This Fungus Is Quickly Spreading, and Climate Change May Be to Blame

A highly drug-resistant fungus has been spreading in hospitals across the United States, and scientists say climate change may be partially to blame. The fungus, called Candida auris, is a type of yeast that can cause sepsis, fever or low blood pressure in people with weakened immune systems. 

This month, the state of Washington reported its first case of Candida auris, a testament to the rapid spread. With national health officials sounding the alarm about the fungus, “it was only a matter of time before we’d see our first case,” Nigel Turner, division director of Communicable Disease Control for the Tacoma-Pierce County Health Department in Tacoma, Washington, tells KING 5’s Christine Pae.

Candida auris is “kind of our nightmare scenario,” Luis Ostrosky, a professor of infectious diseases at McGovern Medical School at UTHealth Houston, tells Camille Fassett of the Associated Press (AP). “It’s a potentially multidrug resistant pathogen with the ability to spread very efficiently in health care settings… We’ve never had a pathogen like this in the fungal infection area.”

A Pierce County man was diagnosed July 13 with colonization due to Candida auris, a multidrug-resistant fungus that can cause serious infections. It’s believed to be the first locally acquired case in Washingtonhttps://t.co/iLgsfsrn6m

— Tacoma-Pierce County Health Department (@TPCHD) July 18, 2023

The genus Candida includes about 200 species of fungi. This group is the most common cause of fungal infections in humans, though about 90 percent of all Candida infections are caused by just five species. Candida albicans, the most prevalent, can lead to vaginal yeast infections and thrush. While Candida infections are usually treatable with one of three available classes of antifungals, C. auris strains can be resistant to all three. C. auris can spread in healthcare settings when people touch contaminated surfaces or equipment or by transmitting from person to person, per the Centers for Disease Control and Prevention (CDC). 

C. auris was discovered in 2009 when doctors in Japan isolated it from a patient’s ear canal (auris is the Latin word for ear). In 2016, it was first reported in the U.S., and it has since infected thousands of Americans. Nationwide, clinical cases have risen from 476 in 2019 to 1,471 in 2021—and last year, cases totaled 2,377. 

One of the prominent theories for the rapid explosion of C. auris infections is global warming. Usually, the high temperature of the human body keeps fungal infections at bay. But as it gets hotter outside, the fungus is getting a chance to adapt to increasingly warmer environments.

“I think the way to think about how global warming is putting selection pressure on microbes is to think about how many more really hot days we are experiencing,” Arturo Casadevall, a microbiologist and immunologist at Johns Hopkins University, tells the AP. “Each day at [100 degrees Fahrenheit, or 37.7 degrees Celsius] provides a selection event for all microbes affected—and the more days when high temperatures are experienced, the greater probability that some will adapt and survive.”

Another possible explanation is the widespread use of antifungals, which over time has led to resistance, reports Zaria Gorvett for BBC Future.

Infections with any species of Candida can be fatal if they are invasive—or enter areas of the body where Candida are not usually present, such as the bloodstream or internal organs. Based on limited patient data, the CDC reports that 30 to 60 percent of people with C. auris infections have died, though many also had other serious illnesses.

Patients in hospitals or nursing homes are especially at risk, as they may have catheters or ventilators entering their bodies. The fungus can stick to a variety of surfaces in these environments, from bed rails to floors to the ends of thermometers. CDC officials have said the Covid-19 pandemic exacerbated the spread, as shortages of personal protective equipment caused nursing gowns and gloves to be reused.

C. auris infections are not only difficult to treat, but they can be hard to identify. Many clinicians are unaware of the existence of the fungus, and while a blood test can be used to screen for infection, this method only catches about half of the cases, Ostrosky tells the AP. 

Arjun V.K. Sharma, a writer and infectious disease resident physician, calls for C. auris screenings to become standard in healthcare facilities and for patients’ statuses to be shared across institutes, in an opinion piece published in the Los Angeles Times.

“Climate change will invariably bring new fungal diseases,” Sharma writes in the L.A. Times. “A threat to our collective well-being is best met with a collective effort. C. auris offers us a chance to strengthen that response.”