Field assessment of the burden and determinants of malaria transmission to inform tailoring of interventions (microstratification) in Ibadan and Kano metropolis: Study protocol

Introduction: Rapid urbanization in Nigerian cities may likely result in small-scale variation in malaria transmission with a higher malaria burden in informal settlements and slums. However, data is unavailable to quantify city-level variations in transmission risk and to inform selection of appropriate interventions. Together with the National Malaria Elimination Programme (NMEP), we are conducting field and modeling studies to understand how malaria risk varies at the smallest administrative units (wards) in two major Nigerian cities - Ibadan and Kano - to inform tailoring of interventions for cities in the 2026 - 2030 National Malaria Strategic Plan. Methods and Analysis: This is a mixed-method research design involving qualitative and quantitative research methods. Model-based clustering and field visits were conducted to identify study wards in Ibadan and Kano.We will carry out formative qualitative studies to inform sampling strategies for formal settlements, informal settlements and slums and the design of survey questionnaires. Multistakeholder dialogues will be used to guide definitions of formal settlements, informal settlements, and slums and to identify such settlement typologies for the study. Focus groups discussions, key informant interviews and cognitive pre-testing will be used to inform the design of cross-sectional surveys and longitudinal studies. Cross-sectional surveys will be conducted in the wet and dry seasons across wards in the study cities and within different settlement types at the household and health facility levels to map all-age and under-five malaria prevalence and evaluate related risk factors. A 12-month longitudinal study among children under the age of 10 years will provide information on malaria seasonality in the two cities and related factors. Entomological surveys will be used to undertaken for eight months (four months in each season) per city to assess local transmission risk in both cities. Descriptive and regression analysis will be applied to study data to assess malaria prevalence, seasonality and related factors, respectively. Mathematical models of malaria transmission for each study ward will be developed based on study data to inform assessment of the impact of various intervention scenarios specified by the NMEP on malaria transmission. Ethics and Dissemination: This protocol, including study methods and informed consent procedures, has been approved by Nigeria National Health Research Committee and Ethical Review Committees of Oyo and Kano States Ministry of Health, University of Ibadan/University College Hospital, Osun State University and Northwestern University. Study results will be disseminated to all the relevant stakeholders and communities where the studies are carried out within four weeks upon completion of fieldwork and analysis of the data