[Progress of schistosomiasis control in People's Republic of China in 2023].

To understand the progress of national schistosomiasis elimination program of China in 2023 and summarize the lessons and experiences, data on the endemic status of schistosomiasis and national schistosomiasis surveillance results in the People's Republic of China were collected and analyzed at a national level. By the end of 2023, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to consolidate the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan and Hubei provinces were identified to achieve the criteria of transmission interruption in 2020, and Anhui, Jiangxi and Hunan provinces achieved the criteria of transmission interruption in 2023. A total of 451 counties (cites, districts) were found to be endemic for schistosomiasis in China in 2023, including 26 250 endemic villages covering 73 034 500 residents at risk of infections. Among the 451 endemic counties (cities, districts), 78.49% (354/451) achieved the criteria of schistosomiasis elimination and 21.51% (97/451) achieved the criteria of transmission interruption, respectively. In 2023, a total of 4 216 643 individuals received immunological tests, with 47 794 sero-positives identified, and a total of 184 216 individuals received parasitological examinations, with 4 egg-positives detected. A total of 27 768 cases with advanced schistosomiasis were documented in China by the end of 2023. In 2023, 539 548 bovines were raised in schistosomiasis-endemic areas of China, and 125 440 bovines received immunological tests, with 124 sero-positives detected, while no egg-positives were identified among the 133 508 bovines receiving parasitological examinations. In 2023, snail survey was performed at an area of 641 339.53 hm2 and 184 819.77 hm2 snail habitats were identified, including 51.53 hm2 emerging snail habitats and 642.25 hm2 reemerging snail habitats. In 2023, there were 20 198 schistosomiasis patients receiving praziquantel chemotherapy, and 598 183 person-time individuals and 283 954 herdtime bovines were given expanded chemotherapy. In 2023, snail control with chemical treatment was performed in 116 347.95 hm2 snail habitats, and the actual area of chemical treatment was 65 690.89 hm2, while environmental improvements were performed in snail habitats covering an area of 1 334.62 hm2. The national schistosomiasis surveillance results showed that the mean prevalence of Schistosoma japonicum infections were both zero among humans and bovines in 2023, and no S. japonicum infection was detected in snails. These data demonstrated that transmission interruption of schistosomiasis had been achieved across all endemic provinces in China in 2023, and the endemic status of schistosomiasis tended to be stable, while advanced cases were predominant among all schistosomiasis cases. However, the areas of snail habitats remained high and cattle re-raising was very common in some regions. Intensified schistosomiasis surveillance and forecast and snail control in high-risk areas are needed.

[Progress of schistosomiasis control in People's Republic of China in 2022].

This report presented the endemic status of schistosomiasis and analyzed the data collected from the national schistosomiasis prevention and control system and national schistosomiasis surveillance program in the People's Republic of China in 2022. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to maintain the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan, Hubei, Anhui, Jiangxi and Hunan provinces maintained the criteria of transmission control by the end of 2022. A total of 452 counties (cites, districts) were found to be endemic for schistosomiasis in China in 2022, with 27 434 endemic villages covering 73 424 400 people at risk of infections. Among the 452 endemic counties (cities, districts), 75.89% (343/452), 23.45% (106/452) and 0.66% (3/452) achieved the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. In 2022, 4 317 356 individuals received serological tests for schistosomiasis, and 62 228 were sero-positive. A total of 208 646 individuals received stool examinations for schistosomiasis, with one positive and another two cases positive for urine microscopy, and these three 3 cases were imported schistosomiasis patients from Africa. There were 28 565 cases with advanced schistosomiasis documented in China by the end of 2022. Oncomelania hupensis snail survey was performed in 18 891 endemic villages in China in 2022 and O. hupensis snails were found in 6 917 villages (36.62% of all surveyed villages), with 8 villages identified with emerging snail habitats. Snail survey was performed at an area of 655 703.01 hm2 and 183 888.60 hm2 snail habitats were found, including 110.58 hm2 emerging snail habitats and 844.35 hm2 re-emerging snail habitats. There were 477 200 bovines raised in the schistosomiasis endemic areas of China in 2022, and 113 946 bovines received serological examinations for schistosomiasis, with 204 sero-positives detected. Among the 131 715 bovines received stool examinations, no positives were identified. In 2022, there were 19 726 schistosomiasis patients receiving praziquantel chemotherapy, and expanded chemotherapy was performed in 714 465 person-time for humans and 234 737 herd-time for bovines in China. In 2022, snail control with chemical treatment was performed at an area of 119 134.07 hm2, and the actual area of chemical treatment was 65 825.27 hm2, while environmental improvements were performed at an area of 1 163.96 hm2. Data from the national schistosomiasis surveillance program of China showed that the mean prevalence of Schistosoma japonicum infections was both zero in humans and bovines in 2022, and no S. japonicum infection was detected in O. hupensis snails. These data demonstrated that the endemic status of schistosomiasis continued to decline in China in 2022, with 3 confirmed schistosomiasis patients that had a foreign nationality and all imported from Africa, and the areas of snail habitats remained high. Further improvements in the construction of the schistosomaisis surveillance and forecast system, and reinforcement of O. hupensis survey and control are required to prevent the re-emerging schistosomiasis.

Progress of schistosomiasis control in People’s Republic of China in 2022 / 中国血吸虫病防治杂志

This report presented the endemic status of schistosomiasis and analyzed the data collected from the national schistosomiasis prevention and control system and national schistosomiasis surveillance program in the People’s Republic of China in 2022. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to maintain the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan, Hubei, Anhui, Jiangxi and Hunan provinces maintained the criteria of transmission control by the end of 2022. A total of 452 counties (cites, districts) were found to be endemic for schistosomiasis in China in 2022, with 27 434 endemic villages covering 73 424 400 people at risk of infections. Among the 452 endemic counties (cities, districts), 75.89% (343/452), 23.45% (106/452) and 0.66% (3/452) achieved the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. In 2022, 4 317 356 individuals received serological tests for schistosomiasis, and 62 228 were sero-positive. A total of 208 646 individuals received stool examinations for schistosomiasis, with one positive and another two cases positive for urine microscopy, and these three 3 cases were imported schistosomiasis patients from Africa. There were 28 565 cases with advanced schistosomiasis documented in China by the end of 2022. Oncomelania hupensis snail survey was performed in 18 891 endemic villages in China in 2022 and O. hupensis snails were found in 6 917 villages (36.62% of all surveyed villages), with 8 villages identified with emerging snail habitats. Snail survey was performed at an area of 655 703.01 hm2 and 183 888.60 hm2 snail habitats were found, including 110.58 hm2 emerging snail habitats and 844.35 hm2 re-emerging snail habitats. There were 477 200 bovines raised in the schistosomiasis endemic areas of China in 2022, and 113 946 bovines received serological examinations for schistosomiasis, with 204 sero-positives detected. Among the 131 715 bovines received stool examinations, no positives were identified. In 2022, there were 19 726 schistosomiasis patients receiving praziquantel chemotherapy, and expanded chemotherapy was performed in 714 465 person-time for humans and 234 737 herd-time for bovines in China. In 2022, snail control with chemical treatment was performed at an area of 119 134.07 hm2, and the actual area of chemical treatment was 65 825.27 hm2, while environmental improvements were performed at an area of 1 163.96 hm2. Data from the national schistosomiasis surveillance program of China showed that the mean prevalence of Schistosoma japonicum infections was both zero in humans and bovines in 2022, and no S. japonicum infection was detected in O. hupensis snails. These data demonstrated that the endemic status of schistosomiasis continued to decline in China in 2022, with 3 confirmed schistosomiasis patients that had a foreign nationality and all imported from Africa, and the areas of snail habitats remained high. Further improvements in the construction of the schistosomaisis surveillance and forecast system, and reinforcement of O. hupensis survey and control are required to prevent the re-emerging schistosomiasis.

[Progress of schistosomiasis control in People's Republic of China in 2021].

This report presented the endemic status of schistosomiasis and analyzed the data collected from the national schistosomiasis prevention and control system and national schistosomiasis surveillance sites in the People's Republic of China at a national level in 2021. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to consolidate the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan, Hubei, Anhui, Jiangxi and Hunan provinces maintained the criteria of transmission control by the end of 2021. A total of 451 counties (cites, districts) were found to be endemic for schistosomiasis in China in 2021, with 27 571 endemic villages covering 73 250 600 people at risk of infections. Among the 451 endemic counties (cities, districts), 75.17% (339/451), 22.17% (100/451) and 2.66% (12/451) achieved the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2021, 29 037 cases with advanced schistosomiasis were documented in China. In 2021, 4 405 056 individuals received serological tests and 72 937 were sero-positive. A total of 220 629 individuals received stool examinations and 3 were positive. In 2021, snail survey was performed in 19 291 endemic villages in China and Oncomelania snails were found in 7 026 villages, accounting for 36.42% of all surveyed villages, with 12 villages identified with emerging snail habitats. Snail survey was performed at an area of 686 574.46 hm2 and 191 159.91 hm2 snail habitats were found, including 1 063.08 hm2 emerging snail habitats and 5 113.87 hm2 reemerging snail habitats. In 2021, 525 878 bovines were raised in the schistosomiasis endemic areas of China, and 115 437 received serological examinations, with 231 positives detected. Among the 128 719 bovines received stool examinations, no positives were identified. In 2021, there were 19 927 schistosomiasis patients receiving praziquantel chemotherapy, and 729 113 person-time individuals and 256 913 herd-time bovines were given expanded chemotherapy. In 2021, snail control with chemicals was performed in 117 372.74 hm2 snail habitats, and the actual area of chemical treatment was 65 640.50 hm2, while environmental improvements were performed in snail habitats covering an area of 1 244.25 hm2. Data from the national schistosomiasis surveillance sites of China showed that the mean prevalence of Schistosoma japonicum infections were both zero in humans and bovines in 2021, and no S. japonicum infection was detected in snails. The results demonstrate that the overall endemic status of schistosomiasis remained at a low level in China in 2021; however, the progress towards schistosomiasis elimination was slowed and the areas of snail habitats rebounded mildly. Strengthening researches on snail diffusion and control, and improving schistosomiasis surveillance and forecast are recommended to prevent reemerging schistosomiasis.

[Endemic situation of schistosomiasis in Suzhou City from 2010 to 2020].

OBJECTIVE: To analyze the endemic status of schistosomiasis in Suzhou City from 2010 to 2020, so as to provide the evidence for formulating the future schistosomiasis control strategy. METHODS: The data pertaining to the endemic status of schistosomiasis in Suzhou City from 2010 to 2020 were retrieved from the annual schistosomiasis control report, the information management platform of schistosomiasis (parasitic diseases) in Jiangsu Province and the Parasitic Diseases Control Information Management System of Chinese Center for Disease Control and Prevention, including snail survey data, snail control data and schistosomiasis examination data, and were retrospectively reviewed. Differences of proportions were tested for statistical significance with chi-square test, and the trends in proportions were evaluated using the chi-square test for trends. RESULTS: Elimination of schistosomiasis was achieved in Suzhou City in 2018, and there were 3.528 9 million residents living in schistosomiasis-endemic villages of 81 townships in 9 counties. A total of 707 600 labor-days were used for snail survey in 11 586 village-times in Suzhou City from 2010 to 2020, covering 18 572.73 hm2, and snail habitats were detected with an area of 68.61 hm2, including emerging snail habitats of 37.30 hm2. A total of 23 144 snails were dissected, and no Schistosoma japonicum infection was detected. Reemerging and emerging snail habitats were predominantly found in inlands. During the period from 2010 to 2020, snail control was performed in Suzhou City for 71 000 labor-times, and snail control was done covering 269.34 hm2 through chemical treatment and covering 3.48 hm2 through environmental improvements. A total of 674 002 person-times received serological tests for S. japonicum infections in Suzhou City from 2010 to 2020, with seroprevalence of 0.38%, and a total of 33 835 person-times received stool examinations, with no egg-positives identified. The sero-prevalence of S. japonicum infections appeared an overall tendency towards a rise in Suzhou City from 2010 to 2020 (χ2 = 129.48, P < 0.001). The sero-prevalence of S. japonicum infections appeared high among local residents in 2016, and remained stable in other years, while the sero-prevalence of S. japonicum infections appeared an overall tendency towards a rise among mobile populations (χ2 = 54.11, P < 0.001). There were 278 800 and 175 202 serological tests among local residents and mobile populations in Suzhou City from 2013 to 2020, and 0.50% and 0.35% sero-prevalence rates were detected, respectively. The sero-prevalence of S. japonicum infections was significantly higher among local residents than among mobile populations in Suzhou City (χ2= 54.76, P < 0.001). CONCLUSIONS: There is a risk of rebound of schistosomiasis in Suzhou City. Integrated control should be reinforced to prevent the risk of rebound of schistosomiasis in Suzhou City.

[Epidemiological trends of schistosomiasis in Poyang County of Jiangxi Province from 2004 to 2020 based on the Joinpoint regression model].

OBJECTIVE: To analyze the dynamic changes of schistosomiasis in Poyang County of Jiangxi Province from 2004 to 2020, so as to provide insight into the development of the schistosomiasis elimination strategy. METHODS: Schistosomiasis control data were captured from Poyang County from 2004 to 2020, and the epidemiological data of schistosomiasis were collected from national schistosomiasis surveillance sites in Poyang County from 2005 to 2020. The endemic status of schistosomiasis was analyzed in Poyang County from 2004 to 2020, and a Joinpoint regression analysis was performed to investigate the trends of schistosomiasis in Poyang County from 2004 to 2020. RESULTS: The sero-prevalence and egg-prevalence of human Schistosoma japonicum infections reduced from 24.39% (24 976/102 397) and 4.53% (259/5 721) in 2004 to 5.37% (2 421/45 100) [annual percent change (APC) = average annual percent change (AAPC) = -8.64%] and 0 (0/3 963) in 2020 (APC = AAPC = -32.07%) in Poyang County, and the trends were both significant (both P < 0.01). The sero-prevalence of S. japonicum infections reduced from 1.21% (294/24 332) in bovines in 2013 to 0.58% (35/5 999) in 2020 in Poyang County, with one turning point (AAPC = -8.20%, P > 0.05). There were no townships or villages with emerging snail habitats in Poyang County from 2004 to 2020, and there were three turning points of trend in the proportion of snail areas detected in total snail areas (AAPC = -2.30%, P > 0.01). The sero-prevalence and adjusted prevalence of S. japonicum infections reduced from 60.82% (742/1 220) and 10.16% (124/1 220) in local residents in 2005 to 5.73% (70/1 221) and 0 in 2020 in national schistosomiasis surveillance sites of Poyang County, and the trends for sero-prevalence (APC = AAPC = 17.47%, P < 0.01) and adjusted prevalence of S. japonicum infections (APC = AAPC = -44.92%, P < 0.01) were both statistically significant. S. japonicum infections were identified in 10 (2005) and 2 local livestock (2007), with prevalence of 10.00% (10/100) and 13.33% (2/15), respectively, and S. japonicum infections were detected in snails in 2008 and 2009; however, no positive samples of mixed O. hupensis were detected by loop-mediated isothermal amplification. CONCLUSIONS: The endemic situation of schistosomiasis control had remarkably reduced in Poyang County from 2004 to 2020; however, there are still challenges for consolidating schistosomiasis control achievements and even elimination of schistosomiasis.

Endemic situation of schistosomiasis in Suzhou City from 2010 to 2020 / 中国血吸虫病防治杂志

Objective To analyze the endemic status of schistosomiasis in Suzhou City from 2010 to 2020, so as to provide the evidence for formulating the future schistosomiasis control strategy. Methods The data pertaining to the endemic status of schistosomiasis in Suzhou City from 2010 to 2020 were retrieved from the annual schistosomiasis control report, the information management platform of schistosomiasis (parasitic diseases) in Jiangsu Province and the Parasitic Diseases Control Information Management System of Chinese Center for Disease Control and Prevention, including snail survey data, snail control data and schistosomiasis examination data, and were retrospectively reviewed. Differences of proportions were tested for statistical significance with chi-square test, and the trends in proportions were evaluated using the chi-square test for trends. Results Elimination of schistosomiasis was achieved in Suzhou City in 2018, and there were 3.528 9 million residents living in schistosomiasis-endemic villages of 81 townships in 9 counties. A total of 707 600 labor-days were used for snail survey in 11 586 village-times in Suzhou City from 2010 to 2020, covering 18 572.73 hm2, and snail habitats were detected with an area of 68.61 hm2, including emerging snail habitats of 37.30 hm2. A total of 23 144 snails were dissected, and no Schistosoma japonicum infection was detected. Reemerging and emerging snail habitats were predominantly found in inlands. During the period from 2010 to 2020, snail control was performed in Suzhou City for 71 000 labor-times, and snail control was done covering 269.34 hm2 through chemical treatment and covering 3.48 hm2 through environmental improvements. A total of 674 002 person-times received serological tests for S. japonicum infections in Suzhou City from 2010 to 2020, with seroprevalence of 0.38%, and a total of 33 835 person-times received stool examinations, with no egg-positives identified. The sero-prevalence of S. japonicum infections appeared an overall tendency towards a rise in Suzhou City from 2010 to 2020 (χ2 = 129.48, P < 0.001). The sero-prevalence of S. japonicum infections appeared high among local residents in 2016, and remained stable in other years, while the sero-prevalence of S. japonicum infections appeared an overall tendency towards a rise among mobile populations (χ2 = 54.11, P < 0.001). There were 278 800 and 175 202 serological tests among local residents and mobile populations in Suzhou City from 2013 to 2020, and 0.50% and 0.35% sero-prevalence rates were detected, respectively. The sero-prevalence of S. japonicum infections was significantly higher among local residents than among mobile populations in Suzhou City (χ2= 54.76, P < 0.001). Conclusions There is a risk of rebound of schistosomiasis in Suzhou City. Integrated control should be reinforced to prevent the risk of rebound of schistosomiasis in Suzhou City.

Progress of schistosomiasis control in People’s Republic of China in 2021 / 中国血吸虫病防治杂志

This report presented the endemic status of schistosomiasis and analyzed the data collected from the national schistosomiasis prevention and control system and national schistosomiasis surveillance sites in the People’s Republic of China at a national level in 2021. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to consolidate the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan, Hubei, Anhui, Jiangxi and Hunan provinces maintained the criteria of transmission control by the end of 2021. A total of 451 counties (cites, districts) were found to be endemic for schistosomiasis in China in 2021, with 27 571 endemic villages covering 73 250 600 people at risk of infections. Among the 451 endemic counties (cities, districts), 75.17% (339/451), 22.17% (100/451) and 2.66% (12/451) achieved the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2021, 29 037 cases with advanced schistosomiasis were documented in China. In 2021, 4 405 056 individuals received serological tests and 72 937 were sero-positive. A total of 220 629 individuals received stool examinations and 3 were positive. In 2021, snail survey was performed in 19 291 endemic villages in China and Oncomelania snails were found in 7 026 villages, accounting for 36.42% of all surveyed villages, with 12 villages identified with emerging snail habitats. Snail survey was performed at an area of 686 574.46 hm2 and 191 159.91 hm2 snail habitats were found, including 1 063.08 hm2 emerging snail habitats and 5 113.87 hm2 reemerging snail habitats. In 2021, 525 878 bovines were raised in the schistosomiasis endemic areas of China, and 115 437 received serological examinations, with 231 positives detected. Among the 128 719 bovines received stool examinations, no positives were identified. In 2021, there were 19 927 schistosomiasis patients receiving praziquantel chemotherapy, and 729 113 person-time individuals and 256 913 herd-time bovines were given expanded chemotherapy. In 2021, snail control with chemicals was performed in 117 372.74 hm2 snail habitats, and the actual area of chemical treatment was 65 640.50 hm2, while environmental improvements were performed in snail habitats covering an area of 1 244.25 hm2. Data from the national schistosomiasis surveillance sites of China showed that the mean prevalence of Schistosoma japonicum infections were both zero in humans and bovines in 2021, and no S. japonicum infection was detected in snails. The results demonstrate that the overall endemic status of schistosomiasis remained at a low level in China in 2021; however, the progress towards schistosomiasis elimination was slowed and the areas of snail habitats rebounded mildly. Strengthening researches on snail diffusion and control, and improving schistosomiasis surveillance and forecast are recommended to prevent reemerging schistosomiasis.

Epidemiological trends of schistosomiasis in Poyang County of Jiangxi Province from 2004 to 2020 based on the Joinpoint regression model / 中国血吸虫病防治杂志

Objective To analyze the dynamic changes of schistosomiasis in Poyang County of Jiangxi Province from 2004 to 2020, so as to provide insight into the development of the schistosomiasis elimination strategy. Methods Schistosomiasis control data were captured from Poyang County from 2004 to 2020, and the epidemiological data of schistosomiasis were collected from national schistosomiasis surveillance sites in Poyang County from 2005 to 2020. The endemic status of schistosomiasis was analyzed in Poyang County from 2004 to 2020, and a Joinpoint regression analysis was performed to investigate the trends of schistosomiasis in Poyang County from 2004 to 2020. Results The sero-prevalence and egg-prevalence of human Schistosoma japonicum infections reduced from 24.39% (24 976/102 397) and 4.53% (259/5 721) in 2004 to 5.37% (2 421/45 100) [annual percent change (APC) = average annual percent change (AAPC) = −8.64%] and 0 (0/3 963) in 2020 (APC = AAPC = −32.07%) in Poyang County, and the trends were both significant (both P < 0.01). The sero-prevalence of S. japonicum infections reduced from 1.21% (294/24 332) in bovines in 2013 to 0.58% (35/5 999) in 2020 in Poyang County, with one turning point (AAPC = −8.20%, P > 0.05). There were no townships or villages with emerging snail habitats in Poyang County from 2004 to 2020, and there were three turning points of trend in the proportion of snail areas detected in total snail areas (AAPC = −2.30%, P > 0.01). The sero-prevalence and adjusted prevalence of S. japonicum infections reduced from 60.82% (742/1 220) and 10.16% (124/1 220) in local residents in 2005 to 5.73% (70/1 221) and 0 in 2020 in national schistosomiasis surveillance sites of Poyang County, and the trends for sero-prevalence (APC = AAPC = 17.47%, P < 0.01) and adjusted prevalence of S. japonicum infections (APC = AAPC = −44.92%, P < 0.01) were both statistically significant. S. japonicum infections were identified in 10 (2005) and 2 local livestock (2007), with prevalence of 10.00% (10/100) and 13.33% (2/15), respectively, and S. japonicum infections were detected in snails in 2008 and 2009; however, no positive samples of mixed O. hupensis were detected by loop-mediated isothermal amplification. Conclusions The endemic situation of schistosomiasis control had remarkably reduced in Poyang County from 2004 to 2020; however, there are still challenges for consolidating schistosomiasis control achievements and even elimination of schistosomiasis.

[Surveillance of schistosomiasis in Xiaogan City from 2016 to 2020].

OBJECTIVE: To analyze the surveillance data of schistosomiasis in Xiaogan City, Hubei Province from 2016 to 2020, so as to provide the scientific evidence for understanding the epidemiological changes of schistosomiasis and evaluating the schistosomiasis control strategy. METHODS: A total of 16 surveillance sites were selected in the schistosomiasis endemic foci of Xiaogan City from 2016 to 2020, where Schistosoma japonicum infections in humans, livestock and Oncomelania snails and the schistosomiasis transmission risk were monitored. The schistosomiasis surveillance results were descriptively analyzed. RESULTS: During the period from 2016 to 2020, there was no schistosomiasis emergency epidemic in Xiaogan City. A total of 660 sero-positive individuals were identified in Xiaogan City during the 5-year period, and the seroprevalence of S. japonicum infections reduced from 2.08% in 2016 to 0.97% in 2020. Higher seroprevalence of S. japonicum infections was detected in men than in women, and in individuals at ages of over 60 years than in those at other age groups; however, no egg-positives were detected in humans or livestock. The mean density of living snails was 0.05 to 0.06 snails/0.1 m2 during the 5-year period, and the occurrence of frames with snails increased from 2.99% in 2016 to 3.92% in 2020; however, no S. japonicum infection was found in snails. CONCLUSIONS: The endemic situation of schistosomiasis remarkably decreases in Xiaogan City during the period from 2016 through 2020. Further improvements of the sensitive and effective schistosomiasis surveillance system are required with an emphasis on the monitoring of the schistosomiasis transmission risk and management of floating populations.

[Endemic status of schistosomiasis in People's Republic of China in 2020].

This report presented the endemic status of schistosomiasis in the People's Republic of China at a national level in 2020, and analyzed the data collected from the national schistosomiasis prevention and control system and national schistosomiasis surveillance sites. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to consolidate the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan, Hubei, Anhui, Jiangxi and Hunan provinces maintained the criteria of transmission control by the end of 2020. A total of 450 counties (cites, districts) were found to be endemic for schistosomiasis in China, with 28 376 endemic villages covering 71 370 400 people at risk of infections. Among the 450 endemic counties (cities, districts), 74.89% (337/450), 21.87% (98/450) and 3.33% (15/450) achieved the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2020, 29 517 cases with advanced schistosomiasis were documented in China. In 2020, 11 117 655 individuals received inquiry examinations and 1 798 580 were positive; 5 263 082 individuals received serological tests and 83 179 were sero-positive. A total of 273 712 individuals received stool examinations and 3 were positive, including one case of acute schistosomiasis. In 2020, snail survey was performed in 19 733 endemic villages in China and Oncomelania snails were found in 7 309 villages, accounting for 37.04% of all surveyed villages, with 15 villages identified with emerging snail habitats. Snail survey covered an area of 736 984.13 hm2 and 206 125.22 hm2 snail habitats were found, including 1 174.67 hm2 emerging snail habitats and 1.96 hm2 habitats with infected snails. In 2020, 544 424 bovines were raised in the schistosomiasis-endemic areas of China, and 147 887 received serological examinations, with 326 positives detected, while 130 673 bovines received stool examinations, with no positives identified. In 2020, there were 19 214 patients with schistosomiasis receiving praziquantel chemotherapy, and 964 103 person-time individuals and 266 280 herd-time bovines were given expanded chemotherapy. In 2020, molluscicide treatment was performed in 136 141.92 hm2 snail habitats, and the actual area of chemical treatment was 71 980.22 hm2, while environmental improvements were performed in snail habitats covering an area of 1 464.03 hm2. Data from the national schistosomiasis surveillance sites of China showed that the mean prevalence of Schistosoma japonicum infections were both zero in humans and bovines in 2020, and no S. japonicum infection was detected in snails. The results demonstrate that the overall endemic status of schistosomiasis remains at a low level in China and the goal of the National Thirteenth Five-Year Plan for Schistosomiasis Control was achieved as scheduled; however, the endemic situation of schistosomiasis rebounded in local areas. Precision schistosomiasis control and intensified monitoring of the endemic situation and transmission risk of schistosomiasis are required to be performed to facilitate the progress towards elimination of schistosomiasis steadily.

[Longitudinal surveillance of schistosomiasis in hilly regions of Sichuan Province from 2015 to 2019].

OBJECTIVE: To investigate the changes in the endemic situation of schistosomiasis in national surveillance sites of Sichuan Province, so as to provide the scientific evidence for formulating the schistosomiasis elimination strategy. METHODS: From 2015 to 2019, 63 national schistosomiasis surveillance sites were assigned in Sichuan Province, in which Schistosoma japonicum infections were monitored in humans, livestock, wild feces and snails. The monitoring data were descriptively analyzed. RESULTS: A total of 94 119 person-time local residents were serologically screened for S. japonicum infections in 63 national surveillance sites of Sichuan Province from 2015 to 2019, with sero-prevalence rates ranging from 1.28% to 3.11%, and the sero-positives were predominantly detected in local residents at ages of over 50 years and in farmers. A total of 94 119 person-time mobile populations were serologically screened for S. japonicum infections in the national surveillance sites during the 5-year period, with sero-prevalence of 1.10% to 1.59%. There were no egg-positives identified in either local residents or mobile populations. Among the 6 126 herd-time livestock detected, no egg-positives were identified, and no S. japonicum infection was detected in the 205 wild feces. Snail survey was performed covering an area of 8 484.08 hm2, and 724.80 hm2 snail habitats were identified, including 2.43 hm2 emerging snail habitats and 63.00 hm2 re-emerging snail habitats. The mean occurrence of frames with snails was 6.87% to 19.63%, and the mean density of living snails was 0.18 to 0.62 snails/0.1 m2 in the national surveillance sites of Sichuan Province from 2015 to 2019; however, no S. japonicum infection was detected in snails. CONCLUSIONS: The endemic situation of schistosomiasis has reduced to the lowest level in Sichuan Province; however, there is a rise in snail habitats, and there is still a risk of schistosomiasis resurgence. Further improvements of the surveillance system for schistosomiasis are required to achieve the goal of schistosomiasis elimination in Sichuan Province as soon as possible.

Surveillance of schistosomiasis in Xiaogan City from 2016 to 2020 / 中国血吸虫病防治杂志

Objective To analyze the surveillance data of schistosomiasis in Xiaogan City, Hubei Province from 2016 to 2020, so as to provide the scientific evidence for understanding the epidemiological changes of schistosomiasis and evaluating the schistosomiasis control strategy. Methods A total of 16 surveillance sites were selected in the schistosomiasis endemic foci of Xiaogan City from 2016 to 2020, where Schistosoma japonicum infections in humans, livestock and Oncomelania snails and the schistosomiasis transmission risk were monitored. The schistosomiasis surveillance results were descriptively analyzed. Results During the period from 2016 to 2020, there was no schistosomiasis emergency epidemic in Xiaogan City. A total of 660 sero-positive individuals were identified in Xiaogan City during the 5-year period, and the seroprevalence of S. japonicum infections reduced from 2.08% in 2016 to 0.97% in 2020. Higher seroprevalence of S. japonicum infections was detected in men than in women, and in individuals at ages of over 60 years than in those at other age groups; however, no egg-positives were detected in humans or livestock. The mean density of living snails was 0.05 to 0.06 snails/0.1 m2 during the 5-year period, and the occurrence of frames with snails increased from 2.99% in 2016 to 3.92% in 2020; however, no S. japonicum infection was found in snails. Conclusions The endemic situation of schistosomiasis remarkably decreases in Xiaogan City during the period from 2016 through 2020. Further improvements of the sensitive and effective schistosomiasis surveillance system are required with an emphasis on the monitoring of the schistosomiasis transmission risk and management of floating populations.

Endemic status of schistosomiasis in People’s Republic of China in 2020 / 中国血吸虫病防治杂志

This report presented the endemic status of schistosomiasis in the People’s Republic of China at a national level in 2020, and analyzed the data collected from the national schistosomiasis prevention and control system and national schistosomiasis surveillance sites. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to consolidate the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan, Hubei, Anhui, Jiangxi and Hunan provinces maintained the criteria of transmission control by the end of 2020. A total of 450 counties (cites, districts) were found to be endemic for schistosomiasis in China, with 28 376 endemic villages covering 71 370 400 people at risk of infections. Among the 450 endemic counties (cities, districts), 74.89% (337/450), 21.87% (98/450) and 3.33% (15/450) achieved the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2020, 29 517 cases with advanced schistosomiasis were documented in China. In 2020, 11 117 655 individuals received inquiry examinations and 1 798 580 were positive; 5 263 082 individuals received serological tests and 83 179 were sero-positive. A total of 273 712 individuals received stool examinations and 3 were positive, including one case of acute schistosomiasis. In 2020, snail survey was performed in 19 733 endemic villages in China and Oncomelania snails were found in 7 309 villages, accounting for 37.04% of all surveyed villages, with 15 villages identified with emerging snail habitats. Snail survey covered an area of 736 984.13 hm2 and 206 125.22 hm2 snail habitats were found, including 1 174.67 hm2 emerging snail habitats and 1.96 hm2 habitats with infected snails. In 2020, 544 424 bovines were raised in the schistosomiasis-endemic areas of China, and 147 887 received serological examinations, with 326 positives detected, while 130 673 bovines received stool examinations, with no positives identified. In 2020, there were 19 214 patients with schistosomiasis receiving praziquantel chemotherapy, and 964 103 person-time individuals and 266 280 herd-time bovines were given expanded chemotherapy. In 2020, molluscicide treatment was performed in 136 141.92 hm2 snail habitats, and the actual area of chemical treatment was 71 980.22 hm2, while environmental improvements were performed in snail habitats covering an area of 1 464.03 hm2. Data from the national schistosomiasis surveillance sites of China showed that the mean prevalence of Schistosoma japonicum infections were both zero in humans and bovines in 2020, and no S. japonicum infection was detected in snails. The results demonstrate that the overall endemic status of schistosomiasis remains at a low level in China and the goal of the National Thirteenth Five-Year Plan for Schistosomiasis Control was achieved as scheduled; however, the endemic situation of schistosomiasis rebounded in local areas. Precision schistosomiasis control and intensified monitoring of the endemic situation and transmission risk of schistosomiasis are required to be performed to facilitate the progress towards elimination of schistosomiasis steadily.

Longitudinal surveillance of schistosomiasis in hilly regions of Sichuan Province from 2015 to 2019 / 中国血吸虫病防治杂志

Objective To investigate the changes in the endemic situation of schistosomiasis in national surveillance sites of Sichuan Province, so as to provide the scientific evidence for formulating the schistosomiasis elimination strategy. Methods From 2015 to 2019, 63 national schistosomiasis surveillance sites were assigned in Sichuan Province, in which Schistosoma japonicum infections were monitored in humans, livestock, wild feces and snails. The monitoring data were descriptively analyzed. Results A total of 94 119 person-time local residents were serologically screened for S. japonicum infections in 63 national surveillance sites of Sichuan Province from 2015 to 2019, with sero-prevalence rates ranging from 1.28% to 3.11%, and the sero-positives were predominantly detected in local residents at ages of over 50 years and in farmers. A total of 94 119 person-time mobile populations were serologically screened for S. japonicum infections in the national surveillance sites during the 5-year period, with sero-prevalence of 1.10% to 1.59%. There were no egg-positives identified in either local residents or mobile populations. Among the 6 126 herd-time livestock detected, no egg-positives were identified, and no S. japonicum infection was detected in the 205 wild feces. Snail survey was performed covering an area of 8 484.08 hm2, and 724.80 hm2 snail habitats were identified, including 2.43 hm2 emerging snail habitats and 63.00 hm2 re-emerging snail habitats. The mean occurrence of frames with snails was 6.87% to 19.63%, and the mean density of living snails was 0.18 to 0.62 snails/0.1 m2 in the national surveillance sites of Sichuan Province from 2015 to 2019; however, no S. japonicum infection was detected in snails. Conclusions The endemic situation of schistosomiasis has reduced to the lowest level in Sichuan Province; however, there is a rise in snail habitats, and there is still a risk of schistosomiasis resurgence. Further improvements of the surveillance system for schistosomiasis are required to achieve the goal of schistosomiasis elimination in Sichuan Province as soon as possible.

[Endemic status of schistosomiasis in People's Republic of China in 2019].

This report presented the endemic status of schistosomiasis in the People's Republic of China at a national level in 2019, and analyzed the data collected from the national schistosomiasis prevention and control system and 455 national schistosomiasis surveillance sites. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai, Zhejiang, Fujian, Guangdong and Guangxi continued to consolidate the achievements of schistosomiasis elimination, Sichuan Province achieved transmission interruption, Jiangsu newly achieved the standard of transmission interruption and 5 provinces of Yunnan, Hubei, Anhui, Jiangxi and Hunan maintained transmission control by the end of 2019. There were 450 endemic counties (cities, districts) endemic for schistosomiasis, including 28 500 endemic villages covering 70 667 800 people at risk of infections. Among the 450 endemic counties (citis, districts), 66.89% (301/450), 28.44% (128/450) and 4.67% (21/450) kept the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2019, a total of 30 170 advanced schistosomiasis cases were documented in China. In 2019, a total of 12 090 712 individuals received inquiry examinations and 1 740 764 were positive; 5 158 369 individuals received serological tests and 89 753 were seropositive. A total of 327 475 individuals received stool examinations and 5 were positive, including one case of acute schistosomiasis. In 2019, snail survey was performed in 19 726 endemic villages in China and Oncomelania snails were found in 7 322 villages, accounting for 37.12% of all surveyed villages, with 6 villages with emerging snail habitats. Snail survey covered an area of 585 286.24 hm2 and 174 270.42 hm2 snail habitats were found, including emerging snail habitats of 64.20 hm2; however, no infected snails were identified. In 2019, a total of 605 965 bovines were raised in the schistosomiasis endemic areas of China, and 183 313 received serological examinations, with 1 176 positives detected, while 134 978 bovines received stool examinations, with 7 positives identified. In 2019, there were 28 557 patients with schistosomiasis receiving praziquantel chemotherapy, and expanded chemotherapy was given to 1 008 083 person-times; there were 7 bovines with schistosomiasis receiving praziquantel chemotherapy, and 296 053 herd-times expanded chemotherapy was given to bovines. In 2019, snail habitats at an area of 128 754.26 hm2 were given chemical treatment, and the actual area of chemical treatment was 69 605.55 hm2, while environmental improvements were performed in snail habitats covering an area of 2 847.00 hm2. Data from the 455 national schistosomiasis surveillance sites of China showed that the mean Schistosoma japonicum infection rates were both zero in humans and bovines in 2019, and no infected snails were found. The results demonstrate that the overall endemic situation of schistosomiasis remains at a lower infection level in China; however, there is still a risk of schistosomiasis transmission. To achieve the target set in the National Thirteenth Five-Year Plan for Schistosomiasis Control and consolidate the achievements of schistosomiasis control, precision control on schistosomiasis still needs to be reinforced in China.

[Endemic situation of schistosomiasis in national surveillance sites of Hubei Province from 2015 to 2019].

OBJECTIVE: To analyze the changing tendency in the endemic situation of schistosomiasis in the national surveillance sites of Hubei Province, so as to provide the scientific evidence for facilitating the progress towards the elimination of schistosomiasis in the province. METHODS: According to the National Schistosomiasis Surveillance Scheme (2014 version), a total of 65 national schistosomiasis surveillance sites were assigned in Hubei Province, and the Schistosoma japonicum infections in humans, domestic animals, snails and wild feces were monitored in these national surveillance sites from 2015 to 2019. All data pertaining to the surveillance results were descriptively analyzed. RESULTS: There were 151 159 person-time local residents and 70 928 person-time mobile populations screened for S. japonicum infections in the 65 national surveillance sites of Hubei Province from 2015 to 2019, and the seroprevalance of S. japonicum infections reduced from 3.45% (1 077/31 197) in 2015 to 1.57% (431/27 371) in 2019 among local residents and from 1.06% (98/9 249) in 2015 to 0.81% (116/14 318) in 2019 among mobile populations. During the period from 2015 through 2019, there were 22 egg-positive local residents and 2 egg-positive mobile populations identified in 2015, with 0.07% and 0.02% prevalence rates of S. japonicum infections, respectively. During the 5-year period, a total of 7 025 herd-time domestic animals examined for S. japonicum infections, with no infections detected, and a total of 2 035 wild feces were tested, with no egg-positives identified in the 65 national surveillance sites of Hubei Province. Snail survey was conducted covering 28 767.35 hm2 during the 5-year period, and the area of snail habitats ranged from 1 609.82 to 2 119.81 hm2. The mean density of living snails and occurrence of frames with snails reduced from 0.360 5 snails/0.1 m2 and 11.26% in 2015 to 0.175 9 snails/0.1 m2 and 8.43% in 2019, respectively, and no S. japonicum infection was found in snails during the 5-year period. In addition, no snails were found in the potential schistosomiasis transmission foci in the two national surveillance sites in the Three Gorges Dam. CONCLUSIONS: The overall endemic situation of schistosomiasis appears a tendency towards a decline in Hubei Province during the period from 2015 through 2019; however, the schistosomiasis transmission risk remains. Improving the surveillance system of schistosomiasis and increasing the sensitivity and performance of the surveillance system are required to provide insights into the implementation of precision control strategy and interventions in Hubei Province.

[Endemic situation of schistosomiasis in national surveillance sites of Zhenjiang City from 2015 to 2019].

OBJECTIVE: To analyze the endemic situation of schistosomiasis in national surveillance sites of Zhenjiang City from 2015 to 2019, so as to provide the scientific basis for the consolidation of schistosomiasis control achievements and timely treatment of risk factors. METHODS: A total of 7 national schistosomiasis surveillance sites were assigned in Zhenjiang City from 2015 to 2019. According to the National Scheme for Schistosomiasis Surveillance (2014 version), Schistosoma japonicum infections were monitored in local residents, floating populations and livestock, and snail habitats were surveyed in Zhenjiang City from 2015 to 2019. The results of schistosomaisis surveillance in Zhenjiang City from 2015 to 2019 were analyzed. RESULTS: There were 15 848 and 7 779 person-times of local residents and floating populations receiving serological screening of schistosomiasis in 7 national surveillance sites of Zhenjiang City from 2015 to 2019, and the seroprevalence rates were 0.95% to 1.75% and 0.14% to 0.91% among local residents and floating populations, respectively; however, no egg-positives were identified. A total of 1 885 herd-times of livestock were detected, and no egg-positives were found. During the 5-year period, snail survey was conducted in snail habitats and suspected snail habitats covering 3 333.79 hm2, and there were 108.71 hm2 snail habitats identified, including 50.97 hm2 re-emerging snail habitats. The density of living snails was 0.007 to 0.125 snails/0.1 m2 from 2015 to 2019, which showed a trend for a rise year by year (χ2 = 2 732.626, P < 0.01); however, no S. japonicum infections were detected in snails. CONCLUSIONS: The endemic situation of schistosomiasis has been maintained at a low level in Zhenjiang City, and schistosomiasis control achievements are consolidated. However, snails are widely distributed in the city, and there are still risk factors associated with schistosomiasis transmission. Further integrated interventions require to be reinforced to timely manage the risk of transmission of schistosomiasis and promote the progress towards elimination of schistosomiasis.

[Endemic situation of schistosomiasis in national surveillance sites of Hunan Province from 2015 to 2019].

OBJECTIVE: To analyze the changes in the endemic situation of schistosomiasis in national surveillance sites of Hunan Province, so as to provide scientific basis for the development of the schistosomiasis elimination programme in the province. METHODS: According to the requirements of the National Guidelines for Schistosomiasis Surveillance in China (2014 version), a total of 41 national schistosomiasis surveillance sites were assigned in all disease-endemic counties (districts) across Hunan Province. During the period between 2015 and 2019, Schistosoma japonicum infections were monitored in local residents, mobile populations and livestock, and snail status was monitored. The morbidity due to schistosomiasis and snail status was compared between years. RESULTS: The sero-prevalence of S. japonicum infections was 2.57% and 1.56% in local residents and mobile populations in national surveillance sites of Hunan Province from 2015 to 2019, respectively, and the sero-prevalence appeared a tendency towards a decline over years. A higher sero-prevalence rate of S. japonicum infections was seen in men than in women (P < 0.01). During the 5-year study period, the sero-prevalence rate of human S. japonicum infections appeared a tendency towards a decline in the marshland, embankment, inner embankment and hilly types of endemic areas over years. There were 44 and 19 egg -positives detected in local residents and 5 and 1 egg-positives in mobile populations in 2015 and 2016 respectively. A total of 9 346 domestic animals were monitored from 2015 to 2019, and 6 egg-positives were detected in 2015 and 2016 (all were bovine). A total of 0.155 billion m2 settings were surveyed from 2015 to 2019, and the mean density of living snails appeared a tendency towards a decline over years, with a 45.79% reduction in 2019 as compared to 2015. However, no S. japonicum infections were identified in snails during the 5-year period. A total of 1 469 mixed snail samples were detected using loop-mediated isothermal amplification (LAMP), and 6 positive snail samples were identified in 2015 (one sample) and 2017 (5 samples). CONCLUSIONS: The overall endemic situation of schistosomiasis appears a tendency towards a decline in Hunan Province, and the prevalence of S. japonicum infections is at a low level in humans and livestock; however, there is still a risk of schistosomiasis transmission. Improvements of health education, intensification of schistosomiasis examinations in mobile populations and reinforcement of the surveillance-response system is required to consolidate the achievements of schistosomiasis control in Hunan Province.

[Endemic situation of schistosomiasis in national surveillance sites of Anhui Province from 2015 to 2018].

OBJECTIVE: To analyze the endemic situation of schistosomiasis in national surveillance sites of Anhui Province from 2015 to 2018, so as to provide scientific evidence for schistosomiasis control and prevention in Anhui Province. METHODS: According to the National Schistosomiasis Surveillance Programme (2014 version), a total of 51 national schistosomiasis surveillance sites were assigned in Anhui Province in 2015, and Schistosoma japonicum infections in humans and livestock and snail distribution were monitored from 2015 to 2018. RESULTS: A total of 89 638 local residents and 42 609 mobile populations received serological screening of schistosomiasis in 51 national surveillance sites of Anhui Province from 2015 to 2018, and the sero-prevalence of S. japonicum infections was 1.41% to 3.69% in local residents and 0.84% to 2.13% in mobile populations, respectively. There were 5 egg-positive local residents and 1 egg-positive mobile populations detected in 2015, with occupations of farmers and fishermen. There were 6 405 livestock detected for S. japonicum infections, and no egg-positives were identified. Among an area of 12 661 hm2 surveyed in the national schistosomiasis surveillance sites of Anhui Province from 2015 to 2018, the areas of snail habitats were 2 461.27 to 2 628.96 hm2, andthemeandensityoflivingsnailswas 0.3757 to 0.4330 snails/0.1 m2, with no S. japonicum infections identified in snails. CONCLUSIONS: The endemic situation of schistosomiasis is at a low level in Anhui Province; however, the risk of schistosomiasis transmission remains in local regions of the province. The construction of the surveillance-responsesystemshouldbereinforcedtoconsolidatetheachievementsofschistosomiasis control in Anhui Province.