Just like children and adults who contract the dreaded chicken pox, sheep and goats can catch their own "pox" virus. The ORF (Contagious pustular dermatitis virus) is a member of the parapoxvirus genus in the Poxvirus family It is commonly known as "Sore Mouth" or "Scabby Mouth" by shepherds, but is technically known as Contagious Ecthyma.
How is it transmitted?
The Sore Mouth virus can harbor in pastures, barns, and feed surfaces for months. Or it can be passed from animal to animal thru old scabs containing the virus. Open sores or scratches on the skin are prime entrance points for the virus to enter the host. These oral abrasions are often caused by eating rough forage.
What are the Symptoms?
It is most recognizable by the red blisters or thick brown scabs on the skin around the lips or muzzle area. Similar to chicken pox, the sheep or goat will only become immune to that particular strain of virus for the remainder of it's life. They can become reinfected with a different virus strain of ORF, but repeat infections usually occur after a year’s time and are generally less severe.
All breeds of sheep and goats can contract ORF and it is can be found in farms worldwide.
It takes approximately 3 days from initial contact with another sheep or goat with Sore
Mouth before red spots form, then turn into blisters, and then eventually scab over as they heal (17-21 days after initial appearance). Lesions occur primarily on the lips and nostrils of affected animals, but may also develop on other parts of the body: e.g. ears, eyes, feet, limbs, udder, genital areas, and any non-wooly areas.
Sore Mouth is a zoonotic disease, which means it can be transferred to humans so always wear gloves and wash your hands afterwards. It is not transferable from human to human though. Sore Mouth in humans looks like a blister or boil on the skin. Consult with a physician for monitoring of symptoms.
What are the complications of Sore Mouth?
Mouth sores can be painful, especially when eating. In severe causes, sheep will refuse to eat due to the pain. Also, nursing lambs or kids can spread the virus to an ewe's udder which in turn will cause soreness and blisters on the teats. This in turn leads the ewe to refuse the lambs to nurse which in turn leads to lamb starvation and possible mastitis.
What kind of treatments are available?
Because it is a virus, soremouth does not respond to antibiotics. Nor is it usually necessary to treat the lesions unless secondary bacterial infection or maggot infestation occurs.
It is recommended that the crusts not be removed, as this may delay healing, promote scarring, and increase the handler's chance of acquiring the disease. Ewes and does whose udders become infected should receive special care. An udder salve will help to keep the scabs on the teats pliable.
How do you manage Sore Mouth in your flock?
There are vaccines available. As the vaccine is a live virus, precautions must be taken by whomever is administering the vaccine to not contract the virus themselves. Unfortunately, the vaccine does not produce a strong or long-lasting immunity. Vaccination may not always prevent animals from becoming infected, but it may reduce the severity or duration of the disease
Purchased animals should be quarantined to allow any symptoms of Sore Mouth to appear and infect your flock with a possible new strain of Sore Mouth. Unfortunately, some animals can serve as carriers and slip into a flock without detection.
Soremouth can be spread via infected equipment, fences, feed, and bedding. Serious outbreaks can occur in artificially-reared lambs and kids, as they share the same nipples.
The ORF virus can survive for months, possibly years, away from the sheep. Scabs on pasture are not likely to survive the winter, but may survive in barns, pens, and on troughs, feeders, gates, and walls. The virus contain in dried scabs can be infectious for years if maintained in a cool, dry environment.
If you think you have ORF in your flock, consult with your veterinarian to rule out several other diseases (some serious and reportable) whose symptoms may resemble soremouth (foot-and-mouth disease (FMD), sheep and goat pox, and bluetongue)