Infectious agents associated with diarrhoea in neonatal foals in central Kentucky: a comprehensive molecular study.
Authors: Slovis N M, Elam J, Estrada M, Leutenegger C M
Journal: Equine veterinary journal
Summary
# Editorial Summary: Infectious agents in neonatal foal diarrhoea Diarrhoeal disease in young foals often involves multiple pathogens acting simultaneously, yet most diagnostic approaches have focused on single infectious agents. Slovis and colleagues conducted a retrospective molecular study of 88 Thoroughbred foals (37 healthy, 51 with clinical gastrointestinal disease) using real-time PCR to screen faecal samples for nine common infectious agents across Kentucky studfarms. Equine rotavirus proved most prevalent overall at 34.6%, but the critical finding was that coinfections occurred significantly more often in diseased foals (22 out of 51) than healthy ones (4 out of 37), with 63.2% of symptomatic foals carrying at least one detectable pathogen compared to 43.2% of asymptomatic foals. Notably, six of the nine agents showed statistical association with disease—including Clostridium difficile, Cryptosporidium and Neorickettsia risticii—whilst equine coronavirus and Rhodococcus equi did not, suggesting these latter organisms may be incidental findings. For practitioners, this work emphasises the value of comprehensive molecular panels over single-pathogen diagnostics when investigating neonatal diarrhoea, as simultaneous detection of multiple agents provides clinically meaningful prognostic information and may better guide targeted antimicrobial and supportive therapy decisions.
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Practical Takeaways
- •Use multiplex PCR panels rather than single pathogen tests when evaluating foal diarrhoea, as coinfections are significantly associated with disease and may be missed by targeted testing
- •Rotavirus is the most common infectious cause of neonatal diarrhoea in Kentucky Thoroughbreds and should be a primary diagnostic target
- •Coinfections are common in sick foals; presence of multiple agents increases disease risk, so management must address multiple potential pathogens simultaneously
Key Findings
- •Equine rotavirus was the most prevalent infectious agent at 34.6%, while Lawsonia intracellularis was not detected (0%)
- •Coinfections were significantly more frequent in GI-diseased foals (22 of 51) compared to healthy foals (4 of 37; P = 0.0002)
- •Overall prevalence of any infectious agent was 63.2% in diseased foals versus 43.2% in healthy foals
- •Six of nine agents tested were associated with GI disease; equine coronavirus and Rhodococcus equi were not significantly associated with clinical signs