广东省猪十二指肠贾第虫感染现状和分子特征分析

doi:10.16431/j.cnki.1671-7236.2022.04.042

摘要/Abstract

摘要： 【目的】了解广东省不同地区猪源十二指肠贾第虫(Giardia duodenalis,简称贾第虫)的流行现状和分子特征,并评估其人兽共患风险。【方法】从广东省10个地区采集新鲜猪粪样品,采用显微镜镜检,并应用巢式PCR对贾第虫谷氨酸脱氢酶(glutamate dehydrogenase,gdh)基因进行扩增,根据扩增结果计算不同地区和生长阶段猪贾第虫的阳性率。对所有的PCR阳性产物进行测序,将获得的贾第虫gdh基因序列进行BLAST比对,确定贾第虫的基因型;运用Mega 7.0软件的最大似然法构建进化树。【结果】贾第虫包囊呈椭圆形,囊壁较厚,大小为(10~14)μm ×(7~10)μm,具有明显纵向轴柱,细胞核分布于轴柱两侧。521份受检样品中共检测出94份PCR阳性样品,阳性率为18.04%(94/521),其中茂名和清远的阳性率较高,分别达40.00%(10/25)和35.06%(27/77);肇庆和韶关的阳性率较低,分别为3.90%(3/77)和8.57%(3/35);佛山、江门、阳江、河源、广州和惠州的阳性率分别为11.11%(2/18)、15.31%(15/98)、11.43%(4/35)、13.33%(4/30)、9.38%(3/32)和24.47%(23/94)。不同饲养阶段的猪群的阳性率调查发现,母猪的贾第虫阳性率(24.55%)显著高于断奶仔猪(13.30%)(P<0.05),与育肥猪的贾第虫阳性率(19.23%)差异不显著(P>0.05)。基于gdh基因序列的基因分型和系统进化分析共发现5种贾第虫亚集聚体,即集聚体AⅠ和集聚体E的4种不同亚型,包括集聚体E1、E2、E10和E13,其中61.70%(58/94)测序阳性样品属于集聚体AⅠ,38.30%(36/94)属于集聚体E的不同亚型。【结论】广东猪源贾第虫的感染较普遍,不同地区和不同生长阶段的猪感染率存在一定差异。其中,人兽共患性集聚体AⅠ为优势亚集聚体,表明广东省猪源贾第虫存在人兽跨物种传播的风险,应重视该病可能引起的公共卫生问题。

关键词: 猪; 十二指肠贾第虫; gdh基因; 感染率; 人兽共患风险

Abstract: 【Objective】 This study was aimed to evaluate the zoonotic risk of Giardia duodenalis (G.duodenalis) in pigs,and investgate the prevalence and molecular characterization of G.duodenalis in different citys of Guangdong province.【Method】 Fresh pig feces samples were collected from 10 regions in Guangdong province and examined by microscope.Nested PCR was used to amplify the glutamate dehydrogenase (gdh) gene of G.duodenalis,and the positive rates of G.duodenalis in different regions and growth stages were calculated according to the amplification results.All PCR positive products were sequenced,and the gdh gene sequences of G.duodenalis were BLAST compared to determine the genotype of G.duodenalis.The maximum likelihood method of Mega 7.0 software was used to construct the evolutionary tree.【Result】 The cyst of G.duodenalis was oval with thick wall and the size was (10-14) μm×(7-10) μm.It had an obvious longitudinal axis column,and the nucleus was distributed on both sides of the axis column.94 positive samples were detected from 521 samples,and the average positive rate was 18.04%(94/521),among which Maoming (40.00%,10/25) and Qingyuan (35.06%,27/77) had higher positive rate,but Zhaoqing and Shaoguan were lower,with 3.90%(3/77) and 8.57%(3/35) respectively.The positive rates in Foshan,Jiangmen,Yangjiang,Heyuan,Guangzhou and Huizhou were 11.11%(2/18),15.31%(15/98),11.43%(4/35),13.33%(4/30),9.38%(3/32) and 24.47%(23/94),respectively.The positive rate of G.duodenalis in sows (24.55%) was significantly higher than that in weaned piglets (13.30%)(P<0.05),but there was no significant difference between the positive rate of G.duodenalis in sows and fattening pigs (19.23%)(P>0.05).Based on genotyping and phylogenetic analysis of gdh gene,a total of 5 G.duodenalis subtypes were found,including assemblage AⅠ and assemblage E1,E2,E10 and E13,of which 61.70% (58/94) G.duodenalis positive samples belonged to sub-assemblage AⅠ and 38.30% (36/94) belonged to assemblage E.【Conclusion】 The infection of G.duodenalis from pigs in Guangdong province was common,and the positive rates of pigs in different regions and different growth stages were different.The zoonotic sub-assemblage AⅠ was the dominant sub-assemblage,indicating that there was a risk of transmission from animals to humans or vice versa and the possible public health problems caused by the G.duodenalis should be taken seriously.

Key words: pig; Giardia duodenalis; gdh gene; infection rate; zoonotic risk

中图分类号:

S855.9

钟梦龙, 张浩吉, 陈祥杰, 李复坤, 邱茜茜, 李易, 黄福强, 王妮娜, 余新刚. 广东省猪十二指肠贾第虫感染现状和分子特征分析[J]. 中国畜牧兽医, 2022, 49(4): 1592-1598.

ZHONG Menglong, ZHANG Haoji, CHEN Xiangjie, LI Fukun, QIU Xixi, LI Yi, HUANG Fuqiang, WANG Nina, YU Xingang. Infection Status and Molecular Characterization of Giardia duodenalis in Pigs in Guangdong Province[J]. China Animal Husbandry and Veterinary Medicine, 2022, 49(4): 1592-1598.

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