Detection of pulmonary tuberculosis in Chiapas, Mexico.

Purpose: To estimate the prevalence of undiagnosed pulmonary tuberculosis (PTB) and the sensitivity of bacilloscopy in the border region of Chiapas, Mexico.

Methods: We actively sought individuals aged 15 years or more with chronic cough from the Border Region of Chiapas, Mexico in three settings: one regional hospital, seven Primary Care Centers (PCC), and 32 communities. Individuals (a total of 899) reporting chronic cough were asked to provide three samples of sputum for acid-fast smears and cultures. The quality of acid-fast smears was evaluated using culture as the gold standard.

Results: We obtained sputum specimens from 590 of 899 individuals with chronic cough. A diagnosis of PTB was confirmed in 78. A conservative estimate of the overall prevalence of PTB at the population level was 151 per 100,000 (95% CI: 88 to 241). In the regional hospital, the estimated case detection rate was 66% (29/44). The proportion of candidates for PTB therapy that were actually on treatment was 50% (14/28) at the PCC and 11% (2/19) in the communities. The sensitivity of the bacilloscopy was about 90% in the hospital, and slightly lower than 50% in the PCC and the communities.

Conclusion: Improved procedures for PTB detection are required in the studied area to adequately control the disease and to provide therapy to affected patients.