Factors associated with access to Insecticide-Treated Nets and use of house modification in Bagamoyo and Ulanga districts, Tanzania

ABSTRACT Background Insecticide-treated Nets (ITNs) and house modifications are proven vector control tools, yet full coverage has frequently not been achieved. This study investigates factors associated with ITN access and use of house modification in Tanzania. Methods Baseline data from cross-sectional surveys was analysed from 7,240 households in Bagamoyo (60km north of Dar es Salaam) and 1,241 households in Ulanga (a remote rural area), from previous studies on spatial repellants and indoor residual spray evaluation. We estimated the associations between the outcomes: population access to ITNs, ITN per sleeping spaces, presence of window screens and closed eaves, and the covariates household size, age, gender, pregnancy, education, mosquito entry (doors and windows), house modification (window screens & closed eaves), mean distance to mosquito breeding sites and wealth using regression models. Results Population access to ITNs (households with one ITN per two potential people that stayed in the house the previous night of the survey) was 64% (56 - 71) and ITNs per sleeping spaces (households with enough ITNs to cover all sleeping spaces used the previous night of the survey) was 63% (54 - 72) in Bagamoyo, three years after the last Universal Coverage Campaigns (UCC). These findings are both lower than the 80% coverage target of the Tanzania National Malaria Strategic Plan (Tanzania NMSP). In Ulanga, population access to ITNs was 84% (78 - 91) and ITNs per sleeping spaces was 93% (89 - 97), one year after the last UCC. Household size was significantly associated with lower access to ITNs even shortly after UCC. House modification was common in both areas. In Bagamoyo, screened windows were more common than closed eaves (61% vs 14%) whereas in Ulanga more houses had closed eaves than window screens (55% vs 12%). Households in the poorest quintile were less likely to adopt window screening and closing eaves in Bagamoyo, this contrasts with Ulanga district where a greater proportion of poorer households blocked eaves with mud but were less likely to adopt screening. Conclusion Population access to ITN was substantially lower than the targets of the Tanzania NMSP after three years and lower among larger households after one year following ITN campaign. House modification was common in both areas, motivated by wealth. Improved access to ITNs and window screens through subsidy, especially among larger households, uptake of a combination of these two interventions may be maximized.