Diagnostic approaches, aetiological agents and their associations with short-term survival and laminitis in horses with acute diarrhoea admitted to referral institutions.
Authors: Gomez Diego E, Arroyo Luis G, Schoster Angelika, Renaud David L, Kopper Jamie J, Dunkel Bettina, Byrne David, Toribio Ramiro E
Journal: Equine veterinary journal
Summary
This international multicentre review examined diagnostic practices and outcomes in 1,438 horses with acute diarrhoea across 26 institutions on four continents between 2016 and 2020, investigating which pathogens were detected and their associations with mortality and secondary laminitis. Aetiological testing remained inconsistently applied across institutions, with only 29–44% of cases screened for common causative agents including Salmonella spp., Clostridiodes difficile, Neorickettsia risticii and equine coronavirus (ECoV); when testing did occur, positivity rates were modest at 5–13% for most organisms. *Clostridiodes difficile* positivity was strongly associated with non-survival (odds ratio 2.69), whilst *N. risticii* infection significantly increased the risk of developing laminitis (odds ratio 2.76), findings with clear prognostic implications for clinical decision-making and owner counselling. The results underscore substantial variation in diagnostic protocols between referral centres worldwide and highlight the importance of systematic pathogen screening in acute diarrhoea cases, particularly given the established links between specific infectious agents and life-threatening complications such as laminitis—a consideration that should inform both immediate treatment strategies and longer-term farriery and rehabilitation planning for surviving horses.
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Practical Takeaways
- •Acute equine diarrhoea workups remain inconsistent globally; consider advocating for standardized diagnostic protocols at your referral center, particularly C. difficile and N. risticii testing, as positive results carry prognostic significance
- •Monitor N. risticii-positive diarrhoeic horses closely for laminitis development as a complication; this secondary laminitis risk warrants preventive farriery management and close observation during recovery
- •C. difficile-positive cases have significantly worse survival outcomes; early identification of this pathogen should inform intensive care protocols and owner discussions about prognosis
Key Findings
- •Only 29-44% of horses with acute diarrhoea received aetiological testing across 26 institutions, with Salmonella (13%), N. risticii (13%), ECoV (9%), and C. difficile (5%) detection rates among tested horses
- •C. difficile-positive cases had 2.69 times greater odds of non-survival compared to negative cases (95% CI: 1.23-5.91)
- •N. risticii-positive horses had 2.76 times greater odds of developing laminitis than negative horses (95% CI: 1.12-6.81; p=0.029)
- •Diagnostic approaches and pathogen prevalence varied significantly between the 26 institutions across 4 continents