广西全州县市售猫、狗华支睾吸虫感染调查分析

Investigation and analysis of Clonorchis sinensis infection in cats and dogs sold in Quanzhou county,Guangxi

目的了解广西全州县猫、狗华支睾吸虫感染现状,进一步探明华支睾吸虫病狭义非流行区是否存在流行,为华支睾吸虫病综合防控提供依据。方法采用分层随机抽样方法,从全州县东、南、西、北、中5个方位各选择1家农贸市场按季度开展调查。采样总量为猫107只、狗84只。收集猫、狗的完整肝脏、胆囊,观察并记录肝脏病变情况,同时收集可疑虫体进行鉴定、测量、分类并计算感染率。对收集到的不同形态虫体进行COX1基因扩增和测序,通过BLAST比对分析确定虫体种类。采用χ^(2)检验、t检验对华支睾吸虫感染情况的影响因素进行分析。结果本次调查中,41.12%的猫、57.14%的狗来源为本地,其余均来源于外地(湖北)。分别检查107只猫、84只狗的肝脏和胆囊,猫华支睾吸虫感染率为61.68%(66/107),单只猫华支睾吸虫虫体数量最多达1070条;狗华支睾吸虫感染率为2.38%(2/84),均为本地感染。虫体的分布位置在不同感染度猫、狗之间的差异有统计学意义(χ^(2)=47.353,P<0.001);随着感染度增加,虫体异位寄生在胆囊的概率也增加。有大体病理改变(肝表面黄染或肝胆管壁增厚、扩张等)与无大体病理改变的猫、狗感染率间的差异均有统计学意义(χ^(2)_(猫)=49.509,P_(猫)<0.001;P_(狗)<0.001)。猫、狗华支睾吸虫阳性组的肝脏重量(g)与阴性组的肝脏重量(g)间差异均有统计学意义(t_(猫)=3.537,P_(猫)<0.01;t_(狗)=4.185,P_(狗)<0.001)。从本地猫、狗,外地(湖北)猫肝脏中分离到3种不同来源的虫体,其大小和睾丸存在较大差异;经形态学和COX1基因鉴定,均为华支睾吸虫。结论广西全州县虽为华支睾吸虫病狭义非流行区,但市售猫、狗均可检出华支睾吸虫,尤其是猫的感染率较高,今后应进一步加强非流行区动物华支睾吸虫病的调查和防控。

Objective To understand the current status of Clonorchis sinensis infection in cats and dogs in Quanzhou county,Guangxi,and to further explore whether clonorchiasis is endemic in the narrowly defined nonendemic areas,providing a basis for comprehensive prevention and control of the disease.Methods A stratified random sampling method was employed to select one farmer’s market from each of the five directions(east,south,west,north,and central)of Quanzhou county to conduct surveys on a quarterly basis.A total of107 cats and 84 dogs were sampled.Complete livers and gallbladders of cats and dogs were collected,and liver lesions were observed and recorded.Suspected worms were also collected for identification,measurement,classification,and calculation of infection rates.COX1 gene amplification and sequencing were performed on the collected worms with different morphologies,and the species of the worms were determined through BLAST comparison and analysis.Chi-square test and t-test were used to analyze the influencing factors of Clonorchis sinensis infection.Results In this survey,41.12%of cats and 57.14%of dogs were sourced locally,and the rest came from other places(Hubei).The livers and gallbladders of 107 cats and 84 dogs were examined.The infection rate of Clonorchis sinensis in cats was 61.68%(66/107),with a maximum of 1070 worms per individual cat.The infection rate in dogs was 2.38%(2/84),which were locally infected.There was a statistically significant difference in the distribution of worms between cats and dogs with different infection levels(χ^(2)=47.353,P<0.001);as the infection level increased,the probability of ectopic parasitism in the gallbladder also increased.There were statistically significant differences in the infection rates between cats and dogs with gross pathological changes(such as yellowing of the liver surface or thickening and dilation of the liver bile duct wall)and those without gross pathological changes(χ^(2)_(cat)=49.509,P_(cat)<0.001;P_(dog)<0.001).Significant differences were also observed in liver weight(g)between the positive and negative groups of Clonorchis sinensis in cats and dogs(t_(cat)=3.537,P_(cat)<0.01;t_(dog)=4.185,P_(dog)<0.001).Three different sources of worms were isolated from local cats,dogs,and cats from Hubei,and their size and testicles were quite different.Morphological and COX1 gene identification confirmed that they were all Clonorchis sinensis.Conclusions Although Quanzhou county in Guangxi is considered a narrowly defined non-endemic area for clonorchiasis,Clonorchis sinensis can be detected in cats and dogs sold in the market,particularly with a high infection rate in cats.Therefore,further investigation and prevention and control of clonorchiasis in animals in non-endemic areas should be further strengthened.