Assessment of malaria cases and associated factors for continued transmission in hotspot shehias in Magharibi b district, Zanzibar

Abstract

ABSTRACT Background: Malaria is a global health problem, with approximately 247 million cases reported worldwide, 95% of which occur in Africa. Tanzania’s malaria prevalence is estimated at 8% while Zanzibar has a significantly lower burden at less than 1%. Despite efforts to eliminate malaria in Zanzibar, hotspot Shehias in Magharibi B District experiences high periodic transmission. This study aims to identify factors associated with persistent malaria transmission in these hotspots Shehias. Methodology: An explanatory sequential study was conducted in the hotspot Shehias of Magharibi B district using a case-control study with one malaria case matched to three controls. Malaria cases notified from the coconut surveillance system were followed to the households and controls were obtained from neighboring houses. Interviews using a structured questionnaire were conducted to collect data on socio-demographic, socio-economic, behavioral, and environmental factors contributing to persistent transmission. Descriptive analysis was performed to determine the frequencies of categorical variables. A conditional logistic regression model assessed the association between dependent and independent variables, with a p-value of < 0.05 set for significance. Additionally, the Modified grounded theory approach was used for Focus Group Discussions (FGD) to collect data from Magharibi B residents from hotspot shehias which were later transcribed and analyzed to reinforce the quantitative findings. Results: This study focused on individual aged 15 years or older living in Magharibi B hotspot shehias. A total of 144 participants from case – control and 48 malaria negative individuals from 6 FGDs were interviewed. Findings show that Malaria cases were more common among males (69.4%), individuals aged 15–24 years (44.4%), and those with high knowledge of malaria (94.4%). Significant factors associated with malaria transmission included outdoor night stays (Adjusted Odds Ratio [aOR] = 4.73, 95% CI 1.04 – 23.35), and the presence of breeding sites (aOR = 4.48; 95% CI 1.04 – 19.27). FGDs identified additional factors such as negative attitude regarding Insecticide Treated Nets (ITNs) usage among males, outdoor night activities, misconceptions about ITN use, poor housing conditions, and unclean environments with discarded cans and bushes around settlements. Conclusion: Factors contributing to continued malaria transmission in hotspot Shehias in Magharibi B district include outdoor night activities, the presence of breeding sites, negligence, and misconceptions about ITN use. The Zanzibar Malaria Elimination Program should promote behavioral change communication that go in line with entomological monitoring and lava source management.