08/24/2026
🐴 POTOMAC HORSE FEVER: IS YOUR HORSE PROTECTED?
Potomac Horse Fever (PHF) is a serious, seasonal intestinal disease caused by Neorickettsia risticii. Horses can become infected after accidentally ingesting aquatic insects, such as mayflies and caddisflies, carrying the bacteria.
PHF can cause significant illness, including:
🌡️ High fever
💩 Diarrhea and loss of appetite
🤕 Colic
🦶 Painful laminitis
🐴 Abortion in pregnant mares
PHF is not contagious from horse to horse. Instead, environmental exposure plays an important role in transmission.
As PHF continues to be an important concern for horses in our region, we recommend vaccination every 6 months, regardless of whether your horse travels 💉
Has your horse never received a PHF vaccine?
The initial vaccination series consists of:
➡️ An initial dose
➡️ A booster 3–4 weeks later
➡️ Then vaccination every 6 months
If you're not sure when your horse is due, or if you're starting the PHF vaccine series, contact our clinic and we can help you determine the appropriate vaccination schedule for your horse.