Ecological Correlates and Predictors of Lassa Fever Incidence in Ondo State, Nigeria 2017 - 2021: An Emerging Urban Trend

Abstract

Lassa fever (LF) is a highly prevalent disease in many West African countries, including Nigeria. Efforts to combat the disease have primarily focused on rural areas where interactions between rodents and humans are common. However, recent studies indicate a shift in the occurrence of LF from rural to urban areas. We analysed secondary data of reported LF outbreaks from 2017 to 2021 in Ondo State, Nigeria, to identify the distribution pattern, ecological variations, and other determinants of disease spread from the ward level. Data utilised include LF incidence, ecological variables involving elevation, population, nighttime light intensity, vegetation, temperature, market presence, road length, and building area coverage. ArcGIS Pro 3.0 software was employed for spatial analysis. Results revealed a spatio-temporal clustering of LF incidents between 2017 and 2021, with an increasing trend followed by a decline in 2021. All wards in Owo Local Government Area were identified as hotspots for LF. The ecological variables exhibited significant correlations with the number of LF cases in the wards, except for maximum temperature. Notably, these variables varied significantly between wards with confirmed LF and those without. Therefore, it is important to prioritise strategies for mitigating LF outbreaks in urban areas of Nigeria and other West African countries.