Figure 3.

Suggested natural cycle of Cryptococcus gattii and events leading to cryptococcosis. The available information indicates the pathogen can cycle through plants, soil, air and water without any intermediate live hosts (solid line with arrows). Yeast cells of either mating type (MATα or MATa) have been repeatedly isolated from trees especially hollows (solid circle); it is not yet known if cells of C. gattii cells complete their sexual cycle in nature as has been shown in the laboratory (dotted circle). Humans and animals (domestic and wildlife) coming in contact with fungal propagules (yeast cells or sexual spores) mostly remain asymptomatic (dotted lines with arrows), but a small number of infected humans and animals develop serious infections of the lungs and brain. These drawings are not to exact scale. Graphic artist: Andrew Bentley.