Valley fever cases surge in Arizona amid climate change
Arizona reported a record over 20,000 cases of valley fever in 2023, the highest ever recorded. Experts attribute the rise to shifting climate conditions that favor the spread of the soil-borne fungus Coccidioides. The infection, while often mild, poses serious risks for certain groups and highlights broader environmental health concerns.
Valley fever, also known as coccidioidomycosis, is caused by inhaling spores of the fungus Coccidioides, which thrives in the arid soils of the southwestern United States, including Arizona, and parts of Central and South America. The disease is not contagious between people but spreads through dust disturbed by wind, construction, or other activities.
In Arizona, cases have skyrocketed in recent decades. From about 1,500 infections in 1998, the state saw more than 20,000 in 2023 alone, according to health officials. This surge marks a significant increase, with the fungus's habitat expanding due to hotter, drier weather patterns linked to climate change. Increased dust storms, exacerbated by prolonged droughts and reduced vegetation, carry spores over longer distances, heightening exposure risks.
Most infections—around 60%—produce no symptoms, while 40% result in flu-like illness including fever, cough, fatigue, and joint pain. Severe cases can lead to pneumonia, meningitis, or disseminated disease, particularly in vulnerable populations such as pregnant individuals, those with diabetes, and people of African American or Filipino descent. The fatality rate hovers around 1%, but complications can be life-threatening without treatment.
"We’re seeing more cases because the environment is changing," notes Farrin Manian, an infectious disease specialist at the University of Arizona. Antifungal medications like fluconazole are used to treat serious infections, though mild cases often resolve on their own. Diagnosis typically involves blood tests detecting antibodies or imaging like chest X-rays to identify lung involvement.
Beyond climate factors, human activities contribute to the spread. Construction booms in Arizona disturb soil, releasing spores into the air. Health experts recommend precautions such as wearing N95 masks in dusty areas, staying indoors during windstorms, and avoiding soil-disturbing activities during dry seasons. Arizona leads the nation in valley fever cases, underscoring the need for greater awareness and research into prevention amid ongoing environmental shifts.