[Tijuana: endemic zone of Coccidioides immitis infection].

To consider a geographical zone as endemic for Coccidioidomycosis, three requisites are necessary: 1. isolation of the causal agent, Coccidioides immitis, from the environment, 2. a prevalence of infection among the population of that area of at least 5%, and 3. the demonstration of clinical cases of coccidioidomycosis in that population. There are no previous reports on the endemicity of Coccidioidomycosis in Tijuana, Baja California, mexico. We are reporting: a) the isolation of the causal agent, C. immitis from the environment, b) the results of a survey with intradermal antigens of the fungus, with a prevalence of infection among 1 128 healthy subjects of 10%, and c) the incidence of this systemic mycosis among the population of patients of the Tijuana General Hospital during a three-year period.