Meningoencephalitis in a Koala (Phascolarctos cinereus) Due to Cryptococcus Neoformans var. gattii Infection
Alison Spencer1, B.Sc, B. Vet. Med., Charles Ley3, Paul Canfield1, B.V.Sc., Ph.D., Patricia Martin1, M.V.Sc, and Ross Perry2, B.Sc. (Vet.), B.V.Sc.
1The Department of Veterinary Pathology, University of Sydney, New South Wales 2006, Australia
2Western Suburbs Animal Hospital, 195 Parramatta Rd., Homebush, New South Wales, 2140
3Veterinary science student at the University of Sydney
A 10-yr-old male captive koala (Phascolarctos cinereus) was examined for neurologic signs. The animal had a stress leukogram and a hypoalbuminemia. Cerebrospinal fluid analysis revealed inflammatory disease due to yeasts, which on subsequent culture and biotyping proved to be Cryptococcus neoformans var. gattii. A latex-cryptococcal antigen test (LCAT) on serum gave a high titer of 1:512. At necropsy the koala had an extensive meningoencephalitis and focal pneumonia due to cryptococcal organisms. Cryptococcosis has been recorded in koalas before, but biotyping has not been attempted. In this koala, the source of the organism appeared to be forest red gums (Eucalyptus tereticornis), and it was speculated that the animal was predisposed by immunosuppression, possibly triggered by altered management practices.