Piroplasmosis in Horses by a Vet – 2025 Blood-Borne Disease Prevention Guide 🧬🐴
In this article
Piroplasmosis in Horses by a Vet – 2025 Blood-Borne Disease Prevention Guide 🧬🐴
By Dr Duncan Houston, BVSc
Introduction
Piroplasmosis is a serious, tick-borne blood disease that affects all equines—horses, donkeys, and mules. While rare in some areas, recent outbreaks and global movement of horses have increased its importance in 2025. Caused by protozoan parasites that infect red blood cells, piroplasmosis can cause severe illness—or none at all. This guide explains how to recognize, prevent, and avoid spreading this contagious disease in your herd.
What Is Piroplasmosis? 🧬
- Caused by Babesia caballi or Theileria equi
- These protozoa infect and destroy red blood cells
- Infected horses may show acute illness, die quickly, or remain asymptomatic carriers
How It Spreads 🔄
- Ticks: The most common method—especially Dermacentor, Amblyomma, and Rhipicephalus species
- Contaminated needles: Using the same needle on multiple horses
- Non-sterile dental or surgical instruments
- Tattoo equipment or multidose vials used improperly
Symptoms of Piroplasmosis ⚠️
- Fever
- Lethargy and decreased performance
- Anemia (pale gums)
- Jaundice (yellowing of eyes and gums)
- Dark or red-tinged urine
- Colic-like behavior or weakness
In some cases, horses show no clinical signs but still carry and spread the disease.
Diagnosis 🩺
- Serologic testing (ELISA, IFAT) to detect antibodies
- PCR testing to detect parasite DNA
- Blood smear microscopy for acute cases
What Happens If a Horse Tests Positive? 📋
- USDA requires quarantine or euthanasia in endemic control zones
- Horses may be barred from international travel if positive
- Treatment is possible but not always curative—and does not guarantee the horse becomes non-infectious
Prevention in 2025 ✅
1. Use Sterile Needles & Equipment 💉
- One needle, one horse—always
- Use a new, sterile syringe and needle to draw from any multidose vial
- Never reuse tattoo, dental, or surgical tools without full sterilization
2. Control Ticks & Insects 🦟
- Apply equine-safe tick repellents regularly
- Maintain pasture and reduce brush where ticks thrive
- Inspect horses daily for ticks, especially on legs, under tail, and between jaw and ears
3. Quarantine & Test New Arrivals 🧪
- Isolate new horses for 21 days and test for piroplasmosis
- Especially important for horses coming from abroad or known endemic areas
Case Example: Outbreak Prevention
- A Texas ranch brought in two horses from Mexico for training
- Quarantine and pre-entry testing revealed one was positive for T. equi
- Horse was quarantined indefinitely; no other horses became infected
FAQs About Piroplasmosis
Q: Can piroplasmosis be treated?
A: Some drugs (e.g. imidocarb) may reduce clinical signs or parasite load, but many treated horses remain carriers.
Q: Is it contagious between horses directly?
A: No—requires a tick bite or blood-to-blood contact via tools or needles.
Q: Can humans catch it?
A: No—piroplasmosis is equine-specific. The human form (Babesiosis) is unrelated and tick-borne.
Conclusion
Piroplasmosis is a serious blood-borne disease with long-term consequences for horse health, travel eligibility, and herd safety. While many horses survive infection—or never show signs—they can still spread the disease. In 2025, prevention is everything: practice sterile technique, control ticks, and test new horses. Work with your veterinarian to protect your herd and comply with national biosecurity standards.
Want help testing or preventing piroplasmosis? Visit AskAVet.com or use the app 📱 to speak with Dr Duncan Houston for testing, travel guidance, and outbreak response planning. 🩺🐴
