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Chen Y, Wang X, Zhang M, Li J, Gao X, Nan Y, Zhao Q, Zhou EM, Liu B. Identification of two novel neutralizing nanobodies against swine hepatitis E virus. Front Microbiol 2022; 13:1048180. [PMID: 36504801 PMCID: PMC9727072 DOI: 10.3389/fmicb.2022.1048180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 10/31/2022] [Indexed: 11/24/2022] Open
Abstract
Hepatitis E virus (HEV) is thought to be a zoonotic pathogen that causes serious economic loss and threatens human health. However, there is a lack of efficient antiviral strategies. As a more promising tool for antiviral therapy, nanobodies (also named single-domain antibodies, sdAbs) exhibit higher specificity and affinity than traditional antibodies. In this study, nanobody anti-genotype four HEV open reading frame 2 (ORF2) was screened using phage display technology, and two nanobodies (nb14 and nb53) with high affinity were prokaryotically expressed. They were identified to block HEV ORF2 virus like particle (VLP) sp239 (aa 368-606) absorbing HepG2 cells in vitro. With the previously built animal model, the detection indicators of fecal shedding, viremia, seroconversion, alanine aminotransferase (ALT) levels, and liver lesions showed that nb14 could completely protect rabbits from swine HEV infection, and nb53 partially blocked swine HEV infection in rabbits. Collectively, these results revealed that nb14, with its anti-HEV neutralizing activity, may be developed as an antiviral drug for HEV.
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Meester M, Tobias TJ, Bouwknegt M, Kusters NE, Stegeman JA, van der Poel WHM. Infection dynamics and persistence of hepatitis E virus on pig farms - a review. Porcine Health Manag 2021; 7:16. [PMID: 33546777 PMCID: PMC7863251 DOI: 10.1186/s40813-021-00189-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/01/2021] [Indexed: 12/16/2022] Open
Abstract
Background Hepatitis E virus (HEV) genotype 3 and 4 is a zoonosis that causes hepatitis in humans. Humans can become infected by consumption of pork or contact with pigs. Pigs are the main reservoir of the virus worldwide and the virus is present on most pig farms. Main body Though HEV is present on most farms, the proportion of infected pigs at slaughter and thus the level of exposure to consumers differs between farms and countries. Understanding the cause of that difference is necessary to install effective measures to lower HEV in pigs at slaughter. Here, HEV studies are reviewed that include infection dynamics of HEV in pigs and on farms, risk factors for HEV farm prevalence, and that describe mechanisms and sources that could generate persistence on farms. Most pigs become infected after maternal immunity has waned, at the end of the nursing or beginning of the fattening phase. Risk factors increasing the likelihood of a high farm prevalence or proportion of actively infected slaughter pigs comprise of factors such as farm demographics, internal and external biosecurity and immunomodulating coinfections. On-farm persistence of HEV is plausible, because of a high transmission rate and a constant influx of susceptible pigs. Environmental sources of HEV that enhance persistence are contaminated manure storages, water and fomites. Conclusion As HEV is persistently present on most pig farms, current risk mitigation should focus on lowering transmission within farms, especially between farm compartments. Yet, one should be aware of the paradox of increasing the proportion of actively infected pigs at slaughter by reducing transmission insufficiently. Vaccination of pigs may aid HEV control in the future.
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Affiliation(s)
- M Meester
- Farm Animal Health unit, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
| | - T J Tobias
- Farm Animal Health unit, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | | | - N E Kusters
- Wageningen Bioveterinary Research, Lelystad, the Netherlands
| | - J A Stegeman
- Farm Animal Health unit, Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
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Salines M, Dumarest M, Andraud M, Mahé S, Barnaud E, Cineux M, Eveno E, Eono F, Dorenlor V, Grasland B, Bourry O, Pavio N, Rose N. Natural viral co-infections in pig herds affect hepatitis E virus (HEV) infection dynamics and increase the risk of contaminated livers at slaughter. Transbound Emerg Dis 2019; 66:1930-1945. [PMID: 31067014 DOI: 10.1111/tbed.13224] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 04/30/2019] [Accepted: 05/02/2019] [Indexed: 12/23/2022]
Abstract
Hepatitis E virus (HEV) is a zoonotic pathogen, in particular genotype 3 HEV is mainly transmitted to humans through the consumption of contaminated pork products. This study aimed at describing HEV infection patterns in pig farms and at assessing the impact of immunomodulating co-infections namely Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and Porcine Circovirus Type 2 (PCV2), as well as other individual factors such as piglets' immunity and litters' characteristics on HEV dynamics. A longitudinal follow-up was conducted in three farrow-to-finish farms known to be HEV infected. Overall, 360 piglets were individually monitored from birth to slaughter with regular blood and faecal sampling as well as blood and liver samples collected at slaughterhouse. Virological and serological analyses were performed to detect HEV, PCV2 and PRRSV genome and antibodies. The links between 12 explanatory variables and four outcomes describing HEV dynamics were assessed using cox-proportional hazard models and logistic regression. HEV infection dynamics was found highly variable between farms and in a lower magnitude between batches. HEV positive livers were more likely related to short time-intervals between HEV infection and slaughter time (<40 days, OR = 4.1 [3.7-4.5]). In addition to an influence of piglets' sex and sows' parity, the sequence of co-infections was strongly associated with different HEV dynamics: a PRRSV or PCV2/PRRSV pre- or co-infection was associated with a higher age at HEV shedding (Hazard Ratio = 0.3 [0.2-0.5]), as well as a higher age at HEV seroconversion (HR = 0.5 [0.3-0.9] and HR = 0.4 [0.2-0.7] respectively). A PCV2/PRRSV pre- or co-infection was associated with a longer duration of shedding (HR = 0.5 [0.3-0.8]). Consequently, a PRRSV or PCV2/PRRSV pre- or co-infection was strongly associated with a higher risk of having positive livers at slaughter (OR = 4.1 [1.9-8.9] and OR = 6.5 [3.2-13.2] respectively). In conclusion, co-infections with immunomodulating viruses were found to affect HEV dynamics in the farrow-to-finish pig farms that were followed in this study.
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Affiliation(s)
- Morgane Salines
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.,Bretagne-Loire University, Rennes, France
| | - Marine Dumarest
- ANSES, Laboratoire de Santé Animale, UMR 1161 Virology, Maisons-Alfort, France.,INRA, UMR 1161 Virology, Maisons-Alfort, France.,Ecole Nationale Vétérinaire d'Alfort, UMR 1161 Virology, Maisons-Alfort, France
| | - Mathieu Andraud
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.,Bretagne-Loire University, Rennes, France
| | - Sophie Mahé
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.,Bretagne-Loire University, Rennes, France
| | - Elodie Barnaud
- ANSES, Laboratoire de Santé Animale, UMR 1161 Virology, Maisons-Alfort, France.,INRA, UMR 1161 Virology, Maisons-Alfort, France.,Ecole Nationale Vétérinaire d'Alfort, UMR 1161 Virology, Maisons-Alfort, France
| | - Maelan Cineux
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.,Bretagne-Loire University, Rennes, France
| | - Eric Eveno
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.,Bretagne-Loire University, Rennes, France
| | - Florent Eono
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.,Bretagne-Loire University, Rennes, France
| | - Virginie Dorenlor
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.,Bretagne-Loire University, Rennes, France
| | - Béatrice Grasland
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.,Bretagne-Loire University, Rennes, France
| | - Olivier Bourry
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.,Bretagne-Loire University, Rennes, France
| | - Nicole Pavio
- ANSES, Laboratoire de Santé Animale, UMR 1161 Virology, Maisons-Alfort, France.,INRA, UMR 1161 Virology, Maisons-Alfort, France.,Ecole Nationale Vétérinaire d'Alfort, UMR 1161 Virology, Maisons-Alfort, France
| | - Nicolas Rose
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.,Bretagne-Loire University, Rennes, France
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Denner J. Hepatitis E virus (HEV)-The Future. Viruses 2019; 11:E251. [PMID: 30871152 PMCID: PMC6466233 DOI: 10.3390/v11030251] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/05/2019] [Accepted: 03/09/2019] [Indexed: 02/06/2023] Open
Abstract
Hepatitis (HEV) is widely distributed in pigs and is transmitted with increasing numbers to humans by contact with pigs, contaminated food and blood transfusion. The virus is mostly apathogenic in pigs but may enhance the pathogenicity of other pig viruses. In humans, infection can lead to acute and chronic hepatitis and extrahepatic manifestations. In order to stop the emerging infection, effective counter-measures are required. First of all, transmission by blood products can be prevented by screening all blood donations. Meat and sausages should be appropriately cooked. Elimination of the virus from the entire pork production can be achieved by sensitive testing and elimination programs including early weaning, colostrum deprivation, Caesarean delivery, embryo transfer, treatment with antivirals, protection from de novo infection, and possibly vaccination. In addition, contaminated water, shellfish, vegetables, and fruits by HEV-contaminated manure should be avoided. A special situation is given in xenotransplantation using pig cells, tissues or organs in order to alleviate the lack of human transplants. The elimination of HEV from pigs, other animals and humans is consistent with the One Health concept, preventing subclinical infections in the animals as well as preventing transmission to humans and disease.
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