Horse Tests Positive For EHV-1 At Portland Meadows; Exposed Horses Under Quarantine

by | 01.30.2018 | 12:33pm
Racing at Portland Meadows

The Equine Disease Communication Center released the following alert from the Oregon Department of Agriculture on Jan. 30: 

“The Oregon Department of Agriculture is reporting that a case of wild type EHV-1 has been detected at the Portland Meadows race track.  A 7-year old Thoroughbred mare developed mild ataxia on January 25.  Neither the neuropathogenic or wild type strains of EHV-1 were detected by PCR testing on blood EDTA samples.  The EHV-1 neuropathogenic strain was not detected by PCR testing on nasal swab samples, however, the wild type strain was detected.

Portland Meadows race track veterinary authorities have quarantined the index case and high-risk contacts in a barn separate from other horses.  Enhanced biosecurity measures have been implemented.  The index case is stable and non-febrile.  High risk contacts are being closely monitored.  To date, there have been no additional sick animals reported.”

The “wild” strain and the neuropathogenic strains of EHV-1 are different only in one amino acid in their DNA. The two types appear to behave slightly differently in the horse, according to Dr. Josie Traub-Dargatz, professor of equine internal medicine at Colorado State.

“In challenge studies, the amount of virus that's in the blood of the horse seems to be higher with the neuropathogenic strain than the wild type,” she told the Paulick Report in February 2016. “Also, some people believe the scope of disease and the severity among an exposed population would be greater for this neuropathogenic strain, but there have been a couple of outbreaks associated with the wild type and multiple horses were affected.Some laboratories only report that a sample is EHV-1 and don't do subtyping.”

Learn more about testing for EHV-1, disease control, and quarantine procedures here.

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