Trachoma among children in community surveys from four African countries and implications of using school surveys for evaluating prevalence.

BACKGROUND: School surveys provide a convenient platform to obtain large child cohorts from multiple communities and are widely used as a proxy to determine community prevalence of neglected tropical diseases. The purpose of this study was to compare trachoma prevalence between preschool- and school-aged children and children who attend and do not attend school. METHODS: We analysed data from community-based trachoma surveys conducted from 2008-2011 in Ethiopia, Mali, Niger and Nigeria. The surveys utilised a cross-sectional, randomised cluster design. Individual-level data on school attendance was collected. RESULTS: Overall, 75 864 children aged 1-15 years from 2100 communities were included in the analysis. The prevalence of trachomatous inflammation follicular (TF) among these children in surveyed districts was 19.1% (95% CI 17.9-20.2%) in Ethiopia, 6.2% (95% CI 5.4-6.9%) in Niger, 4.6% (95% CI 4.2-4.9%) in Mali and 4.2% (95% CI 3.5-4.9%) in Nigeria. Controlling for age, sex and clustering, the OR of TF for school-attendees compared to non-attendees was 0.64 (95% CI 0.56-0.73) in Ethiopia, 0.67 (95% CI 0.56-0.80) in Mali, 1.03 (95% CI 0.81-1.16) in Niger and 1.06, (95% CI 0.65-1.73) in Nigeria. CONCLUSION: Estimating the prevalence of trachoma through examination of only school-going children risks underestimating the true prevalence.

Evidence for stopping mass drug administration for lymphatic filariasis in some, but not all local government areas of Plateau and Nasarawa States, Nigeria.

An average of six annual rounds of ivermectin and albendazole were distributed in Plateau and Nasarawa States, Nigeria, to eliminate lymphatic filariasis. From 2007 to 2008, population-based surveys were implemented in all 30 local government areas (LGAs) of the two states to determine the prevalence of Wuchereria bancrofti antigenemia to assess which LGA mass drug administration (MDA) could be halted. In total, 36,681 persons from 7,819 households were examined for filarial antigen as determined by immunochromatographic card tests. Overall antigen prevalence was 3.05% (exact upper 95% confidence interval [CI] = 3.41%) with an upper 95% CI range by LGA of 0.50-19.3%. Among 3,233 children 6-7 years of age, overall antigen prevalence was 1.71% (exact upper 95% CI = 2.19%), too high to recommend generally halting MDA in the two-state area. However, based on criteria of < 2% antigenemia among persons > 2 years of age, stopping MDA was recommended for 10 LGAs.

Integrating NTD mapping protocols: Can surveys for trachoma and urinary schistosomiasis be done simultaneously?

We determined whether the school-based "disease mapping" methodology used to assess urinary schistosomiasis (SCH) is useful for determining trachoma interventions and whether the district-based approach recommended for trachoma is useful for SCH control programs. We conducted two separate integrated surveys in eight districts of central Nigeria: school based and district based. A total of 17,189 children were examined for trachoma and 16,238 children were examined for hematuria from 363 schools and 2,149 households. School surveys identified 67 communities warranting praziquantel drug treatment of SCH and 142 trachoma-endemic communities warranting trachoma control activities. In district-level estimates, we identified 24 communities for praziquantel treatment and 0 for trachoma intervention. Integrating trachoma into SCH school-based surveys, and SCH into trachoma surveys, was quick and easy, but in this setting, school-based surveys were more useful for identifying communities where intervention is warranted.

Evaluation of community intervention with pit latrines for trachoma control in Ghana, Mali, Niger and Nigeria.

Trachoma is the leading cause of preventable blindness worldwide and is controlled with an integrated strategy of treatment and prevention which includes latrine provision and promotion. We aimed to evaluate the latrine uptake, construction, and usage in villages participating in latrine promotion programmes supported by The Carter Center in Ghana, Mali, Niger and Nigeria where 113 457 new latrines have been reported from 2002 to 2008. In each country a two stage cluster random sampling design was used to select villages and households for evaluation. Household heads were interviewed using a standardised structured questionnaire and latrines were inspected. The sample included 1154 households (Ghana: 326; Mali: 293; Niger: 300; and Nigeria: 235). Overall, 813 (70.5%, 95% confidence interval [CI] 65.7-74.8) had pit latrines, ranging from 30.3% of households in Niger to over 92.0% of households in Ghana and Mali. Of those with latrines 762 (93.7%) were found to be usable and 659 (86.5%) were in use. Overall 659/1154 (57.1%) of households in the targeted communities were using latrines at least 12 months after latrine promotion was initiated. Latrine promotion had been successful increasing access to sanitation in different country contexts and demonstrates the target population are willing to construct, use and maintain household latrines.

Blinding trachoma in katsina state, Nigeria: population-based prevalence survey in ten local government areas.

PURPOSE: To assess the prevalence of trachomatous inflammation follicular (TF) in children aged 1-9 years and trachomatous trichiasis (TT) in adults aged 15 years or more in Katsina State, Nigeria. METHODS: Cross sectional population-based trachoma prevalence surveys were conducted using multistage cluster random sampling methodology and the WHO simplified grading system for trachoma in ten local government areas (LGAs). Individual and household risk factors were recorded using a standard questionnaire. RESULTS: A total of 11,407 children and 8,901 adults from 2,244 households were surveyed. Prevalence of TF in children aged 1-9 years ranged from 5.0 to 24.0%. Five LGAs exceeded the 10% threshold for intervention and a further three exceeded 10% in the 95% confidence limits. The prevalence of TT in adults aged 15 years or more ranged from 2.3 to 8.0%: all ten LGAs exceeded the 1% intervention threshold. Analysis of risk factors for active trachoma (TF and/or TI) in children showed the following significant independent associations: Presence of ocular discharge OR = 2.34 (95%CI 1.81-3.03); presence of nasal discharge OR = 1.44 (1.22-1.70); reported frequency of face washing once versus at least twice per day OR = 1.27 (1.02-1.58); disposal of trash inside the compound OR = 1.23 (1.02-1.48); and the absence of a household latrine OR = 1.43 (1.15-1.78). CONCLUSIONS: A trachoma control program is warranted in Katsina. Surgical interventions to correct TT are needed immediately in all LGAs surveyed and the full SAFE strategy is justified for five of the ten LGAs, and possibly for another three.