title: Epidemiological impact of mass tuberculosis screening: a 2-year follow-up after a national prevalence survey.
abstract: OBJECTIVE
  To assess the epidemiological impact of mass tuberculosis (TB) screening in the community and the prognosis of bacteriologically negative individuals with abnormal findings on chest radiography (CXR).
  
  
  METHODS
  A follow-up study consisting of two parts--a register match of notified TB cases with 22,160 participants in a national TB prevalence survey, and a repeat medical examination for the subjects of a prevalence survey with abnormal findings on CXR--was conducted 2 years after the prevalence survey in Cambodia.
  
  
  RESULTS
  Thirty-four cases with new smear-positive TB were detected by register match, giving a standardised notification ratio of 0.38 (95%CI 0.27-0.52). An additional seven new smear-positive TB cases and 93 new smear-negative, culture-positive TB cases were detected by medical examination. The incidence rates of bacteriologically positive TB were 8.5% per year (95%CI 6.3-11.2) in cases with a CXR suggestive of active TB and 2.9% per year (95%CI 2.2-3.7) in those with a CXR with other abnormalities.
  
  
  CONCLUSIONS
  Detection and treatment of smear-negative, culture-positive TB cases as well as smear-positive TB cases was associated with a rapid reduction in subsequent incidence of new smear-positive TB. Sputum culture-negative individuals with abnormal CXR findings are at a high risk of disease progression, and require follow-up and potentially preventive treatment.
authors.affiliation: Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Tokyo, Japan. okadak@jata.or.jp
authors.forename: K
authors.initials: K
authors.lastname: Okada
authors.forename: I
authors.initials: I
authors.lastname: Onozaki
authors.forename: N
authors.initials: N
authors.lastname: Yamada
authors.forename: T
authors.initials: T
authors.lastname: Yoshiyama
authors.forename: T
authors.initials: T
authors.lastname: Miura
authors.forename: S
authors.initials: S
authors.lastname: Saint
authors.forename: S
authors.initials: S
authors.lastname: Peou
authors.forename: T E
authors.initials: TE
authors.lastname: Mao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000627:therapeutic use; D002160:Cambodia / Q000453:epidemiology; D002648:Child; D018563:Disease Notification; D005260:Female; D005500:Follow-Up Studies; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D011859:Radiography; D012042:Registries; D013183:Sputum / Q000382:microbiology; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents