No Consistent Link Between Dust Storms and Valley Fever (Coccidioidomycosis)

Abstract

Dust storms, such as those associated with haboobs and strong regional winds, are frequently assumed to cause increases in cases of Valley fever (coccidioidomycosis). The disease is caused by inhaling arthroconidia of Coccidioides fungi that, after being disturbed from semi‐desert subsoil, have become airborne. Fungal arthroconidia can be transported in low‐wind conditions as well as in individual dust events, but there is no reliable evidence that all or most dust storms consistently lead to subsequent increases in coccidioidomycosis cases. Following a review of the relevant literature, this study examines the relationship between dust storms and coccidioidomycosis cases to determine if there is a consistent and general association between them. All recorded dust storms from 2006 to 2020 in and near the Phoenix area of Maricopa County, Arizona and the Bakersfield area of Kern County, California were used in a compositing analysis (superposed epoch analysis) of subsequent coccidioidomycosis cases in each area. Analyses of monthly and weekly disease case data showed no statistical differences in the patterns of coccidioidomycosis cases following dust storms versus non‐dust storm conditions, for the entire data set as well as for seasonal subsets of the data. This study thoroughly analyzes post‐dust storm coccidioidomycosis cases for a large set of dust storms, and it confirms and expands upon previous literature, including a recent study that measured airborne arthroconidia and found no consistent links connecting wind and dust conditions to increases in coccidioidomycosis.

PM10 and Other Climatic Variables Are Important Predictors of Seasonal Variability of Coccidioidomycosis in Arizona

“…Inclement weather, such as dust storms (haboobs), has been proposed to increase the risk of infection by Coccidioides ( 22 , 23 ). Although recent analysis shows no such connection ( 16 ), we still expect wind speed may be important for explaining human disease because of the dispersal of spores that establish infection ( 16 , 17 , 24 , 25 ). Moreover, we hypothesize that the concentration of inhalable particulate matter, quantified as PM10, is important because infectious spores could be dispersed via dust.…”

“…Certain meteorological parameters, such as precipitation and temperature, likely influence the fluctuation of fungal concentrations in the soil and air, which would lead to increases in infections at certain times of the year. Comrie showed evidence of bimodal seasonality of Valley fever cases that coincided with the precipitation regime of the Sonoran Desert and has assessed the role of dust storms (haboobs)—which appear to play no direct role in the incidence of Valley fever ( 15 , 16 ). Talamantes et al found no to weak statistical evidence of climatic factors driving Valley fever cases and attributed fluctuations to human activity ( 17 ).…”

Infectious Diseases Associated with Desert Dust Outbreaks: A Systematic Review

“…All studies were published between 2004 and 2021 [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ]. The affected regions that were studied were Asia (32/51, 62.7%), followed by Europe (9/51, 17.6%), America (6/51, 11.8%), Africa (4/51, 7.8%) and Australia (1/51, 2.0%).…”

“…A significant positive association was found in 10/12 (83.3%) of them. The infectious diseases positively associated with desert dust storms were mostly pneumonia and other respiratory tract infections, including COVID-19, pulmonary tuberculosis and coccidioidomycosis (Valley fever) [ 11 , 13 , 17 , 18 , 19 , 20 , 23 , 24 , 60 , 61 ]. Other infectious diseases that have been positively associated with dust storms are measles and meningococcal meningitis [ 12 , 21 ].…”

“…Other infectious diseases that have been positively associated with dust storms are measles and meningococcal meningitis [ 12 , 21 ]. In two studies, no significant link was noted between dust storms and the infectious diseases studied, pneumonia [ 13 ] or coccidiomycosis [ 11 ].…”