We identified hepatitis E virus (HEV) in rabbits in Virginia, USA. HEV RNA was detected in 14 (16%) of 85 serum samples and 13 (15%) of 85 fecal samples. Antibodies against HEV were detected in 31 (36%) of 85 serum samples. Sequence analyses showed that HEV from rabbits is closely related to genotype 3.

Hepatitis E virus (HEV) is an important human pathogen. In addition to humans, HEV has also been identified in pig, chicken, mongoose, deer, rat, rabbit and fish. There are four recognized and two putative genotypes of mammalian HEV. Genotypes 1 and 2 are restricted to humans, while genotypes 3 and 4 are zoonotic. The recently identified rabbit HEV is a distant member of genotype 3. Here, we first expressed and purified the recombinant capsid protein of rabbit HEV and showed that the capsid protein of rabbit HEV cross-reacted with antibodies raised against avian, rat, swine and human HEV. Conversely, we showed that antibodies against rabbit HEV cross-reacted with capsid proteins derived from chicken, rat, swine and human HEV. Since pigs are the natural host of genotype 3 HEV, we then determined if rabbit HEV infects pigs. Twenty pigs were divided into five groups of four each and intravenously inoculated with PBS, US rabbit HEV, Chinese rabbit HEV, US rat HEV and swine HEV, respectively. Results showed that only half of the pigs inoculated with rabbit HEV had low levels of viraemia and faecal virus shedding, indicative of active but not robust HEV infection. Infection of pigs by rabbit HEV was further verified by transmission of the virus recovered from pig faeces to naïve rabbits. Pigs inoculated with rat HEV showed no evidence of infection. Preliminary results suggest that rabbit HEV is antigenically related to other HEV strains and infects pigs and that rat HEV failed to infect pigs.

Animal enteroviruses shed in the feces of infected animals are likely environmental contaminants and thus can be used as indicators of animal fecal pollution. Previous work has demonstrated that bovine enterovirus (BEV) present in bovine feces contaminates waters adjacent to cattle herds and that BEV-like sequences are also present in shellfish and in deer feces from the same geographical area. However, little information is available about the prevalence, molecular epidemiology, and genomic sequence variation of BEV field isolates. Here we describe an optimized highly sensitive real-time reverse transcription-PCR method to detect BEV RNA in biological and environmental samples. A combination of the amplification procedure with a previously described filtration step with electropositive filters allowed us to detect up to 12 BEV RNA molecules per ml of water. The feasibility of using the method to detect BEV in surface waters at a high risk of fecal pollution was confirmed after analysis of water samples obtained from different sources. The method was also used to study the prevalence of BEV in different cattle herds around Spain, and the results revealed that 78% (78 of 100) of the fecal samples were BEV positive. BEV-like sequences were also detected in feces from sheep, goats, and horses. Nucleotide sequence analyses showed that BEV isolates are quite heterogeneous and suggested the presence of species-specific BEV-like variants. Detection of BEV-like sequences may help in the differentiation and characterization of animal sources of contamination.The environment, including surface waters, is often contaminated with enteric viruses (4, 33), a heterogeneous group of viruses that comprises enteroviruses, noroviruses (Norwalklike viruses), astroviruses, rotaviruses, enteric adenoviruses, and hepatitis A and hepatitis E viruses. Enteroviruses are characterized by their stability, both in the gastrointestinal tract and in the environment, and thus are excreted in feces in large amounts and persist in the environment for long times. As their main transmission route is the fecal-oral route, food and water contaminated with these viruses are major sources of infection. In addition, it is known that rain contributes greatly to dissemination of these viruses in the environment, and therefore, surface waters are believed to be important enteric virus reservoirs.One of the best-studied groups of enteric viruses is the human enteroviruses, in the family Picornaviridae, which have long been recognized as indicators of fecal contamination of water (1,4,5,23,25,26,33). Although less is known about animal enteroviruses, it might be expected that these viruses are also good markers of environmental fecal contamination. Moreover, as most enteroviruses have a narrow host range, usually showing a strong preference for infection of one (or a few related) animal species, their presence in water can indicate that one or a few species are the source of contamination.In this regard, we have recently shown that viruses belonging to the ...

The RNA genome of the hepatitis E virus (HEV) contains a hypervariable region (HVR) in ORF1 that tolerates small deletions with respect to infectivity. To further investigate the role of the HVR in HEV replication, we constructed a panel of mutants with overlapping deletions in the N-terminal, central, and C-terminal regions of the HVR by using a genotype 1 human HEV luciferase replicon and analyzed the effects of deletions on viral RNA replication in Huh7 cells. We found that the replication levels of the HVR deletion mutants were markedly reduced in Huh7 cells, suggesting a role of the HVR in viral replication efficiency. To further verify the results, we constructed HVR deletion mutants by using a genetically divergent, nonmammalian avian HEV, and similar effects on viral replication efficiency were observed when the avian HEV mutants were tested in LMH cells. Furthermore, the impact of complete HVR deletion on virus infectivity was tested in chickens, using an avian HEV mutant with a complete HVR deletion. Although the deletion mutant was still replication competent in LMH cells, the complete HVR deletion resulted in a loss of avian HEV infectivity in chickens. Since the HVR exhibits extensive variations in sequence and length among different HEV genotypes, we further examined the interchangeability of HVRs and demonstrated that HVR sequences are functionally exchangeable between HEV genotypes with regard to viral replication and infectivity in vitro, although genotype-specific HVR differences in replication efficiency were observed. The results showed that although the HVR tolerates small deletions with regard to infectivity, it may interact with viral and host factors to modulate the efficiency of HEV replication.Hepatitis E virus (HEV), the causative agent of hepatitis E, is classified in the genus Hepevirus of the family Hepeviridae (11,17). It is now known that hepatitis E is a zoonotic disease and that animal reservoirs exist for HEV (13, 26-29, 38, 40). The inefficient replication of HEV in cell cultures has hindered progress in understanding the biology of HEV. The problem has been overcome partially by either characterizing individually expressed proteins from expression vectors or transfecting cells and intrahepatically inoculating animals with capped RNA transcripts generated in vitro from infectious clones (16,17,32,33). More recently, efficient in vitro HEV replication systems have been reported (3,31,35,37), which may aid in future understanding of HEV replication.The 7.2-kb RNA genome of HEV contains three open reading frames (ORFs), namely, ORF1, ORF2, and ORF3, flanked by 5Ј-and 3Ј-nontranslated regions (2). The putative functional domains in the ORF1 protein include methyltransferase, protease, helicase, and RNA-dependent RNA polymerase (RdRp) domains (2). ORF2 encodes the major capsid protein, whereas ORF3 encodes a small multifunctional protein (2,6,18,30,39). The methyltransferase and guanylyltransferase activities in capping of the viral RNA (25), the role of RdRp in viral RNA synthesis...