title: Estimating tuberculosis incidence from primary survey data: a mathematical modeling approach.
abstract: There is an urgent need for improved estimations of the burden of tuberculosis (TB).
  
  
  
  To develop a new quantitative method based on mathematical modelling, and to demonstrate its application to TB in India.
  
  
  
  We developed a simple model of TB transmission dynamics to estimate the annual incidence of TB disease from the annual risk of tuberculous infection and prevalence of smear-positive TB. We first compared model estimates for annual infections per smear-positive TB case using previous empirical estimates from China, Korea and the Philippines. We then applied the model to estimate TB incidence in India, stratified by urban and rural settings.
  
  
  
  Study model estimates show agreement with previous empirical estimates. Applied to India, the model suggests an annual incidence of smear-positive TB of 89.8 per 100 000 population (95%CI 56.8-156.3). Results show differences in urban and rural TB: while an urban TB case infects more individuals per year, a rural TB case remains infectious for appreciably longer, suggesting the need for interventions tailored to these different settings.
  
  
  
  Simple models of TB transmission, in conjunction with necessary data, can offer approaches to burden estimation that complement those currently being used.
authors.affiliation: Public Health Foundation of India, New Delhi.
authors.forename: S
authors.initials: S
authors.lastname: Pandey
authors.affiliation: Epidemiology and Research Division, National Tuberculosis Institute, Bangalore, India.
authors.forename: V K
authors.initials: VK
authors.lastname: Chadha
authors.affiliation: Public Health Foundation of India, New Delhi, Center for Disease Dynamics, Economics & Policy, Washington, DC, Princeton Environmental Institute, Princeton, New Jersey, USA.
authors.forename: R
authors.initials: R
authors.lastname: Laxminarayan
authors.affiliation: Public Health Foundation of India, New Delhi, Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: Arinaminpathy
mesh_terms: D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D008962:Models, Theoretical; D012424:Rural Population / Q000706:statistics & numerical data*; D013183:Sputum / Q000382:microbiology; D013997:Time Factors; D014376:Tuberculosis / Q000453:epidemiology*; D014505:Urban Population / Q000706:statistics & numerical data*