Valvular endocarditis in the horse: 20 cases (1993-2020).

Medical records of 20 horses with a confirmed diagnosis of valvular endocarditis at the Ontario Veterinary College between January 1, 1993 and February 3, 2020 were reviewed. The diagnosis was based on physical examination findings, complete blood (cell) count (CBC), serum biochemistry, echocardiography, blood culture, and post-mortem findings. Common presenting signs included tachycardia, pyrexia, weight loss, lameness/joint distension, and a heart murmur. Clinicopathological findings included leukocytosis, anemia, hypoalbuminemia, hyperglobulinemia, and elevated inflammatory markers. Culture from 5 horses yielded Actinobacillus equuli in 2 cases and Actinobacillus suis in 1 case. Of the 20 horses included in this study, 17 were euthanized and 3 were treated. Only 1 case had follow-up more than 1 year after discharge.