title: Risk of latent tuberculosis infection in children living in households with tuberculosis patients: a cross sectional survey in remote northern Lao People's Democratic Republic.
abstract: BACKGROUND
  Tuberculosis is highly prevalent in Laos (289 per 100,000). We evaluated the risk of latent tuberculosis infection (LTBI) among children (0-15 years) living with tuberculosis patients in rural northern Laos.
  
  
  METHODS
  In a cross sectional survey of 30 randomly selected villages, 72 tuberculosis patients were traced and their 317 contacts (148 were children) investigated using a questionnaire, a tuberculin skin tests (positive: > = 10 mm), a 3-day sputum examination for acid-fast bacilli (AFB), and chest radiography.
  
  
  RESULTS
  None of the 148 contact-children received prophylaxis, one had cervical tuberculosis; the risk for LTBI was 31.0%. Awareness of the infectiousness of tuberculosis was low among patients (31%) and their contacts (31%), and risky behavior was common. After multivariate logistic analysis, increased LTBI was found in children with contact with sputum positive adults (OR: 3.3, 95% CI: 1.4-7.7), patients highly positive sputum prior to treatment (AFB >2+; OR: 4.7, 95% CI: 1.7-12.3), and living in ethnic minorities (OR: 5.4, 95% CI: 2.2-13.6).
  
  
  CONCLUSIONS
  The study supports the importance of contact tracing in remote settings with high TB prevalence. Suggestions to improve the children's detection rate, the use of existing guidelines, chemoprophylaxis of contact-children and the available interventions in Laos are discussed. Improving education and awareness of the infectiousness of TB in patients is urgently needed to reduce TB transmission.
authors.affiliation: Institut de Francophonie pour Médecine Tropicale, Vientiane, Lao PDR. nhaituan@yahoo.com
authors.forename: Tuan H
authors.initials: TH
authors.lastname: Nguyen
authors.forename: Peter
authors.initials: P
authors.lastname: Odermatt
authors.forename: Gunther
authors.initials: G
authors.lastname: Slesak
authors.forename: Hubert
authors.initials: H
authors.lastname: Barennes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D016358:Contact Tracing; D003430:Cross-Sectional Studies; D005191:Family Characteristics; D005260:Female; D006801:Humans; D007223:Infant; D007812:Laos / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010808:Physical Examination; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population; D013183:Sputum / Q000382:microbiology; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology* / Q000635:transmission; D055815:Young Adult