Prevalence, lesions, and differential diagnosis of Ollulanus tricuspis infection in cats

Ollulanus tricuspis were found in the stomachs of 26 of 201 cats which were mainly from Washington and Idaho. Twenty-four of the cats were from research or commercial breeding colonies (catteries) and two were pets. Twenty-seven percent of colony cats were infected with O. tricuspis, whereas only 2% of the pet cats were infected. No consistent clinical signs were seen. Histologically there was a significant increase in fibrous connective tissue in the lamina propria and in the number of lymphoid follicles and globule leukocytes in the gastric mucosa of infected cats. Histologic examination revealed no parasites in 13 of the 26 infected cats. The 26 infected cats were identified by examination of stomach washings. An additional 21 cats had larvae of other nematodes in their stomachs. These nematode larvae need to be differentiated from O. tricuspis.