Forwarded from USDA-APHIS:

On August 17, 2006, the National Veterinary Services Laboratories (NVSL) in
Ames, Iowa confirmed vesicular stomatitis in a 10 year old horse on a
premises in Natrona County, Wyoming (this is near Casper).  This is the first confirmed case of
vesicular stomatitis (VS) in the United States in 2006; the last case of VS
was confirmed in late 2005.

VS is a viral disease which primarily affects horses, cattle, and swine.
The viruses that cause VS have a wide host range.  VS also occasionally
affects sheep and goats.  In affected livestock, VS causes blisterlike
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 and drink, and
show signs of lameness.  Weight loss usually follows, and in dairy cows, a
drop in milk production commonly occurs.  Affected livestock may appear to
be clinically normal and continue to eat, but may consume only about half
of their normal quantity of feed.

The clinically ill horse was positive for antibodies to vesicular
stomatitis New Jersey (VS-NJ) virus on the competitive enzyme-linked
immunosorbent assay (cELISA) and was also positive on virus isolation for
VS-NJ virus.  The VS compatible clinical signs and presence of VS-NJ virus
meet the definition to classify this horse as the index case for the Nation
in 2006.  There are an additional 29 clinically normal horses and 25
clinically normal cattle also on the  premises.

The affected horse was initially examined as part of a routine physical
exam by a private veterinary practitioner on August 12, 2006.  The next
day, the owner of the horse noticed that the horse had a swollen muzzle and
contacted the veterinarian who came back to the premises to re-examine the
animal on August 14.  During the re-examination, the practitioner noticed
that the horse had oral lesions that were consistent with a vesicular
condition and immediately contacted APHIS, Veterinary Services in Wyoming.
A foreign animal disease investigation was initiated that same day;
appropriate samples were collected and submitted to NVSL.  There is no
history of recent movement of this horse from the premises, however, the
owners did report a large burden of Culicoides and large numbers of biting
flies in the vicinity.

The affected premises is currently under State quarantine.  Additional
control measures include isolating the horse from the rest of the animals
to ensure that water troughs and feed buckets are not being shared with
other susceptible animals, and increasing insect control measures.

The Wyoming Department of Agriculture is beginning a public and veterinary
practitioner information and education campaign regarding VS.

APHIS Veterinary Services and the Wyoming Department of Agriculture will
continue to monitor the situation and conduct response activities in an
effort to minimize trade restrictions.