Horses are exposed by inadvertently ingesting aquatic insects infected with flukes carrying the bacteria and by drinking flukes directly from rivers or streams. | Photo: Photos.com

An attending veterinarian in New Hampshire confirmed that seven horses were exposed and one Rockingham County horse tested positive for Potomac horse fever (PHF) on Aug. 22. The affected 30-year-old Quarter Horse gelding began showing signs of fever, inappetence, and acute laminitis on Aug. 15 and was subsequently euthanized due to severe deterioration of his condition on Aug. 19.

Because PHF is not a reportable disease in New Hampshire, state officials are unable to provide statistics for the number of cases and whether numbers are within the “normal” range.

“I have not seen any other confirmed cases of PHF in New Hampshire this year,” said attending veterinarian Rachel Roemer, DVM, of Great Bay Equine, in Portsmouth, New Hampshire. “I have seen other cases in the past, but I believe all of the confirmed cases I have seen personally were likely infected out of state. This horse had not left the area in many years, so he was definitely infected here, which is pretty unusual. I do have colleagues who have seen cases that were confirmed to be infected with PHF in New Hampshire and were thought to be locally infected in years past, but I don’t know of any in the past two to three-plus years