An international description of the diagnostic approaches used in different institutions to diagnose acute diarrhea in horses and the pathogens detected is lacking. The aim of this multicenter retrospective case series was to describe the diagnostic approach, aetiological agents, outcome and development of laminitis for diarrheic horses worldwide.
Information from horses with acute diarrhea presenting to participating institutions between 2016 and 2020, including diagnostic approaches, pathogens detected and their associations with outcomes, were compared between institutions or geographic regions.
A total of 1438 horses from 26 participating institutions from 4 continents were included. Six-hundred and thirty (44%) were presented to institutions in North America, 483 (33%) in Europe, 149 (10%) in Latin America, 141 (10%) in Australia and 35 (2%) in Japan. Overall, aetiological testing was limited (44% for Salmonella spp., 42% for Neorickettsia risticii [only North America], 40% for Clostridiodes difficile and 29% for equine coronavirus); however, of those tested, 13% (81/633) of horses tested positive for Salmonella, 13% (35/262) for N. risticii, 9% (37/422) for ECoV and 5% (27/578) for C. difficile. The overall survival proportion for diarrheic horses was 76% (1093/1438, range 40-90%). C. difficile positive cases had greater odds of non-survival than horses negative for C. difficile (OR 2.69, 95% CI 1.23–5.91). In addition, horses that were positive for N. risticii had greater odds of developing laminitis than negative horses (OR 2.76, 95% CI 1.12–6.81; p = 0.029).
Bottom Line
This study highlighted limited and inconsistent diagnostic investigations in cases of acute diarrhea in horses. Detection rates of pathogens are similar to previous reports. Non-survival was associated with C. difficile positive results, and development of laminitis was associated with N. risticii.
