Cryptococcus gattii outbreak expands into the Northwestern United States with fatal consequences.

In the past decade, the primary fungal pathogen Cryptococcus gattii has evolved and adapted to the temperate climate of the Pacific Northwest region of North America. This pathogen is now endemic and an increasingly common cause of life-threatening pulmonary and central nervous system infections that are difficult to manage and, in some cases, fatal to humans and other mammals throughout the region. A series of recent reports provide evidence that evolutionary, climatic, and anthropogenic factors may be causing the expansion of the Vancouver Island outbreak genotype into the United States, with the concomitant emergence of a unique genotype in the state of Oregon. Ongoing studies address the molecular epidemiology, roles of mating and genetic exchange, and geographic origins of this unprecedented outbreak of fungal infection of considerable public health magnitude.