Estimating the Intracluster Correlation Coefficient for the Clinical Sign "Trachomatous Inflammation-Follicular" in Population-Based Trachoma Prevalence Surveys: Results From a Meta-Regression Analysis of 261 Standardized Preintervention Surveys Carried Out in Ethiopia, Mozambique, and Nigeria.

Sample sizes in cluster surveys must be greater than those in surveys using simple random sampling in order to obtain similarly precise prevalence estimates, because results from subjects examined in the same cluster cannot be assumed to be independent. Therefore, a crucial aspect of cluster sampling is estimation of the intracluster correlation coefficient (ρ): the degree of relatedness of outcomes in a given cluster, defined as the proportion of total variance accounted for by between-cluster variation. In infectious disease epidemiology, this coefficient is related to transmission patterns and the natural history of infection; its value also depends on particulars of survey design. Estimation of ρ is often difficult due to the lack of comparable survey data with which to calculate summary estimates. Here we use a parametric bootstrap model to estimate ρ for the ocular clinical sign "trachomatous inflammation-follicular" (TF) among children aged 1-9 years within population-based trachoma prevalence surveys. We present results from a meta-regression analysis of data from 261 such surveys completed using standardized methods in Ethiopia, Mozambique, and Nigeria in 2012-2015. Consistent with the underlying theory, we found that ρ increased with increasing overall TF prevalence and smaller numbers of children examined per cluster. Estimates of ρ for TF were independently higher in Ethiopia than in the other countries

Trachoma Mapping in Gombe State, Nigeria: Results of 11 Local Government Area Surveys.

PURPOSE: To determine the need or otherwise for establishment of a trachoma elimination program in Gombe State, Nigeria, by estimating the population-based prevalence of trachoma in each Local Government Area (LGA) of Gombe. METHODS: Using a multi-stage, systematic, random, and quasi-random sampling approach and Global Trachoma Mapping Project support, we selected 25 clusters in each LGA. In each cluster, we selected 25 households and all consenting residents aged 1 year and older were examined for trachomatous inflammation-follicular (TF) and trichiasis, using the World Health Organization simplified grading scheme. RESULTS: No LGA in Gombe State had a TF prevalence ≥5% in 1-9-year-olds. All LGAs had trichiasis prevalences above the elimination threshold and should be targeted for community-based delivery of trichiasis surgery. Only three LGAs had household-level improved wash water access of greater than 80%. Access to improved sanitation facilities was also poor as household access to improved sanitation facilities was above 80% in only one LGA. CONCLUSION: A trachoma program focused on delivery of trichiasis surgery is required in Gombe. Improvements in water and sanitation, through engagement with other sectors, are necessary

Prevalence of Trachoma in Katsina State, Nigeria: Results of 34 District-Level Surveys.

PURPOSE: To determine the local government area (LGA)-level prevalence of trachoma in all 34 LGAs of Katsina State. METHODS: A population-based prevalence survey was conducted in each LGA of Katsina State, using the Global Trachoma Mapping Project methodology. We used a 3-stage cluster random sampling strategy to select 25 households from each of 25 clusters. We examined all residents of selected households aged 1 year and older for the clinical signs of trachomatous inflammation-follicular (TF), trachomatous inflammation-intense and trichiasis, using the World Health Organization (WHO) simplified grading scheme. RESULTS: We examined 129,281 persons. Six LGAs had a TF prevalence ≥10%, and another six LGAs had a TF prevalence between 5% and 9.9%; all 12 require mass drug administration with azithromycin plus other interventions. The prevalence of trichiasis was ≥1.0% in 13 LGAs, and there is a need to perform trichiasis surgery in over 26,000 persons to reach targets set by the WHO for elimination of trichiasis. CONCLUSION: The prevalence of TF is generally low in Katsina state, but urgent steps must be taken to implement the full SAFE strategy (surgery, antibiotics, facial cleanliness, environmental improvement) in at least 12 LGAs while also stepping up efforts to provide community-based trichiasis surgery throughout the whole state, in order to make trachoma elimination by 2020 a reality

Mapping Trachoma in Kaduna State, Nigeria: Results of 23 Local Government Area-Level, Population-Based Prevalence Surveys.

INTRODUCTION: To prepare for global elimination of trachoma by 2020, the World Health Organization (WHO) recommends mapping of trachoma at district-level to enable planning of elimination activities in affected populations. The aim of our study was to provide data on trachoma for each local government area (LGA) of Kaduna State, Nigeria, as such data were previously unavailable. METHOD: As part of the Global Trachoma Mapping Project (GTMP), a population-based cross-sectional trachoma survey was conducted in each of the 23 LGAs of Kaduna State, between May and June 2013. The protocols of the GTMP were used. RESULTS: The prevalence of trachomatous inflammation - follicular (TF) in children aged 1-9 years was between 0.03% and 8% across the LGAs, with only one LGA (Igabi) having a TF prevalence ≥5%. The LGA-level prevalences of trichiasis in persons aged 15 years and older were between 0.00% and 0.78%. Eleven LGAs had trichiasis prevalences of 0.2% and over in adults; a threshold equivalent to 1 case per 1000 total population. The LGA-level proportion of households with access to improved water sources ranged from 9% to 96%, while household access to latrines ranged from 5% to 99%. CONCLUSION: Kaduna State has generally hypoendemic trachoma, but a few trichiasis surgeries are still required to attain the WHO elimination targets. Better access to improved water and sanitation is needed

Prevalence of Trachoma in Niger State, North Central Nigeria: Results of 25 Population-Based Prevalence Surveys Carried Out with the Global Trachoma Mapping Project.

PURPOSE: To determine the prevalence of trachoma in each of the 25 local government areas (LGAs) of Niger State, Nigeria. METHODS: A population-based cross-sectional survey was conducted in each Niger State LGA between March and April 2014, as part of the Global Trachoma Mapping Project (GTMP). GTMP protocols were used in planning and conduct of the surveys. Using probability proportional to size, 25 clusters were selected; in each of these clusters, 25 households were enrolled for the survey. All residents aged 1 year and older were examined by GTMP-certified graders for trachomatous inflammation - follicular (TF) and trichiasis using the World Health Organization simplified grading scheme. Additionally, we collected data on household water and sanitation facilities. RESULTS: Only one LGA (Kontagora) had TF prevalence in 1-9-year-olds above 10%; one other LGA (Rafi) had TF prevalence between 5.0 and 9.9%. Six LGAs need trichiasis surgical services provided to achieve a prevalence of <1 case of trichiasis per 1000 total population. The proportion of households with access to improved water sources ranged from 23 to 100%, while household-level access to improved latrines ranged from 8 to 100% across the LGAs. CONCLUSION: The prevalence of trachoma is relatively low in most of Niger State. There is a need for community-based trichiasis surgical services in a small number of LGAs. The trachoma elimination program could engage water and sanitation agencies to augment access to improved water and sanitation facilities, for human rights reasons. Kontagora and Rafi need community-based interventions to reduce the prevalence of active trachoma

Prevalence of Trachoma in Bauchi State, Nigeria: Results of 20 Local Government Area-Level Surveys.

PURPOSE: To determine the prevalence of trachomatous inflammation - follicular (TF) and trichiasis in each of the 20 local government areas (LGAs) of Bauchi State, Nigeria. METHODS: We undertook a population-based prevalence survey in each LGA in Bauchi State, employing the Global Trachoma Mapping Project methodology. We used a 2-stage, systematic and quasi-random sampling strategy. Using probability proportional to size, we selected 25 clusters, in each of which 25 households were selected by random walk. All residents of selected households 1 year and older were examined for TF, trachomatous inflammation - intense, and trichiasis, using the World Health Organization simplified grading scheme. RESULTS: Only two LGAs in Bauchi State had TF prevalences in 1-9-year-olds over 5%, with none having TF prevalences of 10% or greater. Only one LGA had a trichiasis prevalence in adults below the elimination threshold; all the others had trichiasis at levels suggestive of public health significance. In all 20 LGAs, more than 60% of households were within 1 km of an improved source of water for hygiene. CONCLUSION: Efforts need to be made in Bauchi State to provide trichiasis surgery in order to avert trachomatous blindness. Water supplies needs to be sustained and good personal hygiene practices assured so that elimination of trachoma as a public health problem will be achieved and sustained

Prevalence of Trachoma in Kano State, Nigeria: Results of 44 Local Government Area-Level Surveys.

PURPOSE: We sought to determine the prevalence of trachoma in 44 Local Government Areas (LGAs) of Kano State, Nigeria. METHODS: A population-based prevalence survey was conducted in each Kano LGA. We used a two-stage systematic and quasi-random sampling strategy to select 25 households from each of 25 clusters in each LGA. All consenting household residents aged 1 year and above were examined for trachomatous inflammation-follicular (TF), trachomatous inflammation-intense (TI) and trichiasis. RESULTS: State-wide crude prevalence of TF in persons aged 1-9 years was 3.4% (95% CI 3.3-3.5%), and of trichiasis in those aged ≥15 years was 2.3% (95% CI 2.1-2.4%). LGA-level age- and sex-adjusted trichiasis prevalence in those aged ≥15 years ranged from 0.1% to 2.9%. All but 4 (9%) of 44 LGAs had trichiasis prevalences in adults above the elimination threshold of 0.2%. State-wide prevalence of trichiasis in adult women was significantly higher than in adult men (2.6% vs 1.8%; OR = 1.5, 95% CI 1.3-1.7; p = 0.001). Four of 44 LGAs had TF prevalences in 1-9-year-olds between 10 and 15%, while another six LGAs had TF prevalences between 5 and 9.9%. In 37 LGAs, >80% of households had access to water within 30 minutes round-trip, but household latrine access was >80% in only 19 LGAs. CONCLUSION: Trichiasis is a public health problem in most LGAs in Kano. Surgeons need to be trained and deployed to provide community-based trichiasis surgery, with emphasis on delivery of such services to women. Antibiotics, facial cleanliness and environmental improvement are needed in 10 LGAs

Prevalence of Trachoma following Implementation of the SAFE Strategy in Three Local Government Areas of Taraba State, North Eastern Nigeria

INTRODUCTION: In 2019–2020, one round of antibiotic mass drug administration (MDA) was implemented for trachoma elimination purposes in Donga, Gashaka, and Ussa local government areas (LGAs) of Taraba State, Nigeria, following baseline surveys in 2009 (Donga and Gashaka) and 2013–2014 (Ussa). Here, trachoma prevalence post-MDA in these three LGAs is reported. METHODS: In 2019 (Gashaka and Ussa) and 2020 (Donga), population-based, cross-sectional surveys were conducted following World Health Organization (WHO) guidance. A two-stage cluster sampling strategy was used. All residents of selected households aged ≥1 year were examined by Tropical Data-certified graders for trachomatous inflammation—follicular (TF) and trachomatous trichiasis (TT) using the WHO simplified trachoma grading scheme. Data on water, sanitation, and hygiene (WASH) access were also collected. RESULTS: A total of 1,883 households participated. From these households, 4,885 children aged 1–9 years were enumerated, and 4,866 (99.6%) examined. There were 5,050 eligible adults (aged ≥15 years) enumerated in the same households, of whom 4,888 (96.8%) were examined. Age-adjusted TF prevalence in children aged 1–9 years was 0.22% (95% CI: 0.00–0.65) in Donga, 0.0% in Gashaka, and 0.19% (95% CI: 0.00–0.44) in Ussa. The age- and gender-adjusted TT prevalence unknown to the health system in adults aged ≥15 years was 0.08% (95% CI: 0.00–0.19) in Donga, 0.02% (95% CI: 0.00–0.06) in Gashaka, and 0.10% (95% CI: 0.01–0.18) in Ussa. In Donga, Gashaka, and Ussa, respectively, 66%, 49% and 63% of households had access to an improved drinking water source, and 68%, 56% and 29% had access to an improved latrine. CONCLUSION: In all LGAs, the elimination thresholds for TF and TT unknown to the health system have been attained in the target age groups. These LGAs should be re-surveyed after 2 years to show that reductions in TF prevalence have been sustained in the absence of MDA. Health authorities should continue to improve WASH facilities to reduce the risk of later recrudescence

Prevalence of Trachoma in Kogi State, Nigeria: Results of four Local Government Area-Level Surveys from the Global Trachoma Mapping Project.

PURPOSE: To determine the prevalence of trachoma in four Local Government Areas (LGAs) of Kogi State, Nigeria. METHODS: In June 2014, we conducted population-based, cross-sectional surveys according to Global Trachoma Mapping Project (GTMP) protocols in selected LGAs of Kogi State. In each LGA, 25 clusters were selected with probability proportional to size. In each of these clusters, 25 households were enrolled for the survey. All residents of selected households aged ≥1 year were examined by GTMP-certified graders for trachomatous inflammation-follicular (TF) and trichiasis using the simplified trachoma grading scheme. Data on sources of household water and types of sanitation facilities were collected through questioning and direct observation. RESULTS: The age-adjusted TF prevalence in 1-9-year-olds ranged from 0.4% (95% CI 0.1-0.8%) in Bassa to 1.0% (95% CI 0.3-1.9%) in Omala. Across all four LGAs, only one case of trichiasis was found; this individual was in Omala, giving that LGA a trichiasis prevalence in individuals aged ≥15 years of 0.02% (95% CI 0.00-0.07%). Between 77 and 88% of households had access to water for hygiene purposes, while only 10-30% had access to improved sanitation facilities. CONCLUSION: Trachoma is not a public health problem in any of the 4 LGAs surveyed. There is, however, the need to increase access to adequate water and sanitation services to contribute to the health and social and economic well-being of these communities

Baseline Prevalence of Trachoma in 21 Local Government Areas of Adamawa State, North East Nigeria.

PURPOSE: To determine the prevalence of trachoma in each of the 21 local government areas (LGAs) of Adamawa State, Nigeria. METHODS: A population-based cross-sectional survey was conducted in each of the 21 LGAs of Adamawa State between 2017 and 2019. With the support of Tropical Data (TD), surveys were planned and implemented in accordance with World Health Organization (WHO) recommendations. A two-stage cluster sampling technique was used in each LGA, 25 or 30 clusters were selected with a probability of selection proportionate to cluster size, and in each of these clusters, 25 or 30 households were enrolled for the survey. All residents aged 1 year and older within selected households were examined by TD-certified graders for trachomatous inflammation - follicular (TF) and trachomatous trichiasis (TT) using the WHO simplified grading scheme. Additionally, data were collected on household water and sanitation access. RESULTS: All 21 LGAs had TF prevalence in 1-9-year-olds below 5%. The prevalence of TT unknown to the health system in people aged ≥15 years was ≥0.2% in three of the 21 LGAs. Access to improved water and sanitation facilities was <80% in the majority of the surveyed LGAs. Only 12 of the 21 LGAs had ≥50% household-level improved latrine access, and only Yola North had ≥80% household-level improved latrine access. CONCLUSION: There is no need for mass treatment with antibiotics for trachoma elimination purposes in any of these LGAs. There is a need for active TT case finding and provision of community-based TT surgical services in three LGAs. Furthermore, engagement with water and sanitation agencies is needed to augment access to improved water and sanitation facilities across the State; this will help to avoid the recrudescence of active trachoma in the State