An unusual outbreak of erysipelas on a goat farm in Pennsylvania

Erysipelothrix rhusiopathiae infection and septicemia occurred in a 5-d old Boer goat found dead on a farm in western Pennsylvania. On autopsy, there was moderate, focally extensive hemorrhage along the remnants of the urachus and umbilical arteries and the apex of the urinary bladder. Microscopic examination of immunohistochemical stained tissues revealed abundant intracellular and extracellular E. rhusiopathiae antigen-positive bacilli in all tissues stained, including lung, heart, liver, skeletal muscle, kidney, and thymus. Bacteria isolated from liver and urachus were identified as E. rhusiopathiae by MALDI-TOF mass spectrometry and further confirmed by a PCR assay. An epidemiologic investigation was conducted via an on-farm questionnaire after the owners noted a 70% mortality rate from the 2019 kidding season. The epidemiologic investigation showed that E. rhusiopathiae, an opportunistic zoonotic organism, was introduced to the farm through a breach in biosecurity and was likely perpetuated among the resident poultry species.