Educational Tips for Farmers: Sore Mouth in Small Ruminants

Sore Mouth

• Known as the orf virus, sore mouth is a parapoxvirus.
• Sore mouth is zoonotic, which means humans can contract the disease. Wear gloves to check animals suspected to have sore mouth.

Symptoms

• Signs and symptoms include scabby lesions (sores) around the lips and muzzle and in the mouth.
• Nursing mothers can also get lesions on their legs and teats from infected lambs or kids.
• The lesions can last 1 to 2 weeks.
• Lambs and kids are generally more susceptible than adults.
• Signs in humans include lesions or nodules on the hands.

Diagnosis

• Diagnosis is typically from clinical signs but can be confirmed in a laboratory by identifying the virus in a tissue or blood sample.
• Foot and mouth disease, sheep and goat pox, and bluetongue have signs that may resemble sore mouth, so consult with a veterinarian for differential diagnosis.

Transmission

• Sore mouth can be transmitted by direct contact, like muzzle-to-muzzle or muzzle-to-skin.
• Orf virus is very hardy in the scab material and can be viable for months and sometimes even years.
• The virus can be spread through feed, feed troughs, bedding, and even buildings. This makes containment extremely difficult.
• People can also contract this disease from contact with infected animals, especially if they have any open lesions or sores on their hands.

Treatment

• There is no treatment for this virus; the disease must run its course.
• Antibiotics are useful for preventing secondary bacterial infections in severe cases, but these don’t treat the virus itself. Broad-spectrum antibiotic ointment is often applied to the affected areas, but this treatment has little effect on the course of the disease.
• Quarantine affected animals from the herd to slow the spread of the virus.
• Clean the lesions with iodine or chlorohexidine to prevent a secondary bacterial infection.

Prevention

• Sore mouth can be prevented through a live virus vaccination.
• The vaccination is performed by scratching an area without hair or wool and painting the vaccine in the area.
• The vaccine can cause the disease in humans, so caution is advised.
• The vaccine is recommended when introducing new animals to the herd.

Biosecurity

• It is important to purchase new animals from known sources.
• Purchase animals that do not have sore mouth to prevent introducing the disease into your flock/herd.
• Make sure to quarantine new animals for at least 14 days with no nose-to-nose or fenceline contact with the rest of the herd.
• When handling the quarantined animals, it is vital to completely disinfect all clothes, shoes, equipment, etc., before handling the rest of the herd.

M2500 (POD-03-26)

By Kelsey Mazeres, Graduate Student, Animal and Dairy Sciences, and Research Associate, White Sands Beef Unit; Leyla Rios, PhD, Assistant Professor, Animal and Dairy Sciences; and Isaac Jumper, DVM, Assistant Professor, College of Veterinary Medicine.