Scientists Who Studied Candida Auris Fungus Warn Global Warming May Lead to Diseases 'We Don't Even Know About Right Now'

Climate change may have caused a new, potentially deadly drug-resistant fungus known as Candida auris to emerge, warn scientists who say that global warming could lead to the emergence of more diseases we're not yet aware of.

First identified in Japan in 2009, and thought to date back to South Korea in 1996, Candida auris can cause blood, wound, and ear infections which can be deadly. Between 2012 and 2015, it emerged separately across three continents: Africa, the Indian subcontinent, and South America. It can spread in a health care setting, like a hospital, from person to person or when a contaminated surfaces touches equipment. As such, hospital or nursing home patients who have been fitted with lines and tubes are at greatest risk, according to the Centers for Disease Control and Prevention.

Fears around the fungus have been brewing for several years. In 2017, chief of the Mycotic Diseases Branch at the Centers for Disease Control and Prevention (CDC) warned that Candida auris "is behaving in unexpected and concerning ways, causing severe disease in countries across the globe, including the United States."

As of 12 July 2019, a total of 716 cases had been identified in the U.S., according to the The Centers for Disease Control and Prevention, which calls it a "serious global health threat."

Candida auris is problematic because it is not only resistant to a number of antifungal drugs, but it is difficult to spot with regular lab equipment and therefore easy to misidentify.

Dr. Arturo Casadevall, chair in Molecular Microbiology and Immunology at Johns Hopkins Bloomberg School of Public Health and co-author of the latest study published in the journal mBio explained to Newsweek that fungi can struggle to survive a mammal's body temperature. His team believes Candida auris started infecting humans relatively recently because it adapted to higher ambient temperatures resulting from global warming, such that it was able to survive at human temperatures.

"The most mystifying aspect of the emergence of Candida auris as a human pathogen is that it appeared in three different continents at roughly the same time and that the three isolates are genetically distant," he said. "This implies some common trigger in geographically distant sites and given that climate change is occurring globally we decided to focus on that variable."

Casadevall and colleagues studied the evolution of Candida auris, and examined how it responds to heat in comparison to other bugs which shares its genes. Candida auris was found to grow at higher temperatures than the other fungi. The other fungi also couldn't survive the body temperatures of mammals, unlike Candida auris. The researchers therefore believe Candida auris has evolved to withstand higher temperatures.

Casadevall suggested in a statement that this is unlikely to be an isolated case. "Global warming may lead to new fungal diseases that we don't even know about right now," he said.

"If Candida auris is indeed a harbinger of new fungal threats we will need better preparation for the future," he told Newsweek. Casadevall suggested a three-pronged attack involving better surveillance of the fungal kingdom so that new pathogens are identified quickly; more research to develop a better understanding of how fungi cause disease; and the development of new antifungal drugs.

Pointing out the limitations of the study, Christina Cuomo, group leader for the Fungal Genomics Group at the Broad Institute of MIT and Harvard, who was not involved in the research, told Newsweek: "The authors acknowledge that global warming is unlikely to be the sole explanation for the emergence of Candida auris.

"Also, as Candida auris was only detected recently, it is not currently possible to trace when Candida auris became able to grow at higher temperatures," she said.

Cuomo continued: "A major question in understanding the emergence of Candida auris is identifying where else it was prior to the recent outbreaks and where it currently exists in the environment, on other animals, or how commonly it is asymptomatically associated with humans. This is essential both to understand the outbreak and to contain its spread.

"Current large-scale efforts to examine microbial diversity are generating data sets that could be examined for evidence of Candida auris," Cuomo concluded.