RESEARCHERS are warning of a potentially deadly strain of fungus that is spreading among animals and people in the northwestern United States and Canada.
The new strain of the airborne fungus - which is called cryptococcus gattii - appears to be unusually deadly, scientists say.
It had a mortality rate of about 25 percent among the 21 US cases that were analysed for a study.
Symptoms in people and animals may not appear until two weeks or more after exposure and include a cough that lasts for weeks, sharp chest pain, shortness of breath, headache, fever, night-time sweats and weight loss.
"This novel fungus is worrisome because it appears to be a threat to otherwise healthy people," said Edmond Byrnes of Duke University in North Carolina, who led the study.
Researchers said cases had been largely restricted to Vancouver Island but then expanded into neighbouring mainland British Columbia and more recently into Washington and Oregon.
"Based on this historical trajectory of expansion, the outbreak may continue to expand into the neighbouring region of Northern California, and possibly further," the study says.
He added: "Overall it's a pretty low threat, and it's still uncommon in the area, but as the range of the organism expands and the number of cases increases accordingly, it's becoming more of a concern."
The study was published in the Public Library of Science journal PLoS Pathogens.
