Sore Mouth in Goats
Back From the Vet March/April 2019
Reading Time: 3 minutes
Kidding time can be very stressful. In addition to the complications of birth, ensuring that kids are healthy and growing is an arduous task. Young kids are particularly susceptible to a condition called sore mouth. As indicated by the name, affected kids have sores primarily on their mouths.
Sore mouth, orf, or more formally contagious ecthyma, is a viral infection found around the world that occurs in both goats and sheep. It can also occasionally affect other ruminants. The parapoxvirus is very resistant to disinfectants and can survive in the environment for as long as 12 years. The virus causes more severe disease in goats than in sheep. In naive herds, the virus can infect both adult animals and young kids. Once an animal recovers from the infection they are highly resistant to reinfection for the rest of their life.
The infection causes papules which become pustular and burst. The end results are areas of large scabs with proliferative skin tissue under them. These papules begin primarily near the mouth, at the meeting of skin and mucosal tissue, or mucocutaneous junction. Lesions can also occur on the feet near the hooves and on the udders of does nursing infected kids. The infection generally lasts from one to four weeks. More severely infected kids will exhibit decreased feed intake and poor thrift. Those with hoof lesions may experience lameness. Does with udder sores may develop mastitis. Untreated infections may also result in secondary bacterial infections causing more severe disease. There are several diseases that can cause similar clinical signs to sore mouth, including foot and mouth disease, bluetongue, and ulcerative dermatosis of sheep. Contagious ecthyma is most commonly diagnosed via clinical signs, although there are laboratory tests that can be performed to confirm the diagnosis if there is doubt.
The virus is shed in the crust and scab material from infected animals. As mentioned before, it can survive in the environment for years. Any contact of animals, even just nose to nose, can allow for disease transmission. The virus enters the system through damaged skin — cuts or scrapes. Animals eating a rough diet, such as brushes and shrubs, may be more susceptible to infection. It is very difficult to completely eliminate the virus from infected premises.
Contagious ecthyma is also a zoonotic disease. Humans in contact with infected animals may develop similar skin lesions to the animals. In people, the infection is called orf. The lesions appear most commonly on the hands and arms. People may also experience fever and swollen lymph nodes. Most lesions heal spontaneously within a week or so if properly treated, not even leaving scar tissue. Those experiencing such signs should still seek medical attention, as there are several zoonotic conditions that can cause similar signs but have a more severe prognosis, such as anthrax. Animals may spread the virus even when they are not showing clinical signs. It is important for those working with animals, especially in herds known to be affected with sore mouth, to practice good hygiene. Disposable gloves and frequent hand washing are key to infection prevention.
There is no treatment for the viral infection itself in animals. Most infections will be self-limiting and resolve within one to four weeks. The application of softening or antibacterial ointments to the affected areas may help increase feed intake and decrease discomfort. Offering more palatable feeds, such as soft grains, may also help to maximize intake. Animals affected during fly season should be managed carefully to prevent larval infestations in the wounds and transmission of the virus by insects. Animals with secondary bacterial infections may require topical or even systemic antibiotics to facilitate healing. As the virus can be easily spread in the environment, it is important to clean facilities frequently, especially at kidding. Care should be taken to thoroughly disinfect all feeding and water troughs as well as pens. Animals showing signs of the disease should be kept separate from those who are not exhibiting signs. Infected milking nannies should be milked last, and the equipment thoroughly disinfected.
There is a vaccination for contagious ecthyma. The vaccine is a modified live virus vaccine that is scratched into the bare skin on the inner thigh or elbow. The vaccine is seen to be effective if there are pustules forming at the vaccine site a week later. Because the vaccine is a live virus, it should not be used on non-contaminated premises. In affected herds, the vaccine should be used in kids roughly 1 month of age, and repeated in 2-3 months. If animals are to enter affected premises, such as some feedlots, they should be vaccinated 1-2 months prior. When establishing a vaccine protocol for your herd, it is important to consult with your veterinarian.
Although sore mouth is not a disease that causes many deaths, it can have a very high economic impact due to loss of gain in growing animals. Appropriate management is imperative to minimize these losses. Recognizing infection early and implementing appropriate hygiene methods is also necessary to prevent transmission to humans. If animals in your herd begin to show signs of sore mouth, please contact your veterinarian.
Katie Estill, DVM is a veterinarian consultant for Goat Journal, Countryside & Small Stock Journal, and Countryside Network. She works with goats and other large livestock at Desert Trails Veterinary Services in Winnemucca, Nevada.