Risk Factors for Active Trachoma and Ocular Chlamydia trachomatis Infection in Treatment-Naïve Trachoma-Hyperendemic Communities of the Bijagós Archipelago, Guinea Bissau

Abstract

BackgroundTrachoma, 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.Methodology/Principal FindingsA 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/SignificanceIn 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.

Prevalence of and Risk Factors for Trachoma in Southern Nations, Nationalities, and Peoples’ Region, Ethiopia: Results of 40 Population-Based Prevalence Surveys Carried Out with the Global Trachoma Mapping Project

“…Younger children have been associated with higher odds of trachoma in many previous studies. 17–19 In addition, open defecation is thought to increase infection transmission by providing an ecological niche for eye-seeking flies known to carry C. trachomatis . 20,21 Trachoma has been associated with altitude before, 21 but the finding in these surveys of a lower odds of trachoma at high (≥2500m) altitudes is difficult to explain.…”

Population-Based Study of Trachoma in Guatemala

“…We have found, as others have, that not all TF cases were positive for chlamydia, which was expected because follicles take a long time to clear once infection is gone. [8][9][10] Finding evidence for infection in the areas with highest prevalence of trachoma does suggest that there are still pockets of true trachoma in these areas. Most villages even in the sub-districts with trachoma, had access to water and functional latrines.…”

Molecular characteristics of the ompA gene of serotype B Chlamydia trachomatis in Qinghai Tibetan primary school students

“…At present, C. trachomatis is divided into serotypes A-L, which can cause conjunctivitis, reproductive-tract infection, venereal granuloma, neonatal pneumonia, active arthritis and other diseases. Trachoma is closely associated with serotypes A, B, Ba, and C (Last et al, 2014;Ishak et al, 2015). C. trachomatis remains an epidemic in various countries, and Canada is the only high-income country with a trachoma prevalence of >5% (Shattock et al, 2015).…”

“…C. trachomatis remains an epidemic in various countries, and Canada is the only high-income country with a trachoma prevalence of >5% (Shattock et al, 2015). Active trachoma exists in a number of areas in Asia and Africa and other developing countries (Last et al, 2014;King et al, 2013;Nigusie et al, 2015;Burton et al, 2010), and a great number of studies have shown C. trachomatis serotypes differ across regions. For 8 .…”