Mass drug administration coverage and determinants of drug uptake for elimination of onchocerciasis in Ulanga District

Abstract

Background: Ulanga district is one of the areas with high Onchocerciasis endemicity in Tanzania and has been implementing MDA interventions for the past 20 years. However, current reports indicate high prevalence of Onchocerciasis in both human and vector species probably because of poor treatment coverage. Interruption of transmission for elimination of Onchocerciasis requires 100% geographical coverage in all active transmission areas, achieve necessary MDA treatment coverage and demonstrate transmission interruption among vector species. However, treatment coverage gives a picture at community level and does not necessarily guarantee good adherence to drug uptake at individual level in the community. Aim: This study was designed to assess treatment coverage and explore determinants of drug uptake during MDA program that may uncover specific areas of effort concentration Material and Methods: A cross-sectional community-based study using a multistage cluster sampling method was carried out in Ulanga district, Morogoro region from April-June 2019. Study participants were randomly selected from households and interviewed using a structured questionnaire. Key informant interview targeting frontline health workers and community drug distributors (CDD) were carried out. Data from community registers was collected using a checklist. Measures of central tendency and dispersion (mean and standard deviation) were summarized using continuous variables while categorical variables were assessed using frequency and proportions. Bivariate and Multivariate analysis were performed to determine factors associated with MDA uptake through modified Poisson regression. Prevalence Ratio (PR) was used as a measure of association while p-value and χ2 were used as measures of statistical significance. Results: A total of 502 participants were recruited during the study period. The mean age was 37.8 years ±15 SD. From the community register, low treatment coverage of 47.1%, 61.5%, 63.3% and 68% were documented for Mawasiliano, Uponera, Isongo and Togo villages respectively. Coverage from community survey was 68%, 83%, 84% and 79% for Mawasiliano, Uponera, Isongo and Togo villages respectively. These coverages are below the optimal recommended coverage by WHO (85%) for successful transmission interruption. Drug uptake were 3.9 times higher among participants aged ≤ 24 years compared to those above 44yrs [PR = 3.9(95% CI:1.9-8.3), p < 0.05)]. Living in the village for at least a year increased the chances of drug uptake [PR = 3.4 (95% CI:2.4-4.8), p <0.05)]. Those who believed in prevention effects of Ivermectin increased chances to drug uptake during MDA [APR = 13.4(95% CI:2.9-60.9)], p<0.05), while fear of restriction from drinking alcohol after taking drugs was attributable to decreased drug uptake [APR = 12(95% CI: 2.4-60.9), p<0.05)]. Other important determinates of drug uptake were workload and inadequate incentives for CDDs. Conclusion and recommendation: This study has highlighted low coverage of drug uptake as recorded in the community drug distribution register, which indicates that the effectiveness of the MDA activities was not up to the recommended level. There is a need to capitalize on post MDA mop up campaign on poor coverage areas and coverage review surveys immediately after MDA campaign so that there could be alignment between the reported data and actual treatment coverage reported in the community register. Also intensifying awareness of the benefits of ivermectin in Onchocerciasis control as well as to address the community misconceptions and of fear of the drug side effects need to be implemented.