Soremouth Virus Affects Sheep and Humans

Sheep producers need to monitor their flocks for soremouth, a highly contagious viral infection in sheep and humans, North Dakota State University Extension Service sheep specialist Reid Redden says.

Soremouth, also known as contagious ecthyma or orf, is quite common in sheep and goats. It is a member of the pox group of viruses and can survive in the environment for years.

“As the sheep industry is trying to expand with record prices, I expect that we will see some new producers who do not know about the risks of this common disease,” Redden says. “Plus, our medical community needs to be aware of the likelihood of this disease affecting humans.”

Outbreaks of the disease normally affect young lambs that have not been exposed to the virus. Once soremouth breaks out in a flock, most all previously unexposed animals contract the disease, especially when they are fed long-stem or chopped hay in confinement.

Soremouth first appears as small red nodules, which develop into larger blisters and finally form into large brown scabs. These scabs eventually will fall off and the animal will heal without any noticeable scarring. Thereafter, the animal will have lifetime immunity, Redden says.

Humans can contract the disease if they come into contact with infected animals or the vaccine. An abrasion on the hand is the most common way the virus can get into a human body. Infected humans can develop very painful lesions that may last from three to six weeks.

To avoid introducing the virus into a flock, producers should not buy animals with lesions on their nose and mouth, and they should quarantine any newly purchased animals for two weeks.

Shepherds may choose to remove the scabs from their infected animals manually and treat with a mild antiseptic to accelerate the healing process, especially in cases in which the infection is so severe that it restricts the animal’s ability to eat and drink.

Effective vaccines producing long-lasting immunity are available, according to NDSU Extension veterinarian Charlie Stoltenow. However, the vaccines contain a fully virulent soremouth virus. The use of the vaccine introduces the virus to the environment, and vaccinations will need to be continued annually.

Stoltenow recommends that people who handle infected animals or the vaccine wear gloves and wash their hands immediately after handling affected sheep or the vaccine. People also should consult a physician if suspicious lesions develop.

NDSU Agriculture Communication - Oct. 25, 2011