Important Announcement about Equine Herpes
See bottom of this page for
Update May 31, 2011
WSU Veterinarians confirm postmortum equine herpes case
Update May 26, 2011
As of May 26, 2011, a total of 75 confirmed EHV-1 cases have been reported
in 9 states (AZ, CA, CO, ID, NM, NV, OR, UT, WA). Of the 75 confirmed cases,
58 cases are horses that were at the Ogden, Utah event. There are 11 horses
associated with this incident that are dead or have been euthanized; none
are from Washington.
Washington's summary remains seven known EHV-1 positive horses and no
deaths. By county Whitman has three positive cases, and Spokane, Chelan,
Asotin, and Thurston counties have one each. The case in Asotin County was
diagnosed at Washington State University's Veterinary Teaching Hospital.
Update May 25, 2011
WSU Veterinarians confirm third in-patient EHV-1 case
Decontamination suggestions for EHV-1
To decontaminate yourself, we recommend that you take a shower, change
clothes, and wash the clothes that you were wearing when you handled the
These are the recommendations by the American Association of Equine
Practitioners for decontamination of equipment and supplies that may have
been in contact with horses who are shedding herpes virus:
- Horse-specific equipment (feed tubs, water buckets,
halters, etc.) should be clearly identified as belonging to
an individual horse and is to be used only by that horse.
- Shared equipment (lead shanks, lip chains, bits/bridles,
twitches, dose syringes, thermometers, grooming supplies)
should be cleaned of organic debris and disinfected between
- All equipment should be thoroughly scrubbed and cleaned
with a detergent and water, rinsed, disinfected and followed
by a final rinse. This should be done in an area with
minimal foot and traffic flow that can be cleaned and
disinfected after this procedure (preferably not in a
grazing area, but on a solid surface close to a drain).
- Cloth items (saddle cloths, towels, bandages, halter
fleeces, rub rags) should be laundered and thoroughly dried
between each use. (Disinfectant may be added to rinse water,
but additional rinse cycle must be used to remove
- Equipment that cannot be effectively disinfected
(sponges, brushes) should not be shared between horses.
Multiple dose medications (oral pastes/ophthalmic ointments,
etc.) should be labeled for use by a specific horse and not
- Ointments/topical medications should be removed from
larger tubs and portioned into smaller containers for use on
Update May 20, 2011
The WSU College of Veterinary Medicine confirmed two more horses with
Equine Herpes Virus or EHV-1 on May 20. Both horses are inpatients in the
Veterinary Teaching Hospital.
The EHV-1 type is confirmed as the neurotropic form.
The discovery of two more infected horses at WSU means the restrictions
for new, non-emergency horse or camelid patients coming to WSU’s Veterinary
Teaching Hospital will be in place for a minimum of 21 more days.
Emergency services are still available but owners must call ahead first
to ensure the hospital can make special accommodations to protect any
incoming animals. The phone number is: 509-335-7073.
Update May 18, 2011
Washington saw its first EHV-1-positive case discharged from Washington
State University's (WSU) Veterinary Teaching Hospital on May 13 (details
below). Today Debra C. Sellon, DVM, PhD, Dipl. ACVIM, a professor of equine
medicine at WSU, reported that since the discharge all PCR diagnostic tests
run on hospital patients have been negative, and the university hospital
remains under quarantine.
Today (May 18) a second case of EHV-1 was confirmed. The horse presented
with neurologic signs and was taken to Pilchuck Veterinary Hospital (PVH)
in Snohomish. Attending veterinarian Wendy Mollat, DVM, Dipl. ACVIM, said in
a press release issued by the hospital that upon presentation to PVH, "the
horse was immediately admitted to our designated equine isolation
facility and has not been allowed direct or indirect contact with our
general equine population. The horse is clinically stable and will remain
hospitalized until confirmed to be no longer shedding the virus."
A third case was reported today in the state of Washington but no details
May 14, 2011
The Washington State University Veterinary Teaching Hospital is entering
a period of voluntary isolation for equine and camelid patients. This is in
response to a patient that was confirmed to be shedding Equine Herpes Virus
type 1 (EHV-1). In the past week there have been 2 confirmed cases of
EHV-1 in Colorado in horses that competed at the National Cutting Horse
Association Western National Championships in Ogden, Utah. A horse
admitted to the Washington State University Veterinary Teaching Hospital for
evaluation of unrelated problems was found to have competed at the show.
Subsequent diagnostic testing confirmed that the horse was positive for
EHV-1. Due to the potential for spread of the virus, access to the VTH is
currently restricted. During this time, no new equine or camelid patients
may be admitted to the hospital except for critical emergencies. It is
expected that the period of isolation will last at least 2 weeks. There
are currently no horses exhibiting signs of EHV-1 at WSU. Equine Herpes
Virus does not affect cattle, sheep, goats, pigs or birds, and the remainder
of the VTH remains open. There is no risk of transmission to people.
We are taking every precaution to ensure the health and well-being of
animals. We hope that the following information will be helpful .
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, while EHV-4 typically causes respiratory
disease. Neurologic disease, which is generally caused by specific strains
of EHV-1, is called equine herpesvirus myeloencephalopathy (EHM).
What are the common clinical signs of EHV?
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 hind end is most severely affected. Horses with EHM may appear
weak and incoordinated. 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.
How long is the virus shed once a horse is infected?
Shedding by the respiratory route typically lasts for 7-10 days, although
occasionally it may persist longer.
How is EHV spread?
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).
What should I do if my horse has been exposed to EHV?
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, diagnostic testing should be performed. While there are
several testing methods available, the most frequently recommended test is a
PCR to detect the viral genetic material done on a nasal swab.
How do I get more information about EHV?