ABSTRACT
Objective To analyze the trends of human schistosomiasis prevalence in Hubei Province from 2004 to 2018, so as to provide the evidence for formulating the schistosomiasis elimination strategy in the province. Methods All data pertaining to human schistosomiasis prevalence in Hubei Province were collected from 2004 to 2018, and the trends for changes in seroprevalence, egg-positive rate and prevalence of human Schistosoma japonicum infection were analyzed using a Joinpoint regression model. Results Both of the numbers of residents seropositive and egg-positive for S. japonicum infections appeared a tendency towards a decline in Hubei Province from 2004 to 2018, and the prevalence of human S. japonicum infections reduced from 6.85% in 2004 to 0 in 2018. Joinpoint regression analysis showed that the prevalence of human S. japonicum infections appeared an overall tendency towards a reduction in Hubei Province from 2004 to 2018 [average annual percent change (AAPC) = −24.1%, P < 0.01], and the trends for the reduction were both significant during the period from 2004 to 2006 [annual percent change (APC) = −35.1%, P < 0.01] and from 2006 to 2018 (APC = −22.1%, P < 0.01). The prevalence of human S. japonicum infections appeared a tendency towards a decline in islet (AAPC = −25.1%, P < 0.01), inner embankment (AAPC = −26.4%, P < 0.01) and hilly subtypes of schistosomiasis-endemic areas (AAPC = −32.5%, P < 0.01) of Hubei Province from 2004 to 2018, and the prevalence all appeared a tendency towards a decline during the infection control stage (from 2004 to 2008), the transmission control stage (from 2009 to 2013) and the transmission interruption stage (from 2014 to 2018) (AAPC = −28.0%, −24.4% and −63.8%, all P values < 0.01). The seroprevalence of human S. japonicum infections appeared an overall tendency towards a decline in Hubei Province from 2004 to 2018 (AAPC = −14.5%, P < 0.01), and the trends for the reduction were both significant during the period from 2004 to 2012 (APC = −8.4%, P < 0.01) and from 2012 to 2018 (APC = −22.1%, P < 0.01). In addition, the egg-positive rate of human S. japonicum infections appeared an overall tendency towards a decline in Hubei Province from 2004 to 2018 (AAPC = −30.6%, P < 0.05), and the trend for the reduction was significant during the period from 2007 to 2014 (APC = −15.5%, P < 0.01). Conclusions The prevalence of human schistosomiasis appeared a tendency towards a decline in Hubei Province from 2004 to 2018, and the islet and inner embankment subtypes of endemic areas are a high priority for schistosomiasis control during the stage moving towards elimination in Hubei Province.
ABSTRACT
Objective To establish an indicator system for assessment of schistosomiasis transmission risk after transmission interruption in Hubei Province, so as to provide insights into the precise control of schistosomiasis. Methods The indicator system was preliminarily established based on data collection, literature review, expert interviews. Two rounds of expert consultation were performed. The indicator system was screened based on the importance, operability, sensitivity and comprehensive score of the indicators, and the weights of each indicator were calculated. The credibility of the Delphi method was evaluated by calculating the active coefficient of the experts, degree of expert authority and coordination levels of experts’ opinions. Results An indicator system for assessment of schistosomiasis transmission risk was preliminarily established, including 3 primary indicators, 12 secondary indicators and 44 tertiary indicators. A Delphi consultation was performed among 17 experts participating in schistosomiasis control, management and research. Following two rounds of consultation, a risk assessment indicator system was finally constructed, including 3 primary indicators, 10 secondary indicators and 35 tertiary indicators. Among the primary indicators, the variable with the highest normalized weight was the current status of schistosomiasis (0.420 2), followed by social factors (0.397 3) and natural environments (0.182 5). Among the secondary indicators, those with high combined weights included risk monitoring (0.142 3), current snail status (0.140 1), and current prevalence of human and livestock infections (0.137 8). Among the tertiary indicators, those with high combined weights included the positive rate of wild feces (0.049 8), the prevalence of snail infections (0.047 4), and the area of snail habitats submerged by floods (0.046 8). During the two-round consultation, the active coefficients of the experts were 85.00% and 100.00%, the degree of expert authority was both 0.75 and greater, and the coordination levels of experts’ opinions were 0.405 to 0.521 and 0.592 to 0.695 (all P values < 0.05). Conclusion An indicator system for assessment of schistosomiasis transmission risk is successfully established after transmission interruption in Hubei Province based on the Delphi method, which provides insights into the identification of the schistosomiasis transmission risk and the targets for schistosomiasis control in Hubei Province.
ABSTRACT
Objective To investigate the spatial distribution of Oncomelania hupensis snail habitats at the administrative village scale in schistosomiasis-endemic areas of Hubei Province, so as to provide scientific bases for precise control of O. hupensis snails in the province. Methods Data regarding snail distribution at the village level in Hubei Province in 2017 were collected to create a spatial analysis database of snail distribution in Hubei Province. The spatial aggregations of O. hupensis distribution were analyzed using Moran’s I index and Local Moran’s I index. In addition, the distances from schistosomiasis-endemic villages to the Yangtze River were captured using the software ArcGIS 13.0, and their correlations with area of snail habitats were examined with the Spearman correlation method. Results O. hupensis snails were mainly distributed in 5 450 endemic villages from 63 counties of 13 cities in Hubei Province in 2017. The global spatial autocorrelation analysis showed spatial aggregations in the areas of historically accumulated snail habitats, current areas of snail habitats, areas of snail habitats outside the embankment and snail habitats inside the embankment (all Z Scores > 0, all P values < 0.05), and no spatial aggregation was seen in the areas of snail habitats in hilly areas (Z Score > 0, P > 0.05). There were four types of spatial distribution of historically accumulated areas of snail habitats, areas of current snail habitats, areas of snail habitats outside the embankment and snail habitats inside the embankment, including the high-high type (H-H type), high-low type (H-L type), low-high type (L-H type) and random distribution type, and a high percentage of the H-H type was found. There were 340, 125 and 110 endemic villages with the H-H type of areas of historically accumulated snail habitats, current areas of snail habitats and areas of snail habitats outside the embankment, and these villages were mainly concentrated in Wuhan and Jingzhou cities, with almost consistent spatial aggregation locations. There were 319 endemic villages with the H-H type of distribution of snail habitats inside the embankment, which were mainly distributed in Jingzhou, Xiaogan and Huangshi cities. In addition, the areas of historically accumulated snail habitats, current areas of snail habitats and areas of snail habitats outside the embankment negatively correlated with the distance from the endemic villages to the Yangtze River (r = −0.094, P < 0.01; r = −0.225, P < 0.01; r = −0.177, P < 0.01). Conclusion The clustering areas of snail habitats along the Yangtze River Basin, notably the villages near the Yangtze River are key regions for snail monitoring and control in Hubei Province.