Horse Equine Piroplasmosis and Tick-Borne Disease

Equine piroplasmosis is a serious tick-transmitted blood parasite disease that is absent from the UK but poses a growing threat from movement of horses from endemic areas in continental Europe.

Key Facts

Equine piroplasmosis is caused by Theileria equi and Babesia caballi transmitted by Ixodes and Rhipicephalus ticks
The UK is currently free of equine piroplasmosis — it is a notifiable disease and any suspected cases must be reported
Infected horses show fever, anaemia, jaundice, haemoglobinuria, and can die without treatment
Many horses in endemic countries are seropositive carriers showing no clinical signs but remaining infectious to ticks
Movement of horses from endemic countries (Spain, Portugal, Eastern Europe) requires testing and certification
Treatment with imidocarb dipropionate achieves clinical cure but does not always eliminate carrier status

Welfare Considerations

Equine piroplasmosis causes severe acute welfare suffering in clinically affected horses — the combination of profound anaemia from blood cell destruction, haemolysis causing jaundice and kidney damage, and high fever creates a life-threatening systemic illness. Horses without access to treatment in endemic areas may die. The welfare concern for UK horses relates to the risk of disease introduction from horses imported or returning from endemic areas. The notifiable disease status ensures rapid veterinary and APHA response to any UK case, protecting the resident horse population. Tick control on horses travelling to and returning from endemic areas is a preventive welfare measure.

What You Can Do

Test horses returning from endemic countries for piroplasmosis as required by movement regulations and veterinary guidance
Apply appropriate tick prevention before, during, and after travel to endemic areas in southern and eastern Europe
Report any horse with fever, jaundice, and haemoglobinuria to your vet immediately — piroplasmosis must be considered as a differential
Contact APHA if piroplasmosis is suspected in any horse — it is a notifiable disease requiring official investigation