title: Sampling individuals with large sexual networks: an evaluation of four approaches.
abstract: BACKGROUND
  Methods for accessing large sexual networks are essential for investigating the mechanisms for the spread of sexually transmitted infections.
  
  
  OBJECTIVE
  Four samples of cases were compared with the total population to determine which identified the largest networks.
  
  
  METHODS
  Individuals with positive test results for chlamydia during a 6-month period were selected from a laboratory database and linked with sex partner information from a notifiable disease registry. Sexual networks were constructed for a random sample, people with positive results from two or more tests for chlamydia, people with positive tests results for both gonorrhea and chlamydia, and the preceding two groups combined.
  
  
  RESULTS
  The coinfected people combined with the repeaters yielded the highest proportion (47.8%) of large networks (>10 people), followed by the coinfected people, the repeaters, and finally the random sample.
  
  
  CONCLUSIONS
  People coinfected with chlamydia and gonorrhea and those with repeated chlamydial infection present ideal opportunities for both research and prevention.
authors.affiliation: Division of STD Prevention and Control, Population and Public Health Branch, Health Canada, Ottawa, Ontario. ann_jolly@hc-sc.gc.ca
authors.forename: A M
authors.initials: AM
authors.lastname: Jolly
authors.forename: J L
authors.initials: JL
authors.lastname: Wylie
mesh_terms: D002690:Chlamydia Infections / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D016358:Contact Tracing; D016208:Databases, Factual; D018562:Disease Transmission, Infectious / Q000517:prevention & control / Q000706:statistics & numerical data*; D005260:Female; D006069:Gonorrhea / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D006801:Humans; D008297:Male; D008350:Manitoba / Q000453:epidemiology; D011634:Public Health; D012725:Sexual Behavior; D012747:Sexual Partners; D012944:Social Support