辽宁省淡水鱼吸虫囊蚴感染调查

Investigation of trematode metacercariae infection in freshwater fish in Liaoning province

目的了解辽宁省内淡水鱼吸虫囊蚴感染情况及分子特征,为鱼源性寄生虫病防治提供数据支持。方法根据分层随机采样原则于2019-2020年分别在辽宁省14个市采集市售和养殖场淡水鱼,先利用消化法检获不同形态的吸虫囊蚴,生物显微镜下根据囊蚴形态特点进行初步分类。然后分别提取不同种囊蚴的总DNA,对其第二内转录间隔区(ITS2)基因进行PCR扩增,并将扩增产物进行序列测定,将基因序列与GenBank数据库中相关基因序列进行比对分析,再利用MEGA6.0软件构建系统发生树。结果采集16种淡水鱼共672尾,吸虫囊蚴总感染率为8.9%(60/672),其中麦穗鱼吸虫囊蚴感染率为23.2%(60/259);麦穗鱼感染2种吸虫囊蚴,分别为华支睾吸虫囊蚴和外睾吸虫囊蚴,其他鱼类未发现吸虫囊蚴感染。结论麦穗鱼中华支睾吸虫囊蚴感染率较高,对人类健康构成潜在的威胁,应加强宣传与防控;通过形态学结合分子生物方法可以有效鉴定淡水鱼中吸虫囊蚴感染种类。

Objective To understand the infection and molecular characteristics of trematode metacercariae of freshwater fish in Liaoning province,and provide data support for the prevention and control of fishborne parasitosis.Methods Freshwater fish were collected from markets and farms of 14 cities in Liaoning province,and the trematode metacercariae were isolated by artificial digestion method from 2019 to 2020.Different forms of the metacercaria trematodes were collected and classified by morphological characteristics utilizing the microscope.The total DNA of different kinds of metacercariae were extracted,and the internal transcriptional spacer 2(ITS2)sequences were amplified by PCR method.The amplified products were sequenced.The gene sequence was compared with the related gene sequences in GenBank database.The phylogenetic tree was constructed by MEGA6.0 software.Results A total of 672 freshwater fishes of 16 species were collected;the total trematode metacercariae infection rate of freshwater fish was 8.9%(60/672),and the trematode metacercariae infection rate of Pseudorasbora parva was 23.2%(60/259).The results showed that 2 kinds of metacercariae were identified in P.parva,named Clonorchis sinensis and Externus sp.No trematode metacercariae infection was found in other fishes.Conclusions The infection rate of C.sinensis metacercariae was high,which posed a potential threat to human health.Propaganda and prevention and control should be strengthened.The species of metacercariae infection in freshwater fish could be effectively identified by morphological and molecular biological methods.