Alien Invasion: The Fungus That Came to Canada

His doctor was skeptical, but a chest X-ray showed nodules in his lung -- either cancer or the fungus. To James's relief, it was gattii, and after a year of oral medication, he is cured.

"Did I walk past a tree when the fungus was exploding? Who knows," he said. "If I hadn't seen that news report, things could have been very different for me."

By the start of 2003, Bartlett's students had found the fungus in other spots. They eventually concluded that it had infested a several-hundred-mile range on eastern Vancouver Island. Health authorities agreed with business leaders in the adjacent city of Parksville that it was no longer fair to target the park alone, and warning signs at the Rathtrevor Beach park came down in favor of a wider information campaign.

Health authorities still are struggling to strike the right balance with the public. "It's serious, but it's still a very rare disease. Much rarer than influenza, for example," said Eleni Galanis, epidemiologist at the B.C. Center for Disease Control. "People need to be aware of it, in order to treat it. But we don't want people to stop going outside."

If doctors catch the disease early, oral doses of antifungal drugs will kill the cells. Undetected, the fungus can get into the spinal fluid, causing potentially fatal meningitis.

Young went home sick in February 2002. By that summer, she could not walk, had lost her ability to speak, had gone temporarily blind and was slowly starving because she could not keep food down. By the time doctors tested her, the fungus had reached her brain.

"My poor sister couldn't even tell anyone how she was feeling," said Deborah Chow, 51, reminiscing with her family. Finally, with Young's pain clear and the end inevitable, Chow held her sister in the hospital and whispered, "It's okay to go. Dad will be okay. Your son will be okay." She died 45 minutes later.

New cases on Vancouver Island have leveled off at about 25 a year. Eight people have died. Bartlett's focus now is to figure out whether -- and how -- the fungus is moving.

Five human cases have been found on the British Columbia mainland; two people have been sickened in Washington state; and Oregon has had two fatalities from a similar but not identical strain of gattii. Health authorities in Washington and Oregon say the disease is still too rare in their areas to warrant alarm, but they are watching it. Bartlett said it is unclear whether the fungus has been tracked elsewhere on the bottom of shoes or in wheel wells.

"One possibility for what we are seeing on the mainland is the first colonization, like we had on the island in 1999," Bartlett said. Another is that those traces will disappear.

The infected porpoises -- at least 25 of them now -- suggest the fungus is carried by air over the water. Stephen Raverty, a pathologist at the provincial veterinary center in British Columbia, worries that the fungus can attack other species.

Killer whales, whose numbers have dropped sharply here, are cetaceans like the stricken Dall's porpoises. Raverty and others have been tracking the killer whales in Puget Sound, using glassine slides mounted on long poles to catch droplets from the whales' exhalations, to see whether the animals have been infected.

So far, they haven't found the fungus. But animals can act as a sentinel for humans, the scientists say.

"These are the types of things we will see with climate change," Fyfe said. "As the weather in North America gets warmer, we are more likely to be affected by these public health threats."