Quarantine lifted at Michigan farm after threat of neurologic EHV-1 outbreak passes

Only one horse on the property was affected and has since tested negative for the virus twice.

Veterinary officials have lifted the quarantine of a farm in Oakland County, Michigan after the threat of an outbreak of the neurologic form of Equine Herpes Virus-Type 1 (EHV-1) appears to have passed.

Most cases of equine herpesvirus-1 infection cause only mild to moderate respiratory illness but occasionally some lead to life-threatening neurologic disease.

According to the Equine Disease Communication center (EDCC), the farm had been placed under quarantine in November after an 18-year-old Thoroughbred gelding developed neurological signs—difficulty urinating and hind-end weakness—and tested positive for EHV-1.

The quarantine was lifted after the horse subsequently tested negative on two consecutive tests, a minimum of 7 days apart, and all exposed horses went 21 consecutive days without developing EHV-1.

EHV-1 most often causes mild-to-moderate respiratory illness (rhinopneumonitis), but the infection occasionally leads to the life-threatening neurologic disease EHM. The mechanisms through which EHV-1 produces neurologic disease are not yet understood.

While the affected gelding was vaccinated against EHV-1, according to the EDCC, there is no vaccine that specifically protects against EHM, so biosecurity is a crucial part of prevention. EHV-1 spreads from horse to horse through nasal discharge or aerosol droplets. Humans can spread the virus via contaminated hands, clothing and equipment.

To learn more about EHM and how you can protect your horse, click here

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