Identity of a novel swine hepatitis E virus in Taiwan forming a monophyletic group with Taiwan isolates of human hepatitis E virus.
Recently, we found that more than 10% of the cases of acute non-A, non-B, non-C hepatitis in Taiwan were caused by a novel strain of hepatitis E virus (HEV). Since none of these patients had a history of travel to areas where HEV is endemic, the source of transmission remains unclear. The recent discovery of a swine HEV in herd pigs in the United States has led us to speculate that HEV may also circulate in herd pigs in Taiwan and may serve as a reservoir for HEV in Taiwan. Of 275 herd pigs obtained from 10 pig farms in Taiwan, 102 (37%) were seropositive for serum anti-HEV immunoglobulin G (IgG). A 185-bp genomic sequence within the ORF-2 of the HEV genome was amplified and cloned from serum samples of an anti-HEV positive pig and subsequently from serum samples of a patient with acute hepatitis E. Sequence comparison revealed that the swine and human isolates of HEV share 97.3% identity. Phylogenetic analyses further showed that the Taiwan swine and human isolates of HEV form a distinct branch divergent from all other known strains of HEV, including the U.S. swine strain. To examine the potential risk of cross-species transmission of swine HEV to humans, the seroprevalences of anti-HEV IgG in 30 swine handlers, 20 pork dealers, and 50 control subjects were assessed and were found to be 26.7, 15, and 8%, respectively (for swine handlers versus controls, P = 0.048). Our findings may help provide an understanding of the modes of HEV transmission and may also raise potential public health concerns for HEV zoonosis.
Hsieh
S Y
SY
Liver Research Unit, Chang Gung Memorial Hospital, School of Medicine, Chang Gung University, Taoyuan, Taiwan. siming@adm.cgmh.com.tw
Meng
X J
XJ
Wu
Y H
YH
Liu
S T
ST
Tam
A W
AW
Lin
D Y
DY
Liaw
Y F
YF
D000818:Animals; D001483:Base Sequence; D016679:Genome, Viral; D006508:Hepatitis Antibodies / Q000097:blood; D016751:Hepatitis E / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary / Q000821:virology*; D016752:Hepatitis E virus / Q000145:classification* / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D013624:Taiwan / Q000453:epidemiology
D006508:Hepatitis Antibodies; D007074:Immunoglobulin G