EHV-1 in Pennsylvania: Update on Chester County Case

The EHV-1-positive horse died in quarantine due to an unrelated medical issue, not EHM (which develops when EHV affects the central nervous system), the Pennsylvania Department of Agriculture said.

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ehv-1 in pennsylvania
In many horses, the first or only sign of EHV-1 infection is fever, which can go undetected. | Photo: The Horse Staff

On May 23, the Equine Disease Communication Center (EDCC) shared an update from the Pennsylvania Department of Agriculture (PDA) regarding a case of equine herpesvirus-1 (EHV-1) confirmed last week in Chester County.

“The Chester County, Pennsylvania, horse that tested positive for EHV-1 died on May 17 in isolation on a private farm,” the PDA said via the EDCC. “The post-mortem results indicate that the horse died of an unrelated medical issue, not from equine herpes myeloencephalopathy (EHM, the disease caused when EHV affects the central nervous system). There have been no other horses showing signs of EHV-1 infection and there is no ‘outbreak’ as has been reported elsewhere.

“The horse had been placed in isolation at its home farm on May 15 when it began to show signs of illness, including abnormal gait and stance and a high fever. As EHV-1 was detected in the horse’s nasal swab sample, all horses at the Chester County farm were quarantined. Based on the post-mortem findings, the low levels of EHV detected on the nasal swab sample, and the absence of EHV-related illness in any of the horses on the premises, there appears to be little risk even for the horses that were in direct contact with the horse that died

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Written by:

Erica Larson, former news editor for The Horse, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

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