Population-based survey of active trachoma in 11 districts of Burundi

Baseline, Impact and Surveillance Trachoma Prevalence Surveys in Burundi, 2018-2021

PURPOSE

Trachoma is an eye disease caused by the bacterium Chlamydia trachomatis (Ct). It can lead to permanent vision loss. Since 2007, Burundi has included trachoma elimination as part of its fight against neglected tropical diseases and blindness. This study presents the results of trachoma baseline, impact and surveillance surveys conducted in Burundi between 2018 and 2021.

METHODS

Areas were grouped into evaluation units (EU) with resident populations of between 100,000 and 250,000 people. Baseline surveys were conducted in 15 EUs, impact surveys in 2 EUs and surveillance surveys in 5 EUs; in each survey, 23 clusters of about 30 households were included. Consenting residents of those households were screened for clinical signs of trachoma. Access to water, sanitation and hygiene (WASH) was recorded.

RESULTS

A total of 63,800 individuals were examined. The prevalence of TF in 1-9-year-olds was above the elimination threshold of 5% in a single EU at baseline, but fell below the threshold in subsequent impact and surveillance surveys. The prevalence of TT was below the 0.2% elimination threshold in ≥15-year-olds in all EUs surveyed. A high proportion (83%) of households had access to safe drinking water, while only a minority (~8%) had access to improved latrines.

CONCLUSION

Burundi has demonstrated the prevalence levels necessary for trachoma elimination status. With continued effort and the maintenance of existing management plans, trachoma elimination in Burundi is within reach.

Association of environmental risk factors and trachoma in Gashoho Health District, Burundi

Background

Burundi is currently not meeting targets for elimination of trachoma and trichiasis by 2020 (GET2020). The recommended SAFE strategy (Surgery, antibiotics, face washing and environmental improvement) is currently not fully implemented in many areas of Burundi. The existence of associations between face-washing, sanitation and trachoma prevalence remain undocumented.

Methods

A convenience sample of 468 individuals from 117 households was drawn from attendees at trachoma clinics set up in four villages. Trachoma status, sex and age were recorded for all household members. Adult household members were surveyed about access to clean water and toilets, and knowledge of trachoma risk factors. Associations between cases of active trachoma per household and environmental risk factors were evaluated using generalised estimating equations.

Results

The overall prevalence of active trachoma was 7.1% (95% CI 5.0–9.6%), but 19.5% (95% CI13.7–26.4%) in children under nine years old. 0.9% (95% CI 0.3–2.0) of participants had trichiasis. Access to a sanitary toilet more than halved the odds of active trachoma (OR 0.43, 95% CI 0.25–0.74%), however, participants did not appreciate this association.

Conclusion

Access to sanitation was associated with the occurrence of active trachoma. Future research should focus on whether improving knowledge of and access to sanitation might reduce trachoma prevalence.

Household Survey of Trachoma among Children Living in Pernambuco, Brazil

This study analyzed the association between individual and household factors and the incidence of trachoma among a population aged between 1 and 9 years in the state of Pernambuco. This was a population-based household study conducted using a population-based sample of residents from 96 census sectors of the 1778 sectors considered to be at social risk in the state. The estimated odds ratio of the univariate analysis presented a confidence interval of 95%. Weights and clusters were adjusted through the Generalized Linear and Latent Mixed Model (GLLAM) method. Trachoma cases were the dependent variable in the multivariate analysis. The independent variables were selected through the stepwise forward method, with an input criterion of 20% (p < 0.20) and an output criterion of 10% (p < 0.10). The prevalence was 6.65%. Trachoma was associated with a female sex, age of 5–9 years, either the absence of use or infrequent use of soap to wash the hands and face, the presence of nasal secretion, a lack of piped water from a public supply system, a greater number of rooms used for sleeping, a greater number of people living in the same household, and a family income of up to one minimum monthly wage. The prevalence of follicular trachoma in Pernambuco was higher than what is recommended by the World Health Organization (WHO).

Elimination of trachoma as a public health problem in Ghana: Providing evidence through a pre-validation survey

Background

In order to achieve elimination of trachoma, a country needs to demonstrate that the elimination prevalence thresholds have been achieved and then sustained for at least a two-year period. Ghana achieved the thresholds in 2008, and since 2011 has been implementing its trachoma surveillance strategy, which includes community and school screening for signs of follicular trachoma and trichiasis, in trachoma-endemic districts. In 2015–2016, the country conducted a district level population-based survey to validate elimination of trachoma as a public health problem.

Methods

As per WHO recommendations, a cross-sectional survey, employing a two-stage cluster random sampling methodology, was used across 18 previously trachoma endemic districts (evaluation units (EUs) in the Upper West and Northern Regions of Ghana. In each EU 24 villages were selected based on probability proportional to estimated size. A minimum of 40 households were targeted per village and all eligible residents were examined for clinical signs of trachoma, using the WHO simplified grading system. The number of trichiasis cases unknown to the health system was determined. Household environmental risk factors for trachoma were also assessed.

Results

Data from 45,660 individuals were examined from 11,099 households across 18 EUs, with 27,398 (60.0%) children aged 1–9 years and 16,610 (36.4%) individuals 15 years and above All EUs had shown to have maintained the WHO elimination threshold for Trachomatous inflammation-Follicular (TF) (<5.0% prevalence) in children aged 1–9 years old. The EU TF prevalence in children aged 1–9 years old ranged from between 0.09% to 1.20%. Only one EU (Yendi 0.36%; 95% CI: 0.0–1.01) failed to meet the WHO TT elimination threshold (< 0.2% prevalence in adults aged 15 and above). The EU prevalence of trichiasis (TT) unknown to the health system in adults aged ≥15 years, ranged from 0.00% to 0.36%. In this EU, the estimated TT backlog is 417 All TT patients identified in the study, as well as through on-going surveillance efforts will require further management. A total of 75.9% (95% CI 72.1–79.3, EU range 29.1–92.6) of households defecated in the open but many households had access to an improved water source 75.9% (95%CI: 71.5–79.8, EU range 47.4–90.1%), with 45.5% (95% CI 41.5–49.7%, EU range 28.4–61.8%) making a round trip of water collection < 30 minutes.

Conclusion

The findings from this survey indicate elimination thresholds have been maintained in Ghana in 17 of the 18 surveyed EUs. Only one EU, Yendi, did not achieve the TT elimination threshold. A scheduled house-by-house TT case search in this EU coupled with surgery to clear the backlog of cases is necessary in order for Ghana to request validation of elimination of trachoma as a public health problem.

Trachoma is an eye disease caused by an infection with Chlamydia trachomatis. It is the leading cause of blindness due to infection globally. However, trachoma is both treatable and preventable through antibiotics and surgery, and may be preventable with basic hygiene improvements. Thus, the Surgery, Antibiotics, Facial cleanliness and Environmental modification (SAFE) strategy is endorsed by the World Health Organization for the implementation of interventions. Trachoma is a progressive disease. Clinically active trachoma, the follicular (trachomatous-inflammation follicular (TF)) and intense (trachomatous- inflammation intense (TI)) phases are most common in children aged 1–9 years old while complications such as in turned lashes and loss of vision are found mainly in adults. Globally, the disease is earmarked for elimination as a public health problem by the year 2020. In Ghana, studies conducted in 2000–2003 identified trachoma as endemic in the Upper West and Northern regions and by 2004 the elimination strategy based on Surgery, Antibiotics treatment, Face washing and Environmental improvement, was being implemented in all 18 districts in the two regions. Surveys conducted in 2008 indicated that the strategy had been successful with reduction of clinically active trachoma to elimination levels in all 18 districts. Ghana implemented a post-elimination surveillance phase from 2011–2014 and conducted a formal prevalence survey in 2015–2016 using WHO standard grading methodologies, the results of which are presented here. The results showed that TF prevalence was below the 5% elimination target in children aged 1–9 years old in all 18 districts, while TT was below 2 cases in every 1000 persons aged 15 and above in all 18 endemic districts except one (Yendi district). Ghana has put in place a TT case search of all persons 15 years and above in the Yendi district to identify persons with the complications and offer surgery to them. The outcomes of these investigations will enable Ghana to provide evidence for WHO dossier submission, to acknowledge validation of elimination of trachoma as public health problem.

The Global Trachoma Mapping Project: Methodology of a 34-Country Population-Based Study

Purpose: To complete the baseline trachoma map worldwide by conducting population-based surveys in an estimated 1238 suspected endemic districts of 34 countries.

Methods: A series of national and sub-national projects owned, managed and staffed by ministries of health, conduct house-to-house cluster random sample surveys in evaluation units, which generally correspond to “health district” size: populations of 100,000–250,000 people. In each evaluation unit, we invite all residents aged 1 year and older from h households in each of c clusters to be examined for clinical signs of trachoma, where h is the number of households that can be seen by 1 team in 1 day, and the product h × c is calculated to facilitate recruitment of 1019 children aged 1–9 years. In addition to individual-level demographic and clinical data, household-level water, sanitation and hygiene data are entered into the purpose-built LINKS application on Android smartphones, transmitted to the Cloud, and cleaned, analyzed and ministry-of-health-approved via a secure web-based portal. The main outcome measures are the evaluation unit-level prevalence of follicular trachoma in children aged 1–9 years, prevalence of trachomatous trichiasis in adults aged 15 + years, percentage of households using safe methods for disposal of human feces, and percentage of households with proximate access to water for personal hygiene purposes.

Results: In the first year of fieldwork, 347 field teams commenced work in 21 projects in 7 countries.

Conclusion: With an approach that is innovative in design and scale, we aim to complete baseline mapping of trachoma throughout the world in 2015.