Horse Potomac Horse Fever: Welfare During Acute Disease

Potomac horse fever is a serious tick-transmitted disease causing acute welfare harms including severe diarrhea, laminitis, and abortion in affected horses.

Key Facts

Potomac horse fever (equine monocytic ehrlichiosis) is caused by Neorickettsia risticii transmitted through ingestion of infected aquatic insects
Clinical signs include fever, severe watery diarrhea, laminitis, and pregnancy loss in mares, causing significant acute welfare harms
Geographic distribution follows river systems where infected trematode-carrying aquatic insects are present
Vaccination provides partial protection and oxytetracycline treatment is effective if administered early in disease course
Horses on pasture near streams and rivers during insect emergence seasons are at highest risk

Welfare Considerations

Potomac horse fever causes acute severe welfare harms through profuse diarrhea causing dehydration and electrolyte imbalance, secondary laminitis from endotoxemia causing intense foot pain, and pregnancy loss causing stress and discomfort in affected mares. Rapid diagnosis and early tetracycline treatment dramatically improves welfare outcomes. Supportive care including intravenous fluids, anti-endotoxemic treatment, and laminitis management reduces suffering during recovery. Vaccination in endemic areas provides cost-effective welfare protection before disease exposure occurs.

What You Can Do

Vaccinate horses in endemic areas before the peak exposure season with veterinary guidance
Seek emergency veterinary care for horses showing fever combined with diarrhea in endemic regions
Administer early oxytetracycline treatment when Potomac horse fever is suspected as timing significantly affects outcomes
Manage laminitis risk aggressively during Potomac horse fever treatment given the frequency of this serious complication