Neurological Listeriosis in Sheep
(NY) Listeriosis was diagnosed in an adult ewe. The ewe, found down, had a temperature of 104.7° F, was minimally responsive and blind. She died shortly after examination. Feed was round bales and baleage, some poor quality, with no grain. During necropsy it was noted that she was in good condition with abundant body fat, had a good wool coat and had milk in her udder. A fecal egg count was negative for parasites. Formalin-fixed and fresh brain tissue were submitted to AHDC along with other fixed tissues. A sample of fresh brain was sent to New York State Department of Health for Rabies Virus FA testing and was negative. A listeria culture on fresh brain tissue isolated Listeria monocytogenes. Histological examination identified areas of inflammation in the cervical spinal cord. Immunohistochemistry showed areas of strong immunohistoreactivity, confirming bacterial meningitis with Listeria monocytogenes. Listeria monocytogenes causes meningoencephalitis in sheep and can be associated with consuming poorly fermented silage.