Sudden death in a ewe due to Enterococcus hirae septicaemia

Abstract A 2‐year‐10‐month‐old ewe, found dead 10 days post‐lambing, was submitted for postmortem examination to the Royal Veterinary College. Significant gross findings included subcutaneous and pleural haemorrhages, cortical renal haemorrhages, hydropericardium and a mural haemorrhagic thrombus in the right ventricular wall. Histopathology revealed embolic nephritis and mural thrombotic endocarditis with intra‐lesional coccoid Gram‐positive bacteria. Systemic bacteriology identified Enterococcus hirae , confirming septicaemia due to E. hirae in this adult ewe. Although the pathogenesis remains speculative, bacterial translocation from the intestinal tract or mammary gland was considered the most likely source, with periparturient relaxation of immunity potentially facilitating colonisation of the mural endocardium and subsequent embolic dissemination. This report describes acute mortality and confirmed septicaemia caused by E. hirae in an adult ewe, highlighting the need to consider this opportunistic pathogen as a differential diagnosis of septicaemia in sheep and, potentially, other ruminants.