Trends in Oncomelania hupensis distribution in Wuhan City from 2003 to 2022 based on the Joinpoint regression model / 中国血吸虫病防治杂志

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.

Construction of a schistosomiasis transmission risk assessment system in Wuhan City based on analytic hierarchy process / 中国血吸虫病防治杂志

OBJECTIVE@#To construct a schistosomiasis transmission risk assessment system in Wuhan City and preliminary evaluate its application effect, so as to promote the rational allocation of schistosomiasis control resources and accelerate the progress towards schistosomiasis elimination.@*METHODS@#The schistosomiasis risk assessment indicators were collected through referring schistosomiasis surveillance data of Wuhan City from 2014 to 2020, literature review and expert interviews. Indicators within each criterion and sub-criterion were screened using the Delphi method, and a hierarchical structure model was created based on analytic hierarchy process. Quantitative assignment of each indicator was conducted according to relative importance, and the weight and combination weight of each criterion were calculated in each analytic hierarchy framework to create a schistosomiasis transmission risk assessment system, which was used for the schistosomiasis transmission risk assessment in 12 national schistosomiasis surveillance sites in Wuhan City.@*RESULTS@#A three-level schistosomiasis transmission risk assessment system was preliminarily constructed, which included a target layer, 5 criterion layers and 21 sub-criterion layers. Of all indicators in the criterion layer, transmission route had the highest weight (0.433), followed by source of Schistosoma japonicum infection (0.294); and among all indicators in the sub-criterion layer, S. japonicum infection in Oncomelania hupensis and sentinel mice had the highest combination weight (0.125), followed by prevalence of S. japonicum infection in humans (0.091) and bovines (0.053), snail control by chemical treatment (0.049), positive rate of inquiry examinations (0.048), allocation of schistosomiasis control professionals (0.045), and areas of submerged snail-infested settings (0.041). Of the 12 national schistosomiasis surveillance sites in Wuhan City, there were 5 sites with weights of > 0.8, 4 sites with weights of 0.6 to 0.8, and 3 sites with weights of < 0.6 in 2020.@*CONCLUSIONS@#A schistosomiasis transmission risk assessment system has been constructed based on analytic hierarchy process in Wuhan City, which may provide a evidence-based basis for health resource allocation and decision-making for schistosomiasis control.

Practice of engineering management and its effect on schistosomiasis control in Hankou marshland,Wuhan City / 中国血吸虫病防治杂志

Objective To investigate the Oncomelania hupensis snail control effect of schistosomiasis control engineering in marshland within Wuhan City. Methods The engineering measures including surface barrier removal,molluscicide,flatting surface,topsoil stripping,topsoil covering and ditch renovation were applied to transform Hankou marshland. Then the corre-sponding technical parameters of engineering measures were put forward. The situation of snails was analyzed before and after the transform project. Results The total length and area of the project were 6015 m and 87.21 hm2,respectively,including 17.44 hm2 of topsoil landfill,52.08 hm2 of topsoil covering and 23 new ditches. After the transformation,the average length of the new groove,the groove top width,groove depth,height difference,and the average values of slopes and ditch bottom slope were all increased,while the average values of the width and height of the ditch were decreased. At the same time,the marsh-land beach surface had a new slope that the embankment was higher than the river and no living O. hupensis snails were found then. Conclusions The snail breeding environment in Hankou marshland has been effectively changed by the project. Howev-er,the constant monitoring and engineering management are still needed to consolidate the effect.

Investigation of Capillaria hepatica infection in rodents from Wuhan section of Yangtze River marshland / 中国血吸虫病防治杂志

Objective To understand the prevalence of Capillaria hepatica in rodents from Wuhan section of the Yangtze River marshland. Methods Rodents were trapped in Jiang an section of Wuhan marshland of the Yangtze River. The livers of the rodents were examined for pathological changes by unaided eyes and the liver tissues were examined for the eggs of C. hepati-ca by a microscope. Results According to the natural conditions the investigation was carried out in 6 survey areas. Each sur-vey area was placed with 60 mousetraps and all 360 mousetraps were recovered. A total of 31 rodents rodent density 8.61%were captured and examined including 24 Apodemus agrarius 3 Rattus norvegicus 4 Sorex caecutiens and C. hepatica eggs were found in 1 R. norvegicus 1/3 and not found in A. agrarius and S. caecutiens. Conclusion This study has documented a prevalence of C. hepatica in rodents from Wuhan section of the Yangtze River marshland where is a natural epidemic focus of ca-pillariasis hepatica.