PHOENIX — A landmark federal surveillance study published in the CDC's Morbidity and Mortality Weekly Report on February 19, 2026 has confirmed what public health officials in Arizona have been warning about for years: Valley fever (coccidioidomycosis), the fungal lung disease caused by inhaling soil-borne Coccidioides spores, has approximately doubled in incidence across Arizona between 2005 and 2022 — with the most alarming new finding being that the disease is aggressively expanding into regions of the state where it was historically rare. The Phoenix metropolitan area — which sits in Maricopa County at the heart of Arizona's Sonoran Desert region — remains the single hardest-hit area in the country, accounting for the majority of a statewide total that reached 12,522 confirmed cases in 2024 alone.
That 2024 figure represented a 42% increase over the same period in 2023, when 8,841 cases were reported. And the national picture is equally alarming: the U.S. is currently tracking on pace to surpass last year's total in the first half of 2026. In 2023, states reported 21,037 confirmed cases nationally — the highest annual total since modern surveillance began. Valley fever is responsible for an estimated 15% to 30% of all community-acquired pneumonias diagnosed in the Phoenix and Tucson metro areas. The burden falls most heavily on the elderly, people with diabetes, Black and Filipino patients, and those with weakened immune systems.
