Identity of a Novel Swine Hepatitis E Virus in Taiwan Forming a Monophyletic Group with Taiwan Isolates of Human Hepatitis E Virus

Abstract

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.

A review of viral diseases of the European wild boar: Effects of population dynamics and reservoir rôle

“…Hepatitis E is an important disease of public health concern due to its zoonotic character. HEV has been widely reported to infect domestic swine herds around the world (Clayson et al, 1995;Meng et al, 1997Meng et al, , 1999Chandler et al, 1999;Hsieh et al, 1999;Pina et al, 2000). HEV transmission from wild animals to humans has been reported due to the consumption of raw or under-cooked deer or wild boar meat (Matsuda et al, 2003;Tei et al, 2003;Li et al, 2005).…”

Hepatitis viruses and emerging viruses

“…Studies have shown that these strains are very closely related to the human viruses and that they productively infect primates (Meng et al, 1997(Meng et al, , 1998. Phylogenetic analysis indicates that swine viruses are more closely related to their human counterparts within a country than to other swine isolates around the world (Meng et al, 1997;Hsieh et al, 1999;van der Poel et al, 2001;Pei and Yoo, 2002;Nishizawa et al, 2003;Banks et al, 2004). Zoonotic transmission of this virus to the human population has been postulated to occur through the consumption of raw or lightly cooked meat from a naturally infected animal (Teo, 2006;Vasickova et al, 2007).…”

RNA interference inhibits hepatitis E virus mRNA accumulation and protein synthesis in vitro

“…Hepatitis E virus, a member of the genus Hepevirus under the family Hepeviridae, has caused several outbreaks in developing countries and has prevalence in developed countries. HEV is transmitted predominantly by a fecal-oral route (Aggarwal and Krawczynshi, 2000;Hsieh et al, 1999); its prevalence is mainly waterborne. HEV is transmitted across species in humans, pigs, deer and rodents, and can cause experimental infection in chickens, cats and nonhuman primates (Arankalle et al, 2001;Feagins et al, 2008;Gardner and Luciw, 2008;Okamoto et al, 2004;Tei et al, 2003;Vitral et al, 2005).…”