Detection of pulmonary tuberculosis in Chiapas, Mexico

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

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.

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.

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