Analysis of the Spatial Distribution of Aedes Albopictus by Indicator Kriging in an Urban Area of Shanghai, China

Background: Aedes albopictus is a well-recognized vector of major arboviral diseases and a primary pest in tropical and temperate regions of China. The current monitoring system, based on sub-district scale, in most cities of China for the spread of Ae. albopictus has not taken spatial distribution for the analysis of density of species. So it is not accurate enough for epidemic investigations, especially in big cities like Shanghai.Methods: In this study, a new surveillance program integrate the actual monitoring locations was used to investigate the temporal and spatial distribution of Ae. albopictus abundance in an urban area of Shanghai, China, from 2018 to 2019 by using the mosquito-oviposition trap (MOT) method. The study area of 14 sub-districts was divided into 133 grids with a side length of approximately 500 m. The vector abundance and spatial structure of Ae. Albopictus were predicted by the indicator Kriging based on eight MOTs in each grid. Meanwhile, the light trap (LT) method was also used for the analysis and compared with the MOT method.Results: A total of 8,192 MOTs were placed in the study area in 2018, and 7,917 (96.6%) were retrieved with a positive rate of 6.45%, while in 2019, 22,715 (97.0%) of 23,408 MOTs were recovered with a positive rate of 5.44%. When using the LT method, 273 (93.5%) and 312 (94.5%) adult female Ae. albopictus were gathered in 2018 and 2019, respectively. The Ae. albopictus populations in the urban area of Shanghai increased slowly from May, reached a peak in July, and declined gradually from September. The MOT positivity index (MPI) showed a significant positive spatial autocorrelation across the study area, while LT collections indicated a non-significant spatial autocorrelation. The MPI was suitable for spatial interpolation by using the indicator Kriging, and showed different hotspots in different years.Conclusions: The new surveillance system integrate geographic information can help improve our understanding of the spatial and temporal distribution of Ae. albopictus in urban areas of Shanghai and could provide a practical method for decision-makers to implement vector control and management of mosquitoes.