New York Goat Diagnosed with Listeriosis

By Blake Jackson

A goat in New York was recently diagnosed with listeriosis after developing severe neurological symptoms that eventually led to its death. Diagnostic testing performed at the Cornell University Animal Health Diagnostic Center confirmed the infection caused by the bacterium Listeria monocytogenes.

According to the case report, the goat first showed nonspecific symptoms in March, including loss of appetite and depression. The condition later progressed to opisthotonus, a serious neurological condition that causes abnormal body posture and muscle spasms. The animal eventually died despite care efforts. The goat had been fed into a standard diet of hay and corn, and no signs of bloat were observed during examination.

A field of necropsy completed by the attending veterinarian showed few visible abnormalities. However, additional diagnostic samples submitted to Cornell revealed important findings. Histopathologic testing identified necrosuppurative meningoencephalitis with vasculitis and microabscess formation in the brainstem. Bacterial culture of brainstem tissue later confirmed the presence of Listeria monocytogenes.

Listeriosis is an infectious disease that affects many domestic and wild animals, especially ruminants such as goats, sheep, and cattle. The bacteria can survive under a wide range of environmental conditions, including cold temperatures. Livestock most become infected after eating contaminated feed, particularly poor-quality silage.

The disease can appear in three forms: encephalitic, abortive, and septicemic. The encephalitic form is the most common in ruminants and often causes symptoms such as circling, loss of coordination, head tilt, and facial paralysis. Abortive infections can cause pregnancy loss in late gestation, while septicemic infections may result in fever, depression, reduced appetite, and sudden death.

Veterinary experts say bacterial culture remains the most reliable method for confirming listeriosis. In neurological cases, testing brainstem tissue provides the best diagnostic results. Histopathologic examination can also help support diagnosis by identifying brain inflammation and tissue damage.

More information about livestock diseases and diagnostic services is available through the Cornell Animal Health Diagnostic Center website.

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