Jpn. J. Infect. Dis., 55, 31-32, 2002

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Laboratory and Epidemiology Communications

A Queensland Koala Kept in a Japanese Zoological Park was Carrier of an Imported Fungal Pathogen, Filobasidiella neoformans var. bacillispora (Cryptococcus neoformans var. gattii)

Koichi Makimura1,2*, Mizuki Karasawa3, Humio Hosoi3, Toshiki Kobayashi3, Nanako Kamijo3, Kazuhiro Kobayashi3, Hiroshi Hiramatsu3, Takako Akikawa3, Tomoko Yabe3, Ayumi Yamaguchi3, Osamu Ishida3, Arisa Murakamil, Ryuichi Fujisakil, Yayoi Nishiyamal,2, Katsuhisa Uchidal and Hideyo Yamaguchil,2

1Teikyo University Institute of Medical Mycology and 2Genome Research Center, Teikyo University, 359 Otsuka, Hachioji, Tokyo 192-0395 and 3Tama Zoological Park, Hodokubo 7-1-1, Hino-shi, Tokyo l91-0042

Communicated by Hiroshi Yoshikura

(Accepted April 8, 2002)

Filobasidiella neoformans var. bacillispora (anamorph: Cryptococcus neoformans var. gattii) (1) was isolated from a Queensland koala (Phascolactos cinereus adustus) kept in a zoological park in Japan. To our knowledge, this is first isolation of the variant yeast from an animal or human resident in Japan.

A four-year-old male koala (born in the Taronga Zoo, Australia) died of various neurological disorders, including exophthalmos and swelling of the back of the left eye (Fig. 1) and appetite loss. Yeasts were isolated as pure cultures from nose discharge and autopsy materials (brain, nasal cavity, and lung), and diagnosed as Cryptococcus neoformans on the basis of the characteristic thick capsules. Examination by an assimilation test, serological test, and molecular biological test (2) revealed that the yeasts were F. neoformans var. bacillispora.

Cryptococcosis is one of the four life-threatening, deep-seated fungal infections (pulmonary cryptococcosis, meningoencephalitis, etc.) in Japan, and the infection is generally acquired by inhalation. This species of basidiomycetous yeast has two varieties: a Japanese domestic variety, F. neoformans var. neoformans (serotypes A and D) (3) and one known only as an imported mycoses-causing variety, F. neoformans var. bacillispora (serotypes B and C) (4). The endemic area of F. neoformans var. bacillispora infection is geographically restricted to tropical countries including Australia, Brazil, Southern California, Thailand, and others (1).

The clinical features of the cryptococcosis caused by the two varieties are similar, but infection due to F. neoformans var. bacillispora tends to require lengthy antifungal treatment, and is associated with more neurological sequelae than that due to F. neoformans var. neoformans (1). Therefore, from a clinical point of view, differentiation diagnosis of the two agents is important.

F. neoformans var. neoformans is present in pigeon droppings, a major source of infection, but F. neoformans var. bacillispora is not, as it is thermosensitive and cannot survive in pigeon intestine (1). In the endemic area, this yeast has been isolated from red gum trees (Eucalyptus spp.) (1), rotting trees (5), and animals including koala (1). In the present case, the fungus was not isolated from the cage, its surroundings, red gum trees provided as feed, or the zookeepers who had been taking care of the koala. Five other koalas kept in the same cage were free of the symptoms of the infection. Therefore, the risk of the spread of the infection appeared low in the zoological park. It should be noted also that deep-seated mycoses including cryptococcosis are not usually transmitted from animal to human or human to human. The koala probably acquired the infection in the Taronga Zoo in Australia, where it was born. The details of the present case will be reported elsewhere.

This study was partly supported by Health Science Research Grants for Research on Emerging and Re-emerging Infectious Diseases from Ministry of Health, Labour and Welfare of Japan.

REFERENCES

  1. Sorrell, T.C. (2001): Cryptococcus neoformans variety gattii. Med. Mycol., 39, 155-168.
  2. Makimura, K., Tamura, Y., Mochizuki, T., Hasegawa, A., Tajiri, Y., Hanazawa, R., Uchida, K., Saito, H. and Yamaguchi, H. (1999): Phylogenetic classification and species identification of dermatophyte strains based on DNA sequences of nuclear ribosomal internal transcribed spacer I regions. J. Clin. Microbiol., 37, 920-924.
  3. Kohno, S., Varma, A., Kwon-Chung, K.J. and Hara, K. (1994): Epidemiology studies of clinical isolates of Cryptococcus neoformans of Japan by restriction fragment length polymorphism. J. Jpn. Assoc. Infect. Dis., 68, 1512-1517.
  4. Tsunemi, T., Kamata, T., Fumimura, Y., Watanabe, M., Yamawaki, M., Saito, Y., Kanda, T., Ohashi, K., Suegara, N., Murayama, S., Makimura. K., Yamaguchi, H. and Mizusawa, H. (2001): Immunohistochemical diagnosis of Cryptococcus neoformans var. gattii infection in chronic meningoencephalitis: the first case in Japan. Intern. Med., 40, 1241-1244.
  5. Fortes, S. T., Lazera, M.S., Nishikawa, M.M., Macedo, R.C. and Wanke, B. (2001): First isolation of Cryptococcus neoformans var. gattii from a native jungle tree in the Brazilian Amazon rainforest. Mycoses, 44, 137-140.

*Corresponding author: Tel: +81-426-78-3256, Fax: +81-426-78-3256, E-mail: makimura@main.teikyo-u.ac.jp

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