Evidence for Aerosolized Environmental Bacterial Endotoxin as an Environmental Health Hazard

The high incidence of asthma near California's Salton Sea is attributed to dust emitted from the exposed lakebed. A survey of clinical symptoms conducted in the region revealed distinct spatial distribution with strong geospatial correlations between asthma symptoms and prevailing wind direction as well as with PM₁₀ levels. Mice exposed to dust collected across the region showed lung inflammation which was TLR4-dependent; dust inducing the strongest inflammation showed the highest concentrations of LPS. Inflammatory responses and LPS distribution showed a distinct spatial distribution. Environmental halophiles cultured from Salton Sea water produced LPS that induced similar lung inflammation in mice. These results suggest that environmental bacterial LPS entrained in the dust promotes asthma-like disease; thus, perturbations of "natural" ecosystems may produce significant health impacts.