By Meaghan Lee Callahan
Fungal infections are on the rise. However, testing options are not as robust and varied as diagnostics for viral or bacterial infections, even though there are more than 300 fungal species that can cause infections. Experts speaking on a panel at ASM Microbe 2025, in Los Angeles, said public health officials need to increase awareness of fungal pathogens through increased surveillance, diagnostics and, in turn, funding.
Fungus Is Among Us
Although individual cases of fungal infections are much lower than viral infections, fungal infections are increasing. Part of that is related to climate change, according to Pascalis Vergidis, MD, an associate professor of medicine in the Division of Infectious Disease at Mayo Clinic, in Rochester, Minn. “We know that with climate change, there is an impact,” Dr. Vergidis explained. “One of the proposed mechanisms for the rise in Candida auris across three continents simultaneously is the change in global temperature, the increase in global temperature. Candida auris is a thermotolerant organism, so it thrives in higher temperatures.”
It’s not just C. auris. Cases of valley fever, which is caused by Coccidioides, have also been on the rise. Although the numbers are still small compared with other illnesses, fungal infections cost the states of Arizona and California $1.5 billion per year in 2019 dollars, said Rob Purdie, a Valley Fever patient and founding member of the fungal disease nonprofit MyCARE Foundation (JAMA Netw Open 2025;8[6]:e2513572). “I worry a lot about the dimorphic because of changes in climate, the explosion in rates, especially valley fever,” Mr. Purdie said.
To address these increases, the panelists agreed that attention and funding need to focus on increasing surveillance and honing our diagnostics tool kit for fungal infections.
Surveillance
A good place to start tackling the problems with fungal disease is to better understand existing disease rates. Mr. Purdie identified this as one of the biggest knowledge gaps. High estimates put global fatalities from fungal disease at 2 to 3 million people per year. “You look at a disease like valley fever, which is exploding, but still, we have less than 25,000 diagnosed cases a year and estimates as high as 300,000 in the U.S.,” Mr. Purdie said. Surveillance can help us better understand the scope.
Diagnostics
But to increase surveillance, you need diagnostics. “You can’t have surveillance without diagnostics, and diagnostics are critical to surveillance,” Mr. Purdie said.
However, compared with other pathogen types, there aren’t many fungal testing options. “Some of the fungal diseases, we still have very limited options in terms of diagnostics,” said Sean Xiang Zhang, MD, PhD, the director of the medical mycology laboratory, Johns Hopkins Medicine, and an associate professor of pathology at the Johns Hopkins University School of Medicine, in Baltimore.
For example, Dr. Zhang said that for identifying mucormycosis, clinicians are limited to culture or histology. Culture sensitivity can also be really low, he said, such as in the recent fungal meningitis outbreak stemming from a cosmetic surgery center in Mexico. However, metagenomics generation sequencing can help with diagnosis, as it did with the fungal meningitis outbreak.
However, not all labs can handle this kind of testing, especially in “resource-limited settings,” Dr. Zhang said.
As time ran out for the panelists, moderator Megin Nicols, DVM, MPH, DACVPM, the director of the Division of Food, Waterborne and Environmental Diseases at the CDC’s National Center for Emerging and Zoonotic Infectious Diseases, asked one final question: “I’m going to challenge you all,” she said, “one-word answer to say, ‘What do we think is the biggest challenge to diagnostics?’”
The panelists answered in three: money, awareness and collaboration.
