[Study on spatial - temporal characteristics of Schistosoma japonicum infections among human in Hunan Province, 2004-2011]

Abstract

Objective To explore the spatial-temporal characteristics and changing regularities of Schistosoma japonicum infections among human from 2004 to 2011. Methods The township level spatial databases of schistosomiasis in Hunan Province from 2004 to 2011 were established, and the related spatial analysis was performed by SPSS 17.0, ArcGIS 10.1 and SaTScan 7.03. Results The schistosome infection rate among human in Hunan Province sharply decreased from 3.0% in 2004 to 0.8% in 2011. However, the rate among residents in parts of some townships in 2011 was still hovering at a higher level (P₉₀ = 2.12%), and the higher rate was distributed along the Oncomelania hupensis snail ridden areas outside embankment. The autocorrelation analysis showed that the global Moran's I for schistosome infection rate among human was 0.34 to 0.53 from 2004 to 2011, and was higher than the expected value (Z > 8.71, P < 0.05). The local G statistics indicated that the positive hotspot high-high clustering areas were mainly near the coast of Dongting Lake from 2004 to 2011, and the number of townships with schistosomiasis endemic in the clustering areas reached 30 to 70. The spatial scan analysis showed that the number of townships in the clustering areas ran up to 145 to 183 from 2004 to 2011. Conclusions The schistosome infection rate among human decreased significantly in Hunan Province from 2004 to 2011. However, the rate in parts of some townships still remains at a comparatively high level, and there are positive spatial correlation and spatial agglomerations in the schistosome infection rate among human, suggesting that the prevention and control work on schistosomiasis in these areas should be strengthened in the future.

Keywords: Dongting Lake; Schistosomiasis; Spatial Autocorrelation; Spatial Scan; Spatial-temporal distribution.