Kitten in the Netherlands with encephalitozoonosis: histopathology, PCR and immunohistochemistry.

Encephalitozoon cuniculi is known to infect human beings, dogs, mink, cats, rodents, foxes, goats, horses, non-human primates, rats, ticks and the main host the rabbit (Oryctolagus cuniculus). Reports of E cuniculi in domestic cats (Felis catus) with histopathological changes are rare. This report describes an E cuniculi infection in the brain and kidneys of a six-week-old kitten. Postmortem examination was performed and microscopical examination of the brain and kidney revealed nodular infiltrates associated with Gram-positive microsporidian spores consistent with E cuniculi. PCR and immunohistochemistry confirm the findings. While E cuniculi infection in domestic cats is rare, this case demonstrates that it should be taken into consideration as a differential diagnosis for kittens with poor weight gain. Given the serious course of the disease and the risk of transmission to other littermates or other mammals including human beings, it is important to rule out an E cuniculi infection.