To measure the feasibility of using a PPES sampling approach with segmentation within each EA to measure coverage. In addition to collecting data on coverage the team also used mobile devices to collect data on time and distance traveled as well as the availability of village registers. These data contribute to the larger coverage evaluation study taking place in multiple countries.
Preliminary Findings and Lessons Learned
Coverage surveys are an important tool for programs to evaluate their reporting systems and to determine whether effective MDA coverage has been achieved. However, for various reasons coverage surveys are seldom implemented. Some key challenges are: perceived technical difficulty, lack of resources, and lack of standardized guidance on how to conduct coverage surveys. This protocol seeks to pilot a newly refined probability sampling with segmentation approach in 2 districts in Malawi. The two surveys found that the survey coverage was above the WHO target thresholds for Zithromax. Furthermore, the team found the survey methodology to be clear and feasible to implement. This adds further evidence to the previous studies that support the use of the segmentation approach for coverage surveys across all 5 PC NTDs.
The purpose of this project is to create maps that utilize LF risk and prevalence data to predict risk of recrudescence, and to stratify this risk into 3-4 distinct groups. Such maps could subsequently be used to design and simulate the performance of different surveillance strategies.
Preliminary study findings:
The intensity of transmission was quantified by the basic reproductive number (R0).
A map of predicted prevalence of microfilaraemia, developed through Bayesian geostatistical modelling, was linked to mathematical models of the transmission dynamics of lymphatic filariasis.
The models predict a marked geographical heterogeneity in the intensity of lymphatic filariasis transmission in Sub-Saharan Africa.
Further control efforts may be required in areas of higher intensity of transmission.
Conversely, interruption of transmission might be achieved earlier in areas of low intensity of transmission.
The results suggest that intensity of transmission at baseline (R0) and bednet use are the best indicators for the level of surveillance required sub-nationally post-MDA.
Defining what are the appropriate tools to map LF in Loa endemic areas. Identifying if there is a Loa infection threshold that triggers the cross-reactivity in the ICT cards.
Organize existing data for preparation of LF elimination dossiers based on the PacELF programs.
Develop a program evaluation tool to permit program managers to effectively assess coverage and compliance. This study will focus on assessing MDA coverage for lymphatic filariasis by comparing the cost, time and feasibility of the EPI approach (n=480), LQAS design (n=95) and probability sampling alternatives (n=480).
Preliminary study findings:
- All three survey methods were feasible for the teams to implement and cost <$5,000.
- Preschool deworming coverage, provided through the community-based MDA, was <60%.
- The main reason for refusing the medication was that the child had recently been dewormed.
- Approximately 80% of preschool children surveyed received at least one dose of unprogrammed deworming in the past 12 months.
- The main sources of unprogrammed deworming were health centers, local pharmacies, and bodegas.
To compare different diagnostic tools during onchocerciasis mapping, including Ov16 ELISA, OV16 rapid diagnostic test (RDT) and skin snip test.
Comparison of different diagnostic tools during onchocerciasis mapping, including Ov16 ELISA, OV16 rapid diagnostic test (RDT) and skin snip test.