OVC vets lead information night on Potomac Horse Fever

Horse owners are invited to attend an information session about Potomoc Horse Fever on Thursday, Sept. 13 at 7 p.m. at the Sandford Community Centre, located at 433 Sandford Rd. near Uxbridge.

Speakers include Dr. John Baird and Dr. Luis Arroyo from the Ontario Veterinary College.

You are asked to RSVP through one of the following host veterinary clinics:

  • Ballantrae Plaza Equine Veterinary Services at 289-380-6424
  • Brelmar Veterinary Clinic at 705-357-3184
  • Caledon Equine Hospital at 855-838-0961
  • Cannington Veterinary Services at 705-432-3392
  • Port Perry Veterinary Services at 905-982-1243

About Potomac Horse Fever
Prepared by:  Dr. JD Baird and LG Arroyo

POTOMAC HORSE FEVER (PHF) is a seasonal infectious disease caused by a bacterium called Neorickettsia risticii.  This is not a contagious disease. PHF occurs in Ontario mainly between July and September (summer months).  Cases are usually sporadic, which means that on a particular farm only one or two cases may be seen during the summer months.  Most of the cases in Ontario have been reported from eastern and southwestern Ontario. 

There is a great deal of variation in the severity of the clinical signs that an individual horse may exhibit.  Some horses may show some of the following signs: depression (in 90% of cases), anorexia (“off-feed” in 80% of cases), fever (in 70% of cases), diarrhea (60%) and mild colic (30%).  A high percentage (20-25%) of cases may progress to develop laminitis (inflammation of the hoof), which is the most serious complication.

Early diagnosis and treatment of these cases by veterinarians is often very successful.  Severe cases may require intensive treatment including intravenous fluids.

Recent studies conducted on the life cycle of the bacteria responsible for this disease have shown that snails and aquatic insects such as caddisflies, mayflies, and dragonflies are common carriers of the bacterium. Ingestion of contaminated hay, grain, pasture or drinking water with dead insects may result in clinical signs.

The drug of choice to treat PHF is oxytetracycline and should be administered by a licensed veterinarian. Vaccines are available however their efficacy has been questionable.


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