OBJECTIVE: To analyze the distribution characteristics of emerging and reemerging Oncomelania hupensis snails after the criteria for transmission control of schistosomiasis were achieved in China, so as to provide insights into assessment of schistosomiasis transmission risk and formulation of snail control strategies during the elimination phase. METHODS: O. hupensis survey data in China from 2015 to 2021 were collected from the National Schistosomiasis Pevention and Control Information Management System, and the distribution characteristics of emerging and reemerging O. hupensis snails were descriptively analyzed. RESULTS: Emerging and reemerging O. hupensis snails were identified in China each year from 2015 to 2021, with relatively larger areas with emerging and reemerging O. hupensis snail habitats in 2016 and 2021, and relatively higher numbers of counties (districts) where emerging and reemerging O. hupensis snails were detected in 2016 and 2021. A total of 4 586.30 hm² of emerging O. hupensis snail habitats were found in 10 schistosomiasis-endemic provinces of China (except Fujian and Yunnan Provinces) from 2015 to 2021, with 96.80% in Anhui, Hunan and Hubei provinces, where marshland and lake endemic foci were predominant. A total of 21 023.90 hm² of reemerging O. hupensis snail habitats were found in 12 schistosomiasis-endemic provinces of China from 2015 to 2021, with 97.67% in six provinces of Hubei, Sichuan, Jiangxi, Jiangsu, Yunnan and Anhui, where marshland and lake and hilly endemic regions were predominant. Emerging snail habitats were found in 15.08% of all schistosomiasisendemic counties (districts) in China from 2015 to 2021, and 78.75% of all emerging snail habitats were identified in 11 schistosomiasis-endemic counties (districts), with the largest area of emerging snail habitats found in Lixian County, Hunan Province (645.00 hm²). Reemerging snail habitats were found in 47.67% of all schistosomiasis-endemic counties (districts) in China from 2015 to 2021, and 43.29% of all reemerging snail habitats were identified in 11 schistosomiasis-endemic counties (districts), with the largest area of reemerging snail habitats found in Weishan Li and Hui Autonomous County of Hunan Province (1 579.70 hm²). CONCLUSIONS Emerging and reemerging O. hupensis snails were identified in China each year from 2015 to 2021, with much larger areas of reemerging snail habitats than emerging snail habitats, and larger numbers of schistosomiasis-endemic provinces and counties (districts) with reemerging snails were found that those of provinces and counties (districts) with emerging snails. Specific snail control interventions are required tailored to the causes of emerging and reemerging snail habitats. Both emergence and reemergence of O. hupensis snails should be paid attention to in marshland and lake endemic areas, and Guangxi Zhuang Autonomous Region, Shanghai Municipality and Zhejiang Province where schistosomiasis had been eliminated, and reemergence of O. hupensis snails should be given a high priority in hilly areas. In addition, monitoring of O. hupensis snails should be reinforced in snail-free areas after flooding.
Humans ; China/epidemiology* ; Schistosomiasis/prevention & control* ; Cities ; Ecosystem ; Lakes

OBJECTIVE: To establish a surveillance and early warning index system for schistosomiasis transmission risk along the middle and lower reaches of the Yangtze River basin, so as to provide insights into creation of a sensitive and highly efficient surveillance and early warning system for schistosomiasis. METHODS: National and international publications, documents, laws and regulations pertaining to schistosomiasis control were retrieved with keywords including schistosomiasis, surveillance, early warning and control interventions from 2008 to 2022, and a thematic panel discussion was held to preliminarily construct surveillance and early warning index system for schistosomiasis transmission risk along the middle and lower reaches of the Yangtze River basin. The index system was then comprehensively scored and screened using the Delphi method, and the weight of each index was determined using analytic hierarchy process and the modified proportional allocation method. In addition, the credibility of the Delphi method was evaluated using positive coefficient, authority coefficient, degree of concentration and degree of coordination of experts. RESULTS: Following two rounds of expert consultation, a surveillance and early warning index system for schistosomiasis transmission risk in endemic areas along the middle and lower reaches of the Yangtze River basin was preliminarily constructed, including 3 primary indicators, 9 secondary indicators and 41 tertiary indicators. The normalized weights of primary indicators epidemics, natural and social factors and comprehensive control were 0.639 8, 0.145 6 and 0.214 6, respectively, and among all secondary indicators, snail status (0.321 3) and schistosomiasis prevalence (0.318 5) had the highest combined weights, while social factors had the lowest combined weight (0.030 4). Of all tertiary indicators, human egg-positive rate (0.041 9), number of acute schistosomiasis cases (0.041 5), number of stool-positive bovine and sheep (0.041 1), and prevalence of Schistosoma japonicum in free-ranging livestock (0.041 1) had the highest combined weights. During two rounds of consultation, the positive coefficient of experts was both 100%, and the authority coefficient was both 0.9 and greater, while the coordination coefficients were 0.338 to 0.441 and 0.426 to 0.565 (χ² = 22.875 to 216.524, both P values < 0.05). CONCLUSIONS The established surveillance and early warning index system for schistosomiasis transmission risk along the middle and lower reaches of the Yangtze River basin is of great scientific values and authority, which may provide insights into construction of the sensitive and highly efficient surveillance and early warning system for schistosomiasis in the context of low prevalence and low intensity of infection in China.
Animals ; Cattle ; Humans ; Sheep ; Rivers ; Schistosomiasis/prevention & control* ; Schistosoma japonicum ; China/epidemiology* ; Snails

OBJECTIVE: To identify the spatial distribution pattern of Oncomelania hupensis spread in Hubei Province, so as to provide insights into precision O. hupensis snail control in the province. METHODS: Data pertaining to emerging and reemerging snails were collected from Hubei Province from 2020 to 2022 to build a spatial database of O. hupensis snail spread. The spatial clustering of O. hupensis snail spread was identified using global and local spatial autocorrelation analyses, and the hot spots of snail spread were identified using kernel density estimation. In addition, the correlation between environments with snail spread and the distance from the Yangtze River was evaluated using nearest-neighbor analysis and Spearman correlation analysis. RESULTS: O. hupensis snail spread mainly occurred along the Yangtze River and Jianghan Plain in Hubei Province from 2020 to 2022, with a total spread area of 4 320.63 hm², including 1 230.77 hm² emerging snail habitats and 3 089.87 hm² reemerging snail habitats. Global spatial autocorrelation analysis showed spatial autocorrelation in the O. hupensis snail spread in Hubei Province in 2020 and 2021, appearing a spatial clustering pattern (Moran's I = 0.003 593 and 0.060 973, both P values < 0.05), and the mean density of spread snails showed spatial aggregation in Hubei Province in 2020 (Moran's I = 0.512 856, P < 0.05). Local spatial autocorrelation analysis showed that the high-high clustering areas of spread snails were mainly distributed in 50 settings of 10 counties (districts) in Hubei Province from 2020 to 2022, and the high-high clustering areas of the mean density of spread snails were predominantly found in 219 snail habitats in four counties of Jiangling, Honghu, Yangxin and Gong'an. Kernel density estimation showed that there were high-, secondary high- and medium-density hot spots in snail spread areas in Hubei Province from 2020 to 2022, which were distributed in Jingzhou District, Wuxue District, Honghu County and Huangzhou District, respectively. There were high- and medium-density hot spots in the mean density of spread snails, which were located in Jiangling County, Honghu County and Yangxin County, respectively. In addition, the snail spread areas negatively correlated with the distance from the Yangtze River (r = -0.108 9, P < 0.05). CONCLUSIONS There was spatial clustering of O. hupensis snail spread in Hubei Province from 2020 to 2022. The monitoring and control of O. hupensis snails require to be reinforced in the clustering areas, notably in inner embankments to prevent reemerging schistosomiasis.
Animals ; Schistosomiasis/prevention & control* ; Spatial Analysis ; Ecosystem ; Gastropoda ; Rivers ; China/epidemiology*

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.
Animals ; Humans ; Cattle ; Mice ; Analytic Hierarchy Process ; Schistosomiasis/prevention & control* ; Schistosomiasis japonica/epidemiology* ; Snails ; Risk Assessment

Oncomelania hupensis is the only intermediate host of Schistosoma japonicum, and O. hupensis control is an important measure for schistosomiasis control. With the progress of national schistosomiasis control program, the prevalence of schistosomiasis is low in China; however, there are still multiple challenges for O. hupensis breeding and schistosomiasis transmission risk. Considering the target of the national schistosomiasis elimination program and environmental protection in the new era, the introduction of precision identification, precision interventions and precision assessment into O. hupensis control may facilitate the progress towards elimination of schistosomiasis in China.
Animals ; China/epidemiology* ; Schistosoma japonicum ; Schistosomiasis/prevention & control* ; Snails

On February 2022, WHO released the evidence-based guideline on control and elimination of human schistosomiasis, with aims to guide the elimination of schistosomiasis as a public health problem in disease-endemic countries by 2030 and promote the interruption of schistosomiasis transmission across the world. Based on the One Health concept, six evidence-based recommendations were proposed in this guideline. This article aims to analyze the feasibility of key aspects of this guideline in Chinese national schistosomiasis control program and illustrate the significance to guide the future actions for Chinese national schistosomiasis control program. Currently, the One Health concept has been embodied in the Chinese national schistosomiasis control program. Based on this new WHO guideline, the following recommendations are proposed for the national schistosomiasis control program of China: (1) improving the systematic framework building, facilitating the agreement of the cross-sectoral consensus, and building a high-level leadership group; (2) optimizing the current human and livestock treatments in the national schistosomiasis control program of China; (3) developing highly sensitive and specific diagnostics and the framework for verifying elimination of schistosomiasis; (4) accelerating the progress towards elimination of schistosomiasis and other parasitic diseases through integrating the national control programs for other parasitic diseases.
China/epidemiology* ; Disease Eradication ; Humans ; Public Health ; Schistosomiasis/prevention & control* ; World Health Organization

Preventive chemotherapy is one of the pivotal interventions for the control and elimination of schistosomiasis, which is effective to reduce the morbidity and prevalence of schistosomiasis. In order to promote the United Nations' sustainable development goals and the targets set for schistosomiasis control in the Ending the neglect to attain the Sustainable Development Goals: a road map for neglected tropical diseases 2021-2030, WHO released the guideline on control and elimination of human schistosomiasis in 2022, with major evidence-based updates of the current preventive chemotherapy strategy for schistosomiasis. In China where great success has been achieved in schistosomiasis control, the preventive chemotherapy strategy for schistosomiasis has been updated several times during the past seven decades. This article reviews the evolution of the WHO guidelines on preventive chemotherapy and Chinese national preventive chemotherapy schemes, compares the current Chinese national preventive chemotherapy scheme and the recommendations for preventive chemotherapy proposed in the 2022 WHO guideline on control and elimination of human schistosomiasis, and proposes recommendations for preventive chemotherapy during the future implementation of the 2022 WHO guideline, so as to provide insights into schistosomiasis control among public health professionals engaging in healthcare foreign aid.
China/epidemiology* ; Humans ; Prevalence ; Public Health ; Schistosomiasis/prevention & control* ; World Health Organization

Schistosomiasis is a parasitic disease that seriously hinders socioeconomic developments and threatens public health security. To achieve the global elimination of schistosomiasis as a public health problem by 2030, WHO released the guideline on control and elimination of human schistosomiasis on February, 2022, with aims to provide evidence-based recommendations for schistosomiasis morbidity control, elimination of schistosomiasis as a public health problem, and ultimate interruption of schistosomiasis transmission in disease-endemic countries. Following concerted efforts for decades, great achievements have been obtained for schistosomiasis control in China where the disease was historically highly prevalent, and the country is moving towards schistosomiasis elimination. This article reviews the successful experiences from the national schistosmiasis control program in China, and summarizes their contributions to the formulation and implementation of the WHO guideline on control and elimination of human schistosomiasis. With the progress of the "Belt and Road" initiative, the world is looking forward to more China's solutions on schistosomiasis control.
China/epidemiology* ; Disease Eradication ; Humans ; Public Health ; Schistosomiasis/prevention & control* ; World Health Organization

Currently, the national schistosomiasis control program of China is moving from transmission interruption to elimination, and there are multiple challenges during the stage moving towards the progression of schistosomiasis elimination, including a high difficulty in shrinking snail-infested areas, unstable achievements for infectious source control, imperfect surveillance system and a reduction in schistosomiasis control and administration. Based on the core suggestions proposed in the 2022 WHO guideline on control and elimination of human schistosomiasis, recommendations on schistosomiasis surveillance system building, development of novel diagnostics, adjustment of the schistosomiasis control strategy and maintaining and improvements of the schistosomiasis control capability are proposed for the national schistosomiasis control program of China in the new era according to the actual status of schistosomiasis control in China. Formulation of the national schistosomiasis control strategy and goal from One Health perspective, verification of transmission interruption and elimination of schistosomiasis, precision implementation of schistosomiasis control interventions with adaptations to local circumstances, development and application of highly sensitive and specific diagnostics are recommended for elimination of schistosomiasis in China. In addition, the implementation of the 2022 WHO guideline on control and elimination of human schistosomiasis may guide the elimination of schistosomiasis in China.
Animals ; China/epidemiology* ; Goals ; Humans ; Schistosomiasis/prevention & control* ; Snails ; World Health Organization

OBJECTIVE: To evaluate the diagnostic efficacy of indirect haemagglutination assay (IHA) for detection of Schistosoma japonicum infections among boatmen and fishermen in Dongting Lake region, so as to provide insights into improving the schistosomiasis surveillance program among boatmen and fishermen. METHODS: The boatmen and fishermen were detected for S. japonicum infections using IHA and Kato-Katz technique or miracidium hatching test nylon gauze simultaneously at schistosomiasis testing sites in the anchor sites for boatmen and fishermen in the Dongting Lake region during the period from 2014 to 2016, and using IHA for serological screening followed by parasitological testing of seropositives during the period from 2017 to 2019. The sensitivity and specificity of IHA were evaluated for detection of S. japonicum infections among boatmen and fishermen, with the 2014-2016 parasitological testing results as a gold standard. In addition, the seroprevalence of S. japonicum infections was compared among boatmen and fishermen with different characteristics and among years. RESULTS: A total of 306 schistosomiasis testing sites were assigned for boatmen and fishermen, and a total of 143 360 person-time boatmen and fishermen were tested for S. japonicum infections in the Dongting Lake region from 2014 to 2019. The sensitivity and specificity of IHA were 69.9%, 97.3% and 96.1% (χ² = 74.6, P < 0.05), and 70.9%, 74.5% and 71.9% for detection of S. japonicum infections from 2014 to 2016 (χ² = 29.4, P < 0.05), respectively. The seroprevalence of S. japonicum infections reduced from 30.3% in 2014 to 1.8% in 2019 among boatmen and fishermen, appearing an overall tendency towards a decline (Z = 1 552.4, P < 0.05). In addition, male, individuals at ages of 45 to 60 years, full-time boatmen and fishermen were more likely to be seropositive for S. japonicum infections (all P values < 0.05). CONCLUSIONS The seroprevalence of S. japonicum infections appeared a tendency towards a decline among boatmen and fishermen in the Dongting Lake region year by year from 2014 to 2019. IHA presented a high efficacy for screening of S. japonicum infections among boatmen and fishermen in the Dongting Lake region.
Animals ; China/epidemiology* ; Hemagglutination ; Humans ; Lakes ; Male ; Middle Aged ; Prevalence ; Schistosoma japonicum ; Schistosomiasis/epidemiology* ; Schistosomiasis japonica/prevention & control* ; Seroepidemiologic Studies