title: Can We Use Antibodies to Chlamydia trachomatis as a Surveillance Tool for National Trachoma Control Programs? Results from a District Survey.
abstract: BACKGROUND
  Trachoma is targeted for elimination by 2020. World Health Organization advises districts to undertake surveillance when follicular trachoma (TF) <5% in children 1-9 years and mass antibiotic administration has ceased. There is a question if other tools could be used for surveillance as well. We report data from a test for antibodies to C. trachomatis antigen pgp3 as a possible tool.
  
  
  METHODS
  We randomly sampled 30 hamlets in Kilosa district, Tanzania, and randomly selected 50 children ages 1-9 per hamlet. The tarsal conjunctivae were graded for trachoma (TF), tested for C. trachomatis infection (Aptima Combo2 assay: Hologic, San Diego, CA), and a dried blood spot processed for antibodies to C. trachomatis pgp3 using a multiplex bead assay on a Luminex 100 platform.
  
  
  RESULTS
  The prevalence of trachoma (TF) was 0.4%, well below the <5% indicator for re-starting a program. Infection was also low, 1.1%. Of the 30 hamlets, 22 had neither infection nor TF. Antibody positivity overall was low, 7.5% and increased with age from 5.2% in 1-3 year olds, to 9.3% in 7-9 year olds (p = 0.015). In 16 of the 30 hamlets, no children ages 1-3 years had antibodies to pgp3.
  
  
  CONCLUSIONS
  The antibody status of the 1-3 year olds indicates low cumulative exposure to infection during the surveillance period. Four years post MDA, there is no evidence for re-emergence of follicular trachoma.
authors.affiliation: Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Sheila K
authors.initials: SK
authors.lastname: West
authors.affiliation: Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Munoz
authors.affiliation: Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Jerusha
authors.initials: J
authors.lastname: Weaver
authors.affiliation: National Institute for Medical Research, Kilosa, Tanzania.
authors.forename: Zakayo
authors.initials: Z
authors.lastname: Mrango
authors.affiliation: Division of Infectious Diseases, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Laura
authors.initials: L
authors.lastname: Dize
authors.affiliation: Division of Infectious Diseases, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Gaydos
authors.affiliation: Division of Infectious Diseases, Johns Hopkins University, Baltimore, Maryland, United States of America.|Division of Intramural Research, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, United States of America.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Quinn
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Diana L
authors.initials: DL
authors.lastname: Martin
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D002692:Chlamydia trachomatis / Q000276:immunology / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D015995:Prevalence; D012423:Rural Health; D018571:Sentinel Surveillance; D013636:Tanzania / Q000453:epidemiology; D014141:Trachoma / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology
chemical_list: D000907:Antibodies, Bacterial