Equine Piroplasmosis

What is Equine Piroplasmosis?

Equine Piroplasmosis is a blood-borne protozoal infection caused by Theileria (Babesia equi and/or Babesia caballi that is carried and transmitted by ticks.  The protozoa can also be transferred from an infected horse by using contaminated needles, syringes, catheters or intravenous tubing.  Horses are often carriers and don’t show any clinical signs. Piroplasmosis is not endemic in the United States but infected horses illegally brought to the US can be the source of the disease.

Clinical Signs: Clinical signs of acute equine piroplasmosis are the following:

  • Weakness 
  • Lethargy
  • Lack of appetite
  • Fever
  • Anemia
  • Jaundice
  • Swollen abdomen
  • Labored breathing
  • Constipation
  • Colic
  • Hemoglobinuria (red urine)

Diagnosis: Diagnosis is made by measuring antibody titers to the organism in serum (a component of whole blood), using an ELISA (enzyme-linked immunosorbent assay), CFT (complement fixation test), or IFA (immunofluorescent assay). The parasite can also be detected by microscopic examination of a blood smear.

Treatment: All EP-infected horses are managed under official state quarantine. Treatment for EP requires enrollment in the USDA-APHIS EP treatment program in which a high-dose imidocarb dipriopionate protocol is used to achieve permanent clearance of the organism from the horse. The time to reach negative antibody status varies and can take from several months to 2 years after completion of successful treatment.

Prevention: Use of sterile needles, syringes and intravenous catheters. Instruments contaminated with blood should be cleaned and sterilized before using on other horses. 


April 30, 2021
Polk County, IA
Confirmed Case(s) - Official Quarantine