Colorado EHV-1 Quarantine Released

The Colorado Department of Agriculture has released the quarantine placed on a Douglas County premises after a case of equine herpesvirus (EHV-1) was confirmed at the location in May.

"We are pleased with the release of the quarantine; the department responded quickly to control this disease," said State Veterinarian Keith Roehr, DVM. "The fact that there was only one confirmed case shows that the cooperative efforts of the premises and Colorado's vigilant horse owners are a vital part of disease mitigation."

The affected horse was imported by a private owner from Iowa, through a transport company and was euthanized after showing severe neurologic signs associated with EHV-1. Three facilities received horses from the same transport vehicle, and all horses at those facilities remain free of EHV-1 clinical signs.

"While there was limited spread of this disease, it could have been much worse," Roehr said. "We encourage horse owners and event managers to always observe basic biosecurity practices such as limiting horse-to-horse contact, separating feeding, watering, and tack supplies, and eliminating shared water sources at events to minimize transmission of all infectious diseases."

Although it's not transmissible to humans, EHV-1 is highly contagious among horses and camelids, and it is generally passed from horse to horse via aerosol transmission (when affected animals sneeze/cough) and contact with nasal secretions. The disease can cause a variety of ailments in equines, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and myeloencephalopathy (EHM, the neurologic form).

Myeloencephalopathy is characterized by fever, ataxia (incoordination), weakness or paralysis of the hind limbs, and incontinence. Should a horse with potential EHV-1 exposure display any of the aforementioned clinical signs, a veterinarian should be called to obtain samples and test for the disease.

The vaccines available for EHV-1 immunization do not protect against EHM, however these immunizations do protect against the respiratory and abortion forms of the disease. The vaccines are thought to reduce the shedding of the virus and may decrease the amount of circulating virus in the system of infected horses; therefore, vaccinations prior to exposure could help reduce the severity of infection. Horse owners are encouraged to consult a veterinarian to determine the best vaccination and treatment strategy for their horses.

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