The Molecular Epidemiological Investigation Of Epidemiological Strain PEDV In The Partial Area Of Jiangxi Province Duirng2012to2013

Porcine epidemic diarrhea virus (PEDV) belongs to the family of Coronaviridae,genus Alphacoronavirus and it can cause porcine epidemic diarrhea (PED), which is anacute, highly contagious and devastating enteric disease. Porcine of different ages andvarieties are easy to get infection, especially suckling piglets and the mortality of porcinecan reach100%.There are some common clinical symptoms, including loss of appetite,watery diarrhea, vomiting, dehydration, and eventually acidosis. The outbreaks of PEDVinfections have been reported in many swine-producing countries, and cause severeeconomic losses in swine industry. Recent years, the incidence of PED has increasedsignificantly in Jiangxi Province. Therefore, our objective in this study was to investigatethe infection and prevalence of PEDV in swine farms in different places of Jiangxiprovince, and to analyze the epidemic strain sequence.In this study, MEGA5.0was used to compare the sequence of PEDV S genesubmitted to GenBank, which leaded us to find out the most conserved sequence amongS gene of PEDV strain. The specific primers were designed according to the DANStarsoftware princeples The size of the amplified product was1139bp. After the improvedthe condition of reaction, we establish the reverse transcription polymerase chain reaction(RT-PCR) method to detect PEDV, which of best Tm was57.9℃. Utilizing this methodto detect134diarrhea piglets feces or intestinum tenue tissue samples seemly withinfection of PEDV, which were collected from Jiangxi Province. The results showed that82(61.2%) fecal or intestinal samples had been confirmed positive for PEDV byRT-PCR. We cloned and analysis the sequence of S gene from21PEDV positivesamples collected from Yichun, Nanchang, the area was relative concentration of raisingpigs, comparing with the referenced PEDV strains. The results suggested that nucleotidesequences homology were95%-96%,95.1%-96.8%,97.3%-99.5%respectively and theamino acid sequences similarity were94.2%-96.3%,93.7%-96.6%,96.3%-98.4%respectively via analyzing the sequences of S genes of Jiangxi epidemic strain PEDVcomparing with the reference strains including CV777(the vaccine strain), KNU-0905(Korean strains), HuN (Hunan strain), The result of sequence comparison with otherPEDV reference strains and phylogenetic analysis indicated that Jiangxi strains are closerto HuN (Hunan strains) and differ genetically from CV777(the vaccine strain).