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Published Date: 2011-05-28 22:19:06
Subject: PRO/AH/EDR> Equine herpesvirus, equine - North America (05)
Archive Number: 20110528.1639

EQUINE HERPESVIRUS, EQUINE - NORTH AMERICA (05)
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Date: 27 May 2011
Source: DVM Veterinary News Magazine [edited]
http://veterinarynews.dvm360.com/dvm/Veterinary+Equine/Outbreak-New-equine-herpes-virus-cases-emerge/ArticleStandard/Article/detail/724806?contextCategoryId=378

Secondary exposures make up about half of all confirmed equine
herpesvirus cases, veterinary officials report. Suspected or confirmed
cases remain under voluntary or sanctioned quarantine.

Of the 47 cases of equine herpesvirus (EHV-1) now confirmed across 9
western states, 14 were contracted through secondary or tertiary
exposure, veterinary officials report. Another 28 cases of equine
herpesvirus myeloencephalopathy (EHM), the neurologic form of the
disease, have been reported, 25 from direct exposure during the recent
National Cutting Horse Association competition in Ogden, Utah.

The U.S. Department of Agriculture (USDA) Animal and Plant Health
Inspection Services (APHIS) now places the total number of EHV-1/EHM
cases at 75. Eleven of those horses died or were euthanized.

In the last week, 15 new cases have surfaced, APHIS reports.

More than 400 horses in 19 states were exposed to the virus at the
Utah event, and another 1635 are at risk of secondary or tertiary
exposure, APHIS says in its 26 May 2011 update on the outbreak.

Although the incubation period for EHV-1 is 2 to 14 days, Dr. Leonard
Eldridge, Washington's state veterinarian, says the virus can be shed
for up to 28 days. The Nevada Department of Agriculture says it
observed horses that attended the Utah event through 22 May 2011 for
signs of infection. Horses at risk of secondary infection will be
observed until 5 Jun 2011.

APHIS says horses known to have been exposed to the virus have been
notified by state animal health officials, and suspected or confirmed
cases are under voluntary or state quarantine.

As of 25 May 2011, here are USDA's totals on the outbreak:

Arizona - 2 EHV-1 and 1 EHM from direct exposure, 8 EHV-1 from
secondary/tertiary exposure;

California - 9 EHV-1 and 6 EHM from direct exposure, 1 EHV-1 from
secondary/tertiary exposure;

Colorado - 9 EHV-1 and 6 EHM from direct exposure, 1 EHV-1 from
secondary/tertiary exposure;

Idaho - 1 EHV-1 and 3 EHM from direct exposure, 2 EHV-1 from
secondary/tertiary exposure;

Nevada - 1 EHV-1 from direct exposure, 2 EHM from secondary/tertiary
exposure;

New Mexico - 2 EHV-1 and 1 EHM from direct exposure, 1 EHM from
secondary/tertiary exposure;

Oregon - 4 EHV-1 and 1 EHM from direct exposure;

Utah - 1 EHV-1 and 4 EHM from direct exposure, 2 EHV-1 from
secondary/tertiary exposure;

Washington - 4 EHV-1 and 3 EHM from direct exposure.

Nine horses with confirmed cases of EHV-1/EHM through direct exposure
died or were euthanized, plus another 2 horses with confirmed cases
contracted through secondary exposure.

Horse owners are being advised to notify veterinarians if they
participated in the NCHA event or if their horse suddenly comes down
with a temperature above 102 F, which typically precedes clinical
signs, veterinarians say.

Related Links: Equine herpesvirus outbreak: 44 horses test positive
in 9 western states, veterinarians report [Further coverage is
available on the DVM News Magazine web-site.].

[Byline: Rachael Whitcomb]

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[This outbreak seems to continue to spread, but hopefully it will
begin to subside soon. - Mod.TG]

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