Equine Herpes Virus Update

Credit: herpes-nasal-discharge www.aphis.udsa.gov

Just this past week, three cases of Equine Herpes virus (Rhino virus) Type 1 were reported in Wisconsin, New York, and Virginia.

Equine Herpes virus actually has nine forms discovered to date, four of which are linked to serious disease in horses:

• EHV-1: Can cause four manifestations of disease in horses:

· respiratory disease

· abortion

· neonatal death, and,

· a neurological form called Equine Herpes Myeloencephalopathy. EHM is most often due to mutant or neuropathogenic strains of EHV-1, so called because of a particular mutation in the genome.

• EHV-3: Causes a venereal disease called equine coital exanthema that affects the external genitalia.

• EHV-4: Causes a nonfatal upper respiratory tract disease in foals and is uncommonly associated with abortion and rarely with neurologic disease.

• EHV-5: Is thought to be linked to a fatal, progressive fibrotic pneumonia in some horses.

To help control the spread of EHV-1 (and 4 for that matter), state veterinarians recommend that owners keep horses with a fever and clinical signs of contagious respiratory infection at home and not take them to shows, competitions, clinics, or public trail rides. Although humans can’t be infected by EHV-1, they can aid in spreading it to their horses. Therefore, owners of affected horses should wash and disinfect their hands and change their clothes before coming into contact with healthy horses to prevent the potential spread of these infectious organisms.

What about vaccination? Some strains of Rhino virus are included in vaccinations, but not all. Also, this virus is a sneaky little bugger and mutates so that vaccines do not neutralize it. Also- horse owners who give their horses intranasal Flu/ Rhino vaccines should do their research- not all intranasal vaccines for Flu/ Rhino effectively cover the horse for rhino virus protection.

The USDA puts out a great info booklet on Equine Herpes virus that is a MUST HAVE for every barn. It covers the various types of EHV, signs and symptoms, how it is spread, and how it can be prevented. See also: EHV-1 aka Equine Herpes Virus on Horse Journal Online.

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