Climate Change, Wildfire & the Spread of Valley Fever

Climate change and infectious diseases: surveillance of factors contributing to increasing cases of coccidioidomycosis (Valley fever) in the western United States.  As the western US experiences prolonged drought and increasingly large and intense wildfires, particulate matter in the form of dust and wildfire smoke is becoming more prevalent, concurrent with increases in Valley fever incidence.  Valley fever is an emerging fungal infection caused by Coccidioides spp., soil dwelling fungi that are found more commonly in and around rodent burrows. Infection results from inhalation of airborne Coccidioides spores that can co-occur with components of particulate matter (e.g., mineral dust) and may be transported in smoke. Transitions from extreme dry and extreme wet conditions, which are becoming more frequent under climate change, have been associated with sharp spikes in incidence. Novel means of bio-surveillance are of interest for characterizing and predicting where the greatest health risks will exist in the future. This presentation takes a One Health approach to examine links between climate, zoonotic hosts (rodents), and the exchange between soil and the atmosphere in a novel approach to surveilling biological and climatological conditions contributing to infectious disease spread in our rapidly-warming world.

Impact/Purpose

There are gaps in our understanding of the conditions facilitating aerosolization, airborne concentration, and transport of the Coccidioides fungus, which causes Valley fever, under both ambient air conditions and during specific events that elevate particulate matter and dust concentrations, such as dust storms and wildfires.  Spatially explicit UAS-based sampling could enhance understanding of Coccidioides aerobiology and enable detection in hard-to-reach or hazardous air masses, including dust storms and wildland fire smoke. Understanding how, where, and when fungal spores are aerosolized and transported is crucial for developing strategies to predict and reduce exposure to Coccidioides, such as the development of near-term forecasting systems for elevated exposure risk.

Citation

Markwiese, J. Climate Change, Wildfire & the Spread of Valley Fever. One Health Community of Practice: EPA, States (AFWA, ASTHO & ECOS) and Tribes, durham, NC, October 22, 2024.