In many horses, the first or only sign of EHV-1 infection is fever, which can go undetected. | Photo: Stephanie L. Church/The Horse
The Arizona Department of Agriculture has confirmed three additional cases of equine herpesvirus-1 (EHV-1) in Maricopa County, the Equine Disease Communication Center (EDCC) reported May 16.
On May 11, the EDCC said an unvaccinated 5-year-old Quarter Horse gelding exhibited acute onset neurologic signs—including ataxia (incoordination) and weakness—before testing positive for EHV-1 on May 7. At that time, the EDCC said that horse was recovering. They noted that 13 horses at his home premises were considered exposed.
Subsequently, three exposed horses were confirmed EHV-1-positive on May 14, the EDCC said:
- A 12-year-old vaccinated pony became lethargic on May 10 and is recovering;
- A 20-year-old undervaccinated Quarter Horse started exhibiting ataxia (incoordination) and muscle fasciculation (twitching) on May 9 and is recovering; and
- Another undervaccinated horse became ataxic on May 10 and is recovering.
Maricopa County, Arizona
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