What is the appropriate age range of individuals to be included in a survey to estimate the prevalence of trachomatous trichiasis?

Karimurio, J; Rono, Hillary; Mesurier, Richard Le; Mwanthi, Mutuku A.; Keeffe, Jill

doi:10.1136/bjo.2010.193268

Cited by 2 publications

(4 citation statements)

References 4 publications

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“…We focused on persons 40 years of age or older, since the vast majority of trichiasis patients fall within this age group. 13 Recruited study participants who consented to be in the study presented to a central location for conjunctival examination and swabbing. Trained staff assessed the right eye of each individual for the clinical signs of trachoma using 32.5 binocular loupes, according to the WHO simplified grading system.…”

Section: Methodsmentioning

confidence: 99%

Association of Conjunctival Bacterial Infection and Female Sex in Cicatricial Trachoma

Cevallos¹,

Whitcher²,

Melese

et al. 2012

Invest. Ophthalmol. Vis. Sci.

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In a region of Ethiopia with endemic trachoma, conjunctival bacterial growth was more common in females than that in males. S. pneumoniae and H. influenzae, both of which frequently colonize the nasopharynx of children, were more common in females, suggesting that the preponderance of infection in females may be attributable to close contact with children. This finding is consistent with the theory that childcare activities may preferentially expose females to ocular chlamydial infection. (ClinicalTrials.gov number, NCT00221364.).

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Section: Methodsmentioning

confidence: 99%

Association of Conjunctival Bacterial Infection and Female Sex in Cicatricial Trachoma

Cevallos¹,

Whitcher²,

Melese

et al. 2012

Invest. Ophthalmol. Vis. Sci.

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“…Surveys to estimate low prevalence thresholds require large samples [ 3 ]. Different lower age limits of TT survey participants have been used in an attempt to lower survey samples and cost but they end up lowering precision in estimation of the prevalence and backlog [ 4 ]. Between 2004 and 2007 in Kenya, surveys were conducted in people 15+ years old (TT 15) as recommended by the World Health Organization [ 5 – 7 ].…”

Section: Introductionmentioning

confidence: 99%

“…Between 2004 and 2007 in Kenya, surveys were conducted in people 15+ years old (TT 15) as recommended by the World Health Organization [ 5 – 7 ]. Thereafter, a lower age limit of 40 years (TT 40) was adopted [ 4 ]. Lower age limits of 30 and 40 years have been used in the Pacific Islands [ 8 ] and Australia [ 9 ] respectively.…”

Section: Introductionmentioning

confidence: 99%

“…However, the project had not utilised non-technical or lay persons to identify TT cases during scientific studies. There is no standardised prevalence survey method available to certify the elimination of TT and all the survey methods described above [ 4 , 5 , 10 ] do not have adequate power to do so. Moreover, eye camps where only the community members who turn up are screened for TT cannot provide accurate data to calculate prevalence in the whole community.…”

Section: Introductionmentioning

confidence: 99%

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Use of validated community-based trachoma trichiasis (TT) case finders to measure the total backlog and detect when elimination threshold is achieved: a TT methodology paper

Karimurio

Rono²,

Njomo

et al. 2017

Pan Afr Med J

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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.

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What is the appropriate age range of individuals to be included in a survey to estimate the prevalence of trachomatous trichiasis?

Abstract: The estimated backlog of untreated TT in people aged ≥40 years old in Turkana was 5932 and the overall TT backlog was likely to be 6358-8523. These findings cannot be generalised because all surveys were carried out in the same country.

Cited by 2 publications

References 4 publications

Association of Conjunctival Bacterial Infection and Female Sex in Cicatricial Trachoma

Association of Conjunctival Bacterial Infection and Female Sex in Cicatricial Trachoma

Use of validated community-based trachoma trichiasis (TT) case finders to measure the total backlog and detect when elimination threshold is achieved: a TT methodology paper

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