VESICULAR STOMATITIS, EQUINE - USA: (ARIZONA)

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A ProMED-mail post

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International Society for Infectious Diseases


Date: 28 May 2010
Source: Arizona Department of Agriculture press release [edited]



Vesicular Stomatitis Virus Found In Horses in Arizona
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The Arizona Department of Agriculture has confirmed Vesicular
Stomatitis Virus (VSV) in horses on a premises in Cochise County. The
case-positive premises where VSV was discovered has been quarantined.
This disease causes blister-like lesions to form in the mouth and on
the dental pad, tongue, lips, nostrils, hooves, and teats. These
blisters swell and break, leaving raw tissue that is so painful that
infected animals generally refuse to eat or drink and show signs of
lameness. Severe weight loss usually follows, and in dairy cows, a
severe drop in milk production commonly occurs. Affected dairy cattle
can appear to be normal and will continue to eat about half of their
feed intake.

Why is this important?

While vesicular stomatitis can cause economic losses to livestock
producers, it is a particularly significant disease because its
outward signs are similar to (although generally less severe than)
those of foot-and-mouth disease, a foreign animal disease of
cloven-hoofed animals that was eradicated from the United States in
1929. The clinical signs of vesicular stomatitis are also similar to
those of swine vesicular disease, another foreign animal disease. The
only way to tell these diseases apart is through laboratory tests.

Can humans "get it?"

Humans can also become infected with vesicular stomatitis when
handling affected animals. However, we have no human cases to report.

Which animals are most susceptible?

Horses, swine and cattle are most at risk. However, other animals may
also contract the disease.

Has this disease been found in the U.S. before?

Last year [2009] Texas and New Mexico had a few cases of VSV. This
year Arizona is the 1st state to detect the disease, which occurs
sporadically on 5 to 8 year cycles.

Why is this occurring now?

Vesicular stomatitis is most likely to occur during warm months in
the Southwest, particularly along riverways and in valleys. Arizona
last had confirmed cases of VSV in the spring of 2005.

How is this disease handled?

The following actions have been recommended to the owners of the horses:
. This report was primarily compiled from
.

- Separate animals with lesions from healthy animals, preferably by
stabling. Animals on pastures apparently are affected more frequently
with this disease.

- As a precautionary measure, do not move animals from premises
affected by vesicular stomatitis for at least 30 days after the last
lesion found has 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 protective measures when handling affected animals to avoid
human exposure to this disease.

What if a viewer/reader suspects they have animal(s) with this problem?

They should immediately contact their veterinarian or the State
Veterinarian's office.

--
Communicated by:
ProMED-mail


[Vesicular stomatitis virus is one of those interesting diseases that
emerges every once in a while without much warning until it bursts
uninvited into our livestock population. It does not occur every
year, but in the past several years it has been almost yearly.

The problem with vesicular stomatitis is twofold. One, there is
inevitably a disruption of production in cattle; not only will the
sick animal produce less, but disease management tactics must be
very stringent. The 2nd problem is that the clinical signs are
similar to that of foot and mouth disease (FMD), with which it can
easily be confused (though horses are resistant to FMD and
susceptible to VS).

In this case, the diagnosis of the disease in an equine 1st
forestalls any worry about FMD, until an animal susceptible to FMD,
such as a bovine, appears with similar clinical signs. Consequently,
surveillance must be ever vigilant.

VS can be transmitted by contamination by transcutaneous or
transmucosal route and by arthropod transmission (_Phlebotomus_, and
_Aedes_, etc.). Incubation of the disease may be as long as 21 days.

According to the OIE, clinical signs can be summarized as follows:

- excessive salivation

- blanched raised or broken vesicles of various sizes in the mouth:

Horses: upper surface of the tongue, surface of the lips and around
nostrils, corners of the mouth and the gums

Cattle: tongue, lips, gums, hard palate, and sometimes muzzle and
around the nostrils

Pigs: snout:

- Lesions involving feet of horses and cattle are not exceptional

- Teat lesions occur in dairy herds

- Foot lesions and lameness are frequent in pigs

- Recovery in around 2 weeks

- Complication: loss of production and mastitis in dairy herds due
to secondary infections, lameness in horses

There are 2 major serotypes: New Jersey, and Indiana. We would like
to know which of the 2 strains this one is.

Portions of this comment have been extracted from:
- Mod.TG]

[The interactive HealthMap/ProMED map for Arizona is available at:
- CopyEd.EJP]

[see also:
2009
----
Vesicular stomatitis, equine - USA (03): (NM) 20090623.2294
Vesicular stomatitis, equine - USA (02): (TX) 20090616.2230
Vesicular stomatitis, equine - USA: (TX) 20090613.2188
2007
----
Vesicular stomatitis, equine - Belize (Cayo): OIE 20070319.0967
2006
----
Vesicular stomatitis, equine - USA (WY)(02): OIE 20060825.2395
Vesicular stomatitis, equine - USA (WY) 20060818.2314]
....................tg/ejp/lm

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