[Trends in Oncomelania hupensis distribution in Wuhan City from 2003 to 2022 based on the Joinpoint regression model].

Abstract

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.