Human Hepatitis E Virus Sequences Research Articles

Investigating animal reservoirs for hepatitis E virus in Bangui, Central African Republic.

Hepatitis E virus (HEV) is a major cause of enterotropic viral hepatitis, a major public health problem in many developing countries. In Central African Republic (CAR), HEV genotypes 1, 2, and 3 have been found to have an impact on human health. However, data on HEV in animal reservoirs are still lacking for CAR. Here, we investigated the presence of HEV in farmed pigs and goats in Bangui, the capital city of CAR, using molecular methods. In a prospective study, fecal samples from 61 pigs and 39 goats from farms in five districts (2nd, 4th, 6th, 7th, 8th) of Bangui were collected and tested for HEV RNA by real-time RT-PCR. The samples were further analyzed by nested-PCR and sequenced to determine the genotype and subtype to which the virus belong. In total, 22/100 (22.0%) feces samples were successfully amplified for HEV RNA by real time RT-PCR. All positive samples were from pigs (22/61; 36.1%), while all goat samples were negative (0/39). Twelve HEV RNA samples (12/22 or 54.5%) were successfully amplified by nested RT-PCR, and subsequently sequenced. Phylogenetic analysis revealed that the obtained sequences clustered with subtype 3h and were genetically related to the human HEV sequences from CAR. This study confirms that pigs constitute an HEV reservoir, with genotype 3 being the major circulating strain. Further studies are needed to investigate other local reservoirs and to improve knowledge of the molecular epidemiology of HEV in CAR.

Estimation of hepatitis E virus (HEV) pig seroprevalence using ELISA and Western blot and comparison between human and pig HEV sequences in Belgium

Zoonotic transmission of hepatitis E virus (HEV) is of special concern, particularly in high income countries were waterborne infections are less frequent than in developing countries. High HEV seroprevalences can be found in European pig populations. The aims of this study were to obtain prevalence data on HEV infection in swine in Belgium and to phylogenetically compare Belgian human HEV sequences with those obtained from swine. An ELISA screening prevalence of 73% (95% CI 68.8–77.5) was determined in Belgian pigs and a part of the results were re-evaluated by Western blot (WB). A receiver operating characteristic curve analysis was performed and scenarios varying the ELISA specificity relative to WB were analysed. The seroprevalences estimated by the different scenarios ranged between 69 and 81% and are in agreement with the high exposure of the European pig population to HEV. Pig HEV sequences were genetically compared to those detected in humans in Belgium and a predominance of genotype 3 subtype f was shown in both swine and humans. The high HEV seroprevalence in swine and the close phylogenetic relationships between pig and human HEV sequences further support the risk for zoonotic transmission of HEV between humans and pigs.

Indigenous Hepatitis E Virus Genotype 1 Infection, Uruguay

Indigenous Hepatitis E Virus Genotype 1 Infection, Uruguay

Genetic characteristics and pathogenicity of human hepatitis E virus in Nanjing, China

To investigate the genetic characteristics and pathogenicity of hepatitis E virus (HEV) and assess the potential risk factors for sporadic hepatitis E. Sixty-two serum samples from the patients with acute hepatitis E were collected, including 23 cases coinfected with hepatitis B virus. Anti-HEV detection and partial HEV RNA amplification were performed by enzyme immunoassays and reverse transcription-nested polymerase chain reaction (RT-nPCR) method, respectively, and PCR products were sequenced. The isolated human HEV sequences were analyzed phylogenetically. The positive rate of serum HEV RNA were 21.0% (13/62), including 5 cases of liver failure. All the 13 isolates shared a 82.1%-98.0% nucleotide homology with each other and had identities of 74.7%-81.0%, 75.3%-78.6%, 75.3%-80.0% and 82.1%-96.1% with the corresponding regions of HEV genotypes 1-4, respectively. The human HEV strain GS-NJ-12 shared a 100% nucleotide identity with the swine HEV strain swIM6-43 isolated from Inner Mongolia, China. Swine may be a principal risk factor for occurrence of sporadic hepatitis E in eastern China, and genotype 4 HEV can induce acute liver failure.

Seroprevalence and molecular detection of hepatitis E virus in Yunnan Province, China

In this study, the prevalence and characteristics of hepatitis E virus (HEV) in pigs and the general population in the Yunnan province, China, were evaluated. Nine hundred sixty sera, 95 liver and 60 feces samples were randomly collected from pig farms and abattoirs, in addition 173 human sera were sampled in the provincial capital city for a serological survey and an RT-nPCR assay. The screening results showed that among 621 samples collected from five pig farms, the HEV-specific IgG positive rate ranged from 73.2% to 83.5%, and the overall seroprevalence was 78.9% (490/621). A further analysis revealed that the seroprevalence increased with age. The positive rate of human serum samples was 39.9% (69/173). HEV RNA was detected in five swine feces, six swine liver and one anti-HEV-IgM-positive human serum sample by RT-nPCR. Sequence and alignment of the 348-nt PCR-amplified products of 12 HEV strains identified nine distinct nucleotide sequences. Phylogenetic and molecular evolutionary analysis revealed that these nine sequences shared 84.2% to 100.0% nucleotide sequence identity with each other, with all isolates belonging to genotype 4 HEV and clustering with other Chinese swine and human HEV sequences determined earlier. This study results suggest that the prevalence of genotype 4 HEV is serious, both in pig herds and in the human population, and authorities should pay more attention to the prevalence of HEV in southwest China.

Detection of hepatitis E virus of genotype 3 in a farm pig in Kinshasa (Democratic Republic of the Congo)

Autochthonous hepatitis E is an emerging disease in industrialized countries where a growing body of data indicates that pigs represent a reservoir for hepatitis E virus (HEV) of genotype 3 or 4. In Africa, only HEV genotypes 1 and 2 have been identified in hepatitis E outbreaks as well as in sporadic cases. We aimed to investigate whether commercial pigs in sub-Saharan Africa might represent an HEV reservoir using molecular assays. Faecal samples from 40 pigs of the Pietrain race housed in a farm in Kinshasa (Democratic Republic of the Congo) were tested using in-house real-time reverse transcription (RT)-PCR and sequencing assays. HEV RNA was detected in faeces of one (2.5%) pig, and the HEV sequence obtained from this pig was classified genotype 3c, and was genetically related to human HEV sequences from France (89–92% nucleotide similarity) and pig HEV sequences from The Netherlands (88–91% nucleotide similarity). Epidemiological investigations revealed that Kinshasa farm pigs tested in the present study are descendants of pigs imported from Belgium in 2002, suggesting that pig HEV genotype 3c recovered in our study may have been imported from Belgium to Democratic Republic of the Congo. Our findings, although needing to be confirmed in further studies, also suggest that pigs in sub-Saharan Africa may be an HEV reservoir.

Sources of Hepatitis E Virus Genotype 3 in the Netherlands

Non-travel-related hepatitis E virus (HEV) genotype 3 infections in persons in the Netherlands may have a zoonotic, foodborne, or water-borne origin. Possible reservoirs for HEV transmission by water, food, and animals were studied. HEV genotype 3/open reading frame 2 sequences were detected in 53% of pig farms, 4% of wild boar feces, and 17% of surface water samples. HEV sequences grouped within 4 genotype 3 clusters, of which 1 is so far unique to the Netherlands. The 2 largest clusters contained 35% and 43% of the animal and environmental sequences and 75% and 6%, respectively, of human HEV sequences obtained from a study on Dutch hepatitis E patients. This finding suggests that infection risk may be also dependent on transmission routes other than the ones currently studied. Besides the route of exposure, virus characteristics may be an important determinant for HEV disease in humans.

Non-travel related Hepatitis E virus genotype 3 infections in the Netherlands; A case series 2004 – 2006

BackgroundHuman hepatitis E virus (HEV) infections are considered an emerging disease in industrialized countries. In the Netherlands, Hepatitis E virus (HEV) infections have been associated with travel to high-endemic countries. Non-travel related HEV of genotype 3 has been diagnosed occasionally since 2000. A high homology of HEV from humans and pigs suggests zoonotic transmission but direct molecular and epidemiological links have yet to be established. We conducted a descriptive case series to generate hypotheses about possible risk factors for non-travel related HEV infections and to map the genetic diversity of HEV.MethodsA case was defined as a person with HEV infection laboratory confirmed (positive HEV RT-PCR and/or HEV IgM) after 1 January 2004, without travel to a high-endemic country three months prior to onset of illness. For virus identification 148 bp of ORF2 was sequenced and compared with HEV from humans and pigs. We interviewed cases face to face using a structured questionnaire and collected information on clinical and medical history, food preferences, animal and water contact.ResultsWe interviewed 19 cases; 17 were male, median age 50 years (25–84 y), 12 lived in the North-East of the Netherlands and 11 had preexisting disease. Most common symptoms were dark urine (n = 16) and icterus (n = 15). Sixteen ate pork ≥ once/week and six owned dogs. Two cases had received blood transfusions in the incubation period. Seventeen cases were viremic (genotype 3 HEV), two had identical HEV sequences but no identified relation. For one case, HEV with identical sequence was identified from serum and surface water nearby his home.ConclusionThe results show that the modes of transmission of genotype-3 HEV infections in the Netherlands remains to be resolved and that host susceptibility may play an important role in development of disease.

Hepatitis E Virus RNA in Commercial Porcine Livers in The Netherlands

Human hepatitis E virus (HEV) infections by genotype 3 strains in industrialized countries are hypothesized to be caused by pigs. To examine this hypothesis, the potential health risks of transmission routes should be examined. Possible foodborne transmission was studied by quantifying the presence and infectivity of HEV in commercial porcine livers in The Netherlands. A comparison of four tissue disruption and seven RNA extraction methods revealed that mechanical disruption followed by silica-based RNA extraction gave the highest RNA yields and was therefore employed on commercial porcine livers. Four (6.5%) of 62 porcine livers were HEV RNA positive by reverse transcriptase PCR and Southern blot hybridization. Each positive liver was estimated to contain ∼65 PCR-detectable units per g. Sequences were obtained for three of four positive livers and classified as HEV genotype 3. Ninety-three percent similarity to Dutch human HEV sequences and 97% similarity to Dutch swine HEV sequences were observed. To determine whether positive livers contained infectious HEV particles, extracts from livers with known HEV RNA sequences were inoculated intravenously in pigs. Two control pigs were included: one was inoculated with a high dose known to result in infection (104 PCR-detectable units of HEV RNA), and the other was inoculated with a lower concentration of virus that equaled the concentration of PCR-detectable units in commercial livers (∼20 PCR-detectable units). Infection was observed in the high-dose control, but not in other pigs, suggesting a dose-dependent response in pigs. Hence, the implications of HEV RNA in commercial porcine livers in The Netherlands are unknown. However, HEV RNA is present in commercial porcine livers, and sufficient heating of porcine livers before consumption as precautionary measure is recommended.

Swine HEV infection in south India and phylogenetic analysis (1985-1999).

Hepatitis E is endemic in India. It was recently noted that although all the Indian human hepatitis E virus (HEV) isolates (1976-2001) were placed in genotype I, the swine HEV recovered from western India (2000) belonged to genotype IV. This was in contrast to reports from the United States and Taiwan wherein both human and swine HEV belonged to the same genotype, i.e., genotypes III and IV, respectively. In order to validate these findings further, we retrospectively examined serum samples collected from pigs from southern India. Sequential serum samples from 45 (1985-1987) and 12 (1999) pigs from Karnataka state, south India, were screened for the presence of HEV RNA (nested PCR) and IgG-anti-HEV (ELISA). PCR products (Open Reading Frame-2 region) were sequenced and subjected to phylogenetic analysis. In this study, 42/45 (1985-1987) and 12/12 (1999) pigs showed seroconversion to IgG anti-HEV antibodies, with a mean age at seroconversion of 4.8 +/- 1.6 months. Four samples collected in 1999 and two samples collected during 1985 were HEV RNA positive. All swine HEV sequences clustered with genotype IV, demonstrating that swine HEV was prevalent among south Indian pigs for at least for 16 years and, similar to western India, belonged to genotype IV. Thus, genotype I and IV HEV continue to circulate in humans and pigs, respectively, from India. Whether swine HEV infects humans remains to be determined.

Human and swine hepatitis E viruses from Western India belong to different genotypes

Background/Aims : Hepatitis E is endemic in India. Earlier, we showed prevalence of IgG antibodies to hepatitis E virus (IgG-anti-HEV) in different animal species and inability of at least one human hepatitis E virus (HEV) strain to infect pigs. In the US where hepatitis E is not endemic in humans, zoonotic spread of HEV was suspected as swine and human HEV were closely related and cross-species infection was documented. The present study attempts to identify and partially characterize swine HEV from India. Methods : Serum samples from 284 pigs were screened for the presence of HEV-RNA (nested polymerase chain reaction; PCR) and IgG-anti-HEV (enzyme-linked immunosorbent assay; ELISA). PCR products (Open Reading Frame-2 region) were sequenced and subjected to phylogenetic analysis. Two sero-negative pigs were inoculated with swine HEV-positive serum pool. Results : ELISA and PCR positivity were 42.9 and 4.6%, respectively. All Indian swine HEV sequences clustered with genotype IV . Pigs could be experimentally infected with swine HEV. Conclusions : Swine HEV circulates in Indian pigs. In contrast to US and Taiwan wherein both human and swine HEV isolates belong to same genotype, Indian human HEV isolates belong to genotype I whereas genotype IV circulates in swine. Though experimental infection with Indian swine HEV was possible, at least one human HEV strain could not infect pigs.