Tuberculosis in Mexico and the USA, Comparison of Trends Over Time 1990-2010

BACKGROUND The aim was to compare tuberculosis trends in Mexico and United States and to evaluate Mexican diagnostic methods and contact investigation. METHODS Retrospective comparative study of tuberculosis cases and incidence rates between both countries (1990-2010). Diagnostic methods and contact investigations were also evaluated for Mexico. Estimates were obtained from official websites. RESULTS In Mexico, no clear trend was found over time for cases. Pulmonary (PTB) and all forms of tuberculosis (AFTB) incidence decreased 2.0% annually. There was a negative correlation between the mean contacts examined per case and AFTB incidence (r(2)=-0.44, p=0.01) with a 33% reduction in AFTB incidence. In United States, PTB and AFTB cases have been decreasing 6.0% and 5.6% annually, respectively. The incidence decreased 7.3% and 6.8%, respectively. CONCLUSION The incidence of tuberculosis in Mexico is decreasing slightly over time at 2% annually. In the United States, cases and incidence rates have been decreasing at a higher rate (5% to 7% annually). The inverse association between number of contacts examined per state and incidence rates in Mexico underscore the importance of reinforcing and improving contact investigations with the likely translation of a decrease of TB incidence at a higher rate.