Clinical and epidemiological implications of swine hepatitis E virus infection.
In nonendemic areas, most patients with acute hepatitis E were infected through traveling to endemic areas. However, some patients did not have a history of foreign travel before infection. Furthermore, high seroprevalence rates of antibody to hepatitis E virus (anti-HEV) were found in the general adult population in some countries without any recorded outbreak of hepatitis E. The significance of anti-HEV assay in these subjects remains obscure. To study if swine might be a source of HEV infection, HEV was tested in sera of 235 pigs in Taiwan, and from 5 patients with acute HEV infection who either denied or did not provide any foreign travel history. Three (1.3%) pigs had detectable swine HEV RNA. The swine and human HEV strains from Taiwan formed a monophyletic group, distinct from three previously reported groups: the United States human and swine HEV strains, the Mexico strain, and the largest group composed of the Asian and the African strains. The identity of nucleotide sequences was 84-95% between swine and human HEV strains in Taiwan, and 72-79% between Taiwan strains and those from different areas. The predicted amino acid sequence of a Taiwan swine HEV strain within the peptide 3-2 used in commercial anti-HEV assay showed a high identity (91-94%) with those of other human and swine HEV strains. Swine may be a reservoir of HEV and subclinical swine HEV infection may occur. Cross-reactivity of current anti-HEV assay may account for the high prevalence rate of anti-HEV in the general population in nonendemic areas.
Wu
J C
JC
Institute of Clinical Medicine and Division of Gastroenterology, Veterans General Hospital, National Yang-Ming University School of Medicine, Taipei, Taiwan. jcwu@vghtpe.gov.tw
Chen
C M
CM
Chiang
T Y
TY
Sheen
I J
IJ
Chen
J Y
JY
Tsai
W H
WH
Huang
Y H
YH
Lee
S D
SD
D000328:Adult; D000368:Aged; D000818:Animals; D003001:Cloning, Molecular; D005260:Female; D016751:Hepatitis E / Q000453:epidemiology / Q000635:transmission* / Q000662:veterinary* / Q000821:virology; D016752:Hepatitis E virus / Q000145:classification / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D012367:RNA, Viral / Q000032:analysis; D016415:Sequence Alignment; D016036:Seroepidemiologic Studies; D013552:Swine; D013553:Swine Diseases / Q000635:transmission* / Q000821:virology*; D013624:Taiwan / Q000453:epidemiology; D014195:Travel; D014766:Viremia / Q000662:veterinary* / Q000821:virology
D012367:RNA, Viral