| Hepatitis E virus (HEV) is zoontic disease, caused by HEV, and it does a great harm to human health. Among animals that carry HEV, pigs have the highest infection rate and virus burden.The isolated virus from pigs share the higher homology with human.The research on pigs is high meaningful for prevention and control of the disease.To accurately determine the prevalence of HEV infections among Shanghai pig farms.918 pig fecal samples were collected from 40 pig farms located in all ten Shanghai suburban districts, 444 fecal samples were collected in the first time ,the other 474 fecal samples were collected for following investigation. tested for the presence of HEV RNA using RT-nPCR. Genetic analysis based on an amplified 150-bp ORF2 fragment, revealed 220 samples to be HEV RNA positive from the 918 samples, positive rate was 24%.and the prevalence of HEV infection within the different pig farm between 0.0% and 75%. In the investigation, we discovered that genotype 3 and genotype 4 HEV coexisted in the 36th pig farm,to learn the detail for coexisting ,we do continue investigation in the farm. The results indicated genotype 4 was the dominant genotype. Choose part of the positive samples in each farm randomly, and clone the amplified fragment to T vector for determining the HEV RNA sequence. phylogenetic analysis indicated that 28 isolates belonged to HEV genotype 4, and that had a high percent identity with two HEV strains isolated in Shanghai. 14 isolates belonged to HEV genotype 3, it had a a high percent identity with a HEV strains isolated in Japan. The results before suggest that there have been only genotype 4 exited on mainland China. Our data indicated that genotype 3 HEV was widespread among Shanghai suburbs although further study is required to determine the source and zoonotic nature of the virus.To abtain the serological evidence of HEV infection in pig farm of Shanghai. We collected 118 sera form growing pigs aged 4 W, 8 W, 18 W, and sows. The antibody of HEV was detected by a double-antigen sandwich ELISA with the kits from Bejing Wantai biological medicine products company . Detected HEV RNA by RT-nPCR of the sera. The results showed that the HEV antibody positive rate of the total sera was 90.7%,and the positive rate of 4 W, 8 W, 18 W, and sows were 85.7% (30/35) ,88% (32/35 ) ,94% (33/35 ) and 92.3% (12/13 ) . In the all samples we detected 12 sample was positive for HEV RNA. the positive rate was 10.2%,and the result showed that the farm has o high level of HEV antibody, but we can detected the HEV RNA in the high HEV antibody samples.To following investigation whether two different genotype HEV strain infected in one pig.refer to the Epidemiological genotype in china. We designed two series special primers for RT-nPCR. the aim fragment for genotype3 was 64bp ,based on the ORF2,and genotype was 440bp bassed on the ORF1 and ORF2.the result indicated that the genotype 3 and genotype 4 HEV can exist in One pig . phylogenetic analysis showed that the genotype 4 isolates SW-CSH4 shared 94.5 % homogeneity with T21 isolated in china ,the homogeneity with other genotype reference sequence below 81%, belonged to the 4a subtype of HEV. the genotype 3 isolates SW-CSH3 shared 95.7% homogeneity with US2 isolated in USA , the homogeneity with other genotype 3 reference sequence on the 85%,belonged to the 3a subtype of HEV. |
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