats (wild and domestic) caused by infection with the parapoxvirus or orf virus.
  • Disease is also referred to as soremouth.
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Contagious Ecthyma
Typical signs of contagious ecthyma include extensive scabbing of the face and lips.
  • Present in areas of southern BC in some populations of bighorn sheep (Ovis canadensis) and mountain goats (Oreamnos americanus).
  • Usually reported during the rut when these species are in more close association, and during the winter when these animals are using road salt or salt blocks. Contagious ecthyma also is likely to be reported during the hunting season when humans see animals more closely.
Hosts, Transmission and Life Cycle
  • Contagious ecthyma may be more likely to be transmitted to wildlife when there is contact with domestic sheep and goats.
  • It is considered to be endemic in some populations of bighorn sheep and mountain goats in BC.
  • Experimental infections in moose (Alces alces), white-tailed deer (Odocoileus virginianus), and elk (Cervus canadensis) showed that the effects were mild. Not observed in these species in the wild.
  • Likely following a similar pattern in domestic animals, transmission occurs as a result of direct contact with infected animals or when cuts and abrasions are in contact with contaminated objects, such as salt blocks.
  • The virus can survive outside of the host for extended periods, perhaps years. Scab material lying in places of habitual use may serve as recurring reservoirs of infection.
Life Cycle:
  • Presence of contagious ecthyma in bighorn sheep and mountain goats most likely is the result of transmission of orf virus from domestic sheep or goats.
Signs and Symptoms
  • Animals may appear restless, nervous and show excessive licking of the lips and nostrils, and scratching of the head.
  • Scabby lesions associated with this disease are most commonly found on the lips, skin of the face, udder, within the mouth and above the hooves.
  • Lesions range in size from tiny crusts to large merging scabs that may cover the lips.
  • If mouth lesions are severe enough, animals will not feed; lameness may ensue due to lesions on the feet in young animals. Both scenarios may lead to loss of condition or death by starvation.
  • Generally, affected animals recover uneventfully; however, in severe outbreaks, death may occur in younger animals.
  • Initial scabs form 7 days after infection followed by a 10 day cycle of pustules to scabs.
  • After 3 weeks, lesions begin to subside and typically do not scar.
  • Short-term immunity (up to 5 months) is thought to occur following an infection.
Meat Edible?
  • Meat from an infected animal is suitable for consumption; however, trim off affected parts.
  • Meat from severely affected animals may be of inferior quality due to the poor condition of the animal.
Human Health Concerns and Risk Reduction
  • Orf, or contagious ecthyma, is a zoonosis and, as such, appropriate precautions should be taken when handling an animal suspected of having this disease.
  • Orf is an occupational hazard of those who handle domestic goats and sheep.
  • In humans, lesions similar to those in animals, including swollen/painful lymph nodes and mild fever, may occur. Skin lesions usually subside within 6 weeks without scarring. Most likely to be contracted by humans during the hunting season when hunters are in direct contact with infected animals.
Samples for Diagnosis
  • Scabs and the tissue immediately surrounding the scabs.
Further Reading
  • Alaska Department of Fish and Game – Contagious Ecthyma
  • BC Ministry of Environment Wildlife Health Fact Sheet – Contagious Ecthyma (PDF file)
  • Elkin B., Zamke R.L. 2001. Common Wildlife Diseases and Parasites in Alaska. Alaska Department of Fish and Game. Anchorage, AK.
  • Robinson A.J., Kerr P.J. 2001. Poxvirus infections. Pp. 179-201 in E.S. Williams, I.K. Barker (eds.), Infectious Diseases of Wild Mammals. 3rd Ed. Iowa State University Press. Ames, IA.
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