On September 10, 2015, the National Veterinary Services Laboratories in Ames Iowa confirmed a finding of vesicular stomatitis virus (VSV) infection in three horses from a premises in Scotts Bluff County, Nebraska. This is the first VSV finding in Nebraska this year.
Since the beginning of this summer’s outbreak, 420 VSV-affected premises have been identified and quarantined in eight states (Arizona, Colorado, Nebraska, New Mexico, South Dakota, Texas, Utah, and Wyoming). Currently, according to USDA’s Animal and Plant Health Inspection Service (APHIS), there are 103 affected premises remaining under quarantine in 6 states (Colorado, Nebraska, New Mexico, South Dakota, Utah, and Wyoming).
Last summer, a total of 435 VS-positive premises were confirmed in four U.S. states including Arizona Colorado, Nebraska and Texas.
The virus is spread primarily by insect vectors, and thus tends to disappear during the winter in temperate climates and break out during the summer, particularly in areas where wet conditions encourage insect populations.
Vesicular stomatitis virus (VSV) is classified as a rhabdovirus, and there are two serotypes, New Jersey and Indiana. Outbreaks this year have involved the New Jersey serotype. Infection with one serotype is not cross-protective for the second serotype. Clinical signs of VS, which can affect equines, cattle, bison, sheep, goats, pigs and camelids include vesicles, erosions, and sloughing of the skin on the muzzle, tongue, teats and above the hooves.
Insect vectors are the primary source of transmission of VS although mechanical transmission occurs in some species. Fly control is a key component in preventing spread of the virus.
Rarely, VS can affect humans, typically those who are in contact with infected animals. In humans the disease typically causes flu-like symptoms.
According to APHIS, when a definite diagnosis is made on a farm, veterinarians and producers should take the following steps:
· Separate animals with lesions from healthy animals, preferably by stabling. Animals on pastures tend to be affected more frequently with this disease.
· As a precautionary measure, do not move animals from premises affected by vesicular stomatitis until at least 21 days after lesions in the last affected animal have healed.
· Implement on-farm insect control programs that include the elimination or reduction of insect breeding areas and the use of insecticide sprays or insecticide-treated eartags on animals.
· Use personal protective measures when handling affected animals to avoid human exposure to this disease.
APHIS offers weekly VS updates and information on the disease on its vesicular stomatitis website.