title: Contact tracing and the estimation of sexual mixing patterns: the epidemiology of gonococcal infections.
abstract: OBJECTIVE
  The concept of a core group of individuals who change sexual partners frequently has played an important role in the study of the epidemiology of sexually transmitted diseases (STDs). It is widely believed that the core group is important in the persistence of infection and that it provides a sensible target for control interventions. GOAL OF THIS STUDY AND STUDY DESIGN: Simple mathematical models are used to assess the significance of sexual mixing between core and noncore groups. Published data from contact tracing studies, which base the definition of the core group on gonorrhea incidence by area of residence, are used to derive estimates of the degree of mixing within and between groups.
  
  
  RESULTS
  Analyses reveal patterns of high mixing within core groups in the urban study sites, which suggests that within-group transmission ensures the persistence of gonococcal infection in the community as a whole.
  
  
  CONCLUSIONS
  An extension of the analysis of contact tracing data to facilitate the development of mathematical models of STD transmission is detailed.
authors.affiliation: Parasite Epidemiology Research Group, Imperial College, London, England.
authors.forename: G P
authors.initials: GP
authors.lastname: Garnett
authors.forename: R M
authors.initials: RM
authors.lastname: Anderson
mesh_terms: D016358:Contact Tracing; D005260:Female; D006069:Gonorrhea / Q000453:epidemiology* / Q000635:transmission; D006801:Humans; D015994:Incidence; D008297:Male; D008962:Models, Theoretical; D015995:Prevalence; D012725:Sexual Behavior; D012747:Sexual Partners; D014505:Urban Population