Molecular Characterization of Swine Hepatitis E Virus from Southeastern Brazil

Despite serological evidences of presence of hepatitis E virus (HEV) in humans or other animals, until this study the virus had not been detected and molecular characterization of the isolate that circulates in Brazil had not been described. Thus, we collected stool samples of young pigs and tested for presence of HEV RNA by RT-PCR, using primers for partial amplification of ORF2 sequence. Phylogenetic analysis with sequence obtained from the amplified products revealed that the HEV isolate identified here was most closely related to HEV isolates of genotype 3, which is commonly detected in HEV infected pigs. Nucleotide sequence analyses carried out with the entire amplified fragment, ORF2/ORF3 overlapping and ORF2 non-overlapping sequences showed highest identities with the US isolate of genotype 3. Similarly, amino acid sequence analyses done with the entire amplified fragment, ORF2 non-overlapping, ORF2 and ORF3 overlapping sequences also showed highest identities with the genotype 3 isolate. Presence, in Brazil, of HEV of genotype 4, which also infects pigs, as well as HEV strains that infect humans still remain to be detected and characterized.