Abstract:

Objective To analyze the spatial distribution of current schistosomiaisis cases in Anhui Province as reference for facilitating the control of the disease. Methods The epidemiological data of current schistosomiasis cases in Anhui from January 2017 to October 2018, including age, gender, occupation, education, current address, disease stage, economic status, health insurance and treatment, were collected from Epidemiological Dynamics Data Collection Platform (EDDC). A database of Anhui schistosomiasis cases was established using Microsoft Excel 2010. SPSS18.0 was used to analyze the statistical significance of epidemiological characteristics of schistosomiasis cases in Anhui. ArcGIS 10.2 clustering module was used to analyze the spatial autocorrelation of chronic and advanced schistosomiasis cases identified at township level, among them the global spatial autocorrelation analysis was performed using global Moran’s I index and the local spatial autocorrelation analysis using local Getis-Ord G coefficient. Results A total of 20 345 schistosomiasis cases were reported in the province during January 2017-October 2018, including 15 080 chronic clinic cases and 5 265 advanced cases. There was no acute case reported during the period. More male cases (11 319) than female cases (9 026) were reported with male and female ratio of 1.25 : 1. Average age of all cases was 57.8 ± 12.2. Among all chronic cases, the average age was 54.8 ± 11.2 years old. Most of the cases were farmers (96.4%, 14 540/15 080) with low education (primary school/51.9%, middle school/23.0% and illiterate/21.8%). Total 4.9% (736/15 080) of the chronic cases came from families with low income. Among all advanced cases, the average age was 66.4 ± 10.7 years old. The main occupation was farmers (93.8%, 4 936/5 265) with low education level (illiterate/43.6%, primary school/38.1% and middle school/15.2%). More than 10% of the cases (528/5 265) came from the poor families with low income. Chronic cases were distributed in 249 townships within 42 counties (cities or districts) along Yangtze River Basin. There were 38 townships with prevalence of chronic cases higher than 0.5%. The advanced cases were mainly distributed in 340 townships within 45 countries (cities or districts) along Yangtze River Basin and Xin’an River Basin. There were 3 counties with prevalence of advanced schistosomiasis cases higher than 0.5%. The global autocorrelation analysis at the township level showed that both prevalence of chronic schistosomiasis (Moran’s I = 0.202 5, P < 0.01) and the advanced schistosomiasis (Moran’s I = 0.183 4, P < 0.01) possesed spatial autocorrelation in Anhui Province. Analysis of local autocorrelation showed that highly concentrated areas of chronic schistosomiasis were mostly distributed in the townships along the upper and middle reaches of the Yangtze River in Anhui, and highly concentrated areas of advanced schistosomiasis were mainly distributed along the upper and middle reaches of the Yangtze River and the Xin’an River Basin. Conclusion There is spatial accumulation of schistosomiasis case in Anhui Province. The upper and middle reaches of the Yangtze River remain the key areas for schistosomiasis prevention and control in Anhui Province.

Key words: Schistosomiasis, Spatial autocorrelation analysis, Anhui Province