title: The Yield of Community-Based "Retrospective" Tuberculosis Contact Investigation in a High Burden Setting in Ethiopia.
abstract: OBJECTIVE
  To determine the yield and determinants of retrospective TB contact investigation in selected zones in Ethiopia.
  
  
  METHODS
  This was a community-based cross-sectional study conducted during June-October 2014.Trained lay providers performed symptom screening for close contacts of index cases with all types of TB registered for anti-TB treatment within the last three years. We used logistic regression to determine factors associated with TB diagnosis among the contacts.
  
  
  RESULTS
  Of 272,441 close contacts of 47, 021 index cases screened, 13,886 and 2, 091 had presumptive and active TB respectively. The yield of active TB was thus 768/100, 000, contributing 25.4% of the 7,954 TB cases reported from the study zones over the study period. The yield was highest among workplace contacts (12,650/100, 000). Active TB was twice more likely among contacts whose index cases had been registered for TB treatment within the last 12 months compared with those who had been registered 24 or more months earlier (adjusted odds ratio, AOR: 1.77 95% CI 1.42-2.21). Sex or clinical type of TB in index cases was not associated with the yield. Smear negative (SS-) index cases (AOR: 1.74 955 CI 1.13-2.68), having index cases who registered for treatment within <12 months (AOR: 2.41 95% CI 1.51-3.84) and being household contact (AOR: 0.072 95% CI 0.01-0.52) were associated with the occurrence of active TB in children.
  
  
  CONCLUSIONS
  The yield of retrospective contact investigation was about six times the case notification in the study zones, contributing a fourth of all TB cases notified over the same period. The yield was highest among workplace contacts and in those with recent past history of contact. Retrospective contact screening can serve as additional strategy to identify high risk groups not addressed through currently recommended screening approaches.
authors.affiliation: Management Sciences for Health, Help Ethiopia Address the Low Performance of Tuberculosis (HEAL TB) Project, Addis Ababa, Ethiopia.
authors.forename: Zewdu
authors.initials: Z
authors.lastname: Gashu
authors.affiliation: Management Sciences for Health, Help Ethiopia Address the Low Performance of Tuberculosis (HEAL TB) Project, Addis Ababa, Ethiopia.
authors.forename: Degu
authors.initials: D
authors.lastname: Jerene
authors.affiliation: Management Sciences for Health, Help Ethiopia Address the Low Performance of Tuberculosis (HEAL TB) Project, Addis Ababa, Ethiopia.
authors.forename: Mitiku
authors.initials: M
authors.lastname: Ensermu
authors.affiliation: Management Sciences for Health, Help Ethiopia Address the Low Performance of Tuberculosis (HEAL TB) Project, Addis Ababa, Ethiopia.
authors.forename: Dereje
authors.initials: D
authors.lastname: Habte
authors.affiliation: Management Sciences for Health, Help Ethiopia Address the Low Performance of Tuberculosis (HEAL TB) Project, Addis Ababa, Ethiopia.
authors.forename: Muluken
authors.initials: M
authors.lastname: Melese
authors.affiliation: Management Sciences for Health, Help Ethiopia Address the Low Performance of Tuberculosis (HEAL TB) Project, Addis Ababa, Ethiopia.
authors.forename: Nebiyu
authors.initials: N
authors.lastname: Hiruy
authors.affiliation: Management Sciences for Health, Help Ethiopia Address the Low Performance of Tuberculosis (HEAL TB) Project, Addis Ababa, Ethiopia.
authors.forename: Endale
authors.initials: E
authors.lastname: Shibeshi
authors.affiliation: Oromia regional Health Bureau, Addis Ababa, Ethiopia.
authors.forename: Shallo D
authors.initials: SD
authors.lastname: Hamusse
authors.affiliation: Amhara regional Health Bureau, Bahirdar, Ethiopia.
authors.forename: G
authors.initials: G
authors.lastname: Nigussie
authors.affiliation: Management Sciences for Health, Help Ethiopia Address the Low Performance of Tuberculosis (HEAL TB) Project, Addis Ababa, Ethiopia.
authors.forename: B
authors.initials: B
authors.lastname: Girma
authors.affiliation: United States Agency for International Development (USAID), Addis Ababa, Ethiopia.
authors.forename: Yewulsew
authors.initials: Y
authors.lastname: Kassie
authors.affiliation: United States Agency for International Development (USAID), Addis Ababa, Ethiopia.
authors.forename: Yared Kebede
authors.initials: YK
authors.lastname: Haile
authors.affiliation: Management Sciences for Health, Center for Health Services, Arlington, Virginia, United States of America.
authors.forename: Pedro
authors.initials: P
authors.lastname: Suarez
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D016358:Contact Tracing / Q000706:statistics & numerical data*; D003430:Cross-Sectional Studies; D019353:Endemic Diseases; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D016017:Odds Ratio; D012189:Retrospective Studies; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*