Prevalence of liver fluke infection in Irish horses and assessment of a serological test for diagnosis of equine fasciolosis.
Authors: Quigley A, Sekiya M, Egan S, Wolfe A, Negredo C, Mulcahy G
Journal: Equine veterinary journal
Summary
# Liver Fluke in Irish Horses: Prevalence and Diagnostic Challenges Fasciola hepatica infection in horses has received limited scientific attention despite its potential consequences for equine health; Quigley and colleagues addressed this knowledge gap by surveying 200 horses at an Irish abattoir between May 2013 and April 2014, using post-mortem liver examination as the gold standard against which to evaluate a serological diagnostic test. Post-mortem inspection revealed a 9.5% prevalence of liver fluke infection, yet surprisingly, infected horses showed no significant differences in body condition score, serum liver enzyme activities, faecal strongyle burden, or haematological parameters compared to uninfected animals, suggesting either subclinical disease or compensatory metabolic responses in this population. When the researchers evaluated a recombinant cathepsin L1 (CL1) ELISA—a serological test designed to detect antibodies against the parasite—they found high specificity (95.6%) but poor sensitivity (42.1%), meaning the test correctly ruled out infection in most negative cases but missed nearly 60% of naturally infected horses. These findings have important practical implications: conventional blood work cannot reliably indicate fluke status in individual horses, and practitioners cannot depend on this particular serological test for diagnostic confirmation, necessitating alternative detection methods such as faecal analysis or ultrasonography for horses with suspected fasciolosis. The detection of fluke infection in nearly 1 in 10 horses warrants further investigation into whether chronic low-level infection affects performance, fertility, or resilience to other health challenges in equine populations.
Read the full abstract on PubMed
Practical Takeaways
- •Liver fluke affects approximately 1 in 10 horses in Ireland; clinical significance and treatment protocols need clarification through further research
- •The CL1 ELISA cannot be relied upon as a diagnostic test for equine fasciolosis due to poor sensitivity; negative results do not rule out infection
- •Traditional clinical indicators (body condition, bloodwork) are unreliable for identifying fluke-infected horses; necropsy or histological examination remain gold standard diagnostic methods
Key Findings
- •Prevalence of F. hepatica infection in Irish horses was 9.5% (19/200)
- •CL1 ELISA showed high specificity (95.6%) but low sensitivity (42.1%) for fluke diagnosis
- •No significant correlation found between liver fluke infection status and body condition score, age, sex, breed, serum liver enzyme activities, or strongyle infection status
- •Blood biomarkers are poor indicators of liver fluke infection in horses