IntroductionThe World Health Organization recommends TT surveys to be conducted in adults aged 15+ years (TT 15 survey) and certifies elimination of TT as a public health problem when there is less than 1 unknown case per 1,000 people of all ages. There is no standard survey method to accurately confirm this elimination prevalence threshold of 0.1% because rare conditions require large and expensive prevalence survey samples. The aim of this study was to develop an accurate operational research method to measure the total backlog of TT in people of all ages and detect when the elimination threshold is achieved.MethodsBetween July to October 2016, an innovative Community-based, Mapping, Mop-up and Follow-up (CMMF) approach to elimination of TT as a public health problem was developed and tested in Esoit, Siana, Megwara and Naikara sub-locations in Narok County in Kenya. The County had ongoing community-based TT surgical camps and case finders. TT case finders were recruited from existing pool of Community health volunteers (CHV) in the Community Health Strategy Initiative Programme of the Ministry of Health. They were trained, validated and supervised by experienced TT surgeons. A case finder was allocated a population unit with 2 to 3 villages to conduct a de jure pre-survey census, examine all people in the unit and register those with TT (TT all survey). Identified cases were confirmed by TT surgeons prior to surgery. Operated patients were reviewed at 1 day, 2 weeks and 3-6 months. The case finders will also be used to identify and refer new and recurrent cases. People with other eye and medical conditions were treated and referred accordingly. Standardised data collection and computer based data capture tools were used. Case finders kept registers with details of all persons with TT, those operated and those who refused to be operated (refusals). These details informed decision and actions on follow-up and counselling. Progress towards achievement of elimination threshold was assessed by dividing the number of TT cases diagnosed by total population in the population unit multiplied by 1,000.ResultsNarok County Government adopted both the CMMF approach and TT all survey method. All persons in 4,784 households in the four sub-locations were enumerated and examined. The total population projection was 29,548 and pre-survey census 22,912 people. Fifty-three cases of TT were diagnosed. The prevalence was 0.23% and this is equivalent to 2.3 cases per thousand population of all ages. Prior to this study, the project required to operate on at least 30 cases (excess cases) to achieve the elimination threshold of 1 case per 1000 population.ConclusionThe total backlog of TT was confirmed and the project is now justified to lay claim of having eliminated TT as a public health problem in the study area. TT all method may not be appropriate in settings with high burden of TT. Nomadic migrations affect estimation of population size. Non-trachomatous TT could not be ruled-out.

Background Late-stage blinding sequalae of trachoma such as trachomatous trichiasis (TT) typically take decades to develop and often do so in the absence of ongoing ocular Chlamydia trachomatis infection. This suggests that most TT risk accumulates in early life; as a result, population-level TT incidence and prevalence can remain high years after C. trachomatis transmission among children has decreased. In Embu and Kitui counties, Kenya, the prevalence of trachomatous inflammation – follicular is low in children. In this survey, we set out to determine the prevalence of TT in ten evaluation units (EUs) in these counties. Methods We undertook ten cross-sectional prevalence surveys for TT. In each EU, people aged ≥15 years were selected by a two-stage cluster sampling method and examined for TT. Those with TT were asked questions on whether they had been offered management for it. Prevalence was adjusted to the underlying age and gender structure of the population. Results A total of 18,987 people aged ≥15 years were examined. Per EU, the median number of examined participants was 1,656 (range: 1,451 − 3,016) and median response rate was 86% (range: 81 − 95%). The prevalence of TT unknown to the health system in people aged ≥15 years was above the threshold for elimination (≥0.2%) in all ten EUs studied (range: 0.2–0.7%). TT was significantly more common in older than younger individuals and in women than in men. Discussion Provision of surgical services should be strengthened in Embu and Kitui counties of Kenya to achieve the World Health Organization threshold for eliminating TT as a public health problem.