ACVIM Releases EHV-1 Consensus Statement

The American College of Veterinary Internal Medicine has released its consensus statement on equine herpesvirus-1 (EHV-1). According to the authors, a perceived increase in the occurrence of equine herpesvirus myeloencephalopathy (the neurologic form of EHV-1) was the impetus for the statement.

The publication addresses 10 key areas to guide veterinarians in understanding and managing EHV-1 disease.

Disease Mechanisms Researchers know the virus causes abortions by attacking the inner lining of the blood vessels. In pregnant mares, disruption of the uterine lining can lead to abortions, usually in the third trimester. Less is known about how the virus invades the central nervous system. Researchers are focusing on the virus receptors involved in the immune response to infection.

PCR Testing The statement provides a table of key information about EHV-1 strains to help veterinarians interpret the significance of PCR results.

Epidemiology The most current data about the prevalence of the virus strain variants guides provides a context for clinical practice.

Risk Factors Risk factors for EHV-1 disease include characteristics of the virus, host, and environmental factors.

Diagnosis, Prognosis and Screening The statement provides detailed guidelines for interpreting EHV-1 tests, as well as a list of testing samples and when to use them.

Vaccines Vaccines can help reduce EHV-1 infection in herds, but no vaccination can directly prevent EHV-1 disease. The statement summarizes available vaccines and points to the AAEP recommendations for vaccination.

Prevention for Neurologic and Abortigenic Forms Prevention measures can be summarized by the acronym SISS: segregation of at-risk horses, isolation of new horses, subdivision of pregnant mares into small, physically-separated groups during gestation, and stress reduction.

Controlling EHV-1 Outbreaks The acronym DISH summarizes control measures: disinfection, isolation, submission of clinical samples, and implementation of hygienic measures to prevent the spread of disease.

Responding to an outbreak The statement provides guidelines for what to do in an outbreak, how to lift quarantine, and how to decontaminate after an outbreak.

Treatment Approaches The authors discuss supportive care, drug therapy, and use of immunostimulants for treating EHV-1 disease. More research is needed to determine which of these approaches are best, and in what circumstances.

The key to future progress depends on understanding how the virus works, and how it spreads in horse populations.

"Diagnosis and treatment EHV-1 disease is an ongoing topic," according to Nicola Pusterla, DVM, PhD, Dipl. ACVIM, one of the statement's authors.

About the Author

Nancy Zacks, MS

Nancy Zacks holds an M.S. in Science Journalism from the Boston University College of Communication. She grew up in suburban Philadelphia where she learned to ride over fields and fences in nearby Malvern, Pa. When not writing, she enjoys riding at an eventing barn, drawing and painting horses, volunteering at a therapeutic riding program, and walking with Lilly, her black Labrador Retriever.

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