By Kimberley Clementi

A new study has found that New Mexicans are likely among the most at-risk populations for Valley fever, which is caused by inhaling spores of a fungus that thrives in arid soils, with increased risk in drier, dustier parts of the state.

 

The first sign is a fever. A cough develops next, and possibly shortness of breath. Then comes fatigue and muscle aches. Residents in New Mexico might dismiss these symptoms as a cold or the flu but they could indicate a relatively unknown infection: Valley fever. 

A newly published study in the journal Pathogens led by a New Mexico Tech biologist confirms that Valley fever, or coccidioidomycosis, is on the rise in New Mexico. Reported cases statewide have nearly tripled over the last decade.

“Based on the disease incidence and evidence for a high amount of underreporting, people in New Mexico are likely among the most at-risk populations for Valley fever in the United States,” said Paris Salazar-Hamm, a faculty member in the Department of Biology at New Mexico Tech.

Salazar-Hamm led a statewide collaboration with researchers from the University of New Mexico, New Mexico State University, and Los Alamos National Library examining the presence of Valley fever in New Mexico. The comprehensive study identified areas and populations in New Mexico with the highest case incidences and established a baseline for future enhanced epidemiologic surveillance throughout the state. 

Valley fever is caused by inhaling spores of Coccidioides, a fungus that thrives in arid soils. Spores may become airborne due to high winds, construction, or farming, and could cause infection if inhaled into the lungs. While most cases are minor, the disease can be severe and even fatal for vulnerable populations. 

Outdated Classifications of Endemicity

Early research on Valley fever from the 1930s defined endemic regions as semi-arid-to-arid climates at low elevations. California and Arizona were the first two states recognized as endemic regions with other southwestern states following over time.

Despite evidence dating back to World War II supporting endemicity in New Mexico – specifically, skin tests of military recruits who showed prior exposure to Coccidioides spores – the state has long been considered a low-incidence jurisdiction by the Centers for Disease Control and Prevention (CDC). 

Past studies on Valley fever have largely excluded New Mexico or only mentioned it anecdotally as part of the range. According to Salazar-Hamm, an advanced PubMed search accessed in early 2025 revealed only 22 of 6,533 publications on the subject included “New Mexico.” That’s what makes the new study so groundbreaking. 

Data-driven Prevention for New Mexico

In the study, the New Mexico-based investigation built on 80 years of tangential data of disease presence in the state. 

Scientists examined nearly two decades of public health records – roughly 1,500 human cases between 2006 and 2023 – and analyzed 300 soil samples collected near Las Cruces. They also tested a selection of rodents from museum collections over the past 27 years. 

For the first time, scientists detected the disease-causing fungus, Coccidioides, in New Mexico soil – a finding that challenges speculative claims the state is less endemic than its neighbors, Arizona and California. Additionally, the team uncovered data suggesting grasslands are a likely habitat for the pathogen and confirmed previous findings that rodent burrows have a higher positivity rate than surrounding soils. 

The environmental detection supported what researchers have long suspected: that locally acquired infections are occurring in several parts of the state. Scientists validated detections in Catron, Doña Ana, Sierra, and Socorro Counties but caution that the disease-causing fungus is likely more widespread than that.

“Our findings highlight the urgent need for public health initiatives focused on early diagnosis, disease surveillance, and prevention as Valley fever continues to emerge in new areas,” said Salazar-Hamm.

The study also confirmed that older adults and Indigenous populations are among the most affected. The team urged increased healthcare provider education and environmental monitoring to ensure timely diagnosis and improve patient outcomes.

The research appeared in the article The Epidemiology of Coccidioidomycosis (Valley fever) and the Disease Ecology of Coccidioides spp. In New Mexico (2006-2023) and was funded by Los Alamos’ Laboratory Directed Research and Development program.