Less Typical Courses of Rhodococcus equi Infections in Foals

Simple Summary For decades, Rhodococcus equi infections remain one of the most common causes of death in foals before weaning, coming from endemic studs. The pathogen can create many problems other than its classical form-pneumonia. Such issues are described in the clinical cases presented in this paper. The first case concerns the potential contribution of rhodococcal infection to a grave outcome in a prematurely born foal lost as a yearling. Another presents so-called "extrapulmonary disorders" (EPD) and a theory of inherited immunodeficiency in a breeding dam line from one stud. The third case is connected with a suspected atypical location of the pulmonary abscess. The last example is associated with drug-induced anhidrosis. These clinical pictures may be considered rare or interesting and worth presenting in a scientific report. This article aims to present several interesting and less typical courses of Rhodococcus equi infections in foals, collected during the 2019-2021 foaling seasons in some Polish studs. The study was conducted by the Division of Veterinary Epidemiology and Economics, Warsaw University of Life Sciences-SGGW, and concentrated on ultrasonographic contribution to diagnostics and treatment of the disease. Among many standard cases of rhodococcal pneumonia, some rare ones occurred. The aforementioned issues include the potential contribution of rhodococcal infection to a grave outcome in a prematurely born filly, lost as a yearling, so-called "extrapulmonary disorders" (EPD), a hypothesis of inherited immunodeficiency with grave outcome in a breeding dam line from one stud, and macrolide-induced anhidrosis. The main benefit of this report would be to supplement the general picture of clinical rhodococcosis.