The Gambia Trachomatous Trichiasis Surveys: Results from Five Evaluation Units Confirm Attainment of Trachoma Elimination Thresholds.

INTRODUCTION Trichiasis is present when in-turned eyelashes touch the eyeball. It may result in permanent vision loss. Trachomatous trichiasis (TT) is caused by multiple rounds of inflammation associated with conjunctival Chlamydia trachomatis infection. Surveys have been designed to estimate the prevalence of TT in evaluation units (EUs) of trachoma-endemic countries in order to help develop appropriate programme-level plans. In this study, TT-only surveys were conducted in five EUs of The Gambia to determine whether further intensive programmatic action was required. METHODS Two-stage cluster sampling was used to select 27 villages per EU and ~25 households per village. Graders assessed the TT status of individuals aged ≥15 years in each selected household, including the presence or absence of conjunctival scarring in those with TT. RESULTS From February to March 2019, 11595 people aged ≥15 years were examined. A total of 34 cases of TT were identified. All five EUs had an age- and gender-adjusted prevalence of TT unknown to the health system <0.2%. Three of five EUs had a prevalence of 0.0%. CONCLUSION Using these and other previously collected data, in 2021, The Gambia was validated as having achieved national elimination of trachoma as a public health problem. Trachoma is still present in the population, but as its prevalence is low, it is unlikely that today's youth will experience the exposure to C. trachomatis required to precipitate TT. The Gambia demonstrates that with political will and consistent application of human and financial resources, trachoma can be eliminated as a public health problem.

[1]  E. Harding-Esch,et al.  Prevalence of Trachomatous Trichiasis in Ten Evaluation Units of Embu and Kitui Counties, Kenya. , 2022, Ophthalmic epidemiology.

[2]  J. Keenan,et al.  Can we eradicate trachoma? A survey of stakeholders , 2020, British Journal of Ophthalmology.

[3]  Nabil Aziz,et al.  Piloting a trachomatous trichiasis patient case-searching approach in two localities of Sudan , 2020, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[4]  M. Burton,et al.  Progression of scarring trachoma in Tanzanian children: A four-year cohort study , 2019, PLoS neglected tropical diseases.

[5]  F. Armah,et al.  Access to improved water and sanitation in sub-Saharan Africa in a quarter century , 2018, Heliyon.

[6]  N. Sepúlveda,et al.  Serology reflects a decline in the prevalence of trachoma in two regions of The Gambia , 2017, Scientific Reports.

[7]  S. Brooker,et al.  The Global Trachoma Mapping Project: Methodology of a 34-Country Population-Based Study , 2015, Ophthalmic epidemiology.

[8]  S. West,et al.  Mass Treatment with Azithromycin for Trachoma: When Is One Round Enough? Results from the PRET Trial in The Gambia , 2013, PLoS neglected tropical diseases.

[9]  T. Gebre,et al.  Epilation for Trachomatous Trichiasis and the Risk of Corneal Opacification , 2012, Ophthalmology.

[10]  N. Grassly,et al.  Targeting Antibiotics to Households for Trachoma Control , 2010, PLoS neglected tropical diseases.

[11]  E. Cromwell,et al.  The excess burden of trachomatous trichiasis in women: a systematic review and meta-analysis. , 2009, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[12]  B. Munoz,et al.  Constant ocular infection with Chlamydia trachomatis predicts risk of scarring in children in Tanzania. , 2009, Ophthalmology.

[13]  S. West,et al.  Contribution of Sex-linked Biology and Gender Roles to Disparities with Trachoma , 2004, Emerging infectious diseases.

[14]  P. S. Lee,et al.  Trachoma in the Gambia , 1998, The British journal of ophthalmology.

[15]  A. Foster,et al.  National survey of blindness and low vision in The Gambia: results. , 1989, The British journal of ophthalmology.