Surveillance for coccidioidomycosis (CM) and a case-control study for risk factors among adults were conducted in Kern County, California. From January 1995 through December 1996, 905 cases of CM were identified, for an annual incidence of 86 cases per 100,000 population. A total of 380 adults were enrolled in the case-control study: 77 had severe pulmonary disease, 33 had disseminated disease, and 270 control patients had mild disease. Independent risk factors for severe pulmonary disease included diabetes, recent history of cigarette smoking, income of < $15,000 per year, and older age. Oral antifungal therapy before hospitalization was associated with a reduced risk of CM pneumonia. Risk factors for disseminated disease were black race, income of < $15,000 per year, and pregnancy. Early treatment of CM with oral antifungal agents may prevent severe pulmonary disease in groups considered to be at high risk, such as elderly individuals, persons with diabetes, and smokers. Persons at risk for severe CM may benefit from vaccination once an effective CM vaccine is available.

Coccidioidomycosis is a fungal disease acquired through the inhalation of spores of Coccidioides spp., which afflicts primarily humans and other mammals. It is endemic to areas in the southwestern United States, including the San Joaquin Valley portion of Kern County, California, our region of interest (ROI). Recently, incidence of coccidioidomycosis, also known as valley fever, has increased significantly, and several factors including climate change have been suggested as possible drivers for this observation. Up to date details about the ecological niche of C. immitis have escaped full characterization. In our project, we chose a three-step approach to investigate this niche: 1) We examined Landsat-5-Thematic-Mapper multispectral images of our ROI by using training pixels at a 750 m×750 m section of Sharktooth Hill, a site confirmed to be a C. immitis growth site, to implement a Maximum Likelihood Classification scheme to map out the locations that could be suitable to support the growth of the pathogen; 2) We used the websoilsurvey database of the US Department of Agriculture to obtain soil parameter data; and 3) We investigated soil samples from 23 sites around Bakersfield, California using a multiplex Polymerase Chain Reaction (PCR) based method to detect the pathogen. Our results indicated that a combination of satellite imagery, soil type information, and multiplex PCR are powerful tools to predict and identify growth sites of C. immitis. This approach can be used as a basis for systematic sampling and investigation of soils to detect Coccidioides spp.

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Persons incarcerated in endemic areas constitute a susceptible population that should be considered at risk for coccidioidomycosis. Further studies are needed to identify populations that may benefit from early antifungal treatment for pulmonary coccidioidomycosis.

C occidioidomycosis (Valley fever or San Joaquin Valley fever) is a pulmonary and systemic infection that results from respiratory exposure to aerosolized arthroconidia spores of soil-dwelling species of Coccidioides fungi (1). Coccidioides fungi and coccidioidomycosis are strongly associated with the semiarid climate of the Lower Sonoran life zone of the southwestern United States and parts of Mexico, Central America, and South America. Most US cases occur in Arizona and California. However, the fungus and locally acquired cases have recently been reported as far north as Washington state, potentially related to changes in climate and land use patterns (2,3). In California, the species most often implicated in human infection is C. immitis, whereas in Arizona it is C. posadasii (2,3). After an incubation period of ≈1-3 weeks, most infected persons experience few or mild symptoms, and the condition usually resolves within weeks or months, often unrecognized (4,5). Approximately 40% of infected persons experience an influenza-like illness with cough, fever, and fatigue that typically resolves without treatment. Approximately 1% of cases involve dissemination to skin, bone, meninges, and other tissues (6); patients with disseminated disease require long-term antifungal therapy and may die (7). Risk factors for disseminated disease include male sex, age >60 years, pregnancy, immunocompromise, and African and Filipino ancestry (8). Case identification is based on clinically compatible illness with confirmatory laboratory evidence or skin-test conversion (9). Local health departments may find it impractical to obtain clinical information and thus may identify cases solely on the basis of laboratory results (4). Because most cases are subclinical, public health surveillance substantially underestimates infection risk. McCotter et al. estimated that the true number of cases is ≈4-6-fold greater than that captured by public health surveillance (2). Residence in or visits to coccidioidomycosis-endemic areas may lead to exposure and infection. The largest outbreaks have been associated with natural phenomena. A December 1977 dust storm in California's San Joaquin Valley (an area of high coccidioidomycosis endemicity, from which the disease derives its common name) resulted in a ≥10-fold increase in incidence in 15 of the state's 58 counties (1,10). The 1994 Northridge, California, earthquake was responsible for 203 outbreak-associated cases, including 3 deaths (11). Occupational risk has been associated with soil-disruptive activity involving archeologists (12), film crews (13), solar power farm construction workers (14,15), roadway and construction workers