Geographic Distribution of Endemic Fungal Infections among Older Persons, United States

To investigate the epidemiology and geographic distribution of histoplasmosis, coccidioidomycosis, and blastomycosis in older persons in the United States, we evaluated a random 5% sample of national Medicare data from 1999 through 2008. We calculated national, regional, and state-based incidence rates and determined 90-day postdiagnosis mortality rates. We identifi ed 776 cases (357 histoplasmosis, 345 coccidioidomycosis, 74 blastomycosis). Patient mean age was 75.7 years; 55% were male. Histoplasmosis and blastomycosis incidence was highest in the Midwest (6.1 and 1.0 cases/100,000 person-years, respectively); coccidioidomycosis incidence rate was highest in the West (15.2). On the basis of available data, for 86 (11.1%) cases, there was no patient exposure to a traditional disease-endemic area. Knowledge of areas where endemic mycosis incidence is increased may affect diagnostic or prevention measures for older adults at risk. F ungal infections have become an increasing problem for older persons in the United States (1-4). Compared with years past, older adults today are more likely to be considered for transplantation, receive aggressive regimens of chemotherapy, or take immunosuppressive drugs for rheumatologic or autoimmune diseases. In addition, increasing longevity has enabled older adults to travel and participate in outdoor activities where they might be exposed to opportunistic fungal organisms that they did not encounter in their youth or for which primary immunity has waned. Major opportunistic infections in older adults include the endemic mycoses histoplasmosis, blastomycosis, and coccidioidomycosis. These infections are acquired through inhalation of spores in the environment and are often associated with outdoor activities and geographic exposures (2,5-8). Increasing age and decreasing cell-mediated immunity as a result of transplantation, chemotherapy, or other immunosuppressive medications (e.g., tumor necrosis factor- inhibitors) are the main predisposing factors