Chin J Schisto Control ›› 2021, Vol. 33 ›› Issue (2): 127-.

### National surveillance of Oncomelania hupensis in China, 2015—2019

LI Yin-Long, DANG Hui, GUO Su-Ying, CAO Chun-Li, Lü Shan*, XU Jing, LI Shi-Zhu

1. National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research)； NHC Key Laboratory of Parasite and Vector Biology； WHO Collaborating Centre for Tropical Diseases； National Center for International Research on Tropical Diseases, Shanghai 200025, China
• Online:2021-04-30 Published:2021-04-30

### 2015—2019年全国血吸虫病监测点钉螺监测结果分析

1. 中国疾病预防控制中心寄生虫病预防控制所（国家热带病研究中心）、国家卫生健康委员会寄生虫病原与媒介生物学重点实验室、世界卫生组织热带病合作中心、国家级热带病国际联合研究中心（上海 200025）
• 作者简介:李银龙，男，硕士，助理研究员。研究方向：血吸虫病流行病学

Abstract: Objective　To analyze the monitoring data of Oncomelania hupensis in the national schistosomiasis surveillance sites of China from 2015 to 2019, so as to understand the changes of Oncomelania snail status in the schistosomiasis?endemic areas of China and to provide the scientific evidence for Oncomelania snail control. Methods　According to the requirements of National Scheme for Schistosomiasis Surveillance in China (2014 Edition), national schistosomiasis surveillance sites were assigned in all schistosomiasis?endemic counties (cities, districts) and the potential endemic counties (cities, districts) in the Three Gorges Reservoir areas, and Oncomelania snail status was monitored according to different epidemic types. In endemic areas, Oncomelania snail survey was performed by means of systematic sampling and environmental sampling, and the occurrence of frames with Oncomelania snails and the prevalence of Schistosoma japonicum infections in Oncomelania snails were calculated, while in potential endemic areas, the risk of imported Oncomelania snails and Oncomelania snails in floating debris were monitored. Results　Oncomelania snail survey was performed covering an area of 116 834.16 hm2 in the national schistosomiasis surveillance of China from 2015 to 2019, with 35 007.62 hm2 Oncomelania snail habitats identified. A total of 6 908 292 frames were surveyed during the 5?year period, and there were 364 555 frames detected with Oncomelania snails, with a 5.28% mean occurrence of frames with Oncomelania snails. Among 997 508 living Oncomelania snails captured, no S. japonicum infections were detected, and loop?mediated isothermal amplification (LAMP) assay detected 18 positive mixed Oncomelania snail samples. During the period from 2015 to 2019, 147.20 hm2 emerging Oncomelania snail habitats were identified, with an overall tendency towards a rise seen in the proportion of emerging Oncomelania snail habitats in plain regions with waterway networks (0.12% to 92.00%), a tendency towards a rise followed by decline seen in marshland and lake regions (0 to 96.72%), and a large fluctuation in hilly regions (0 to 88.49%). A total of 831.10 hm2 re?emerging Oncomelania snail habitats were found in the national schistosomiasis surveillance sites of China from 2015 to 2019, with an overall tendency towards a rise seen in the proportion of re?emerging Oncomelania snail habitats in marshland and lake regions (16.05% to 79.66%), an overall tendency towards a decline seen in hilly regions (19.25% to 81.00%), and a minor fluctuation in plain regions with waterway networks (1.10% to 10.14%). During the 5?year period from 2015 to 2019, a total of 48 656 kg floating debris were captured in 4 surveillance sites in the Three Gorges Reservoir areas, and 2 204 snails were found, with no Oncomelania snails identified. Conclusions　The areas of Oncomelania snail habitats tended to be stable in the national schistosomiasis surveillance sites of China during the period from 2015 to 2019, however, there was a gradual rise in the area of Oncomelania snail habitats year by year, and LAMP assay identified positive Oncomelania snail samples, suggesting Oncomelania snail control is far from optimistic in China.

CLC Number: