In light of the recent cases reported in southern Arizona, the following is a basic overview of the viral disease Vesicular Stomatitis. In the United States this virus generally occurs in the Southwestern and Western states with a wide variation in number of cases that occur and locations that are affected each year. It can also occur in Central and South America. In 2014 there were cases reported in the states of TX, CO, and NE. In Arizona the last outbreak was reported in 2010.
Appearance of the virus often occurs during warmer months and its spread is not fully understood. Factors that have been identified in the spread of the virus include: insect vectors (e.g. flies), mechanical transmission, and movement of exposed/affected animals. Spread between animals occurs with contact or exposure to saliva of infected animals and/or fluid from ruptured vesicles.
Animal affected include horses, cattle, as well as occasionally swine, sheep, goats, llamas, and alpacas. Horses tend to be the most sensitive and severely affected, but there can be great economic loss for dairy cattle due to lesions of the teat and secondary infection of the udder (i.e. mastitis). The incubation period ranges from 2 to 8 days. The disease is characterized by blister-like lesions that can occur in the mouth (i.e. tongue, gums, lips, dental pad, etc), coronary band/foot, vulva, prepuce, and teats/udder. Fever can also occur immediately proceeding or at the time of lesions first appearance.
In the horse specifically lesions usually occur on the tongue, lips, around the nostrils, corners of the mouth, gums, as well as coronet band and ventral abdomen. Most animals recover in approximately 2 weeks unless secondary infection occurs.
In rare cases humans can be infected with the disease. Symptoms of illness include fever, muscle aches, headache, and malaise similar to influenza. Most cases of infection are associated with the handling of infected animals and protective clothing, gloves, and hygiene should be used to protect oneself.
There is no cure or vaccination for Vesicular Stomatitis only supportive care for affected animals. In cases of confirmed outbreaks measures are taken to contain the infection and stop the spread. These include:
Separation of animals with lesions from healthy animals
Halting of any movement of animals from affected premises at least 21 days AFTER lesions in the last affected animals have healed.
On-farm insect control programs such as eliminate/reduce insect breeding areas and use of insecticide sprays (for premises and animals)
Protective gear for personnel handling affected animals
Confirmation of Vesicular Stomatitis is diagnosed via viral isolation from samples of lesions, blister fluid, or antibody testing of serum from affected animals. If there is concern that an animal is affected with Vesicular Stomatitis, regardless of species, contact your veterinarian so that the proper examination and diagnostic tests can be performed and other animals in the vicinity can be protected. For more information please see the following links: