Molecular epidemiology of hepatitis E virus in humans, pigs and wild boars in Sweden

Widén, Frederik; Sundqvist, Lena; Matyi-Toth, A.; Metreveli, Giorgi; Belák, Sándór; Hallgren, Gunilla; Nordér, Helené

doi:10.1017/s0950268810001342

Cited by 76 publications

(80 citation statements)

References 41 publications

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“…However, the finding of an identical genotype 3 strain at two different samplings, 18 weeks apart, indicates a local strain and possibly autochthonous infections. The high similarity to a HEV strain found in a local piglet increases the possibility of a zoonotic transmission, which has also been found in other Scandinavian countries (Widen et al 2011). A different genotype 3 strain was found in effluent from plant A and Food Environ Virol (2015) 7:213-223 221 supports the view that genotype 3 could be causing most domestic HEV infections in Norway.…”

Section: Discussionmentioning

confidence: 52%

A 1-Year Quantitative Survey of Noro-, Adeno-, Human Boca-, and Hepatitis E Viruses in Raw and Secondarily Treated Sewage from Two Plants in Norway

2015

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A study of enteric viruses in raw and treated sewage from two secondary treatment plants, which received sewage from Oslo city (plant A) and small municipalities in Hedmark county in Norway (plant B), showed high levels of noro-, adeno-, and bocavirus throughout the year. A seasonal variation was observed for adeno- and GII norovirus with higher levels during winter and bocavirus that had more positive samples during winter. The virus concentrations in raw sewage were comparable in the two plants, with medians (log10 genome copies per liter) of 6.1, 6.3, 6.0, and 4.5 for noro GI, noro GII, adeno-, and bocavirus, respectively. The level of hepatitis E virus was not determined as it was below the limit of quantification. The mean log10 virus reduction was 0.55 (plant A) and 1.44 (plant B) with the highest reduction found in the plant with longer hydraulic retention time. The adenoviruses were dominantly serotype 41, while serotype 12 appeared sporadically. Of the 102 raw and treated sewage samples that were tested, eight were positive for hepatitis E virus of which four were from treated sewage. Two of the four obtained gene sequences from hepatitis E virus originated from the rural sewage samples and showed high similarity with a genotype 3 strain of hepatitis E virus detected in local piglets. Two other hepatitis E virus sequences obtained from urban sewage samples showed high similarities with genotype 3 strains isolated from urban sewage in Spain and a human genotype 1 isolate from India. The study gives information on the levels of noroviruses in raw and treated sewage, which is valuable to risk assessment, information indicating that some infections with hepatitis E viruses in Norway have a regional origin and that human bocavirus 2 and 3 are prevalent in the Norwegian population.

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Section: Discussionmentioning

confidence: 52%

A 1-Year Quantitative Survey of Noro-, Adeno-, Human Boca-, and Hepatitis E Viruses in Raw and Secondarily Treated Sewage from Two Plants in Norway

2015

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“…In this context, the categorization of virus isolates at levels below genotype loses much of its importance. Epidemiological studies of virus outbreaks (31,32), infectious sources (33,34), transmission events (35,36), or mixed infections (37) can demonstrate phylogenetic relationships without requiring the assignment of isolates to particular subtypes.…”

Section: Discussionmentioning

confidence: 99%

Genetic Variability and the Classification of Hepatitis E Virus

Smith

Purdy

Simmonds

2013

J Virol

129

111

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bThe classification of hepatitis E virus (HEV) variants is currently in transition without agreed definitions for genotypes and subtypes or for deeper taxonomic groupings into species and genera that could incorporate more recently characterized viruses assigned to the Hepeviridae family that infect birds, bats, rodents, and fish. These conflicts arise because of differences in the viruses and genomic regions compared and in the methodology used. We have reexamined published sequences and found that synonymous substitutions were saturated in comparisons between and within virus genotypes. Analysis of complete genome sequences or concatenated ORF1/ORF2 amino acid sequences indicated that HEV variants most closely related to those infecting humans can be consistently divided into six genotypes (types 1 to 4 and two additional genotypes from wild boar). Variants isolated from rabbits, closely related to genotype 3, occupy an intermediate position. No consistent criteria could be defined for the assignment of virus subtypes. Analysis of amino acid sequences from these viruses with the more divergent variants from chickens, bats, and rodents in three conserved subgenomic regions (residues 1 to 452 or 974 to 1534 of ORF1 or residues 105 to 458 of ORF2) provided consistent support for a division into 4 groups, corresponding to HEV variants infecting humans and pigs, those infecting rats and ferrets, those from bats, and those from chickens. This approach may form the basis for a future genetic classification of HEV into four species, with the more divergent HEV-like virus from fish (cutthroat trout virus) representing a second genus.

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“…Since HEV is common among Swedish pigs and wild boars (58,59), the strains in sewage need to be sequenced to identify if they derive from infected humans, animals, or contaminated food products. The seroprevalence of anti-HEV is comparably high in Sweden (60,61), but there are only 10 to 15 notified cases yearly, indicating that most cases are subclinical.…”

Section: Discussionmentioning

confidence: 99%

Detection of Pathogenic Viruses in Sewage Provided Early Warnings of Hepatitis A Virus and Norovirus Outbreaks

Hellmér

Paxéus

Magnius

et al. 2014

Appl Environ Microbiol

431

302

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dMost persons infected with enterically transmitted viruses shed large amounts of virus in feces for days or weeks, both before and after onset of symptoms. Therefore, viruses causing gastroenteritis may be detected in wastewater, even if only a few persons are infected. In this study, the presence of eight pathogenic viruses (norovirus, astrovirus, rotavirus, adenovirus, Aichi virus, parechovirus, hepatitis A virus [HAV], and hepatitis E virus) was investigated in sewage to explore whether their identification could be used as an early warning of outbreaks. Samples of the untreated sewage were collected in proportion to flow at Ryaverket, Gothenburg, Sweden. Daily samples collected during every second week between January and May 2013 were pooled and analyzed for detection of viruses by concentration through adsorption to milk proteins and PCR. The largest amount of noroviruses was detected in sewage 2 to 3 weeks before most patients were diagnosed with this infection in Gothenburg. The other viruses were detected at lower levels. HAV was detected between weeks 5 and 13, and partial sequencing of the structural VP1protein identified three different strains. Two strains were involved in an ongoing outbreak in Scandinavia and were also identified in samples from patients with acute hepatitis A in Gothenburg during spring of 2013. The third strain was unique and was not detected in any patient sample. The method used may thus be a tool to detect incipient outbreaks of these viruses and provide early warning before the causative pathogens have been recognized in health care.

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Molecular epidemiology of hepatitis E virus in humans, pigs and wild boars in Sweden

Cited by 76 publications

References 41 publications

A 1-Year Quantitative Survey of Noro-, Adeno-, Human Boca-, and Hepatitis E Viruses in Raw and Secondarily Treated Sewage from Two Plants in Norway

A 1-Year Quantitative Survey of Noro-, Adeno-, Human Boca-, and Hepatitis E Viruses in Raw and Secondarily Treated Sewage from Two Plants in Norway

Genetic Variability and the Classification of Hepatitis E Virus

Detection of Pathogenic Viruses in Sewage Provided Early Warnings of Hepatitis A Virus and Norovirus Outbreaks

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