A Review of Coccidioidomycosis in California: Exploring the Intersection of Land-use, Population Movement, and Climate Change.

Abstract

California has seen a surge in coccidioidomycosis (Valley fever), a disease spread by the Coccidioides Immitis fungus found in soil throughout the state, particularly in the San Joaquin Valley. In this paper, we reviewed epidemiologic studies examining outbreak and sporadic cases of coccidioidomycosis and considered their possible relationship to environmental conditions, particularly the state's growing aridity, drought and wildfire conditions. Most of the studies we reviewed pertained to cases occupationally-acquired in construction, military, archeological and correctional institutional settings where workers faced exposure to dust in Coccidioides Immitis-endemic areas. A few reviewed outbreaks in the general population related to dust exposure from natural disasters, including an earthquake-associated landslide and a dust storm that carried particles long distances from endemic areas. Although many of California's coccidioidomycosis outbreaks have been occupationally-related, changing demographics and new, immunologically-naive populations in dry, endemic areas could expose the general population to Coccidioides Immitis spores. Given the high rate of infection among largely healthy workers, the general population, comprised of some elderly and immunocompromised individuals, could face additional risk. With climate-related events like drought and wildfires also increasing in endemic areas, future research is needed to address the possible associations between these phenomena and coccidioidomycosis outbreaks.