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Prevalence of Hepatitis E Virus Infection in Pigs at the Time of Slaughter, United Kingdom, 2013 - Volume 21, Number 8—August 2015 - Emerging Infectious Disease journal - CDC

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Prevalence of Hepatitis E Virus Infection in Pigs at the Time of Slaughter, United Kingdom, 2013 - Volume 21, Number 8—August 2015 - Emerging Infectious Disease journal - CDC

Volume 21, Number 8—August 2015


Prevalence of Hepatitis E Virus Infection in Pigs at the Time of Slaughter, United Kingdom, 2013

Sylvia Grierson, Judith Heaney, Tanya Cheney, Dilys Morgan, Stephen Wyllie, Laura Powell, Donald Smith, Samreen Ijaz, Falko Steinbach, Bhudipa Choudhury, and Richard S. TedderComments to Author 
Author affiliations: Animal and Plant Health Agency, Addlestone, United Kingdom (S. Grierson, T. Cheney, S. Wyllie, L. Powell, F. Steinbach, B. Choudhury)Public Health England, London, United Kingdom (J. Heaney, D. Morgan, S. Ijaz, R.S. Tedder)University of Edinburgh, Edinburgh, Scotland, United Kingdom (D. Smith);University of Surrey, Guildford, United Kingdom (F. Steinbach)University College London, London (R. S. Tedder)


Since 2010, reports of infection with hepatitis E virus (HEV) have increased in England and Wales. Despite mounting evidence regarding the zoonotic potential of porcine HEV, there are limited data on its prevalence in pigs in the United Kingdom. We investigated antibody prevalence, active infection, and virus variation in serum and cecal content samples from 629 pigs at slaughter. Prevalence of antibodies to HEV was 92.8% (584/629), and HEV RNA was detected in 15% of cecal contents (93/629), 3% of plasma samples (22/629), and 2% of both (14/629). However, although HEV is prevalent in pigs in the United Kingdom and viremic pigs are entering the food chain, most (22/23) viral sequences clustered separately from the dominant type seen in humans. Thus, pigs raised in the United Kingdom are unlikely to be the main source of human HEV infections in the United Kingdom. Further research is needed to identify the source of these infections.
Hepatitis E virus (HEV) that infects humans is composed of 4 genotypes (G1–4), each with a different geographic distribution and host range (1). Although G1 and G2 infect humans only, G3 and G4 infect humans and animals. HEV G3 and G4 are distributed worldwide, with G3 most commonly infecting both humans and pigs in Europe (2).From the observed incidence of acute HEV infection in blood donors (3), it is clear that HEV G3 infection in humans in England is far more common than previously thought. Realistic estimates are >100,000 infections annually.
Public Health England instituted enhanced surveillance of HEV infections in England and Wales in 2003 (4) and identified a recent and marked increase in the number of patients seeking treatment for HEV infections. In 2013, a total of 691 cases were identified, of which 477 (69%) were considered indigenous (occurring in persons who had not traveled outside England and Wales). Sequencing of strains from these acutely infected persons has identified an emergent phylogenetic cluster of HEV G3 infection in humans, which is likely to represent a zoonosis acquired through the consumption of undercooked meat (B. Said, pers. comm.).
In an early study in the United Kingdom of porcine samples archived during 1991–2001, antibodies to HEV were detected in 85.5% of 256 samples tested (5). More recent studies across Europe indicate that many pig herds show evidence of HEV G3 infection (610). A transient viremia in pigs is associated with dissemination of HEV into muscle and other tissues (11). A recent UK study found HEV RNA in 6 of 63 pork sausages tested, of which 5 were in a single batch of 11 (12), and a case−control study in England and Wales showed that human consumption of processed pork products is associated with an increased risk of acquiring HEV (13). It has long been considered plausible that the persistence of viremia in infected pigs up to the time of slaughter could provide a potential vehicle for zoonotic transmission to humans (14). We conducted surveillance of pigs at slaughter to investigate the epizoology of HEV in the United Kingdom and the extent of infection at the time pigs enter the food chain.
Dr. Grierson is a research scientist in the Department of Virology at the Animal and Plant Health Agency, Weybridge, UK. Her research interests focus on the molecular characterization and epidemiology of veterinary viruses, primarily relating to pig diseases.


We thank colleagues at the Public Health England Blood Borne Virus Unit and the Animal and Plant Health Agency for their support and assistance.
The data collection described here was undertaken as part of a national “2013 Zoonoses in UK Pigs Abattoir Study” jointly funded by the Department for Environment, Food, and Rural Affairs; the Food Standards Agency; Veterinary Medicines Directorate; Public Health England (PHE); and UK pig industry levy boards including the British Pig Executive (a division of the Agriculture and Horticulture Development Board), Ulster Pork and Bacon Forum, and Quality Meat Scotland. Representatives from the Animal and Plant Health Agency (formerly known as the Animal Health and Veterinary Laboratories Agency); Department for Environment, Food, and Rural Affairs; and PHE designed the study. The laboratory testing, data collection, analysis, and interpretation of the information presented here were undertaken by staff from PHE and the Animal and Plant Health Agency.


  1. Aggarwal RNaik SEpidemiology of hepatitis E: current status. J Gastroenterol Hepatol2009;24:148493DOIPubMed
  2. Goens SDPerdue ML. Hepatitis E viruses in humans and animals. Anim Health Res Rev. 2004;5:145–56.
  3. Hewitt PEIjaz SBrailsford SRBrett RDicks SHaywood BHepatitis E virus in blood components: a prevalence and transmission study in southeast England. Lancet2014;384:1766-73DOIPubMed
  4. Ijaz SSaid BBoxall ESmit EMorgan DTedder RSIndigenous hepatitis E in England and Wales from 2003 to 2012: evidence of an emerging novel phylotype of viruses. J Infect Dis2014;209:1212-8DOIPubMed
  5. Banks MHeath GSGrierson SSKing DPGresham AGirones REvidence for the presence of hepatitis E virus in pigs in the United Kingdom. Vet Rec2004;154:2237DOIPubMed
  6. Berto ABacker JAMesquita JRNascimento MSBanks MMartelli FPrevalence and transmission of hepatitis E virus in domestic swine populations in different European countries. BMC Res Notes2012;5:190DOIPubMed
  7. Breum Hjulsager CKde Deus NSegalés JLarsen LEHepatitis E virus is highly prevalent in the Danish pig population. Vet Microbiol.2010;146:1449DOIPubMed
  8. Jiménez de Oya Nde Blas IBlázquez ABMartín-Acebes MAHalaihel NGironés OWidespread distribution of hepatitis E virus in Spanish pig herds. BMC Res Notes2011;4:412DOIPubMed
  9. Rose NLunazzi ADorenlor VMerbah TEono FEloit MHigh prevalence of hepatitis E virus in French domestic pigs. Comp Immunol Microbiol Infect Dis2011;34:41927DOIPubMed
  10. Rutjes SABouwknegt Mvan der Giessen JWde Roda Husman AMReusken CBSeroprevalence of hepatitis E virus in pigs from different farming systems in The Netherlands. J Food Prot2014;77:6402DOIPubMed
  11. Bouwknegt MRutjes SAReusken CBStockhofe-Zurwieden NFrankena Kde Jong MCThe course of hepatitis E virus infection in pigs after contact-infection and intravenous inoculation. BMC Vet Res2009;5:7DOIPubMed
  12. Berto AMartelli FGrierson SBanks MHepatitis E virus in pork food chain, United Kingdom, 2009–2010. Emerg Infect Dis2012;18:135860.DOIPubMed
  13. Said BIjaz SChand MAKafatos GTedder RMorgan DHepatitis E virus in England and Wales: indigenous infection is associated with the consumption of processed pork products. Epidemiol Infect2014;142:146775DOIPubMed
  14. Smith JLA review of hepatitis E virus. J Food Prot2001;64:57286.PubMed
  15. BPEX Agriculture and Horticulture Development Board. Pig pocketbook 2014 [cited 2014 Dec 16].
  16. Department for Environment, Food, and Rural Affairs, Public Health England. Zoonoses report, UK, 2012 [cited 2014 Dec 16].
  17. Garson JAFerns RBGrant PRIjaz SNastouli ESzypulska RMinor groove binder modification of widely used TaqMan probe for hepatitis E virus reduces risk of false negative real-time PCR results. J Virol Methods2012;186:15760DOIPubMed
  18. Jothikumar NCromeans TLRobertson BHMeng XJHill VRA broadly reactive one-step real-time RT-PCR assay for rapid and sensitive detection of hepatitis E virus. J Virol Methods2006;131:6571DOIPubMed
  19. Meng XJPurcell RHHalbur PGLehman JRWebb DMTsareva TSA novel virus in swine is closely related to the human hepatitis E virus. Proc Natl Acad Sci U S A1997;94:98605DOIPubMed
  20. Ijaz SArnold EBanks MBendall RPCramp MECunningham RNon-travel-associated hepatitis E in England and Wales: demographic, clinical, and molecular epidemiological characteristics. J Infect Dis2005;192:116672DOIPubMed
  21. Tamura KStecher GPeterson DFilipski AKumar SMEGA6: Molecular Evolutionary Genetics Analysis version 6.0. Mol Biol Evol.2013;30:27259DOIPubMed
  22. Walachowski SDorenlor VLefevre JLunazzi AEono FMerbah TRisk factors associated with the presence of hepatitis E virus in livers and seroprevalence in slaughter-age pigs: a retrospective study of 90 swine farms in France. Epidemiol Infect2014;142:193444DOIPubMed
  23. Leblanc DPoitras EGagné MJWard PHoude AHepatitis E virus load in swine organs and tissues at slaughterhouse determined by real-time RT-PCR. Int J Food Microbiol2010;139:2069DOIPubMed
  24. Di Bartolo IPonterio ECastellini LOstanello FRuggeri FMViral and antibody HEV prevalence in swine at slaughterhouse in Italy. Vet Microbiol.2011;149:3308DOIPubMed
  25. Casas MCortés RPina SPeralta BAllepuz ACortey MLongitudinal study of hepatitis E virus infection in Spanish farrow-to-finish swine herds.Vet Microbiol2011;148:2734DOIPubMed
  26. Andraud MDumarest MCariolet RAylaj BBarnaud EEono FDirect contact and environmental contaminations are responsible for HEV transmission in pigs. Vet Res2013;44:102DOIPubMed
  27. Colson PBorentain PQueyriaux BKaba MMoal VGallian PPig liver sausage as a source of hepatitis E virus transmission to humans. J Infect Dis.2010;202:82534DOIPubMed
  28. Wacheck SWerres CMohn UDorn SSoutschek EFredriksson-Ahomaa MDetection of IgM and IgG against hepatitis E virus in serum and meat juice samples from pigs at slaughter in Bavaria, Germany. Foodborne Pathog Dis2012;9:65560DOIPubMed
  29. Satou KNishiura HTransmission dynamics of hepatitis E among swine: potential impact upon human infection. BMC Vet Res2007;3:9.DOIPubMed
  30. Backer JABerto AMcCreary CMartelli Fvan der Poel WHTransmission dynamics of hepatitis E virus in pigs: estimation from field data and effect of vaccination. Epidemics. 2012;4:8692DOIPubMed



Suggested citation for this article: Grierson S, Heaney J, Cheney T, Morgan D, Wyllie S, Powell L, et al. Prevalence of hepatitis E virus infection in pigs at the time of slaughter, United Kingdom, 2013. Emerg Infect Dis. 2015 Aug [date cited].
DOI: 10.3201/eid2108.141995

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