Dangerous fungal spores are expected to sweep across at least 11 U.S. states this summer, carried by dust storms that could expose millions to Valley fever, a potentially deadly respiratory illness. The conditions are anticipated to worsen in the coming weeks, with the peak season for exposure lasting through September.
Meteorologists and health experts are warning that dust storms in the Southwest, a region prone to strong desert winds, will stir up spores from the soil. These microscopic particles, known as Coccidioides, can cause Valley fever when inhaled. While the immune system typically fights off the fungus, leading to mild flu-like symptoms, severe infections can spread to organs and bones, becoming fatal.
The North American monsoon season, characterized by thunderstorms and high winds, is expected to exacerbate the situation in states including California, Nevada, Arizona, Utah, Colorado, New Mexico, and Texas. These winds can create massive dust clouds, or haboobs, particularly when the ground is dry. The combination of extreme heat, drought, and monsoon winds is predicted to lead to more frequent and intense dust storms.
Valley fever cases typically begin to peak in October, a few months after the dust storms, as it takes time for the fungus to grow after inhalation. Forecasters have already issued air quality alerts this week due to high-pressure systems trapping smoke, haze, and dust near the ground.
The Centers for Disease Control and Prevention (CDC) has identified at least 11 states as potential breeding grounds for Coccidioides. Beyond the Southwest, these include parts of Washington, Oregon, Idaho, and southern Wyoming. The CDC further warns that the spores could potentially spread across the entire western half of the U.S., reaching as far as Oklahoma, Kansas, Nebraska, the Dakotas, and the Pacific Coast.
AccuWeather climate experts previously warned of a potential 'mini-Dust Bowl' if the current El Niño weather pattern leads to prolonged drought. The historic Dust Bowl of the 1930s devastated farmland across the central U.S. and Great Plains. A new Dust Bowl in areas where Coccidioides can thrive could expose tens of millions of Americans to hazardous spores as dust storms intensify.
Research indicates a significant increase in Valley fever cases in recent years. A 2017 study published in Geophysical Research Letters found an over 800 percent rise in infection rates in the Southwest between 2000 and 2011. The same study also noted a 240 percent increase in large dust storms during the 2000s compared to the 1990s. Researchers attributed this rise primarily to climate change, which is making the region drier, and shifts in Pacific Ocean sea surface temperatures contributing to stronger winds and increased dust.
Coccidioides naturally occurs in dry, sandy soils common in arid regions like the Southwest. It thrives in alkaline soils with hot summers, mild winters, and low rainfall. While generally harmless when undisturbed, it becomes a significant health risk when airborne and inhaled.
The CDC acknowledges that outbreaks have occurred in unexpected locations. The World Meteorological Organization has highlighted that sand and dust storms not only cause aesthetic issues but also impact public health, quality of life, transportation, agriculture, and solar energy production.
Health authorities are advising individuals in dust storm paths to stay indoors with windows closed until the air clears. To minimize risk, the Arizona Department of Health Services recommends avoiding dusty areas like construction sites and wearing an N95 mask or respirator if unavoidable. They also suggest watering down desert soil before spreading it to reduce airborne dust. Drivers encountering dust storms are urged to pull over safely, shut off their vehicles, and use recirculating air conditioning until the storm passes.