| In order to further understand the epidemic situation of cystic echinococcosis in cattle and sheep in Altay,Changji,Yili and Kashi of Xinjiang,and to clarify the genetic differences of the epidemic strains,the cox1 gene fragment and nad5 gene fragment of the mitochondrial genome of Echinococcus granulosus was amplified by PCR,then the amplification results were sequenced and analyzed for gene polymorphism,to obtain the corresponding genetic difference information.Cattle(352)and sheep(5,202)were screened for cystic echinococcosis in slaughterhouses located in Altay,Changji,Yili and Kashi in Xinjiang.4 cattle and 116 sheep,respectively were suspected to be infected with Echinococcus cysts.Among them,protoscoleces from a cattle and 35 sheep were successfully separated.The highest infection intensity was found in Kashi sheep,where up to 32 hydatid cysts were recovered in a sheep.A total of 156 samples from 3 cattle and 96 sheep were amplified by PCR using 1,649 bp mitochondrial cox1 gene.Cluster analysis of the target fragments showed that all the cyst samples were Echinococcus granulosus G1,with 53 different haplotypes showing 99.7% ～100% homology with previously reported G1.57 nucleotide sequences were found to have base substitution,accounting for about 3.46% of the total number of analysis sites,and the difference between gene sequences was between 0%～0.3%;base transition and transversion existed in all mutations of nucleotide sequences of the isolates,and the number of transition was significantly higher than that of transversion,without deletion or insertion.Among them,were 52 base transition sites,3 base transversion sites,and 2 base transition and transversion sites.Also,129 samples from 3 cattle and 86 sheep were amplified by PCR using 680 bp mitochondrial nad5 gene fragment.The result of cluster analysis of the target fragments was consistent with that of cox1 gene.It was determined that the epidemic strain was G1 genotype,with 24 different haplotypes and the homology was 99.56%～99.85%;24 nucleotides were found to have base substitution,accounting for about 3.53% of the total number of analysis sites,and the difference between gene sequences was between 0%～0.44%;only base transition was found in all mutations of nucleotide sequences of the isolates.No transversion,deletion or insertion were detected.Of the samples suspected for hydatidosis,3 cattle and 97 sheep were confirmed as cystic echinococcosis based on PCR amplification of the cox1 and nad5 gene.Changji had the highest infection prevalence(3.69%),followed by Kashi(1.85%),Yili(1.46%),and lastly,Altay(0.68%).The infection prevalence in liver and lung was 1.06% and 0.74% respectively.The results of this study demonstrate that a single host can harbor multiple haplotypes,and could also potentially harbor different strains.In this study,the genotypes of E.granulosus in Altay,Changji,Yili and Kashi of Xinjiang were identified,and the molecular epidemiological data of cystic echinococcosis in these areas were obtained which provides scientific basis for formulating effective control measures. |
