The Detection Of PEDV And Cloning Of Major Virulence Genes In A Large-scale Piggery

Porcine epidemic diarrhea(PED) is a diarrhea disease of swine caused by porcine epidemic diarrhea virus(PEDV), which was characterized by acute enteritis and lethal watery diarrhea followed by dehydration leading to death with a high mortality rate in piglets. The morbidity and mortality rate of newborn piglets is very high, up to 45.0%. The disease spreads around the world, brings a huge economic losses to the swine industry.We obtained the suspected PEDV piglets as the research object from a large-scale piggery located in Shaanxi Weinan during November to December, 2014. Through the clinical observation and RT-PCR detection, the results showed that in the sample collected from incidence piglets, PEDV infection positive rate was 45.0%.In addition, we studied the separation strains PEDV ORF3, M and S three virulence related gene cloning. According to the reported genome sequence of strain CV777(Accession No. AF353511.1), three pairs of PCR primers were designed to amplify the full-length of ORF3 gene, M gene and S gene. The products were cloned, sequenced and analysed. Compared with CV777 strain, we found that M gene is highly conservative, can be used as a diagnostic target gene of PED; WN strains, in comparison with ORF3 gene of classical strains CV777,base mutations in total there are 11 base mutations,whether these bases mutation leads to a change in the virus virulence remains to be studied. S genemutated large, in the core neutralization epitope(CEO, 499aa-638aa) of S protein, a total of nine amino acids mutation happened.