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.
［摘要］ 目的 分析湖南省国家血吸虫病监测点疫情变化趋势, 为制定全省血吸虫病消除策略提供依据。方法 按照《全国血吸虫病监测方案 (2014 年版) 》要求, 在湖南省 41 个血吸虫病流行县 (市、区) 设国家血吸虫病监测点。2015-2019 年开展本地人群、流动人群、家畜血吸虫感染监测和螺情监测, 对各年病情和螺情数据进行分析。结果 2015-2019 年, 湖南省国家血吸虫病监测点本地居民和流动人口血吸虫病血检阳性率分别为 2.57% 和 1.56%, 均呈逐年降低趋势, 男性血检阳性率均高于女性 (P < 0.01); 5 年间, 洲滩型、洲垸型、垸内型和丘陵型 4 种流行区人群血检阳性率均呈逐年下降趋势。2015-2019 年, 2015 年和 2016 年分别检出 44 例和19例本地人群粪检阳性、5例和 1 例流动人口粪检阳性。5年累计监测家畜 9 346 头·次, 2015、2016 年检出粪检阳性家畜6头 (均为牛)。2015-2019 年, 共进行钉螺调查 1.55 亿 m2, 活螺平均密度总体呈逐年下降趋势, 2019 年较 2015 年下降 45.79%; 5 年间未查获血吸虫感染性钉螺; 采用环介导等温扩增技术 (LAMP) 检测混合钉螺样本 1 469 份, 2015、2017 年分别检出阳性混合样本 1 份和 5 份。结论 湖南省血吸虫病疫情总体呈下降趋势, 人、畜血吸虫感染率处于较低水平; 但血吸虫病传播风险依然存在, 今后应加强健康教育、加大流动人群查病力度、进一步完善血吸虫病监测体系, 以巩固已取得的防治成果。.
Keywords: Endemic situation; Hunan Province; Schistosomiasis; Surveillance.