[Evaluation of therapeutic coverage of mass treatment campaign against lymphatic filariasis in two health districts in Burkina Faso].

Background & rationale: Burkina Faso has been implementing preventive chemotherapy against lymphatic filariasis since 2001. While 61 health districts (HDs) have stopped mass drug administration (MDA), transmission persists in 9 HDs despite good reported MDA coverage. To validate the reported coverage, an independent post-MDA survey was conducted in Tenkodogo and Fada N'Gourma HDs in September 2018.

Materials & methods: The study population consisted of all persons in the visited communities. The Coverage survey sample builder (CSSB) tool was used to calculate the sample size and to conduct the random selection of households. A total of 30 villages per HD were selected. The investigators were Ministry of Education agents and health workers not involved in MDA. Data were collected on smartphones through the KoBoCollect application regarding age, sex, drug ingestion (ivermectin + albendazole), adverse events, and whether respondents understood MDA guidelines. Stata Version 14 software was used for data analysis.

Results: A total of 3,741 individuals were surveyed, 53.3% were female and the median age was 14 years. Surveyed epidemiological coverage was 74% [95% CI: 72-76.1] in Fada N'Gourma and 79.1% [95% CI: 77.2-80.9] in Tenkodogo, compared to reported coverages of 82.6% and 83% respectively. Village-level coverage ranged from 32.9% to 100% in Fada N'Gourma and from 56.7% to 93.3% in Tenkodogo. In total, 99% of those treated said they had swallowed the drugs in front of the community drug distributor (CDD) and confirmed the use of dose poles. The main reasons for non-treatment were non-visitation of the compound by CDD (54%) and absences during MDA (43%). Results showed that surveyed coverage was lower than reported coverage in both HDs, yet both were above the 65% threshold recommended by WHO. However, major variations of coverage have been noted among villages. Directly observed treatment appeared to have been well respected.

Discussion & conclusion: The main challenges to increase coverage will be the systematic revisiting of households with absentees and the targeting of all households in each village.