Geospatial modeling of geographical spread of Aedes species, in relation to climatic and topographical factors in Lagos State, Nigeria.

The ecology and biology of mosquito disease vectors of the genus Aedes are highly dynamic, adapting to various climatic and topographic factors which makes their control challenging. Evidence-based control of Aedes mosquitoes requires a detailed understanding of this adaptability, which is greatly influenced by environmental dynamics. Understanding the drivers of their distribution is hence pertinent to predict disease risk. To better understand drivers and dynamics, we studied the distribution of Aedes mosquitoes in Lagos State, Nigeria, and its connection to climatic and human factors. Aedes larvae and adults were collected from eight Local Government Areas (LGAs, four urban and four rural) in Lagos State, resulting in 98 occurrence points. Using 23 environmental variables, we modeled the geographic distribution of Aedes spp. under current climatic conditions. Human population density was overlaid to estimate the risk of arboviral diseases. Although Aedes mosquitoes were found in all the eight LGAs in different proportions, species distribution varied considerably. Both Aedes aegypti and Aedes albopictus were found across the LGAs with evidence of species partitioning. Virtually all the LGAs were predicted to be highly suitable environments for Aedes mosquitoes, with only two LGAs being moderately suitable. Anthropogenic factors including the extensive accumulation of tires contribute to larval habitat availability for both Aedes aegypti and Aedes albopictus. Urban areas with high population density were also associated with increased larval habitat availability when compared with rural areas. Furthermore, the model suggests that LGAs sharing border with Ogun State are highly suitable environments for Aedes spp. Our study highlights that the main contributing factors to Aedes distribution were precipitation and temperature in the coldest quarter. This paper aims to understand how human and climatic factors affect Aedes mosquitoes distribution in Lagos State, which is crucial to prevent disease transmission.