Three years ago, U.S. health officials warned hundreds of thousands of clinicians to watch for a new, quickly spreading and highly drug-resistant type of yeast that was causing potentially fatal infections.

Candida auris has become a global health threat since it was identified a decade ago, especially for patients with compromised immune systems. It has been reported in more than 30 countries and is probably more widespread than that because the organism is hard to identify without specialized methods.

It is resistant to multiple antifungal drugs, and can spread between patients in hospitals and other health care facilities. The fungus can lead to infections of the bloodstream, heart or brain, and early studies estimate that it is fatal in 30 to 60% of patients.

Researchers have never been able to isolate the fungus from the natural environment or figure out how genetically distinct versions emerged independently at roughly the same time in India, South Africa and South America.

Now U.S. and Dutch researchers have a new theory: They propose that global warming may have played a key role and suggest that this may be the first example of a fungal disease emerging from climate change, said a study in mBiwo, a journal of the American Society of Microbiology.

Fungal infections in humans are rare. Mammals have more advanced immune systems than other organisms, and most fungi in the environment cannot grow at the temperatures of the human body, said Arturo Casadevall, one of the authors of the new study, who is a microbiologist and immunologist at Johns Hopkins Bloomberg School of Public Health.

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A strain of Candida auris cultured in a petri dish at the Centers for Disease Control and Prevention.

But as the climate has gotten warmer, the researchers say, C. auris was able to adapt, which helped it replicate in the human body's temperature of 98.6 degrees.

Something happened to allow the organism to "bubble up and cause disease", Casadevall said. "You gotta try to think, what could be the unifying cause here? But the one thing they have in common is that the world is getting warmer."

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