California and federal public health officials say valley fever, a potentially lethal but often misdiagnosed disease infecting more and more people around the nation, has been on the rise as warming climates and drought have kicked up the dust that spreads it.

The fever has hit California’s agricultural heartland particularly hard in recent years, with incidence dramatically increasing in 2010 and 2011. The disease — which is prevalent in arid regions of the United States, Mexico, Central and South America — can be contracted by simply breathing in fungus-laced spores from dust disturbed by wind as well as human or animal activity.

The fungus is sensitive to environmental changes, experts say, and a hotter, drier climate has increased dust carrying the spores.

“Research has shown that when soil is dry and it is windy, more spores are likely to become airborne in endemic areas,” said Dr. Gil Chavez, Deputy Director of the Center for Infectious Diseases at the California Department of Public Health.

Variance in range and scope of endemic illness, is important from a public health standpoint; and for purposes of sentinel tracking and prevention, as well as diagnosis & treatment.

This particular fungus Coccidioides immitis incidence is in Arid and Semi-arid climates throughout the Western Hemisphere, essentially along the spine of the continents. Respiratory infections of Coccidioidomycosis have been on the rise since 1991 in Southern California and the San Joaquin Valley. The increased incidence has spread throughout the Southwest US as far as Southwest Texas. The increased incidence is due in part to the increased population densities, and to diminished rainfall, with increased dust cover, in these areas. Occurrence is concomitant with dust inhalation, incubation is 1 to 4 weeks, symptoms are persistent cough, fever, chills, and pleuritic pain. Disseminated disease (in the immune suppressed), resembles tuberculosis, and can be fatal. Usually the illness is self limiting, over 2 to 3 months, acute treatment is with Fluconazole, and prevention involves dust control measures.