Fasciola hepatica in UK horses.
Authors: Howell A K, Malalana F, Beesley N J, Hodgkinson J E, Rhodes H, Sekiya M, Archer D, Clough H E, Gilmore P, Williams D J L
Journal: Equine veterinary journal
Summary
# Editorial Summary: Fasciola hepatica in UK Horses Whilst liver fluke (Fasciola hepatica) is well-established in UK ruminants, its prevalence and clinical significance in horses has remained largely undocumented. Howell and colleagues conducted a multi-phase investigation combining abattoir surveys, serological testing using a validated ELISA (71% sensitivity, 97% specificity), and a case-control comparison of 269 horses to establish the burden of fluke infection and its association with equine liver disease. Results revealed that 2.2% of abattoir horses harboured adult flukes, whilst sero-prevalence across the wider population reached 8.7%—substantially higher than previously recognised. Sero-positive horses demonstrated significantly elevated odds of liver disease, though clinical presentation proved variable: approximately one-third remained asymptomatic, whilst others exhibited non-specific signs alongside blood biochemistry abnormalities. Critically, genotypic analysis confirmed that equine flukes originate from the same parasite population affecting sheep and cattle, indicating shared grazing-based transmission risk. These findings should prompt equine practitioners to reconsider fluke as a differential diagnosis in cases of unexplained liver dysfunction or poor performance, particularly given the under-recognition documented here. Farriers and coaches working with horses on mixed grazing should advocate for integrated parasite control programmes that account for fluke exposure alongside conventional anthelmintic strategies, whilst veterinarians should consider serological screening when liver disease is suspected.
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Practical Takeaways
- •Liver fluke should be considered as a potential cause of liver disease in horses, as it is more prevalent than previously recognized in UK populations
- •Include F. hepatica screening when investigating horses with suspected liver disease, as many infected horses may show non-specific or no clinical signs
- •Implement fluke control measures as part of integrated parasite management plans for horse operations, particularly on mixed grazing farms with ruminants
Key Findings
- •Sero-prevalence of F. hepatica in UK horses was 8.7%, with 2.2% (4/183) showing adult flukes at abattoir examination
- •Horses with clinical signs consistent with liver disease had significantly higher odds of testing ELISA-positive for F. hepatica compared to controls
- •One-third of 23 sero-positive horses showed no clinical signs, while others displayed non-specific clinical signs and blood test abnormalities
- •Genotypic analysis confirmed that liver flukes from horses originate from the same parasite population as those found in sheep and cattle