Generalised Listeria monocytogenes infection in a dog

A 6-year-old Doberman bitch was presented for an acute onset of circling, hemiparesis and depression. Clinical examination revealed conjunctivitis, abdominal pain, anaemia, decreased facial sensation, decreased jaw, tongue and pharyngeal tone, decreased conscious proprioception, decreased flexor withdrawal reflexes, and abnormal hemiwalking and hemistanding. Pancytopaenia was evident on haematological evaluation. Bone marrow cytology revealed a bacterial infection. Cerebrospinal fluid analysis was normal. Despite antibiotic treatment, the dog died. On autopsy, widespread multifocal inflammatory lesions were found to be present in the lungs, liver, spleen, meninges, lymph nodes, adrenal glands and kidneys. Listeria monocytogenes was isolated in pure culture from these organs and tissues. Histopathological examination showed numerous gram-positive intracellular rod-shaped bacteria seen in all the above-mentioned organs.