title: Risk factors for active trachoma and ocular Chlamydia trachomatis infection in treatment-naïve trachoma-hyperendemic communities of the Bijagós Archipelago, Guinea Bissau.
abstract: BACKGROUND
  Trachoma, caused by ocular infection with Chlamydia trachomatis, is hyperendemic on the Bijagós Archipelago of Guinea Bissau. An understanding of the risk factors associated with active trachoma and infection on these remote and isolated islands, which are atypical of trachoma-endemic environments described elsewhere, is crucial to the implementation of trachoma elimination strategies.
  
  
  RESULTS
  A cross-sectional population-based trachoma prevalence survey was conducted on four islands. We conducted a questionnaire-based risk factor survey, examined participants for trachoma using the World Health Organization (WHO) simplified grading system and collected conjunctival swab samples for 1507 participants from 293 randomly selected households. DNA extracted from conjunctival swabs was tested using the Roche Amplicor CT/NG PCR assay. The prevalence of active (follicular and/or inflammatory) trachoma was 11% (167/1508) overall and 22% (136/618) in 1-9 year olds. The prevalence of C. trachomatis infection was 18% overall and 25% in 1-9 year olds. There were strong independent associations of active trachoma with ocular and nasal discharge, C. trachomatis infection, young age, male gender and type of household water source. C. trachomatis infection was independently associated with young age, ocular discharge, type of household water source and the presence of flies around a latrine.
  
  
  CONCLUSIONS
  In this remote island environment, household-level risk factors relating to fly populations, hygiene behaviours and water usage are likely to be important in the transmission of ocular C. trachomatis infection and the prevalence of active trachoma. This may be important in the implementation of environmental measures in trachoma control.
authors: Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors: Anna R
authors: AR
authors: Last
authors: Disease Control and Elimination Theme, Medical Research Council Unit, The Gambia, Fajara, The Gambia.
authors: Sarah E
authors: SE
authors: Burr
authors: MRC Tropical Epidemiology Group, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors: Helen A
authors: HA
authors: Weiss
authors: Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors: Emma M
authors: EM
authors: Harding-Esch
authors: Programa Nacional de Saúde de Visão, Ministério de Saúde Publica, Bisssau, Guiné Bissau.
authors: Eunice
authors: E
authors: Cassama
authors: Programa Nacional de Saúde de Visão, Ministério de Saúde Publica, Bisssau, Guiné Bissau.
authors: Meno
authors: M
authors: Nabicassa
authors: Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors: David C
authors: DC
authors: Mabey
authors: Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors: Martin J
authors: MJ
authors: Holland
authors: Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors: Robin L
authors: RL
authors: Bailey
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D003228:Conjunctiva / Q000382:microbiology; D003430:Cross-Sectional Studies; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D006169:Guinea-Bissau / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012737:Sex Factors; D014141:Trachoma / Q000453:epidemiology* / Q000382:microbiology; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial