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Human and porcine hepatitis E virus strains, United Kingdom.

We describe a case of acquired infection of a strain of hepatitis E virus (HEV HEV
hepatitis E virus


hemagglutinating encephalomyelitis virus of pigs.
) with a 100% amino acid identity to the analogous region in strains of HEV circulating in a United Kingdom pig herd. This case further supports the theory that autochthonous autochthonous /au·toch·tho·nous/ (aw-tok´thah-nus)
1. originating in the same area in which it is found.

2. denoting a tissue graft to a new site on the same individual.
 HEV infection in industrialized in·dus·tri·al·ize  
v. in·dus·tri·al·ized, in·dus·tri·al·iz·ing, in·dus·tri·al·iz·es
1. To develop industry in (a country or society, for example).

 countries is zoonotic Zoonotic
A disease which can be spread from animals to humans.

Mentioned in: Zoonosis

Hepatitis E virus (HEV) is a common cause of acute hepatitis in many developing countries (1). HEV is often waterborne and causes an illness similar to hepatitis A. During the icteric ic·ter·ic
1. Relating to or affected with jaundice.

2. Used to treat jaundice.

A remedy for jaundice.


pertaining to or affected with jaundice.
 phase, patients may be viremic (2). In the last few years, sporadic cases of hepatitis E have been reported in industrialized countries in the absence of foreign travel or other known risk factors. Nucleotide sequence analysis of some of these viruses has indicated a high degree of sequence identity with the sequences of HEV detected in pigs (3-5) and in pig meat purchased in retail outlets in Japan (6). More recently, the most direct evidence of zoonotic transmission yet available was described in a case study from Japan. In this case, members of a family group were infected following consumption of uncooked Sika deer meat. The virus identified from the patients was shown to be identical to that recovered from uneaten quantities of meat from the same deer (7). In the United Kingdom, autochthonously acquired hepatitis E has been reported rarely and a short (98-bp) section of the virus genome has been sequenced from one such patient (8). Serologic evidence of HEV infection has been detected in U.K. pigs in a preliminary study (9) In two pigs from separate farms, an HEV genome was detected by reverse transcription--polymerase chain reaction (RT-PCR RT-PCR

reverse transcriptase-polymerase chain reaction. See PCR1.
) and sequenced (strains 1-40 and 14-P354). These sequences identified the porcine strains as nearly identical to the 98-bp U.K. human HEV sequence in HEV genotype 111 (9). Further study is underway to determine the prevalence and strain diversity of HEV infection in U.K. pigs.

The Study

In June 2000, a 58-year-old woman, who worked as a shop assistant, was seen at a rapid access "jaundice hotline" clinic with a 5-day history of myalgia and jaundice. She had not traveled outside the United Kingdom for 10 years and had no contact with farm or domestic animals. She was not a vegetarian and, although she admitted to eating raw sausage and bacon in the past, she claimed not to have done so in the 3 months before her illness. Examination confirmed jaundice and tenderness in the right upper quadrant right upper quadrant Physical exam The abdominal region that contains the liver, duodenum and head of pancreas . Her liver function tests Liver Function Tests Definition

Liver function tests, or LFTs, include tests for bilirubin, a breakdown product of hemoglobin, and ammonia, a protein byproduct that is normally converted into urea by the liver before being excreted by the kidneys.
 showed elevated levels of bilirubin Bilirubin

The predominant orange pigment of bile. It is the major metabolic breakdown product of heme, the prosthetic group of hemoglobin in red blood cells, and other chromoproteins such as myoglobin, cytochrome, and catalase.
, 46 [micro]mol/L; alanine aminotransferase, 2,421 IU/L; and alkaline phosphatase, 200 IU/L. Blood drawn at this time was positive for anti-HEV immunoglobulin (Ig) M; no serologic evidence indicated active infection with Epstein-Barr virus, cytomegalovirus, or hepatitis A, B, or C. Results of a liver ultrasound were normal, and serologic evidence did not indicate autoimmune or metabolic liver disease. One month later, she felt better, was no longer jaundiced, and results of her liver function tests were generally normal. A diagnosis of acute hepatitis E was made.

Total RNA RNA: see nucleic acid.
 in full ribonucleic acid

One of the two main types of nucleic acid (the other being DNA), which functions in cellular protein synthesis in all living cells and replaces DNA as the carrier of genetic
 was extracted in Trizol (Sigma, Poole, UK) from a blood sample drawn from the patient at the time she sought treatment. Template cDNA from the blood extraction was prepared by a reverse transcriptase step, according to standard protocols. A nested PCR PCR polymerase chain reaction.

polymerase chain reaction

Polymerase chain reaction (PCR) 
 was used to detect HEV from the prepared cDNA samples. This assay used degenerate oligonucleotide primers to amplify a 348-bp fragment of open reading frame 2 (ORF2) of HEV as described by Meng et al. (1997) (10).

Cycling parameters were the same as those described by Meng et al. (10), except for annealing annealing (ənēl`ĭng), process in which glass, metals, and other materials are treated to render them less brittle and more workable.  temperatures of 60[degrees]C and 55[degrees]C for external and internal primer pairs, respectively, and an extension time of 1 min. RT-PCR products were subjected to electrophoresis on a 2% agarose gel containing ethidium bromide and visualized under UV light.

Amplicons of correct size were excised from 2% agarose gels, purified with QIAquick Gel Extraction Kit (Qiagen Ltd., Crawley, UK), and sequenced with Big Dye Terminator Cycle Sequencing Ready Reaction (Applied Biosystems, Warrington, UK). Sequences comprising 304 bp of HEV ORF2 were assembled by SEQMAN (DNASTAR) and phylogenetic analysis was performed using PHYLIP PHYLIP Phylogeny Inference Package (genetics software)  (ver 3.6) with NEIGHBOR. Bootstrap confidence values were calculated by using SEQBOOT and CONSENSE (available from

Analysis of the 304-bp nucleotide sequence obtained between the primer sequences showed 16 and 32 nucleotide differences from the two U.K. pig strains 1-40 and 14-P354, respectively. However, all of these differences were silent when the gene sequence was translated into amino acids; the putative amino acid sequence of the virus detected in the patient had 100% identity with that of the two U.K. pig strains. Based on the nucleotide data the phylogeny of the three strains was determined (Figures 1 and 2), showing a very close relationship between the three strains in the genotype III lineage. In Japan, high sequence similarities have been demonstrated between human and pig HEV strains within genotype III and genotype IV (5).



HEV was discovered in pigs as recently as 1997 (10), despite evidence from several countries that it had been present since at least the early 1990s. The lack of recognized clinical disease in pigs (11) was undoubtedly a factor in this late discovery. The similarity of the human strain detected in this case to the two U.K. pig strains is suggestive of zoonotic transmission, as is the finding of higher Prevalence of anti-HEV antibodies in those who work with pigs (12) and the observation that in 9 of 10 hepatitis E patients in Japan, the disease developed within 2-8 weeks of consumption of grilled or undercooked pork (6). Consideration is being given within the U.K. Department for Environment, Food and Rural Affairs The Department for Environment, Food and Rural Affairs (Defra) is the United Kingdom government department responsible for environmental protection, food production and standards, agriculture, fisheries and rural communities in England.  to research proposals to gain better understanding of HEV in the U.K. pig herd. Screening patients who present with acute hepatitis for evidence of HEV infection is a simple way to improve the assessment of human HEV infection. Rapid access jaundice hotline clinics (13) are an ideal venue for such testing because patients may present while still viremic, allowing molecular characterization of infecting viruses as in this case. Work is currently in progress to assess the incidence of hepatitis E in a cohort of over 650 acutely jaundiced patients who have contacted the jaundice hotline in the past 5 years.

This work was supported in part by Defra project SE05 t 5


(1.) Labrique AB, Thomas DL, Stoszek SK, Nelson KE. Hepatitis E: an emerging infectious disease An emerging infectious disease (EID) is an infectious disease whose incidence has increased in the past 20 years and threatens to increase in the near future. EIDs include diseases caused by a newly identified microorganism or newly identified strain of a known microorganism (e.g. . Epidemiol Rev 1999;21:162-79.

(2.) Zhang JZ, Im SW, Lau SH, Chau TN, Lai ST, Ng SP. Occurrence of hepatitis E virus IgM, low avidity avidity /avid·i·ty/ (ah-vid´i-te)
1. the strength of an acid or base.

2. in immunology, an imprecise measure of the strength of antigen-antibody binding based on the rate at which the complex is formed. Cf.
 IgG serum antibodies, and viremia viremia /vi·re·mia/ (vi-re´me-ah) the presence of viruses in the blood.

The presence of viruses in the bloodstream.
 in sporadic cases of non-A, -B, and -C acute hepatitis. J Med Viral 2000;66:40-8.

(3.) Wu JC, Chen CM, Chiang TY, Sheen IJ. Chen JY, Tsai WH. et al. Clinical and epidemiological implications of swine hepatitis E virus infection. J Med Virol 2000;60:166-71.

(4.) Okamoto H, Takahashi M, Nishizawa T, Fukai K, Muramatsu U, Yoshikawa A. Analysis of the complete genome sequence of indigenous swine hepatitis E virus isolated in Japan. Biochem Biophys Res Commun 2001:289:929-36.

(5.) Nishizawa T, Takahashi M. Mizuo H, Miyajima H, Gotanda Y, Okamoto H. Characterization of Japanese swine and human hepatitis E virus isolates with 99% identity over the entire genome. J Gen Virol 2003;84:1245-51.

(6.) Yazaki Y, Mizuo H, Takahashi, M, Nishizawa T, Sasaki, N, Gotanda Y, el al. Sporadic acute or fulminant hepatitis E in Hokkaido, Japan, may be foodborne, as suggested by the presence of hepatitis E virus in pig liver as food. J Gen Virol 2003;84:2351-7.

(7.) Tei S, Kitajima N, Takahashi K, Mishiro S. Zoonotic transmission of hepatitis E virus from Sika deer to human beings. Lancet 2003;362:371-3.

(8.) Wang Y, Levine DF, Bendall RP, Teo CG, Harrison TJ. Partial sequence analysis of indigenous hepatitis E virus isolated in the United Kingdom. J Med Virol 2001;65:706-9.

(9.) Banks M, Grierson SS, King DP Gresham A. Girones R, Widen F, et al. Evidence for the presence of Hepatitis E virus in pigs in the UK. Vet Rec 2004;154:223-7.

(10.) Meng XJ, Purcell RH, Halbur PG, Lehman JR, Webb DM, Tsareva TS, et al. A novel virus in swine is closely related to the human hepatitis E virus. Proc Natl Acad Sci U S A 1997:94:9860-5.

(11.) Meng XJ, Halbur PG, Haynes JS, Tsaeva TS, Bruna JD Royer RL, ct al. Experimental infection of pigs with the newly identified swine hepatitis E virus (swine HEV), but not with human strains of HEV. Arch Virol 1998;143:1405-15.

(12.) Meng XJ, Wiseman B, Elvinger F, Guenette DK, Toth TE, Engle RE, et al. Prevalence of antibodies to hepatitis E virus in veterinarians working with swine and in normal blood donors in the United States and other countries. J Clin Microbiol 2002;40:117-22.

(13.) Mitchell J, Hussaini H, McGovern D, Farrow R, Maskell G, Dalton H. The "jaundice hotline" for the rapid assessment of patients with jaundice. BMJ BMJ n abbr (= British Medical Journal) → vom BMA herausgegebene Zeitschrift  2002:325:213-5.

Dr. Banks has been a research virologist virologist

microbiologist specializing in virology.
 at the Veterinary Laboratories Agency The Veterinary Laboratories Agency (VLA) is an executive agency of the UK government department, the Department for Environment, Food and Rural Affairs(Defra). It carries out animal disease surveillance, diagnostic services and veterinary scientific research for government and  for over 20 years. He has a background in the control of animal herpesviruses Herpesviruses
A family of viruses responsible for cold sores, chicken pox, and genital herpes.

Mentioned in: Skin Resurfacing
, working with the European Union and Office Internationale des Epizooties. His current research interests lie in the pathogenesis of porcine multisystemic mul·ti·sys·tem·ic
Relating to a disease or condition that affects many organ systems of the body.


affecting more than one body system.
 wasting syndrome and the incidence and prevalence of animal hepatitis E virus in relation to zoonoses Zoonoses

Infections of humans caused by the transmission of disease agents that naturally live in animals. People become infected when they unwittingly intrude into the life cycle of the disease agent and become unnatural hosts.

Address lot correspondence: Malcolm Banks, Veterinary Laboratories Agency, New Haw haw, common name for several plants, e.g., the hawthorn and the black haw (see honeysuckle). , Addlestone, Surrey, UK, KT153NB; fax: +44-0-1932-357239; email:

Malcolm Banks, * Richard Bendall, ([dagger]) Sylvia Grierson, * Graham Heath, * Jonathan Mitchell, ([double dagger]) and Harry Dalton ([dagger])

* Veterinary Laboratories Agency, New Haw, Addlestone, Surrey, United Kingdom; ([dagger]) Royal Cornwall Hospital, Treliske, Truro, Cornwall, United Kingdom; and ([double dagger]) Kings College Hospital, Denmark Hill, London, United Kingdom
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Title Annotation:Dispatches
Author:Dalton, Harry
Publication:Emerging Infectious Diseases
Geographic Code:4EUUK
Date:May 1, 2004
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