August 25, 2022

Valley Fever a Concern for Wildland Firefighters in the Southwestern U.S.

A recent outbreak of Valley Fever among wildland firefighters who worked in a California region near the Tehachapi Mountains highlights the importance of respiratory protection and training to better protect these workers, according to an article published by CDC in this week’s Morbidity and Mortality Weekly Report (MMWR). Seven firefighters from two crews came down with respiratory illness in summer 2021, and they each visited an emergency department two or three times due to cough, chest pain, or shortness of breath. All of the firefighters tested negative for SARS-CoV-2, and three who were hospitalized received serologic test results that were positive for coccidioidomycosis. The hospitalized firefighters were treated with antifungal medication.

Valley Fever, or coccidioidomycosis, is a disease caused by the inhalation of Coccidioides fungal spores, which are present in the soil of semiarid areas such as Arizona and California in the southwestern United States as well as parts of Mexico and Central and South America. The disease can cause symptoms such as fatigue, cough, fever, shortness of breath, headaches, body aches, joint pain, and rash. Severe cases of Valley Fever can result in hospitalization or death.

The onset of the firefighters’ illness and their work histories suggest that they were likely exposed to Coccidioides while responding to a fire near the Tehachapi Mountains, a mountain range that forms part of the boundary between the San Joaquin Valley and the Mojave Desert. The firefighters dug trenches and “mopped up” the fire, tasks that involved digging and moving soil “with heavy dust exposure and without respiratory protection,” the MMWR report notes. They all reported having been fit-tested for a respirator and trained to minimize dust exposure.

The report’s authors urge fire agencies to evaluate the feasibility of respirator use under certain conditions—during dust-generating activities away from active burning, for example.

“Use of respiratory protection is challenging in wildland firefighting because of concerns about respirator flammability and compatibility with other equipment, as well as the hot, strenuous nature of the emergency-related work,” CDC’s report explains. “As frequency of coccidioidomycosis and wildfires increase in California, exploration of protective equipment and additional training are needed to better protect wildland firefighters.”

The MMWR report is available from CDC’s website.