关键词: 血吸虫病, 疫情, 分布, 消除

Abstract:

Objective To analyze the schistosomiasis epidemic situation post-reassessment in five provinces (Municipality, Autonomous Region) that have achieved schistosomiasis elimination as of the end of 2023, including Shanghai, Zhejiang, Fujian, Guangdong, and Guangxi, and to provide scientific evidence for further control and elimination of schistosomiasis. Methods The data relevant to schistosomiasis control and including examinations in residents and livestock, snail survey and molluscaciding in endemic counties, cities, and districts of Shanghai, Zhejiang, Fujian, Guangdong, and Guangxi in 2015 to 2023 were collected from National Schistosomiasis Control and Prevention Information Management System, as well as schistosomiasis case report information from China CDC management System of Systematic Surveillance Reports of Disease Prevention and Control Information. The data collected were analyzed. Results From 2015 to 2023, 64 cases of schistosomiasis were reported in five provinces, including 50 cases of schistosomiasis japonica imported from other provinces in China and 14 cases of African schistosomiasis imported from other countries. Schistosomiasis eleimination achieved in 112 historically endemic counties in the five provinces, where the number of schistosomiasis cases decreased from 1 038 in 2015 to 780 in 2023, showing a 24.86% reduction, and no local infection cases were reported. The existing schistosomiasis cases were comprised of local advanced schistosomiasis (1 028 cases) and imported schistosomiasis cases (10 cases), all of which were distributed in Zhejiang Province. The overall serological tests positive rate was 0.59% in 2015 (827/141 204) to 0.17% in 2023 (228/136 002). Among them, the average sero-positive rate in Changshan County of Zhejiang Province was the highest (1.87%, 1 469/78 484). The number of bovines decreased by 51.93% from 125 362 in 2015 to 60 267 in 2023, 29 298 received serological examinations, with 8 positive detected in 2015 only. A total of 4 284 bovines received stool examinations, with no positives identified. From 2015 to 2023, snail distribution was reported in 38 counties. The actual snail habitats increased from 75.26 hm² (1 hm² = 10 000 m²) in 2015 to 86.35 hm² in 2023. Hill and water network types were the main snail habitat types. From 2015 to 2018, the area of emerging snail habitats increased annually, peaking at 12.57 hm² in 2018, while from 2019 to 2023, the area was fluctuated and decreased to 0.56 hm² by 2023. From 2015 to 2023, molluscicide treatment was annually performed in 2 076.95 hm² to 2 307.35 hm² snail habitats, 19 735.08 hm² snail habitats received molluscicide treatment in total throughout the 9 years. Environmental improvements were performed in snail habitats covering an area of 110.63 hm², among which Guangdong Province had the largest improved area (58.53 hm², 52.91%). Conclusion The five provinces have been continueing to consolidate the achievements of schistosomiasis elimination. It is recommended that the five provinces persist the control concept of surveying and eliminating remaining snails and preventing exogenous sources of infection, underline the issue of emerging and reemerging snail habitats, and continuously strengthen risk surveillance and epidemic information management to consolidate the achievements in schistosomiasis elimination.

Key words: Schistosomiasis, Endemic situation, Distribution, Elimination