Fatal encephalitozoonosis in two koalas.

Abstract

Two young koalas from a fauna park, recently out of the pouch and approximately 6 months old, were found dead with no previous clinical signs or gross lesions. On histopathological examination, large numbers of spores consistent with a microsporidian organism were present intracellularly within the small intestinal mucosa. Electron microscopy and polymerase chain reaction studies (sequencing the 5' end of the SSU RNA gene) identified the organism as Encephalitozoon intestinalis with 100% homology with those of previously reported human isolates. This is believed to be the first report of this organism in a marsupial.