Regional Increases in Incidence of Coccidioidomycosis (Valley Fever) — Arizona, 2005–2022

Incidence of coccidioidomycosis (Valley fever), a fungal infection caused by inhalation of Coccidioides species spores, has increased substantially across the southwestern United States in association with increasing aridity, warming temperatures, and precipitation volatility.Arizona and California report >95% of U.S. coccidioidomycosis cases, and incidence in Arizona has increased statewide.Patterns within Arizona's distinct climatological regions have not been characterized, especially in regions outside the known zone of persistently high levels of disease occurrence (hyperendemicity) in the southwest Sonoran Desert region.In this study, surveillance data reported to the Arizona Department of Health Services since 2005 were used to calculate coccidioidomycosis incidence within six ecological regions.During 2005-2022, annual incidence approximately doubled in Arizona, with >95% of cases reported from the Sonoran Desert region.Although the Plateaus and Mojave Desert regions (in the northern parts of the state) reported