CDC: rare fungus a factor in 15 deaths since 2004

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New data from the Centers for Disease Control and Prevention shows that, since 2004, an aggressive strain of the Cryptococcus gattii fungus has caused at least 60 infections, and among the 45 for which the outcome is known, 15 deaths, the Associated Press reports. The fungus is currently concentrated in the Pacific Northwest — according to the CDC, of the 60 cases since 2004, 15 have been in Washington state, 43 in Oregon, and one each in California and Idaho. C. gattii grows on trees and experts believe it infects humans if they breathe in its tiny spores, yet health officials say that the overall risk to public health remains very low and that there is no need for people to avoid the outdoors. More important, they say, is that physicians and other health care providers are aware of the rare fungus and know how to recognize symptoms of exposure — which can include regular coughing, shortness of breath and headache. If caught in time, the C. gattii infection can be treated with antifungal medication.

This past April research by Edmond Byrnes, a graduate student in microbiology at Duke University, that was published in the journal PLoS Pathogens raised concerns about aggressive strains of C. gattii in the Pacific Northwest. That study cited 6 human deaths and 15 other infections resulting from exposure to the virulent strain. As Alice Park reported then for TIME:

C. gatti is normally found in tropical climates in South America, Australia and Papua New Guinea. In these endemic regions, it tends to favor eucalyptus trees… The fungus was somehow carried from the southern hemisphere to North America, where it was found on Vancouver Island in 1999. (It was rare — at its peak, between 2002 and 2005, there were 36 cases per million population per year in the region reported to health officials.) One of the new strains of highly virulent C. gattii was determined to have originated on Vancouver Island; the other is thought to have emerged in Oregon, possibly from a strain that had spread south from British Columbia.

In lab animals, Byrnes reports, these two strains are 100% lethal, causing death within three weeks. That’s reason for concern from a scientific standpoint, he says, since other known strains of the fungus are not as deadly. But, again, the fungus is so rare in the real-world, that from a public-health perspective, there’s no need for alarm.”

Though this latest CDC data suggests a high death rate among people infected with C. gattii, researchers point out that many people may have such subtle symptoms that they do not even realize they’re infected — and as such wouldn’t be counted among the cases — and that many of those who do become severely ill had underlying medical conditions that made them more susceptible to infection.

In other words, the advice offered by Byrnes back in April still stands:

“These infections are still rare, and from an overall health perspective, I don’t think anyone should be concerned, but should just be aware that it is increasing geographically and incidence-wise in [the Pacific Northwest]… For the average person, I don’t think this is anything to be too worried about.”

Read the full AP story here. And read the TIME article about C. gattiihere.