Abstract
Land-use changes, such as deforestation and agriculture, can influence mosquito vector populations and malaria transmission. These land-use changes have been linked to increased incidence in human cases of the zoonotic malaria Plasmodium knowlesi in Sabah, Malaysian Borneo. This study investigates whether these associations are partially driven by fine-scale land-use changes creating more favourable aquatic breeding habitats for P. knowlesi anopheline vectors. Using aerial remote sensing data, we developed a sampling frame representative of all land use types within a major focus of P. knowlesi transmission. From 2015 to 2016 monthly longitudinal surveys of larval habitats were collected in randomly selected areas stratified by land use type. Additional remote sensing data on environmental variables, land cover and landscape configuration were assembled for the study site. Risk factor analyses were performed over multiple spatial scales to determine associations between environmental and spatial variables and anopheline larval presence. Habitat fragmentation (300 m), aspect (350 m), distance to rubber plantations (100 m) and Culex larval presence were identified as risk factors for Anopheles breeding. Additionally, models were fit to determine the presence of potential larval habitats within the areas surveyed and used to generate a time-series of monthly predictive maps. These results indicate that land-use change and topography influence the suitability of larval habitats, and may partially explain the link between P. knowlesi incidence and deforestation. The predictive maps, and identification of the spatial scales at which risk factors are most influential may aid spatio-temporally targeted vector control interventions.
Highlights
Land-use changes, such as deforestation and agriculture, can influence mosquito vector populations and malaria transmission
The key objective of this study was to address the gap in our understanding of the role of land use change and finescale environmental factors in driving increases in incidence of human P. knowlesi by increasing the availability of vector larval habitats
The probability of detecting Anopheles larvae in aquatic habitats did not very between land classes, and there was no association between deforestation and Anopheles larvae presence
Summary
Land-use changes, such as deforestation and agriculture, can influence mosquito vector populations and malaria transmission. Models were fit to determine the presence of potential larval habitats within the areas surveyed and used to generate a time-series of monthly predictive maps These results indicate that land-use change and topography influence the suitability of larval habitats, and may partially explain the link between P. knowlesi incidence and deforestation. Study sites were selected based on high village incidence of P. knowlesi malaria and large vector populations Their results, may not be representative of Kudat’s various habitat types and their different ecologies. This will result in an accurate representation of the variability of vector breeding sites across a study site, rather than an overrepresentation of habitats which are easy to access or for which there is a prior knowledge of association with larval p resence[21] Such data can provide a comprehensive picture of the whole vector population across the full range of land types in the study site. This could highlight areas where aquatic habitats likely or unlikely to be present, which may be useful for formulation of vector control strategies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
