As Planet Warms, A Superbug Fungus Has Started Killing Humans

In 2009, officials in Japan identified the presence of a deadly 'superbug' fungus called Candida auris in a human patient for the first time. Other infections involving this fungus began popping up in hospitals around the world, including in the United States in 2016, according to the CDC. The sudden rise of C. auris as a human pathogen was surprising and a new study indicates that climate change may be the cause.

Most fungal species are adapted to living in relatively cool natural environments like the soil and trees. Humans, in comparison, are typically too warm for fungus infections to happen, making such cases rare and limited to only a small percentage of known fungal species.

That may change, however, as the planet becomes warmer and fungus species start adapting to the warmer temperatures. That's according to a study led by Johns Hopkins Bloomberg School of Public Health's Arturo Casadevall, MD, PhD, who previously published a 2010 paper warning that climate change could spur the rise of more fungal pathogens.

C. auris's surprising appearance as a human pathogen appeared in multiple 'distinct families' of the fungus that existed separately in different parts of the world. This consistent change across continents and the fungus' seemingly sudden ability to infect humans indicates that C. auris may be the first fungal species to adapt to a warmer climate and, as a result, become a threat to human health.

As part of their study, the scientists studied a few dozen fungal species, including C. auris and its closest relatives. The temperature range for these species was analyzed and found to be higher for the new C. auris pathogen impacting humans compared to the other species. It's unclear how this fungal species development resistance to typical treatments and anti-fungal drugs.

Based on current estimates, between 30- and 60-percent of people infected with C. auris have died as a result.