Disease Triangle Dynamics of Coccidioidomycosis in Northern Arizona

Coccidioides species are the etiological agent of Valley fever (Vf). Disease ranges from pneumonia to extrapulmonary infection. If diagnosis is delayed or missed, the risk of severe disease increases. We investigate the disease triangle (intersection of pathogen, host, and environment) of Vf in Northern Arizona, where the risk of acquiring the disease is lower but prevalent and rising. We inspect reported and hospitalized cases of VF hosts. Then assess pathogen origin by comparing Northern Arizona clinical isolates to isolates from other regions. Lastly, we survey Northern Arizona soils for evidence of Coccidioides. We found that cases of Vf are increasing some requiring hospitalization. The Northern Arizona Coccidioidies isolates were genetically related to Southern Arizona populations. However, we detected Coccidioides DNA in Northern Arizona soils. We expect that cases will continue to increase and suggest increased awareness and screening for the disease is crucial to limit severe illness in Northern Arizona. Article Summary LineOur work is the first description of the Valley fever disease triangle in Northern Arizona, which considers the complex interaction between host, pathogen and environment in the region. Our data suggests that the prevalence of diagnosed cases is rising in the region, some of which are extreme enough to necessitate hospitalization. We present the first evidence of Coccidioides spp. in Northern Arizona soils, suggesting that the pathogen is maintained in the local environment. Until disease prevention is an achievable option via vaccination, we anticipate that incidence of Valley fever will rise in the area. Therefore, enhanced disease awareness and screening for the coccidioidomycosis is vital to the communities of Northern Arizona.