Equine trypanosomiasis, a systematic review: Disease management.
Authors: Raftery Alexandra G, Gummery Lauren, Garcia Karelhia, Mohite Dinesh, Capewell Paul, Sutton David
Journal: Equine veterinary journal
Summary
# Editorial Summary: Equine Trypanosomiasis Management Equine trypanosomiasis remains a neglected protozoal disease with significant welfare and economic implications across affected regions. Raftery and colleagues conducted a systematic review of 30 studies (spanning 1980–2022) to evaluate how disease management interventions affect disease severity in individual horses and prevalence at population level, finding substantial variation in treatment efficacy across the four main *Trypanosoma* species affecting equines. Whilst trypanocides effectively clear blood parasitaemia in *T. evansi* infections, clinical relapse occurred in approximately one quarter of treated animals (25% of 241 horses), and poor prognosis was evident once neurological signs developed (63% mortality in 12 of 19 affected horses), whereas *T. equiperdum* showed potential curability with combination protocols before central nervous system invasion. Population-level data supported multifaceted control programmes as more effective than treatment alone, with early intervention (within 2 days of infection) yielding superior outcomes; importantly, adverse effects remained uncommon overall (1% of 7,888 horses), though isometamidium chloride carried a notable shock response risk (13%). The evidence underscores that whilst trypanocides remain valuable short-term interventions for haemolymphatic disease, reliance on chemotherapy in isolation is insufficient—optimisation of treatment protocols to prevent relapse and neurotrypanosomiasis, alongside integrated vector and epidemiological control strategies, is essential for improving outcomes in practice.
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Practical Takeaways
- •Early detection and treatment initiation within 2 days of infection significantly improves clinical outcomes; establish rapid diagnostic protocols
- •Once neurological signs develop, prognosis is poor regardless of treatment; focus on prevention and early-stage haemolymphatic disease management
- •Monitor closely for severe adverse reactions to isometamidium chloride (shock response in ~13% of treated horses); have appropriate emergency support available during treatment
Key Findings
- •Trypanocides were effective for blood parasitaemia clearance in T. evansi, but clinical relapses occurred in 25% of treated equines (60/241)
- •Neurological disease had poor prognosis with 63% mortality (12/19 equines) despite treatment
- •Early treatment (<2 days post-infection) was more effective than delayed treatment at population level
- •Isometamidium chloride at 0.5 mg/kg i.v. caused shock response in 13% of treated equines (14/105), though overall side effects were rare at 1% (70/7888)