| Equine herpes virus |
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| State vet advises precautions with equine herpes virus-1 (rhino) |
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A case of equine herpes virus-1 (EHV-1) was reported in Oregon, May 2, 2009. EHV-1 is a highly contagious respiratory virus that can cause mild neurological symptoms in horses. The Oregon horse is not infected with the severe neurological or mutant strain of EHV-1 previously diagnosed in East Coast and California horses back in 2007. No other EHV-1 cases have been reported this year.
There are no restrictions on the movement of horses within Oregon, at this time.
Even though EHV-1 is not a regulatory disease, and does not require reporting, veterinarians and horse owners are asked to inform the State Veterinarian's Office of confirmed cases.
State Veterinarian Don Hansen urges horse owners to take precautions. Veterinarians should work closely with their equine clients to develop plans that address the clients' ability to prevent EHV-1 in their horses. If a horse is suspected of having EHV-1, the horse should be isolated. Do not use the same equipment when handling other horses.
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| EHV-1 informational links |
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The following link for EHV-1 from UC Davis may help readers become informed about this disease.
The full text of UC Davis Center for Equine Health disease information and links may be accessed at: http://www.vetmed.ucdavis.edu/ceh/ehv1_general.cfm
Highlights from the UC Davis report are summarized below:
- At this time, enforcement of strict biosecurity measures and hygiene practices is likely effectively reduce the risk of infection.
- Stress and lack of previous exposure to the virus may make the horse more susceptible to EHV-i.
- Recent research demonstrates that viral shedding is reduced in horses with high circulating titers of virus-neutralizing (VN) antibody, as well as in horses that have been vaccinated recently with the Rhinomune MLV vaccine.
- Fever in excess of 102 F may be the only observable sign of infection when horses are incubating the virus.
- Biosecurity measures with rapid separation and isolation of identified suspect cases are key to disease control. Horse-to-horse contact; aerosokl transmission; and contamination of hands, equipment, tack, and feed, all play a role in the spread of EHV-1.
- As with all contagious diseases, if horses are commingled with strange horses, an unknown degree of inherent risk exists for exposure to EHV-1. Many factors may enhance or reduce the amount of risk. If the choice is made to commingle with a population that has the potential to harbor EHV-1 infected individuals, there is no foolproof way to completely eliminate the risk of exposure.
- Since EHV-1 is considered to be endemic within the horse population, random testing of normal horses for EHV-1 by PCR diagnostics can detect horses with nonreplicating (dead) viral DNA; latent, low-level, transient carriage of virus; or viral levels that are not sufficient to pose a significant risk for disease transmission.
- The significance of a positive PCR in an asymptomatic horse is unknown, regardless of the test being employed or the laboratory performing the test. There is simply not sufficient to justify or recommend control measures or quarantine procedures for horses testing positive for EHV-1 in the absence of clinical signs of disease.
- If horses are exposed to new horses, especially in stressful competitive environments or following long distance travel, it is helpful to establish a disease-monitoring plan under the advice of a veterinary practitioner. Temperature monitoring (two times per day) is a tool to be used for a differential diagnosis that could include EHV-1.
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