关键词: 血吸虫病, 传播阻断, 防控策略, 江西省

Abstract:

Objective To analyze the implementation of and evaluate the effectiveness of the schistosomiasis control strategy in Jiangxi Province during the stage of transmission interruption from 2016 to 2023, so as to provide insights into achieving the goal of schistosomiasis elimination. Methods The integrated strategy with an emphasis on management of the source of Schistosoma japonicum infection was implemented in Jiangxi Province from 2016 to 2023. Schistosomiasis control data were collected from 39 endemic counties (cities, districts) in Jiangxi Province, including examinations and chemotherapy for humans and livestock, snail control, health education, and multi-sectorial integrated control projects, and schistosomiasis surveillance data were extracted from the Information Management System for Parasitic Disease Prevention and Control. All statistical analyses were performed using the software SPSS 25.0, and the implementation of snail surveys and control, examinations and chemotherapy for schistosomiasis, disease surveillance, and integrated control measures was descriptively analyzed. Differences of proportions were tested for statistical significance with chi-square test. Results A total of 116 million Chinese Yuan were allocated to the schistosomiasis control programme in Jiangxi Province from 2016 to 2023, where the demonstration and promotion areas for the integrated strategy with an emphasis on management of the source of S. japonicum infection were built in 17 key schistosomiasis-endemic counties (cities/districts). As of the end of 2023, among 39 endemic counties (cities, districts), 24 achieved the criteria of schistosomiasis elimination and 15 achieved transmission interruption. Serological tests were performed for S. japonicum infections among 4 570 976 person-times in Jiangxi Province from 2016 to 2023, with annual seroprevalence of S. japonicum infections ranging from 1.68% to 3.21% (χ² = 4 833.74, P < 0.01), and the seroprevalence of S. japonicum infections appeared a tendency towards a decline among local residents (χ² = 360.88, P < 0.05) and floating populations (χ² = 156.82, P < 0.05) over years, with reductions of 47.88% and 47.58%, respectively. Parasitological tests were performed for schistosomiasis among 333 270 person-times, with no egg-positives detected since 2020. The number of current schistosomiasis cases decreased from 12 212 in 2016 to 5 454 in 2023 in Jiangxi Province, with a reduction of 55.34%, and the current schistosomiasis cases were all advanced cases since 2021, appearing a tendency towards a slow decline. The number of fenced livestock decreased from 101 630 in 2016 to 64 695 in 2023 in Jiangxi Province, with a reduction of 36.34%, with no egg-positive detected in bovines since 2020; however, there were two sites identified with S. japonicum infected wild stool samples in 2021 and one site with S. japonicum infected wild stool samples in 2023, including two hare stool samples and one bovine stool sample. No S. japonicum infection was detected in snails during the 8-year period from 2016 to 2023; however, the actual area of snail habitats increased by 8.69%, with an 8.48% increase in the area of snail habitats in marshland and lake regions and a 15.35% increase in hilly and marshland regions, respectively. The area of emerging snail habitats was 25.38 hm² (1 hm² = 10 000 m²), which was mainly detected in 2020 (0.89 hm²), 2021 (11.69 hm²), and 2022 (12.8 hm²). Results from schistosomiasis surveillance showed an 88.00% decline in the average density of living snails in national surveillance sites in Jiangxi Province. Conclusion The prevalence of schistosomiasis is low and appeared a tendency towards a decline in Jiangxi Province. However, a high priority requires to be given to control of emerging and re-emerging snails, wildlife surveillance, and management of cross-regional population mobility.

Key words: Schistosomiasis, Transmission interruption, Control strategy, Jiangxi Province