Climate change led to evolution of killer superbug
A DEADLY superbug which suddenly started infecting humans evolved because of global warming. Scientists believe it is the first fungal disease to emerge because of climate change.
The fungus, called Candida auris (C.auris), was first identified in Japan in 2009, in the ear canal of a 70-year-old woman. It has since spread around the globe, emerging in five continents, with the first UK case detected in 2013.
Since then it has caused outbreaks in at least 55 hospitals across Britain, infecting more than 200 patients. It has been linked to eight deaths.
Public health experts are alarmed by the rapid spread of the fungus, which has been likened to a superbug because it has proved resistant to the main three classes of drug treatment.
But researchers now believe that as global temperatures have risen, C.auris evolved to thrive in conditions which mirror the internal temperature of the body – 97-99F (36-37C) – making humans a perfect breeding ground.
“The reasons fungal infections are so rare in humans is that most of the fungi in the environment cannot grow at the temperatures of our body,” said Dr Arturo Casadevall, lead author and a molecular microbiology expert at Johns Hopkins University in Baltimore.
“Something happened to allow this organism to bubble up and cause disease. We began to look into the possibility that it could be climate change.
“As the climate has got warmer, organisms, including Candida auris, have adapted to the higher temperature, and as they adapt, they break through humans’ protective temperatures. Global warming may lead to new fungal diseases that we don’t even know about right now.”
The fungus is a yeast which, in other forms, can cause skin infections. The new type, which can lead to blood infections, emerged independently in India, South America and Africa.
While healthy patients can usually fend it off, those with compromised immune systems can develop infections, which can prove fatal, or cause major disabilities such as hearing loss.
In the new study, published by the American Society for Microbiology, the researchers found that C.auris is capable of growing at higher temperatures than most of its closely related species. Adaptation to higher temperatures is a contributory cause for its emergence, they concluded, as they called for better surveillance to monitor new diseases. “What this study suggests is this is the beginning of fungi adapting to higher temperatures, and we are going to have more and more problems as the century goes on,” added Dr. Casadevall.
A 2015 C.auris outbreak at the Royal Brompton Hospital and Harefield NHS Foundation trust in London led to the closure of its intensive care unit for two weeks, while 70 patients were infected at the John Radcliffe Hospital in Oxford between 2015 and 2017.