COCCIDIOIDOMYCOSIS IN TULARE COUNTY, CALIFORNIA, 1991 - REEMERGENCE OF AN ENDEMIC DISEASE

In 1991, 1208 cases of coccidioidomycosis were reported to the Califor nia Department of Health Services, compared with an annual average of 450 during 1986-90. We conducted a study in Tulare County to define th e epidemiology of the disease and identify risk factors for severe dis ease, focusing on the epidemic period September 1991-December 1991. To identify cases, we used data from the Coccidioidomycosis Serology Lab oratory at the University of California, Davis, other laboratories, an d the Tulare County Health Department's coccidioidomycosis reporting s ystem. We compared patients who were hospitalized with those who were not to determine risk factors for severe disease. We identified 128 ca ses of acute coccidioidomycosis diagnosed between 1 September and 31 D ecember 1991 (attack rate 41/100 000); south central Tulare County had the highest attack rate. Thirty-five (27%) case-patients were hospita lized. Male sex (relative risk (RR) 2.5, 95% confidence interval (CI) 1.2-5.0), black people and Asian races (RR 4.8, 95% CI 2.4-9.6), and a ge greater than or equal to 20 years (RR 8.3, 95% CI 1.2-57.4) were un ivariately significant and remained independently associated with hosp italization in multivariate analysis. The 1991 Tulare County outbreak of coccidioidomycosis was part of a much larger outbreak that began in California during 1991 and continued through 1993. The outbreak was p receded by an unusually rainy spring. Although dust reduction measures during times of increased coccidioidomycosis incidence can help reduc e exposure, definitive control awaits the development of a safe, effec tive vaccine.