We thank our colleagues for the valuable suggestions during the preparation of this manuscript. We thank K. Govind for providing the ssRNA transcripts to generate dsRNA, J.N.Kalyani for her help in determining the kinetic parameters and B.Chiranjivee for the kind gift of purified RecoP5I protein.  Mortality among patients with tuberculosis requiring intensive care: a retrospective cohort study BACKGROUND: To describe the characteristics of patients with tuberculosis (TB) requiring intensive care and to identify the factors that predicts in-hospital mortality in a city of a developing country with intermediate-to-high TB endemicity. METHODS: We conducted a retrospective, cohort study, between November 2005 and November 2007. The patients with TB requiring intensive care were included. Predictors of mortality were assessed. The primary outcome was the in-hospital mortality. RESULTS: During the study period, 67 patients with TB required intensive care. Of them, 62 (92.5%) had acute respiratory failure and required mechanical ventilation. Forty-four (65.7%) patients died. Coinfection with human immunodeficiency virus was present in 46 (68.7%) patients. Early intensive care unit admission and ventilator-associated pneumonia were independently associated with the in-hospital mortality. CONCLUSIONS: In this study we found a high mortality rate in TB patients requiring intensive care, especially in those with an early ICU admission. Across the world tuberculosis (TB) remains an important public health problem, especially in developing countries. One third of the world's population is infected with Mycobacterium tuberculosis. Brazil is ranking 15 th among the 22 high-burden countries that collectively account for 80% of TB cases globally. The incidence of TB was of 50 cases/100,000 population/yr in 2006, and recently reached approximately 100 cases/ 100,000 population in the city of Porto Alegre (southern Brazil) [1] . Every year, almost 2 million people die of TB, most of them in low-and middle-income countries. The annual death rate from TB in Brazil was estimated at 4.0/100,000 population/yr in 2006 [2] .