Uamporn SiripanyaphinyoDusit LaohasinnarongJuthamas SiripaneeKampon KaeoketMasanori KameokaKazuyoshi IkutaPathom SawanpanyalertThailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections (RCC-ERTOsaka UniversityMahidol UniversityThailand Ministry of Public Health2018-09-132018-09-132009-04-01Journal of Medical Virology. Vol.81, No.4 (2009), 657-66410969071014666152-s2.0-62849092317https://repository.li.mahidol.ac.th/handle/20.500.14594/27726Hepatitis E virus (HEV) infection in pigs was investigated in two principal swine farming areas in Thailand. Anti-HEV antibodies and HEV RNA in sera were examined in 258 pigs reared on five commercial farms from age 1 to 6.5 months and sows. Overall, 167 of 258 (64.7%) pigs were positive for anti-HEV IgG, while 20 of 258 (7.75%) had detectable HEV RNA. Sequence analysis of 20 HEV isolates obtained from viremic pigs revealed thatthey were 92.3-100% identical to each other and had 82.2-88.2% nucleotide similarity to other reported genotype 3 isolates in 415 nucleotide sequences within ORF2 region. Further characterization by sequencing the complete genome of the Thai swine HEV isolate (named Thai-swHEV07) and phylogenetic analysis showed that Thai-swHEV07 segregated into a cluster consisting of swine isolates from Japan, Mongolia, and Kyrgyzstan within the HEV genotype 3. The Thai-swHEV07 had a genomic length of 7,229 nt excluding the polyadenylated region at 3' terminus of the genome. Comparison of Thai-swHEV07 and 27 reported strains of genotype 3 revealed 80.4-85.9% nucleotide identity, with the highest identity of 85.9% to the novel swHEV strain from Mongolia. These findings suggest that genotype 3 HEV isolates are markedly heterogeneous. © 2009 Wiley-Liss, Inc.Mahidol UniversityImmunology and MicrobiologyMedicineArticleSCOPUS10.1002/jmv.21428