Fungi Pose Increasing Threat, Scientists Say

"Dangerous fungal infections are on the rise, and a growing body of research suggests warmer temperatures might be a culprit.

The human body's average temperature of 98.6 degrees Fahrenheit has long been too hot for most fungi to thrive, infectious-disease specialists say. But as temperatures have risen globally, some fungi might be adapting to endure more heat stress, including conditions within the human body, research suggests. Climate change might also be creating conditions for some disease-causing fungi to expand their geographical range, research shows.

"As fungi are exposed to more consistent elevated temperatures, there's a real possibility that certain fungi that were previously harmless suddenly become potential pathogens," said Peter Pappas, an infectious-disease specialist at the University of Alabama at Birmingham.

Deaths from fungal infections are increasing, due in part to growing populations of people with weakened immune systems who are more vulnerable to fungal disease, public-health experts said. At least 7,000 people died in the U.S. from fungal infections in 2021, the Centers for Disease Control and Prevention said, up from hundreds of people each year around 1970. There are few effective and nontoxic medications to treat such infections, they said.

A January study in the journal Proceedings of the National Academy of Sciences showed that higher temperatures may prompt some disease-causing fungi to evolve faster to survive.

Researchers at Duke University grew 800 generations of a type of Cryptococcus, a group of fungi that can cause severe disease in people, in conditions of either 86 degrees Fahrenheit or 98.6 degrees Fahrenheit. The researchers used DNA sequencing to track changes in the fungi's genome with a focus on "jumping genes" -- DNA sequences that can move from one location on the genome to another.

Asiya Gusa, a study co-author and postdoctoral researcher at Duke, said movement of such genes can result in mutations and alter gene expression. In fungi, Dr. Gusa said, the movement of the genes could play a role in allowing fungi to adapt to heat.

Dr. Gusa and her colleagues found that the rate of movement of "jumping genes" was five times higher in the Cryptococcus raised in the warmer temperature." [1]

1. U.S. News: Fungi Pose Increasing Threat, Scientists Say
Mosbergen, Dominique.  Wall Street Journal, Eastern edition; New York, N.Y. [New York, N.Y]. 02 Feb 2023: A.6.