1.Spatiotemporal distribution characteristics analysis of schistosomiasis in Wuhan City, 2013-2022
LI Yang ; WANG Hao ; LIU Cong ; ZHANG Jiajing ; WANG Shuai ; XIONG Yuelin ; LUO Huatang
China Tropical Medicine 2024;24(2):200-
Objective To analyze and visualize the epidemic changes of schistosomiasis in Wuhan from 2013 to 2022 based on a geographical information system (GIS), providing references for further schistosomiasis control activities. Methods According to the historical data of the annual reports of schistosomiasis screening and street-level vector map of Wuhan City from 2013 to 2022, a spatial database of epidemic information at the street level was established. The Joinpoint regression model was utilized to analyze the trend of phased changes in blood positivity rate for schistosomiasis. ArcMap 10.8 was employed for the spatial visualization of the positive rate of serological tests for schistosomiasis among the screened population in the endemic areas of Wuhan over the past decade, as well as conducting hot spot analysis (Getis-Ord Gi*) to explore the spatial clustering relationship and spatiotemporal trends. Heatmaps were generated to reflect the changes in the positive rate of blood tests for schistosomiasis over a decade in various streets, and the areas were classified by the ward’s method of hierarchical clustering using the sum of squared deviations. Results Over the past decade, the overall annual positive rate of schistosomiasis screening in Wuhan declined from 2.23% in 2013 to 0.47% in 2022, showing a general downward trend. The Joinpoint regression model analysis of the blood positive rate indicated the presence of one connection point in 2015; from 2013 to 2015, the annual percent change (APC) of the positive rate was 2.17%, showing an upward trend (P>0.05); from 2015 to 2022, the APC was -23.34%, indicating a downward trend (P<0.05). The map of positive street-level schistosomiasis screening rates for 2013-2022 shows that the positive rate count on the streets of Caidian District and Hannan District in southwestern Wuhan and Huashan Street on the east side, had a significant decrease over the ten years, while the rate in the streets under the jurisdiction of Dongxihu District in the west showed an increase. The hot spot analysis graph revealed that hot spots of the positive rate in Wuhan shifted from the southwest to the west beginning in 2018. The heatmap indicated the largest disparity in trend changes, with the most noteworthy decline in streets under Caidian District and an increasing trend in the streets under Dongxihu District. Conclusions The overall epidemic situation of schistosomiasis in Wuhan is on a downtrend, although the positive rate of blood tests has increased in some areas. This has been attributed to a reduction in the total number of people participating in the blood tests and the slow decrease of antibodies in certain patients who were repeatedly sampled for testing. It is important to further strengthen the construction of monitoring capabilities, improve the sensitivity of monitoring systems, identify potential risks promptly, and handle them properly.
2.Trends in Oncomelania hupensis distribution in Wuhan City from 2003 to 2022 based on the Joinpoint regression model
Yuelin XIONG ; Hao WANG ; Yang LI ; Jiajing ZHANG ; Shuai WANG ; Cong LIU ; Huatang LUO
Chinese Journal of Schistosomiasis Control 2024;36(2):159-164
Objective To analyze the trends in Oncomelania hupensis distribution in Wuhan City, Hubei Province from 2003 to 2022, so as to provide insights into precision schistosomiasis control. Methods Data pertaining to O. hupensis snail survey in Wuhan City from 2003 to 2022 were collected. The trends in the proportion of areas with snail habitats, actual area with snail habitats, mean density of living snails and prevalence of Schistosoma japonicum infection in snails were evaluated in schistosomiasis-endemic areas of Wuhan City from 2003 to 2022 with the slope of trend curve (β), annual percent change (APC) and average annual percent change (AAPC) using a Joinpoint regression model. Results During the period from 2003 through 2022, there were two turning points for the proportion of areas with snail habitats in Wuhan City in 2005 and 2015, with a rise during the period from 2003 to 2005 (β1 = 5.93, t = 1.280, P > 0.05), a decline from 2005 to 2015 (β2 = −0.88, t = −2.074, P > 0.05) and a rise from 2015 to 2022 (β3 = 1.46, t = −2.356, P < 0.05). During the period from 2003 through 2022, there were two turning points for the proportion of areas with snail habitats in islet endemic areas of Wuhan City in 2006 and 2015, with no significant differences in the trends from 2003 to 2006 (β1 = 4.64, t = 1.888, P > 0.05) or from 2006 to 2015 (β2 = −1.45, t = −2.143, P > 0.05), and with a tendency towards a rise from 2015 to 2022 (β3 = 2.04, t = −3.100, P < 0.05). During the period from 2003 through 2022, there were two turning points for the proportion of areas with snail habitats in inner embankment endemic areas of Wuhan City in 2012 and 2020, with a tendency towards a decline from 2003 to 2012 (β1 = −0.39, t = −4.608, P < 0.05) and with no significant differences in the trends from 2012 to 2020 (β2 = 0.03, t = 0.245, P > 0.05) and from 2020 to 2022 (β3 = 1.38, t = 1.479, P > 0.05). During the period from 2003 to 2022, the actual area with snail habitats all appeared a tendency towards a decline in Wuhan City, and in islet and inner embankment endemic areas of Wuhan City from 2003 to 2022 (AAPC = −2.39%, −5.75% and −2.35%, all P values < 0.05). The mean density of living snails reduced from 0.087 snails/0.1 m2 in 2003 to 0.027 snails/0.1 m2 in 2022 in Wuhan City, with a significant difference in the tendency towards the decline (APC = AAPC = −11.47%, P < 0.05). The annual mean decline rate of the mean density of living snails was 17.36% in outside embankment endemic areas of Wuhan City from 2003 to 2022 (APC = AAPC = −17.36%, P < 0.05), and there was no significant difference in the trends in the mean density of living snails in islet endemic areas of Wuhan City from 2003 to 2022 (APC = AAPC = −0.97%, P > 0.05). In addition, the prevalence of S. japonicum infection in snails appeared a tendency towards a decline in Wuhan City from 2003 to 2022 (APC = AAPC = −12.45%, P < 0.05). Conclusions The proportion of areas with snail habitats, actual area with snail habitats, mean density of living snails and prevalence of S. japonicum infection in snails all appeared a tendency towards a decline in Wuhan City from 2003 to 2022. Intensified snail control, modification of snail habitats, shrinking of areas with snails and implementation of grazing prohibition in snail-infested settings are required, in order to facilitate the progress towards schistosomiasis elimination in Wuhan City.