Prevalence of skin reactivity to coccidioidin and associated risks factors in subjects living in a northern city of Mexico.

BACKGROUND: Coccidioidomycosis is a reemerging fungal disease seen mainly in the states located at the Mexican-U.S. border. The finding of advanced cases of the disease are now more frequent.
METHODS: A cross-sectional study was conducted to determine the prevalence of skin reactivity to coccidioidin in the city of Torreón, Coahuila, Mexico, located in the northern region of the country. A multifactorial association of environmental, social, and health conditions was analyzed. A total of 1,653 coccidioidin skin tests was applied in male and female subjects older than 8 years of age.
RESULTS: The overall rate of positive reactivity in this city was 40.2%, with a 95% confidence interval of 37.8-42.5. This was related to time/life exposure risk and to the habitat of unpaved streets. No statistically significant difference regarding gender, socioeconomic level, and working activities was found. The highest reactivity was observed in subjects between 30 and 65 years of age.
CONCLUSIONS: Positive results were related to exposure risk and habitat, principally in the southeast region of the city. These results were applied both to residents and outsiders with no differences between the groups. Of the total, 87.5% were considered high-risk subjects. It is recommended that future surveys be carried out in other northern cities of Mexico to obtain more useful data concerning the extent of the infection and mainly to establish preventive measures, such as appropriate reforestation and urbanization procedures.