Epidemiology, Clinical Features, and Outcomes of Coccidioidomycosis, Utah, 2006–2015

Adrienne Carey; Morgan E. Gorris; Tom Chiller; Brendan Jackson; Wei Beadles; Brandon J. Webb


Emerging Infectious Diseases. 2021;27(9):2269-2277. 

In This Article

Abstract and Introduction


On the basis of a 1957 geographic Coccidioides seropositivity survey, 3 counties in southwestern Utah, USA, were considered coccidioidomycosis-endemic, but there has been a paucity of information on the disease burden in Utah since. We report findings from a recent clinical and epidemiologic study of coccidioidomycosis in Utah. To describe clinical characteristics, we identified all coccidioidomycosis cases in an integrated health system in the state during 2006–2015. For epidemiologic analysis, we used cases reported to the Utah Department of Health during 2009–2015. Mean state incidence was 1.83 cases/100,000 population/year. Washington County, in southwestern Utah, had the highest incidence, 17.2 cases/100,000 population/year. In a generalized linear model with time as a fixed effect, mean annual temperature, population, and new construction were associated with regional variations in incidence. Using these variables in a spatiotemporal model, we estimated the adjusted regional variation by county to predict areas where Coccidioides infections might increase.


Coccidioidomycosis, also known as Valley fever, is caused by Coccidioides immitis and C. posadasii, endemic, dimorphic environmental fungi found in the soil of the southwestern United States, Mexico, and Central and South America.[1] Clinical infection ranges from asymptomatic to diverse manifestations including pneumonia, soft tissue and osteoarticular infection, meningitis, and disseminated disease.[2] On the basis of findings from the seminal 1957 seropositivity survey[3] that established the commonly accepted geographic distribution of Coccidioides in the United States, 6 states were classified as coccidioidomycosis-endemic (Arizona, California, Nevada, New Mexico, Texas, and Utah); California and Arizona had the highest seroprevalence.[4] On the basis of that study, 3 counties in southwestern Utah were considered coccidioidomycosis-endemic: Iron, Kane, and Washington.[3] With the exception of reports from a widely publicized 2001 outbreak of coccidioidomycosis at an archeological dig in Uintah County in the US Park Service's Dinosaur National Monument,[5–7] there are few published data on this disease in Utah. However, recent data suggest that southwestern Utah might represent an area of increased disease burden.[8] Here we report a description of the epidemiology of coccidioidomycosis in Utah and explore environmental and climatic factors contributing to regional variations in statewide incidence using data from cases reported to the Utah Department of Health (UDOH) during 2009–2015. We also describe clinical characteristics and outcomes using patient-level data from the Intermountain Healthcare System during 2006–2015.