Canadian scientists were baffled when in 2001, dead porpoises began washing up on the southeastern shore of Vancouver Island. Autopsies of the animals revealed their lungs were packed with flower-like tumors that left barely enough room for air.
Soon cats and dogs on the island started having trouble breathing, and people began coming to doctors with strange symptoms. They coughed constantly, had headaches and night sweats. X-rays showed lung and brain nodules, but the culprit wasn't cancer. When doctors biopsied the tissue, they discovered an alien strain of yeast.
Cryptococcus gattii as it was named, was once limited to the tropics and sub-tropics, but it suddenly jumped ship around 2000 and started appearing in a new and deadly form. Since then it's spread to mainland British Columbia, Washington and Oregon, and it shows no sign of stopping.
For more on this outbreak, we're joined by Jennifer Frazer, a freelance writer and blogger for Scientific American and the author of a piece about the fungus in this month's issue of the magazine.