Evidence of zoonotic transmission of Cryptococcus neoformans from a pet cockatoo to an immunocompromised patient

Background: Although cryptococcosis has been associated with birds for almost 50 years, point sources for infection have not been identified. Objective: To document zoonotic transmission of Cryptococcus neoformans. Design: Case report. Setting: A home in Boston, Massachusetts. Patient: A 72- year-old woman who received a diagnosis of cryptococcal meningitis in November 1998. The patient, who had been taking immunosuppressant drugs since undergoing renal transplantation in 1989, owned a pet cockatoo. Measurements: Cryptococcus neoformans was isolated from the feces of the cockatoo. Isolates from excreta and from the patient were compared by using biochemical profiles, monoclonal antibody binding patterns, restriction fragment length polymorphism analysis, and karyotyping. Results: The isolates from the patient and the cockatoo had identical biochemical profiles, the same monoclonal antibody immunofluorescence patterns, and indistinguishable patterns on restriction fragment length polymorphism analysis and karyotyping. Conclusions: The indistinguishable patient and cockatoo isolates strongly suggest that the patient's infection resulted from exposure to aerosolized cockatoo excreta. Although the incidence of cryptococcal infection due to such exposure is unknown, it may be prudent to advise immunocompromised patients to avoid pet birds and avian excreta.