Genetic Variation Of Bovine Enterovirus In Jilin Province And Antigenic Difference With Caprine Enterovirus

Enterovirus(EV)is a member of Enterovirus genus within the family of Picornaviridae.Based on the latest virus taxonomy,the genus of Enterovirus consists of 12 species Enterovirus(A-J)and 3 species Rhinovirus(A-C),which are the etiological agents contributing to neurological,respiratory and digestive disorders in human and animals.Out of 12 enterovirus species,EV-E,EV-F and EV-G are closely related to diseases affecting on the livestock industry,while EV-E and EV-F were usually isolated from the cattle,while EV-G was usually isolated from the pigs.Previously,we isolated a HY12 enterovirus(EV-E)in 2012 and CEV-JL14(EV-G)in 2014 from cattle and goats,respectively,with severe diarrhea and high morbidity and mortality,demonstrating the EV-E and EV-G infection in our country for the first time.Although much progrss has been made recently regarding the enterovirus infection in cattle and goats,it remains largely unknown for the genetic diversity of bovine enteroviruses.Therefore,exploring the molecular genetic variability of BEV and the antigenic difference between BEV and CEV,will provide a theoretical basis for the understanding of the mechanism underlying enterovirus mutation and evolution.In this study,the double antibody sandwich ELISA was used to detect the 326 bovine feces samples from different regions of Jilin province from 2012 to 2017.The results showed different percentage of enterovirus infections in bovine in different areas of Jilin province,and the infection rate was 10.5%-20.4%.Eight BEV strains were isolated from feces samples using MDBK cells.RT-PCR was then used to amplify the 5’-UTR genomic sequences from eight isolated virus strains and ELISA-positive samples.The resulting sequences of the amplified fragments were compared and analyzed with the BEV sequences available on GenBank.Phylogenetic tree was constructed through bioinformatics software.The results showed that the nucleotide homology of the isolated BEV strains and BEV HY12 was between 79.3%-98.2%,which showed a certain molecular difference,and all of the isolated BEV strains belonged to E enterovirus.In addition,cross neutralization test and cross immunofluorescence assay were used to study the antigenic difference between BEV HY12 and CEV JL14.Results demonstrated that although HY12 and CEV-JL14 shared a weak crossreaction,they still belong to different serotypes.This result will provide the basis for the further study of diagnosis,prevention and control of enterovirus infection.