Coccidioidomycosis-associated Hospitalizations, California, USA, 2000–2011

Coccidioidomycosis, also known as Valley fever, is a reemerging infectious disease caused by inhalation of Coccidioides fungi spores, which reside in the soil of regions where coccidioidomycosis is endemic, including the southwestern United States (1–5). California and Arizona have the highest rates of reported coccidioidomycosis cases in the United States (4,6). In California, the pathogen is most common in the San Joaquin Valley, and compared with other Californians, residents of this region are at increased risk for infection (6,7). Although most coccidioidomycosis cases are asymptomatic, symptomatic disease will develop in ≈40% of patients and can range from self-limited influenza-like illness to disseminated disease and chronic meningitis (7,8). Symptomatic disease can require expensive and aggressive treatments, prolonged absence from work or school, multiple hospitalizations, and years of monitoring (9,10). Populations at particular risk for severe disease include African Americans, immunocompromised persons, and persons >65 years of age (2,11). Over the past decade, increases in the number of reported cases of coccidioidomycosis have been documented from Arizona and California (6,12–16). In California, the rates of reported cases increased >6-fold from 2000 to 2011 (2.4 to 14.4 cases/100,000 population, respectively) (13,15). Cases among prisoners in California also increased during this time, making prisoners a population of concern (17,18). To determine the epidemiology, extent, and effect of the disease in California, we reviewed coccidioidomycosis-associated hospitalizations in the state for 2000–2011.