Spatio-temporal distribution characteristics of Oncomelania hupensis in Anhui Province from 2011 to 2020

Abstract

To analyze the spatial-temporal distribution characteristics of Oncomelania hupensis snails in Anhui Province from 2011 to 2020, to provide insights into precision control of O. hupensis snails in Anhui Province. O. hupensis snail distribution data were collected in Anhui Province from 2011 to 2020 and descriptively analyzed, including actual area of snail habitats, area of emerging snail habitats and area of Schistosoma japonicum-infected snails. The actual area of snail habitats and area of emerging snail habitats were subjected to spatial autocorrelation analysis, hotspot analysis, standard deviation ellipse analysis and space-time scanning analysis, and the clusters of snail distribution and settings at high risk of snail spread were identified in Anhui Province from 2011 to 2020. The actual area of snail habitats gradually decreased in Anhui Province from 2011 to 2020. The actual area of snail habitats were 26 238.85 hm2 in Anhui Province in 2020, which were mainly distributed in marshland and lake regions. There was a large fluctuation in the area of emerging snail habitats in Anhui Province during the period from 2011 to 2020, with the largest area seen in 2016 (1 287.65 hm2), and 1.96 hm2 emerging infected snail habitats were detected in Guichi District, Chizhou City in 2020. Spatial autocorrelation and hotspot analyses showed spatial clusters in the distribution of actual areas of snail habitats in Anhui Province from 2011 to 2020 (Z = 3.00 to 3.43, all P values < 0.01), and the hotspots were mainly concentrated in the marshland and lake regions and distributed along the south side of the Yangtze River, while the cold spots were mainly concentrated in the mountainous regions of southern Anhui Province. There were no overall spatial clusters in the distribution of areas of emerging snail habitats (Z = -2.20 to 1.71, all P values > 0.05), and a scattered distribution was found in local regions. Standard deviation ellipse analysis showed relatively stable distributions of the actual areas of snail habitats in Anhui Province from 2011 to 2020, which was consistent with the flow direction of the Yangtze River, and the focus of the distribution of areas of emerging snail habitats shifted from the lower reaches to upper reaches of Anhui section of the Yangtze River. Space-time scanning analysis identified two high-value clusters in the distribution of actual areas of snail habitats in lower and middle reaches of Anhui section of the Yangtze River from 2011 to 2020, and two high-value clusters in the distribution of areas of emerging snail habitats were identified in mountainous and hilly regions. There were spatial clusters in the distribution of O. hupensis snails in Anhui Province from 2011 to 2020, which appeared a tendency of aggregation towards the south side and upper reaches of the Yangtze River; however, the spread of O. hupensis snails could not be neglected in mountainous and hilly regions. Monitoring of emerging snail habitats should be reinforced in mountainous and hilly regions and along the Yangtze River basin.