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

IntroductionRapid 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. We are conducting field 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 Nigerias National Malaria Strategic Plan. Methods and AnalysisThis is a mixed-method research design involving qualitative and quantitative research methods. We will carry out formative qualitative studies to inform sampling strategies for formal settlements, informal settlements and slums and the design of survey questionnaires. 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. 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 DisseminationThis protocol has been approved by Nigerias National Health Research Committee and relevant institutional Ethical Review Committees. Study results will be disseminated to key stakeholders and study communities. Strength and LimitationsO_ST_ABSStrengthsC_ST_ABSO_LICross-sectional and longitudinal study sampling procedures and questionnaire design are enhanced by a strong formative research foundation C_LIO_LIStudy design and site selection are informed by modeling and local knowledge C_LIO_LIThe combination of human and vector studies will provide detailed information on malaria transmission risk and associated drivers C_LI LimitationsO_LICross-sectional study may not be powered to measure all-age prevalence as sample size estimation is based on prevalence among children under the age of five years C_LIO_LIStudy findings may not adequately measure transmission burden and risk factors in unsampled wards C_LI