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.

Additional evaluation of undiagnosed bovine abortion cases may reveal fetal neosporosis.

Diagnosis of Neospora caninum associated bovine abortion is often made by histological examination of fetal tissues, although this procedure is not very sensitive. One hundred and forty-four undiagnosed bovine abortion cases were evaluated for N. caninum associated bovine abortion using a revised diagnostic protocol. As a result, 12 (8.3%) of these previously undiagnosed bovine abortion cases were definitively diagnosed as N. caninum positive. The 12 new positive cases included 7 that had exhibited histological lesions, and 5 that had not exhibited histological lesions when examined prior to this study. None of the 12 cases had been immunohistochemically (IHC) stained prior to this study. Also, IHC staining implemented during this research revealed tachyzoites without associated histological lesions in at least 1 tissue from 69 (47.9%) of 144 aborted bovine fetuses, and positive IHC staining of cytoplasmic N. caninum antigen in macrophages in at least 1 tissue from 44 (30.6%) of 144 aborted bovine fetuses. These results demonstrate the necessity for more aggressive evaluation of bovine fetuses for neosporosis.