Projecting global occurrence of Cryptococcus gattii

Abstract

Cryptococcus gattii and C. neoformans cause pulmonary and systemic cryptococcosis. Recently, C. gattii was recognized as a distinct pathogen of humans and animals. We analyzed information from 400 publications (1948-2008) to examine whether the fungus occurs globally. Known distribution of C. gattii is possibly limited because specialized reagents for differentiation from C. neoformans are not readily available and not always used, and environmental surveys are patchy. However, autochthonous reports of C. gattii cryptococcosis have now been recognized from tropical and temperate regions. An ongoing outbreak in western Canada strengthens the case that the range of the pathogen has expanded. A few studies have highlighted differences in cryptococcosis between C. gattii and C. neoformans. More than 50 tree species have yielded C. gattii especially from decayed hollows suggesting a possible ecologic niche. This pathogen merits more attention so its environmental occurrence and role in cryptococcosis can be accurately determined.

Figure

Worldwide isolations of Cryptococcus gattii from human clinical, veterinary, and environmental sources. Circles indicate serotype information, diamonds indicate genotype information, and rectangles indicate hybrids between C. gattii and C. neoformans. Existing reports and survey are patchy, and several areas between positive regions share tree species (Table 2) and climatic conditions and would most likely harbor the pathogen. Thus, C. gattii is likely to be more widely distributed than documented.