Strange Fungi Now Stalk Healthy People
A strange fungal disease in Canada and the U.S. heralds a new threat to human health
In 2001 dead porpoises with yeast-packed lungs washed up on the southeastern shore of Vancouver Island in British Columbia. The bloated organs were several times normal weight, with barely any room for air. The island's veterinarians had never seen anything like it. Cats and dogs there were having trouble breathing, too. In cats, the disease could cause a particularly gruesome symptom: weeping holes, produced when a yeast infection ate its way through the skull. At the same time, a few people on the island, located off Canada's Pacific Coast, also began falling ill with an unknown respiratory malady. They coughed constantly, their energy sapped, their sleep stolen. Chest x-rays revealed ominous lung or brain nodules. Biopsied tissue, however, proved the culprit to be not cancer but yeast.
Despite their varying symptoms, the pets, porpoises and humans all shared a single tormenter: Cryptococcus gattii. This fungus had never been seen on the island before, nor was it known to survive outside the tropics and subtropics. Now it was present in the environment, although no one knew where it had come from or how long it had been there. Most worryingly, no one knew how many would be sickened or how far the upstart yeast might travel.
Cryptococcus gattii grows as cream-colored colonies on a laboratory plate.Image: Zachary Zavislak
In Brief
- An airborne yeast that was found to have sickened apparently healthy people on Vancouver Island in British Columbia in 2001 became the first known human fungal pathogen to suddenly become more virulent in a place where the organism was previously unknown.
- Determining where the yeast came from proved difficult. Eventually researchers realized that it was hiding out in surprising locations and that its emergence as a cause of serious illness in British Columbia may well have been prompted by climate change and land development.
- The outbreak is expected to continue. Better diagnostic tools could increase preparedness. Stronger oversight of plant and animal transport across borders, as well as the development of more effective antifungal drugs and vaccines, also could help.
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