title: Annual risk of tuberculosis infection in Chennai city.
abstract: OBJECTIVE
  To study the proportion of children infected with Mycobacterium Tuberculosis in Chennai city.
  
  
  METHODS
  A cluster sampling methodology was adopted to select an estimated sample size of 7000 children from five corporation zones selected systematically from ten zones of the city. A total of 7098 children aged 1-9 years were subjected to Mantoux and test read; 1897 (27%) from slum area and 5201 (73%) from non-slum area.
  
  
  RESULTS
  The prevalence of infection among children without BCG scar was estimated to be 10.5 % (ARTI of 2.0%) and was similar to that among children irrespective of scar status. The prevalence of infection was higher among children in slum areas (11.1%; ARTI 2.1%) compared to non-slum areas (8.9%; ARTI 1.7%); but the difference was not statistically different.
  
  
  CONCLUSIONS
  The tuberculosis situation in Chennai as measured by risk of infection was higher in urban city area than rural areas and comparable to that found in other cities as reported from earlier studies. This information can be used as baseline information for monitoring the epidemiological trends in Chennai city in future.
authors.affiliation: Tuberculosis Research Centre, Mayor V.R. Ramanathan Road, Chetput, Chennai-600 031.
authors.forename: P G
authors.initials: PG
authors.lastname: Gopi
authors.forename: V Venkatesh
authors.initials: VV
authors.lastname: Prasad
authors.forename: M
authors.initials: M
authors.lastname: Vasantha
authors.forename: R
authors.initials: R
authors.lastname: Subramani
authors.forename: A S
authors.initials: AS
authors.lastname: Tholkappian
authors.forename: D
authors.initials: D
authors.lastname: Sargunan
authors.forename: P R
authors.initials: PR
authors.lastname: Narayanan
mesh_terms: D001500:BCG Vaccine / Q000008:administration & dosage; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D007223:Infant; D008297:Male; D011204:Poverty Areas; D015995:Prevalence; D012306:Risk; D014374:Tuberculin Test / Q000706:statistics & numerical data; D014376:Tuberculosis / Q000453:epidemiology* / Q000517:prevention & control; D014504:Urban Health / Q000706:statistics & numerical data*
chemical_list: D001500:BCG Vaccine