Sequencing Of The Complete Genome Of A Strain Of Swine Hepatitis E Virus And Detection Of The Antibody In Several Animals In Shanghai

To obtain the serological evidence of hepatitis E virus(HEV) infection in different animal species in Shanghai area, we collected 252 sera from growing pigs aged 4 W, 9W, 18W, pre-sows and sows from seven farms in seven districts, 96 sera from eight cow farms, 43 from accompanying dogs in clinics, 20 from broilers and 24 from ducks in open plaza and 35 from several species of birds from Shanghai safari park and detected the antibody to HEV by a doulbe-antigen sandwich ELISA(DS- ELISA) with the kits from Beijing Wantai biological medicine products company. The results showed that the antibody to HEV could only be detected in sera from swine, accompanying dogs and cows with the postitive rate being 88.8%(222/252), 27.9%(12/43), 23.9%(23/96)respectively, the average optical values at 490nm for pigs of 4 W, 9W, 18W, pre-sows and sows were 2.01±1.46,1.27±0.77,1.65± 1.40,2.81±1.34 and 2.85 ±1.23 while the postive rates were 85.8%(42/49), 84.3%(59/70), 80.9%(52/63), 97.1 %(34/35) and 100.0%(35/35)respectively, and the postive farm rate for swine and cow were both 100%. Our data indicate that HEV is highly prevalent in swine populations and a significant presence of HEV is existent in accompanying dogs and cows in Shanghai area.Based on the conserved nucleotides of the hepatitis E virus(HEV) genome sequences of four major genotypes, we designed two sets of degenerate primers to amplify a fragment of 507bp within ORF2 by reverse transcription nested polymerase chain reaction(RT-nPCR) to test the presence of HEV RNA in 561 feces samples from growing pigs aged one month, two to four months and sows in 18 farms in nine districts in Shanghai area and part of 98 feces samples from two to three month-old swine in 5 farms from three areas in Xiangjiang province. The results showed the postive rates for HEV RNA and postive farms for one-month swine, two-to-four month-old swine and sows were 8.2%(14/169),15.4%(2/13), 6.9%(55/324) and 72.2% (13/18),17.6%(12/68),75%(3/4) respectively. Nine fragments, one from each farm, amplified from feces samples from six farms in Shanghai and three farms in Xingjiang respectively, were ligated to pMD-18T vectors to produce recombinant plasmids for sequencing. Together with 53 known HEV genomes, the obtained sequences were aligned using DNAStar to get the percentage nucleotide identity.The Clustalx and...