Listerial mesenteric lymphadenitis in 3 cats.

Listeriosis is a rare disease in cats with naturally occurring cases usually being identified in individual animals. Listerial mesenteric lymphadenitis has not been described previously in cats. To describe the clinical and histological features of listerial mesenteric lymphadenitis in cats as well as treatment outcome. Listerial mesenteric lymphadenitis was confirmed in 3 cats by histology, immunohistochemistry, and bacterial culture. The affected cats were young to middle aged and were examined for various clinical signs. On both palpation and abdominal ultrasound examination, all cats had marked mesenteric lymphadenomegaly. Survival was prolonged in all 3 cases. Two of the 3 cats were fed a raw meat-based diet before they developed clinical illness. Lymphadenitis caused by listeriosis has a protracted time course and should be a differential diagnosis for abdominal lymphadenopathy in young to middle-aged cats. Feeding of a raw meat-based diet may be a contributing factor for development of listeriosis in cats.