Articles: Horse News
Equine Herpesvirus Awareness
Texas Animal Health Commission
"Serving Texas Animal Agriculture Since 1893"
2105 Kramer Lane ~ Austin, Texas 78758
512.719.0710 ~ email@example.com ~ http://www.tahc.state.tx.us
For more information contact the Public Information office at
1-800-550-8242, ext. 710 or at firstname.lastname@example.org
An outbreak of Equine Herpesvirus (EHV-1) has been traced to horses that
attended the National Cutting Horse Associations (NCHA) Western National
Championships in Odgen, UT on April 30 - May 8, 2011. Affected horses have
been identified in Colorado. Additional states have possible cases pending
and/or are looking for animals that attended the event and returned home.
Texas does not currently have any confirmed positives. The Texas Animal
Health Commission (TAHC) has identified all horses that attended the show in
Utah and are currently working on contacting the equine owners and advising
them to isolate exposed horses for at least two weeks, follow good
biosecurity practices and watch for possible clinical signs.
Equine Herpes Virus is a common virus in equine populations worldwide. There
are several strains of the virus, with EHV-1 and EHV-4 being most often
involved in clinical disease. EHV-1 can cause respiratory disease, abortion
and neurologic disease. The neurologic disease is sometimes referred to as
Equine Herpes Myeloencephalopathy (EHM.) Although EHV-1 is highly
contagious among horses, it does not pose a threat to human health.
EHV is transmitted primarily by aerosol and through direct and indirect
contact. Aerosol transmission occurs when infectious droplets are inhaled.
The source of infectious droplets is most often respiratory secretions. In
the case of abortions, virus may be present in the placenta, fetal membranes
and fluid, and aborted fetuses.
Direct horse-to-horse contact is a common route of transmission of the
virus, but indirect transmission is also important. This occurs when
infectious materials (nasal secretions, fluids from abortions, etc.) are
carried between infected and non-infected horses by people or fomites
(inanimate objects such as buckets, etc).
Signs of EHV-1
Fever is one of the most common clinical signs and often precedes the
development of other signs. Respiratory signs include coughing and nasal
discharge. Abortions caused by EHV generally occur after 5 months of
gestation. Neurologic signs associated with EHM are highly variable, but
often the hindquarters are most severely affected. Horses with EHM may
appear weak and uncoordinated. Urine dribbling and loss of tail tone may
also be seen. Severely affected horses may become unable to rise.
It is important to remember that none of these signs are specific to EHV,
and diagnostic testing is required to confirm EHV infection. Also, many
horses exposed to EHV never develop clinical signs.
What to do if you suspect your horse has been exposed
If you suspect your horse has been exposed to EHV, contact your
veterinarian. In general, exposed horses should be isolated and have their
temperatures monitored twice daily for 10 days. If an exposed horse
develops a fever or other signs consistent with EHV infection, diagnostic
testing should be performed. Testing of healthy horses is generally not