Meta Analysis Of CCoV Epidemic In China And Molecular Epidemiology Survey Of CCoV In Heilongjiang Province From 2018 To 2019

Canine coronavirus is an infectious disease with wide distribution,high incidence and complicated clinical symptoms.It has been reported that coronavirus mutations will change their hosts from animals to humans,and dogs have close contact with humans as human daily life partners,so it is of great significance to human public health to pay close attention to the CCoV epidemic and genetic variation.In order to fully understand the prevalence of CCoV in China,this experiment uses Meta analysis methods for research.First,collect and screen Chinese and English literature on the prevalence of domestic CCoV published in China from 1997 to 2019 according to the research purpose,and count the published articles,authors,total samples,positive samples,detection methods,and sample source backgrounds of documents that meet the requirements.And other information,and score evaluation based on the comprehensiveness of the information and the level of detail of the experiment.Further extract the background information data of all the samples in the literature and divide them into 9 different subgroups of source region,season,gender,immunization status,etc.,and use statistical methods to analyze the differences between CCoV prevalence under different subgroup classifications and their Relevance of sample background information.Finally,the statistical test method was used to further analyze and verify the heterogeneity of the statistical results of the subgroup analysis and the publication bias.Combined with the results of Meta analysis,this study further designed an experiment to explore the prevalence of CCoV and the genetic evolution of epidemic strains in Heilongjiang,China from 2018 to 2019,collecting 378 copies in 6 regions of Daqing,Harbin,Jixi,Mudanjiang,Jiamusi and Qiqihar of Heilongjiang Diarrhea dog feces samples were detected by RT-PCR,statistical analysis of the correlation between CCoV infection rate and sample background information,and bioinformatics methods were used to perform sequence alignment,homology,and identification of the M and S genes of positive strains.Genetic evolution analysis.Meta-analysis results showed that 24 articles that met the requirements were finally screened out in this study,including information about 5 826 samples from 7 regions.The number of CCoV positives was 2 115,and the total positive rate was 36.3%.The results of the single group analysis showed that the CCoV positive rate was the highest in Southwest China at63%;the CCoV positive rate in South China was the lowest at 6%;and the CCoV positive rate was 55%in the Northeast China.The positive rate of CCoV in the literature published before2016 is 17%higher than that in 2016 and later.The purebred dog has a 39%higher CCoV infection rate than the mongrel dog.The infection rate of CCoV-?in dogs is 55%higher than that of CCoV-?.The difference in CCoV positive rate among other subgroups is small.The correlation results show that under limited data conditions,the CCoV infection rate is not related to the dog's sex,age,immunization status,season of onset,breed,and diarrhea.RT-PCR results showed that the total number of CCoV positive samples was 74,and the total positive rate was 19.58%.Statistical analysis results show that dogs older than 12 months of age have a lower CCoV infection rate than dogs aged 0-6 months,and CCoV infection rates in autumn and winter are lower than in spring.The above differences are statistically significant.The results of the phylogenetic tree construction of the M and S genes showed that the main CCoV strains identified in this experiment were mainly CCoV-?.The CCoV-?and CCoV-?strains identified had the closest relationship with the local epidemic strains in Heilongjiang.The early classical strains of different genotypes have a distant relationship.Compared with 37CCoV identified strains themselves,the M gene nucleotide and amino acid homology were83.2%¹00%and 88.1%¹00%,respectively.Compared with the reference strain,CCoV-I-type identification strain 23/03 has the highest nucleotide and amino acid homology with type-I prototype strain 23/03,and CCoV-?-type identification strain has the same nucleoside as domestic early strain NJ17 The acid has the highest homology with amino acids,and the nucleotides with 341/05 and CB/05 have the lowest homology.Compared with the 3strains of CCoV-?identified strains themselves,the nucleotide homology of S gene nucleotides and amino acids were 97.2%⁹8.4%and 92.8%⁹6.4%respectively;compared with the 4 strains of CCoV-?identified strains themselves,S The nucleotide and amino acid homology of the genes are 85.9%¹00%and 89.8%¹00%,respectively;the M gene deduced amino acid sequence alignment results show that the overall CCoV-?strain compared with the CCoV-?strain,There are 4 amino acid conserved sites,namely A¹²⁹,T¹⁷⁵,M¹⁹⁵,E/DH^202-203.S gene deduced amino acid sequence alignment results showed that:compared with CCoV-?classic strains 23/03 and Elmo/02,there were 7 amino acid identity mutations among the 3 identified strains in this experiment;CCoV-?type identified viruses Compared with the HRB-D6 strains identified in Heilongjiang,HLJ/L4,HLJ/L15 and HLJ/t56 strains had 8 amino acid identity mutations.The analysis results of the N-glycosylation site of the S protein showed that with reference to 23/03,the potential N-glycosylation sites of amino acids 1 194-1 284 of the S protein of the strain were analyzed and identified,and the identified strain HLJ/X24 was only Contains the 1 273th N-glycosylation site,but does not include the 1 234th N-glycosylation site;and the identified strain HLJ/X4 does not contain these 2 potential N-glycosylation sites.Compared with the reference strain,CCoV-?identified strains HLJ/L4 and HLJ/L15 had an additional N-glycosylation site at position 1 246,while identified strain HLJ/t56 at position 1246,There are 2 more N-glycosylation sites in 1 340 positions.The results of antigenicity analysis of M protein showed that the distribution of the highly antigenic amino acid sites of the identified strain HLJ/X14 of the CCoV-?group 5 strain was highly similar to the reference strain of CCoV-?,mainly distributed in the 151¹56,172¹77 amino acids;compared with the reference strain,the identified strain HLJ/28 has an extra high antigenicity region at amino acids173¹77.Compared with the reference strain,the CCoV-?identified strain HLJ/J69 has one more highly antigenic region at amino acids 1 278¹ 286.The above research results show that CCoV infection is present in dog populations in 7regions of China,and the prevalence of CCoV-?strains is higher than that of CCoV-?.In addition,the CCoV infection rates of dogs in different regions,ages and breeds vary greatly.From 2018 to 2019,the CCoV epidemic strains in Heilongjiang area are still mainly CCoV-?.Compared with the classic strains with different genotypes at home and abroad,the M and S genes of CCoV epidemic strains in Heilongjiang area have changed to a large extent that it is suggested that the domestic CCoV epidemic and genetic variation should be continuously monitored.