The World Organization for Animal Health reported May 28 that vesicular stomatitis virus was detected in three horses in Cochise County, Ariz. The organization received the information from John Clifford, DVM, deputy administrator for the U.S. Animal and Plant Health Inspection Service (APHIS).
APHIS and the Arizona Department of Agriculture are conducting an epidemiological investigation of the event.
The premises where the virus was discovered has been quarantined. The owners were advised to separate animals bearing lesions from healthy animals, implement on-farm insect control programs and use protective measures when handling affected animals to avoid human exposure to the disease.
Vesicular stomatitis virus, last detected in Arizona in spring 2005, commonly occurs during warm months in the Southwest, particularly along river ways and in valleys, according to the Arizona Department of Agriculture. Texas and New Mexico had a few cases last year.
Horses, cattle and swine are most susceptible to vesicular stomatitis virus. Infected animals may have blister-like lesions in the mouth and on the dental pad, tongue, lips, nostrils, hooves and teats. The blisters swell and break, leaving raw tissue that may cause the animals to refuse to eat or drink and show signs of lameness, according to the Arizona Department of Agriculture. Severe weight loss usually follows. Dairy cows may have a severe drop in milk production.
The Arizona Department of Agriculture noted that the outward signs are similar to those of foot-and-mouth disease, a foreign animal disease of cloven-hoofed animals that was eradicated from the U.S. in 1929. The clinical signs of vesicular stomatitis also are similar to those of swine vesicular disease, another foreign animal disease. The only way to tell the diseases apart is through laboratory tests, according to the Arizona Department of Agriculture.
In the latest case, vesicular stomatitis virus was confirmed by the National Veterinary Services Laboratory using a competitive ELISA test and a complement fixation test.
Weekly follow-up reports will be submitted, according to the World Organization for Animal Health.