University of Utah researchers collecting samples to map Valley fever’s spread through dirt spores

SALT LAKE CITY — A team of University of Utah researchers is studying a fungal respiratory infection they say is spreading through the soil and dust in Utah.

Researchers don’t yet know exactly which areas of the state have Valley fever, but professor of epidemiology Katharine Walter said the fungus could spread further as the climate changes.

An interdisciplinary research team including Walter is trying to map where the fungus that causes the disease can survive and where it might spread. The researchers received $375,000 for the Climate and Health Interdisciplinary Award through the Burroughs Wellcome Fund to help fund their fungus hunt and raise awareness for those at risk of infection.

Valley fever is difficult to track, as the fungus that causes it doesn’t spread from person to person. It grows stealthily in the soil but never emerges above the surface. Symptoms of the sickness are similar to those seen in influenza and include fatigue, cough, fever, shortness of breath, headache, night sweats, muscle aches or joint pain and rash on the upper body or legs, according to the Centers for Disease Control and Prevention.

In 2019, the CDC reported just over 20,000 confirmed cases of the disease, with very few being in New Mexico and Utah.

“When most people think of fungus, they think of mold or mushrooms, something that you can see,” Katrina Derieg said. Derieg is a vertebrate collections manager at the Natural History Museum of Utah and a member of Walter’s reserach team.

“But this is not a fungus that has any kind of visible fruiting body. It can only be identified with a microscope, which makes it really tricky to identify in the field,” Derieg said.

Because Valley fever is not well known, it often goes undiagnosed or misdiagnosed, which can cause delays in necessary antifungal treatment for those infected.

According to a release from the university, 10 archaeologists working at a dig site in northeastern Utah fell sick with Valley fever in 2001. Valley fever is typically found in hotter, drier states, and previous predictions determined the fungus would not survive in the soil in Utah except for the southwest corner of the state, hundreds of miles from where the archaeologists were.

“There have been incredibly intense recent changes in temperature as well as precipitation and drought here in the American West. These all impact the range of where the fungus can exist,” Walter said.

Walter, Derieg along with University of Utah biology professor Eric Rickart, and professor of atmospheric sciences Kevin Perry are collecting soil and dust samples from a range of climate zones in the state. The samples will be tested for fungal DNA, and the areas will also be searched for traces of fungus in rodents that burrow underground, as rodents are suspected of being an instrumental factor in the movement of the fungus.

The team is focusing on Washington County and St. George, especially, as it is the region with the highest reported prevalence of Valley fever. The university said the rapid construction of the growing metropolitan area is churning up potentially spore-laden dust in previously undisturbed areas of the Mojave Desert.

“Where others see future housing developments, the researchers see the potential for a spike in disease cases,” the university said.

Washington County’s dramatic landscape and topography encompasses a variety of microclimates that can serve as stand-ins for diverse climates across the state. Samples just from the county can give scientists a relatively accurate picture of where fungus thrives statewide.

Combining that information with predictions of how the climate will change over time, the researches hope to gain an understanding of which areas are at risk now and in the future.

“An important component of this project is to educate the public to let them know what is in their community, what signs they should be looking for, and how they can prevent it,” Perry said.

Wearing dust masks on dry, windy days can help reduce risk from airborne spores for those in fungus-ridden areas. Doctors who know the signs and symptoms of Valley fever will be able to catch the disease early and administer proper treatments.

“Because we get sick by inhaling fungal spores that are found in the soil, people who work outside in jobs like construction, agriculture, and firefighting are at extremely high risk of infection and disease,” Walter said. “Valley fever is very much an increasing health justice and environmental justice issue.”

Walter added that Valley fever is not the only disease that will change as the climate shifts.

“This is just one example of an infection that will be, and is already being, dramatically impacted by climate change. There are many others. And the consistent theme is always that the most vulnerable populations are put at highest risk. The urgency of this issue really can’t be overstated,” Walter said. “Valley fever is just one component of this storm we’re all living through.”