We have been notified of the first cases of Vesicular Stomatitis in the United States in over three years. VS is considered a Foreign Animal Disease and is a Reportable Disease in Oklahoma.
So far cases have been discovered in Kinney County and Tom Green County in Texas, Weld County in Colorado, and Sandoval County in New Mexico. Oklahoma has been fortunate to not have cases of VS during the last few outbreaks, but we have had cases in the past and it is very possible we can have them this year.
Vesicular stomatitis (VS) is a viral disease that primarily affects horses and cattle and occasionally swine, sheep, goats, llamas, and alpacas. VS has been confirmed only in the Western Hemisphere. It is known to be an endemic disease in the warmer regions of North, Central, and South America, and outbreaks of the disease in other temperate geographic parts of the hemisphere occur sporadically. The Southwestern and Western United States have experienced a number of vesicular stomatitis outbreaks, the most recent and largest VS outbreak occurred in 2015. Outbreaks usually occur during the warmer months, often along waterways. The time from exposure to the onset of clinical signs is 2-8 days.
VS is spread by insect vectors and direct contact with infected animals. Black flies, sand flies, and midges are the known vectors of this disease, but other insects may also be capable of transmission. Infected animals shed the virus from the lesions (blisters) they develop, so direct contact with infected animals or water, feed, buckets, and other fomites contaminated with saliva from infected animals can also transmit the disease. The virus can also be spread on shoes, clothing, hands, and contaminated equipment.
In affected livestock, the incubation period for vesicular stomatitis ranges from 2 to 8 days. Often, excessive salivation is the first sign of the disease. Close examination of the mouth initially reveals blanched and raised vesicles or blister-like lesions on the inner surfaces of the lips, gums, tongue, and/or dental pad. In addition, these blister-like lesions can form on the lips, nostrils, coronary band, prepuce, vulva, and teats. The blisters swell and break, which causes oral pain and discomfort and reluctance to eat or drink. Lameness and severe weight loss may follow. Body temperature may rise immediately before or at the same time lesions fi rst appear. Dairy cattle often suffer from teat lesions and subsequent mastitis; a severe drop in milk production commonly occurs. Some affected dairy cattle can appear to be normal with no clearly visible signs of illness but may only eat about half of their normal feed intake. If there are no complications such as secondary infection, affected animals typically recover in about 2 weeks.
In horses, vesicular lesions generally occur on the upper surface of the tongue, the lips, around nostrils, corners of the mouth, and gums. Lesions in horses may also be expressed as crusting scabs on the muzzle, lips, or ventral abdomen.
Affected pigs usually first show signs of lameness caused by foot lesions.
There is no specific treatment or cure for vesicular stomatitis. Good sanitation and quarantine practices on affected farms usually contain the infection. When a definite diagnosis is made on a farm, the following procedures are recommended:
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 ear tags on animals.
Use personal protective measures when handling affected animals to avoid human exposure to this disease.
Please notify any of the regulatory veterinarians in Oklahoma if you suspect a patient has this disease.
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