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.
［摘要］ 目的 分析四川省国家血吸虫病监测点疫情变化, 为山丘型流行区制定消除阶段的血吸虫病防控策略提供 依据。方法 2015—2019年, 在四川省设立63个国家血吸虫病监测点, 开展人群和家畜血吸虫病病情、野粪污染、钉 螺分布监测, 并对监测结果进行描述性分析。结果 2015—2019年, 四川省63个国家血吸虫病监测点累计开展本地 人群血清学筛查94 119人·次, 血检阳性率为1.28%~3.11%, 血检阳性者以50岁以上居民和农民为主; 累计开展流动 人群血清学筛查66 915人·次, 血检阳性率为1.10%~1.59%; 均未发现病原学检查阳性者。5 年累计调查各类家 畜6 126头·次, 均未发现粪检阳性病畜。5年累计检测各类野粪205份, 未发现血吸虫阳性。2015—2019年累计开展 钉螺调查8 484.08 hm2, 查出有螺面积724.80 hm2, 其中新发现有螺面积2.43 hm2、复现有螺面积63.00 hm2; 逐年平均有 螺框出现率为6.87%~19.63%, 平均活螺密度为0.18~0.62只/0.1 m2, 5年间均未发现血吸虫感染性钉螺。结论 四川 省血吸虫病流行水平已降至历史最低水平, 但钉螺分布环境有所增加, 血吸虫病疫情发生反复的风险仍然存在。今 后仍应继续加强血吸虫病监测体系建设, 以期尽早实现消除血吸虫病的目标。.
Keywords: Endemic situation; Hilly region; Schistosomiasis; Sichuan Province; Surveillance.