title: Yield of tuberculosis contact investigation in a low-incidence country.
abstract: BACKGROUND
  Tuberculosis (TB) contact tracing is a valid public health measure to control the spread of TB infection in low-burden settings. The aim of this study was to assess the yield of the Piedmont TB contact investigation program and to evaluate the role of its main determinants.
  
  
  METHODS
  The Piedmont TB notification systems were used to identify index TB cases. All cases were classified by contagiousness (sputum-smear-positive, AFB+; culture-positive, CULT+; other-than-defined). TB contacts were screened for active and latent TB infection by clinical manifestations and Tuberculin Skin Test (TST).
  
  
  RESULTS
  833 index TB cases with at least one contact were identified; 4441 contacts were screened, and 3942 (82.8%) were evaluated. TB contacts aged ≤ 35 years, regular and household contacts had a higher probability of being evaluated; foreign-born TB contacts were the least traceable. Higher rates of TB infection were observed in contacts at 35 years of age or younger who also lived in the same household with index cases or exposed to AFB+ or CULT+ index cases.
  
  
  CONCLUSIONS
  More efforts should be focused on young TB contacts, since they are likely to be new infections. An early identification and treatment of TB Infection in this group contributes to the prevention and control of TB transmission. The program should also be extended to the contacts of CULT+ cases.
authors.affiliation: Department of Public Health and Paediatrics, University of Torino, Italy. Electronic address: alberto.borraccino@unito.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Borraccino
authors.affiliation: Cancer Epidemiology Unit, AO Città della Salute e della Scienza and CPO Piemonte, Torino, Italy.
authors.forename: Enrica
authors.initials: E
authors.lastname: Migliore
authors.affiliation: Unit of Pneumology, National Local Health - ASL TO2, Torino, Italy.
authors.forename: Pavilio
authors.initials: P
authors.lastname: Piccioni
authors.affiliation: Cancer Epidemiology Unit, UPO "A. Avogadro" and CPO Piemonte, Novara, Italy; International Agency for Research on Cancer, Lyon, France.
authors.forename: Iacopo
authors.initials: I
authors.lastname: Baussano
authors.affiliation: Unit of Pneumology, National Local Health - ASL TO2, Torino, Italy.
authors.forename: Aurelia
authors.initials: A
authors.lastname: Carosso
authors.affiliation: Unit of Pneumology, National Local Health - ASL TO2, Torino, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Bugiani
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D015510:Clinical Medicine / Q000379:methods; D016358:Contact Tracing / Q000379:methods*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology / Q000635:transmission*; D055815:Young Adult
keywords: Contact tracing yield; Epidemiological surveillance; Low-burden TB settings; Mycobacterium tuberculosis