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Hepatitis E virus (HEV) is a major cause of viral hepatitis worldwide. Pigs are the natural host of HEV genotype 3 and the main reservoir of HEV. As the host range of HEV genotype 3 expands, the possibility that HEV from various species can be transmitted to humans via pigs is increasing. We investigated the potential cross-species transmission of HEV by infecting minipigs with swine HEV (swHEV), rabbit HEV (rbHEV), and human HEV (huHEV) and examining their histopathological characteristics and distribution in various organs. Fifteen specific-pathogen-free Yucatan minipigs were infected with swHEV, rbHEV, huHEV, or a mock control. In the present study, we analysed faecal shedding, viremia, and serological parameters over a seven-week period. Our results indicated that swHEV exhibited more robust shedding and viremia than non-swHEVs. Only swHEV affected the serological parameters, suggesting strain-specific differences. Histopathological examination revealed distinct patterns in the liver, pancreas, intestine, and lymphoid tissues after infection with each HEV strain. Notably, all three HEVs induced histopathological changes in the pancreas, supporting the association of HEVs with acute pancreatitis. Our results also identified skeletal muscle as a site of HEV antigen presence, suggesting a potential link to myositis. In conclusion, this study provides valuable insights into the infection dynamics of different HEV strains in minipigs, emphasizing the strain-specific variations in virological, serological, and histological parameters. The observed differences in infection kinetics and tissue tropism will contribute to our understanding of HEV pathogenesis and the potential for cross-species transmission., (© 2024. The Author(s).)

Infection by hepatitis E virus (HEV) via the oral route causes acute hepatitis. Extra-hepatic manifestations of HEV infection may stem from various causes; however, its distribution in organs such as the liver, as well as the mechanisms underlying HEV-induced cell injury, remain unclear. The objective of this study was to determine the chronological distribution of HEV in various tissues of HEV-challenged miniature pigs and to investigate the mechanisms underlying HEV-induced cell death in the pancreas and liver. Virological and serological analyses were performed on blood and faecal samples. Histopathology of the liver and extra-hepatic tissues was analysed. Cell death pathways and immune cell characterisation in inflammatory lesions were analysed using immunohistochemistry. The liver and pancreas displayed inflammation and cellular injury, and a large amount of HEV was observed in the lesions. The liver was infiltrated by T and natural killer cells. HEV was identified in all organs except the heart, and was associated with immune cells. Although the liver and the pancreas strongly expressed TNF-α and TRAIL, TUNEL assay results were negative. RIP3 and pMLKL were expressed in the pancreas. RIP3, but not pMLKL, was expressed in the liver. Pancreatitis induced in HEV-infected miniature pigs is associated with necroptosis.

Hepatitis E virus (HEV) causes severe hepatitis in pregnant women, with associated poor fetal outcomes. To study HEV viral pathogenesis, pregnant rabbits were infected with low- and high-dose rabbit HEV at 2 weeks gestation. HEV was identified in the serum, feces, and liver tissue of infected rabbits, and dose-dependent fetal mortality rates ranging from 67% to 80% were observed. The aspartate transaminase (AST)/alanine transaminase ratio was significantly higher (P < 0.01) in high-dose infected rabbits than low-dose infected and negative control rabbits 14 days post infection (dpi). Tumor necrosis factor-α (TNF-α) was significantly higher in low-dose (P < 0.01) and high-dose infected rabbits (P < 0.001) than in negative controls 7 dpi. High-dose HEV-infected rabbits produced significantly more interferon-γ (IFN-γ; P < 0.05) than negative control rabbits at 7 and 14 dpi. High levels of AST, TNF-α, and IFN-γ may substantially influence adverse fetal outcomes in pregnant rabbits infected with high-dose HEV., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The aim of this study was to develop an optimal technique for detecting hepatitis E virus (HEV) in swine livers. Here, three elution buffers and two concentration methods were compared with respect to enhancing recovery of HEV from swine liver samples. Real-time reverse transcription-polymerase chain reaction (RT-PCR) and nested RT-PCR were performed to detect HEV RNA. When phosphate-buffered saline (PBS, pH 7.4) was used to concentrate HEV in swine liver samples using ultrafiltration, real-time RT-PCR detected HEV in 6 of the 26 samples. When threonine buffer was used to concentrate HEV using polyethylene glycol (PEG) precipitation and ultrafiltration, real-time RT-PCR detected HEV in 1 and 3 of the 26 samples, respectively. When glycine buffer was used to concentrate HEV using ultrafiltration and PEG precipitation, real-time RT-PCR detected HEV in 1 and 3 samples of the 26 samples, respectively. When nested RT-PCR was used to detect HEV, all samples tested negative regardless of the type of elution buffer or concentration method used. Therefore, the combination of real-time RT-PCR and ultrafiltration with PBS buffer was the most sensitive and reliable method for detecting HEV in swine livers., (Copyright © 2014 Elsevier B.V. All rights reserved.)

This study aimed to develop a specific and sensitive reverse transcription polymerase chain reaction enzyme-linked immunosorbent assay (RT-PCR-ELISA) for detecting hepatitis E virus (HEV). Eight sets of primers and biotinylated probes designed in the ORF2-ORF3 overlapping region of HEV were tested for sensitivity. The ability of nested reverse transcription polymerase chain reaction (RT-PCR) and RT-PCR-ELISA to detect HEV was compared. RT-PCR-ELISA was 10-100 times more sensitive than nested RT-PCR and could detect 0.01 ng/μl HEV in swine stool samples. In terms of specificity, RT-PCR-ELISA did not falsely detect HEV when other viruses such as hepatitis A virus, rotavirus, norovirus genotype I, norovirus genotype II, and Feline calicivirus were present. Therefore, RT-PCR-ELISA appears to be a sensitive and specific method for detecting HEV.

This study aimed to develop a specific and sensitive duplex reverse transcription polymerase chain reaction enzyme-linked immunosorbent assay (duplex RT-PCR-ELISA) for hepatitis A virus (HAV) and hepatitis E virus (HEV). Duplex RT-PCR-ELISA could detect and differentiate HAV and HEV with specific probes. When ELISA technique was used to detect probe-bound RT-PCR products, duplex RT-PCR-ELISA could detect as little as 0.1 ng/μL HAV and HEV from clinical samples. Human norovirus, enterovirus, poliovirus, murine norovirus and feline calicivirus were used for the specificity test; all were negative. Therefore duplex RT-PCR-ELISA can be used for the simultaneous detection of HAV and HEV in contaminated fecal samples., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Swine hepatitis E virus (HEV) was detected in formalin-fixed, paraffin-embedded tissues from naturally infected pigs by nested reverse transcription-polymerase chain reaction (RT-PCR). The results for seminested RT-PCR were compared with those determined by in situ hybridization. The results obtained show that use of xylene deparaffinization, digestion with proteinase K followed by nested RT-PCR is a reliable detection method. Swine HEV nucleic acid was detected in formalin-fixed, paraffin-embedded hepatic tissues from 40 pigs. Distinct positive signals for swine HEV were obtained in the same hepatic tissues by in situ hybridization. Swine HEV nucleic acid was localized to the cytoplasm of hepatocytes and had a granular staining pattern. The rate of agreement between nested RT-PCR and in situ hybridization for the detection of swine HEV in formalin-fixed, paraffin-embedded hepatic tissues was 100%.

Background/aims: The objective of this study was to detect and localize the swine hepatitis E virus (HEV) in the liver and extrahepatic tissues from 20 pigs naturally infected with swine HEV., Methods: cDNA probe 289 base pairs for swine HEV were generated by reverse transcription-polymerase chain reaction. In situ hybridization with a nonradioactive digoxigenin-labeled cDNA probe was used for the detection of swine HEV in formalin-fixed, paraffin-embedded tissues., Results: When liver tissues from the pigs naturally infected with swine HEV were hybridized with the nonradioactive digoxigenin-labeled cDNA probe, a strong signal was seen in hepatocytes and bile duct. Positive hybridization signals were also detected in small and large intestine, lymph node, tonsil, spleen, and kidney., Conclusions: Swine HEV was detected primarily in the hepatocytes. Swine HEV may also replicate in tissues other than the liver. In situ hybridization described in the present study has greatly facilitated the application of in situ hybridization procedures to the clinical setting, thus allowing for the diagnosis of swine HEV infection while preserving the morphology of the tissue.