Identification of interferon-stimulated genes with modulated expression during hepatitis E virus infection in pig liver tissues and human HepaRG cells

Introduction

Hepatitis E virus (HEV) is a common cause of enterically transmitted acute hepatitis worldwide. The virus is transmitted by the fecal-oral route via the consumption of contaminated water supplies and is also a zoonotic foodborne pathogen. Swine are the main reservoir of zoonotic HEV. In humans, HEV infection is usually asymptomatic or causes acute hepatitis that is self-limited. However, fulminant hepatic failure and chronic cases of HEV infection can occur in some patients. In contrast, HEV infection in pigs remains asymptomatic, although the virus replicates efficiently, suggesting that swine are able to control the virus pathogenesis. Upon viral infection, IFN is secreted and activates cellular pathways leading to the expression of many IFN-stimulated genes (ISGs). ISGs can restrict the replication of specific viruses and establish an antiviral state within infected and neighboring cells.

Methods

In this study, we used PCR arrays to determine the expression level of up to 168 ISGs and other IFN-related genes in the liver tissues of pigs infected with zoonotic HEV-3c and HEV-3f and in human bipotent liver HepaRG cells persistently infected with HEV-3f.

Results and discussion

The expression of 12 and 25 ISGs was found to be up-regulated in infected swine livers and HepaRG cells, respectively. The expression of CXCL10, IFIT2, MX2, OASL and OAS2 was up-regulated in both species. Increased expression of IFI16 mRNA was also found in swine liver tissues. This study contributes to the identification of potential ISGs that could play a role in the control or persistence of HEV infection.

First Detection of Hepatitis E Virus (Rocahepevirus ratti Genotype C1) in Synanthropic Norway Rats (Rattus norvegicus) in Romania

Hepatitis E virus (HEV) is an emerging zoonotic pathogen with different viral genera and species reported in a wide range of animals. Rodents, particularly rats, carry the specific genus rat HEV (Rocahepevirus genus, genotype C1) and are exposed occasionally to HEV-3 (Paslahepevirus genus, genotype 3), a zoonotic genotype identified in humans and widely distributed in domestic and feral pigs. In this study, the presence of HEV was investigated in synanthropic Norway rats from Eastern Romania, in areas where the presence of HEV-3 was previously reported in pigs, wild boars and humans. Using methods capable of detecting different HEV species, the presence of HEV RNA was investigated in 69 liver samples collected from 52 rats and other animal species. Nine rat liver samples were identified as being positive for rat HEV RNA (17.3%). High sequence identity (85-89% nt) was found with other European Rocahepevirus. All samples tested from other animal species, within the same environment, were negative for HEV. This is the first study to demonstrate the presence of HEV in rats from Romania. Since rat HEV has been reported to cause zoonotic infections in humans, this finding supports the need to extend the diagnosis of Rocahepevirus in humans with suspicion of hepatitis.

Low prevalence of hepatitis E virus in the liver of Corsican pigs slaughtered after 12 months despite high antibody seroprevalence

Hepatitis E virus (HEV) infection can be acute and benign or evolve to chronic hepatitis with rapid progression toward cirrhosis or liver failure in humans. Hence, hepatitis E (HE) disease is a major public health concern. In countries where pig populations are highly contaminated with HEV, human cases of HE are mainly foodborne, occurring frequently after consumption of raw or undercooked pork products or liver. Among factors associated to the presence of HEV in pork livers from intensive rearing systems, early slaughter (≤6 months) seems to be major. In Corsica, local pigs are raised in extensive farming systems and slaughtered after 12 months. To evaluate if slaughter of pigs over 12 months reduces the risk of HEV presence in livers, 1197 liver samples were randomly collected in 2 Corsican slaughterhouses. Presence of HEV RNA was detected in liver and HEV seroprevalence was determined in paired serum. The sampling included 1083 livers from animals between 12 and 48 months and 114 livers from animals <12 months. The samples were predominantly from semi-extensive and extensive farms (n = 1154). Estimated HEV seroprevalence was high, that is, >88%, and HEV RNA prevalence in adult pig livers (>12 months old) was low, that is, 0.18%. However, in livers from younger animals (<12 months), including piglets below 6 months old, 5.3% (6/114) of the samples were positive for HEV RNA. Sequences recovered from positive livers belonged to HEV genotype 3c and 3f. The presence of infectious HEV was confirmed in two livers by the detection of HEV replication in HepaRG cell cultures. Thus, this study demonstrates the low prevalence of HEV in livers of pigs over 12 months, even in farms with high HEV circulation. This observation may open new perspectives on the preferential use of livers from animals older than 12 months in raw pork liver products.

Common European Origin of Hepatitis E Virus in Human Population From Eastern Romania

The purpose of this research was to improve the epidemiological data on HEV infection in the human population in Romania. The analysis targeted hospitalized subjects with acute hepatitis (n = 94) of unknown etiology from the Infectious Diseases Regional Hospital in Iasi. Moreover, patients without liver disease (n = 40) from a different county hospital located in Eastern Romania were included. The presence of HEV infection and first characterization of human HEV strains was determined using serological and molecular assays. The apparent HEV seroprevalence varied between 29.16% (95% CI, 16.31–42.03) and 32.5% (95% CI, 17.98–47.02) according to patient grouping. Molecular analysis enhanced the detection of two HEV isolates, that clustered in subtype HEV-3c, the most commonly identified subtype in Europe. Identification of acute hepatitis E cases, together with the first detection and molecular characterization of human HEV in Romania represent the originality attributes of the present study.

Modeling the Inactivation of Viruses from the Coronaviridae Family in Response to Temperature and Relative Humidity in Suspensions or on Surfaces

Temperature and relative humidity are major factors determining virus inactivation in the environment. This article reviews inactivation data regarding coronaviruses on surfaces and in liquids from published studies and develops secondary models to predict coronaviruses inactivation as a function of temperature and relative humidity. A total of 102 D values (i.e., the time to obtain a log₁₀ reduction of virus infectivity), including values for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), were collected from 26 published studies. The values obtained from the different coronaviruses and studies were found to be generally consistent. Five different models were fitted to the global data set of D values. The most appropriate model considered temperature and relative humidity. A spreadsheet predicting the inactivation of coronaviruses and the associated uncertainty is presented and can be used to predict virus inactivation for untested temperatures, time points, or any coronavirus strains belonging to Alphacoronavirus and Betacoronavirus genera.IMPORTANCE The prediction of the persistence of SARS-CoV-2 on fomites is essential in investigating the importance of contact transmission. This study collects available information on inactivation kinetics of coronaviruses in both solid and liquid fomites and creates a mathematical model for the impact of temperature and relative humidity on virus persistence. The predictions of the model can support more robust decision-making and could be useful in various public health contexts. A calculator for the natural clearance of SARS-CoV-2 depending on temperature and relative humidity could be a valuable operational tool for public authorities.

Modeling the Inactivation of Viruses from the Coronaviridae Family in Response to Temperature and Relative Humidity in Suspensions or on Surfaces

Temperature and relative humidity are major factors determining virus inactivation in the environment. This article reviews inactivation data regarding coronaviruses on surfaces and in liquids from published studies and develops secondary models to predict coronaviruses inactivation as a function of temperature and relative humidity. A total of 102 D values (i.e., the time to obtain a log10 reduction of virus infectivity), including values for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), were collected from 26 published studies. The values obtained from the different coronaviruses and studies were found to be generally consistent. Five different models were fitted to the global data set of D values. The most appropriate model considered temperature and relative humidity. A spreadsheet predicting the inactivation of coronaviruses and the associated uncertainty is presented and can be used to predict virus inactivation for untested temperatures, time points, or any coronavirus strains belonging to Alphacoronavirus and Betacoronavirus genera.IMPORTANCE The prediction of the persistence of SARS-CoV-2 on fomites is essential in investigating the importance of contact transmission. This study collects available information on inactivation kinetics of coronaviruses in both solid and liquid fomites and creates a mathematical model for the impact of temperature and relative humidity on virus persistence. The predictions of the model can support more robust decision-making and could be useful in various public health contexts. A calculator for the natural clearance of SARS-CoV-2 depending on temperature and relative humidity could be a valuable operational tool for public authorities.

Critical Orientation in the Jungle of Currently Available Methods and Types of Data for Source Attribution of Foodborne Diseases

With increased interest in source attribution of foodborne pathogens, there is a need to sort and assess the applicability of currently available methods. Herewith we reviewed the most frequently applied methods for source attribution of foodborne diseases, discussing their main strengths and weaknesses to be considered when choosing the most appropriate methods based on the type, quality, and quantity of data available, the research questions to be addressed, and the (epidemiological and microbiological) characteristics of the pathogens in question. A variety of source attribution approaches have been applied in recent years. These methods can be defined as top–down, bottom–up, or combined. Top–down approaches assign the human cases back to their sources of infection based on epidemiological (e.g., outbreak data analysis, case-control/cohort studies, etc.), microbiological (i.e., microbial subtyping), or combined (e.g., the so-called ‘source-assigned case-control study’ design) methods. Methods based on microbial subtyping are further differentiable according to the modeling framework adopted as frequency-matching (e.g., the Dutch and Danish models) or population genetics (e.g., Asymmetric Island Models and STRUCTURE) models, relying on the modeling of either phenotyping or genotyping data of pathogen strains from human cases and putative sources. Conversely, bottom–up approaches like comparative exposure assessment start from the level of contamination (prevalence and concentration) of a given pathogen in each source, and then go upwards in the transmission chain incorporating factors related to human exposure to these sources and dose-response relationships. Other approaches are intervention studies, including ‘natural experiments,’ and expert elicitations. A number of methodological challenges concerning all these approaches are discussed. In absence of an universally agreed upon ‘gold’ standard, i.e., a single method that satisfies all situations and needs for all pathogens, combining different approaches or applying them in a comparative fashion seems to be a promising way forward.

Natural viral co-infections in pig herds affect hepatitis E virus (HEV) infection dynamics and increase the risk of contaminated livers at slaughter

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.

Persistent viremia and presence of hepatitis E virus RNA in pig muscle meat after experimental co-infection with porcine reproductive and respiratory syndrome virus

Although hepatitis E virus (HEV) transmission has been demonstrated after consumption of products containing infected pig liver, human cases can be also associated with other pig meat products, such as sausages. Data on HEV viremia and dissemination in muscle meat of infected animals are still sparse, especially during long-term infection. Previously, we have shown that experimental co-infection of pigs with HEV and porcine reproductive and respiratory syndrome virus (PRRSV) lengthens HEV infection up to 49 days and increases the likelihood of the presence of HEV RNA in the liver of the pig at a later stage of infection. In the present study, we show that during experimental HEV-PRRSV co-infection, prolonged HEV viremia, up to 49 days post-inoculation (dpi), is detected. The long-term viremia observed was statistically associated with the absence of HEV seroconversion. HEV RNA was also frequently detected, at a late stage of infection (49 dpi), in the three different types of muscle tested: femoral biceps, psoas major or diaphragm pillar. The HEV RNA load could reach up to 1 · 10⁶ genome copies per gram of muscle. Detection of HEV in muscle meat was statistically associated with high HEV loads in corresponding liver and fecal samples. The presence of HEV in pig blood, femoral biceps and major psoas, corresponding to ham and tenderloin muscles respectively, is of concern for the food industry. Hence, these results indicate new potential risks for consumers and public health regarding pork products.

The Amino-Terminal Region of Hepatitis E Virus ORF1 Containing a Methyltransferase (Met) and a Papain-Like Cysteine Protease (PCP) Domain Counteracts Type I Interferon Response

Hepatitis E virus (HEV) is responsible for large waterborne epidemics of hepatitis in endemic countries and is an emerging zoonotic pathogen worldwide. In endemic regions, HEV-1 or HEV-2 genotypes are frequently associated with fulminant hepatitis in pregnant women, while with zoonotic HEV (HEV-3 and HEV-4), chronic cases of hepatitis and severe neurological disorders are reported. Hence, it is important to characterize the interactions between HEV and its host. Here, we investigated the ability of the nonstructural polyprotein encoded by the first open reading frame (ORF1) of HEV to modulate the host early antiviral response and, in particular, the type I interferon (IFN-I) system. We found that the amino-terminal region of HEV-3 ORF1 (MetYPCP), containing a putative methyltransferase (Met) and a papain-like cysteine protease (PCP) functional domain, inhibited IFN-stimulated response element (ISRE) promoter activation and the expression of several IFN-stimulated genes (ISGs) in response to IFN-I. We showed that the MetYPCP domain interfered with the Janus kinase (JAK)/signal transducer and activator of the transcription protein (STAT) signalling pathway by inhibiting STAT1 nuclear translocation and phosphorylation after IFN-I treatment. In contrast, MetYPCP had no effect on STAT2 phosphorylation and a limited impact on the activation of the JAK/STAT pathway after IFN-II stimulation. This inhibitory function seemed to be genotype-dependent, as MetYPCP from HEV-1 had no significant effect on the JAK/STAT pathway. Overall, this study provides evidence that the predicted MetYPCP domain of HEV ORF1 antagonises STAT1 activation to modulate the IFN response.

Aujeszky's Disease and Hepatitis E Viruses Transmission between Domestic Pigs and Wild Boars in Corsica: Evaluating the Importance of Wild/Domestic Interactions and the Efficacy of Management Measures

Wildlife species as reservoirs of infectious pathogens represent a serious constraint in the implementation of disease management strategies. In the Mediterranean island of Corsica, the dynamics of hepatitis E virus (HEV) and Aujeszky’s disease virus (ADV) are suspected to be influenced by interactions between wild and domestic pigs. To improve our understanding of these influences, we first compared the seroprevalences of both viruses in domestic pig populations from different locations with contrasted levels of wild–domestic interactions, ADV vaccination, biosafety, and farm husbandry. Second, we performed an analysis at a more restricted geographical scale, to assess the matching of ADV or HEV prevalence between sympatric wild boar and outdoor pig farms most exposed to interactions with wildlife. Logistic models were adjusted to the observed data. A high seroprevalence of HEV (>80%) and ADV (40%) in pigs, with no significant difference according to the region, confirms that both pathogens are enzootic in Corsica. Vaccination against ADV had a strong protective effect, even when performed voluntarily by farmers. Farm biosafety had an additional effect on pigs’ exposure, suggesting that contact between wild boars and pigs were involved in disease transmission. A strong correlation in HEV seroprevalence was observed between pigs and wild boars that were in close contact, and significantly lower seroprevalence was observed in pigs when they had little contact with wild boars due to spatial segregation. These results suggest a regular HEV circulation between sympatric wild boar and domestic pigs. The high HEV seroprevalence observed in domestic pigs (>80%) suggests a spillover of the virus from domestic to wild populations through environmental contamination, but this hypothesis has to be confirmed. Conversely, even though avoiding sows’ release on pasture during estrus showed some protecting effect in the free ranging pig farms regarding ADV, ADV seroprevalence was not dependent on the swine populations (wild or domestic) or on the wild–domestic spatial overlap, suggesting two quasi-separate enzootic cycles. This information will prove useful for designing more efficient disease management strategies in Corsica and similar contexts.

Knowledge gaps and research priorities in the prevention and control of hepatitis E virus infection

Hepatitis E virus (HEV), family Hepeviridae, is a main cause of epidemic hepatitis in developing countries and sporadic and cluster cases of hepatitis in industrialized countries. There are an increasing number of reported cases in humans especially in industrialized countries, and there is a high potential for transboundary spread of zoonotic genotypes of the virus through the transport of pigs, pig products and by-products. Bloodborne transmission of the virus has been reported with a significant medical concern. To better coordinate HEV research and design better control measures of HEV infections in animals, a group of HEV experts reviewed the current knowledge on the disease and considered the existing disease control tools. It was concluded that there is a lack of in-depth information about the spread of the virus from pigs to humans. The role of animals other than pigs in the zoonotic transmission of the virus to humans and the extent of foodborne transmission are poorly understood. Factors involved in development of clinical disease such as infectious dose, susceptibility and virulence of virus strains need to be studied more extensively. However, such studies are greatly hindered by the absence of a broadly applicable, efficient and sensitive in vitro cell culture system for HEV. Diagnostic tools for HEV are available but need to be further validated, harmonized and standardized. Commercially available HEV vaccines for the control of HEV infection in animal populations are needed as such vaccines can minimize the zoonotic risk for humans. Anti-HEV drugs for treatment of HEV-infected patients need to be studied more extensively. The detailed expert review can be downloaded from the project website at http://www.discontools.eu/.

Recent knowledge on hepatitis E virus in Suidae reservoirs and transmission routes to human

Hepatitis E virus (HEV) causes self-limiting acute hepatitis in humans that can eventually result in acute liver failures or progress to chronic infections. While in tropical and sub-tropical areas, HEV infections are associated with important waterborne epidemics, in Northern countries, HEV infections are autochthonous with a zoonotic origin. In the past decade, it has become clear that certain HEV genotypes are zoonotic and that swine, and more generally Suidae, are the main reservoir. Zoonotic transmissions of the virus may occur via direct contact with infected pigs, wild boars or consumption of contaminated meat. This review describes the current knowledge on domestic and wild Suidae as reservoirs of HEV and the evidence of the different routes of HEV transmission between these animals and humans.

Molecular detection of hepatitis E virus in wild boar population in eastern Romania

In industrialized countries, Hepatitis E is a recognized zoonosis, with wild boar and swine representing the main reservoirs for zoonotic genotype HEV-3 in Europe. Data related to HEV infection in wild boar population in Romania are restricted to serological surveys. Therefore, our main goal was to determine the HEV prevalence in wild boar population and to characterize HEV strains circulating in Romania. Using TaqMan real-time RT-PCR assay, we analyzed the presence of RNA HEV in 45 liver samples and five spleen samples collected from 50 wild boars. Samples were collected during the 2013-2015 hunting seasons. Nine samples of 50 were tested positive for HEV RNA, resulting an overall prevalence of 18%. Phylogenetic analysis revealed that the isolates clustered in different HEV-3 monophyletic groups, depending on the sampling county. This is the first study signalling, based on molecular analysis, the presence of HEV in wild boar population from Romania. Also, in this study, we report the detection of HEV in splenic tissue from wild boar.

Population genetics, community of parasites, and resistance to rodenticides in an urban brown rat (Rattus norvegicus) population

Brown rats are one of the most widespread urban species worldwide. Despite the nuisances they induce and their potential role as a zoonotic reservoir, knowledge on urban rat populations remains scarce. The main purpose of this study was to characterize an urban brown rat population from Chanteraines park (Hauts-de-Seine, France), with regards to haematology, population genetics, immunogenic diversity, resistance to anticoagulant rodenticides, and community of parasites. Haematological parameters were measured. Population genetics was investigated using 13 unlinked microsatellite loci. Immunogenic diversity was assessed for Mhc-Drb. Frequency of the Y139F mutation (conferring resistance to rodenticides) and two linked microsatellites were studied, concurrently with the presence of anticoagulant residues in the liver. Combination of microscopy and molecular methods were used to investigate the occurrence of 25 parasites. Statistical approaches were used to explore multiple parasite relationships and model parasite occurrence. Eighty-six rats were caught. The first haematological data for a wild urban R. norvegicus population was reported. Genetic results suggested high genetic diversity and connectivity between Chanteraines rats and surrounding population(s). We found a high prevalence (55.8%) of the mutation Y139F and presence of rodenticide residues in 47.7% of the sampled individuals. The parasite species richness was high (16). Seven potential zoonotic pathogens were identified, together with a surprisingly high diversity of Leptospira species (4). Chanteraines rat population is not closed, allowing gene flow and making eradication programs challenging, particularly because rodenticide resistance is highly prevalent. Parasitological results showed that co-infection is more a rule than an exception. Furthermore, the presence of several potential zoonotic pathogens, of which four Leptospira species, in this urban rat population raised its role in the maintenance and spread of these pathogens. Our findings should stimulate future discussions about the development of a long-term rat-control management program in Chanteraines urban park.

Public health risks associated with hepatitis E virus (HEV) as a food-borne pathogen

Hepatitis E virus (HEV) is an important infection in humans in EU/EEA countries, and over the last 10 years more than 21,000 acute clinical cases with 28 fatalities have been notified with an overall 10-fold increase in reported HEV cases; the majority (80%) of cases were reported from France, Germany and the UK. However, as infection in humans is not notifiable in all Member States, and surveillance differs between countries, the number of reported cases is not comparable and the true number of cases would probably be higher. Food-borne transmission of HEV appears to be a major route in Europe; pigs and wild boars are the main source of HEV. Outbreaks and sporadic cases have been identified in immune-competent persons as well as in recognised risk groups such as those with pre-existing liver damage, immunosuppressive illness or receiving immunosuppressive treatments. The opinion reviews current methods for the detection, identification, characterisation and tracing of HEV in food-producing animals and foods, reviews literature on HEV reservoirs and food-borne pathways, examines information on the epidemiology of HEV and its occurrence and persistence in foods, and investigates possible control measures along the food chain. Presently, the only efficient control option for HEV infection from consumption of meat, liver and products derived from animal reservoirs is sufficient heat treatment. The development of validated quantitative and qualitative detection methods, including infectivity assays and consensus molecular typing protocols, is required for the development of quantitative microbial risk assessments and efficient control measures. More research on the epidemiology and control of HEV in pig herds is required in order to minimise the proportion of pigs that remain viraemic or carry high levels of virus in intestinal contents at the time of slaughter. Consumption of raw pig, wild boar and deer meat products should be avoided.

Zoonotic Hepatitis E Virus: Classification, Animal Reservoirs and Transmission Routes

During the past ten years, several new hepatitis E viruses (HEVs) have been identified in various animal species. In parallel, the number of reports of autochthonous hepatitis E in Western countries has increased as well, raising the question of what role these possible animal reservoirs play in human infections. The aim of this review is to present the recent discoveries of animal HEVs and their classification within the Hepeviridae family, their zoonotic and species barrier crossing potential, and possible use as models to study hepatitis E pathogenesis. Lastly, this review describes the transmission pathways identified from animal sources.

Assessment of Domestic Pigs, Wild Boars and Feral Hybrid Pigs as Reservoirs of Hepatitis E Virus in Corsica, France

In Corsica, extensive pig breeding systems allow frequent interactions between wild boars and domestic pigs, which are suspected to act as reservoirs of several zoonotic diseases including hepatitis E virus (HEV). In this context, 370 sera and 166 liver samples were collected from phenotypically characterized as pure or hybrid wild boars, between 2009 and 2012. In addition, serum and liver from 208 domestic pigs belonging to 30 farms were collected at the abattoir during the end of 2013. Anti-HEV antibodies were detected in 26% (21%–31.6%) of the pure wild boar, 43.5% (31%–56.7%) of hybrid wild boar and 88% (82.6%–91.9%) of the domestic pig sera. In addition, HEV RNA was detected in five wild boars, three hybrid wild boars and two domestic pig livers tested. Our findings provide evidence that both domestic pig and wild boar (pure and hybrid) act as reservoirs of HEV in Corsica, representing an important zoonotic risk for Corsican hunters and farmers but also for the large population of consumers of raw pig liver specialties produced in Corsica. In addition, hybrid wild boars seem to play an important ecological role in the dissemination of HEV between domestic pig and wild boar populations, unnoticed to date, that deserves further investigation.

Hepatitis E virus antibody prevalence, RNA frequency, and genotype among blood donors in Cambodia (Southeast Asia)

BACKGROUND

Recent studies conducted in developed countries described hepatitis E virus (HEV) as an emerging infectious threat to blood safety. However, data on HEV among blood donors from southeast Asia are lacking.

STUDY DESIGN AND METHODS

Between July and August 2014, we assessed the presence of HEV immunoglobulin (Ig)G and IgM in 301 Cambodian blood donors. All samples were further tested for the presence of HEV RNA using an in-house reverse transcription-polymerase chain reaction. ORF2/ORF3 phylogenetic analysis was performed on positive HEV RNA specimens.

RESULTS

We found HEV IgG in 28.2% of blood donors from Cambodia. Three blood donors tested positive for HEV IgM with three distinct patterns: IgM(+)/IgG(-)/RNA(-) (n = 1), IgM(+)/IgG(+)/RNA(-) (n = 1), and IgM(+)/IgG(+)/RNA(+) (n = 1). Thus, the prevalence rates of HEV IgM and HEV RNA were 1.0 and 0.3%. Interestingly, the viremic blood donor harbored a HEV strain that belonged to Genotype 3 (HEV-3) and clustered with a Cambodian riverine HEV-3 isolate.

CONCLUSION

Due to the high frequency of Cambodian blood donors with positive HEV IgG, we conclude that HEV is endemic in this country. Large-scale studies must be considered to determine whether Cambodian blood donation screening is warranted to enhance blood safety in regard to HEV. In addition, our findings suggest that river water may be a significant source of exposure to HEV-3.

Susceptibility of Pigs to Zoonotic Hepatitis E Virus Genotype 3 Isolated from a Wild Boar

In Europe, zoonotic hepatitis E virus (HEV) genotype 3 strains mainly circulate in humans, swine and wild boar. The aim of this study was to investigate the potential transmission of a wild boar originating HEV strain (WbHEV) to swine by intravenous or oral inoculation and to study the consequences of infection of a WbHEV strain, a WbHEV strain previously passaged in a pig and a swine HEV strain after oral inoculation. Firstly, an intravenous infection was performed for which five piglets were divided into two groups with three pigs inoculated with a WbHEV field strain and two pigs inoculated with a HEV-negative swine liver homogenate. All pigs were necropsied 8, 9 and 10 days post-inoculation. Secondly, an oral infection of 56 days was performed on 12 piglets divided into four groups inoculated with a WbHEV strain, a WbHEV strain previously passaged in swine, a swine HEV strain or a HEV-negative swine liver homogenate. After intravenous inoculation, HEV RNA was detected in serum, bile, liver, spleen, duodenum, jejunum, colon, lung, gastro-hepatic lymph nodes and faeces in all infected piglets. After oral inoculation, HEV RNA was detected in serum, bile, liver, gastro-hepatic lymph nodes and faeces. Most of HEV-inoculated pigs became seropositive at day 15. This study provides experimental evidence of early viral spread throughout the organism after intravenous infection with a WbHEV strain and supports the notion that such a zoonotic strain could be transmitted via the natural faecal-oral route of infection between wild boar and pigs but also between pigs.

Hepatitis E Virus Exposure is Increased in Pork Butchers from Burkina Faso

We conducted the first survey of zoonotic risk of Hepatitis E virus (HEV) transmissions in Ouagadougou, Burkina Faso, through the direct contact with pork meat during professional activity. Anti-HEV antibodies were more prevalent in pork butchers, 76% than in the general population, which was 47.8% in 2013 (odds ratio = 3.46, 95% CI = 2.85-4.21, P < 0.001). Among slaughter-aged swine, HEV seroprevalence was of 80%, and HEV RNA was detected in 1% of pork livers. Phylogenetic analysis pointed out HEV genotype 3. Thus, in addition to possible HEV contamination through the water source, as in endemic region, zoonotic transmissions of HEV probably occur in west Africa.

High Proportion of Asymptomatic Infections in an Outbreak of Hepatitis E Associated With a Spit-Roasted Piglet, France, 2013

BACKGROUND

On 11 December 2013, 3 clustered cases of hepatitis E were reported on a French coastal island. Individuals had taken part in a wedding meal that included a spit-roasted piglet. The piglet had been stuffed with a raw stuffing partly made from the liver. Investigations were carried out to identify the vehicle of contamination and evaluate the dispersion of the hepatitis E virus (HEV) in the environment.

METHODS

A questionnaire was administered to 98 wedding participants who were asked to give a blood sample. Cases were identified by reverse transcription-polymerase chain reaction and serological tests. A retrospective cohort study was conducted among 38 blood-sampled participants after the exclusion of 14 participants with evidence of past HEV infection. Relative risks (RR) and 95% confidence intervals were calculated based on food consumed at the wedding meal using univariate and multivariable Poisson regressions. Phylogenetic analyses were performed to compare the clinical HEV strains. Strains were detected in the liquid manure sampled at the farm where the piglet was born and in the untreated island wastewater.

RESULTS

Seventeen cases were identified, 70.6% were asymptomatic. Acute HEV infection was independently associated with piglet stuffing consumption (RR = 1.69 [1.04-2.73], P = .03). Of clinical strains from the index cases, veterinary and environmental HEV strains were identical.

CONCLUSIONS

Our investigation attributed this large HEV outbreak to the consumption of an undercooked pig liver-based stuffing. After infection, the cases became a temporary reservoir for HEV, which was detected in the island's untreated wastewater.

Frequent hepatitis E virus contamination in food containing raw pork liver, France

Food products containing raw pork liver are suspected to be vehicles for transmission of hepatitis E virus. Four categories of food products, comprising 394 samples, were analyzed to determine hepatitis E virus prevalence. Virus was detected in 3%–30% of the different categories. Phylogenetic analysis showed high identity with human and swine sequences.

Hepatitis E virus chronic infection of swine co-infected with Porcine Reproductive and Respiratory Syndrome Virus

In developed countries, most of hepatitis E human cases are of zoonotic origin. Swine is a major hepatitis E virus (HEV) reservoir and foodborne transmissions after pork product consumption have been described. The risk for HEV-containing pig livers at slaughter time is related to the age at infection and to the virus shedding duration. Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is a virus that impairs the immune response; it is highly prevalent in pig production areas and suspected to influence HEV infection dynamics. The impact of PRRSV on the features of HEV infections was studied through an experimental HEV/PRRSV co-infection of specific-pathogen-free (SPF) pigs. The follow-up of the co-infected animals showed that HEV shedding was delayed by a factor of 1.9 in co-infected pigs compared to HEV-only infected pigs and specific immune response was delayed by a factor of 1.6. HEV shedding was significantly increased with co-infection and dramatically extended (48.6 versus 9.7 days for HEV only). The long-term HEV shedding was significantly correlated with the delayed humoral response in co-infected pigs. Direct transmission rate was estimated to be 4.7 times higher in case of co-infection than in HEV only infected pigs (0.70 and 0.15 per day respectively). HEV infection susceptibility was increased by a factor of 3.3, showing the major impact of PRRSV infection on HEV dynamics. Finally, HEV/PRRSV co-infection – frequently observed in pig herds – may lead to chronic HEV infection which may dramatically increase the risk of pig livers containing HEV at slaughter time.

La pluralité de l'hépatite E : des formes cliniques aux souches animales

The concept of zoonotic viral hepatitis E has emerged a few years ago in countries where sporadic cases of hepatitis E were not associated with travel in geographical areas where the virus is endemic (tropical or subtropical regions) . Improved diagnostic methods and the awareness of clinicians helped to better assess the impact of infection by hepatitis E virus (HEV) and identify new related syndromes. Similarly, the description of chronic forms of hepatitis E in immunocompromised patients raises the question of the treatment and prevention of this disease. Recent advances in the identification of animal reservoirs of HEV have confirmed that the strains circulating in domestic and wild pigs are genetically close to strains identified in indigenous cases. Characterization of HEV infection in swine herds has identified risk factors associated to the virus spreading. In addition, the identification of HEV in the food chain or products containing pork has shown that it is a food-borne zoonosis. The arrival of recent technologies to identify new agents helped expand the family of HEV related viruses and identify potential new animal reservoirs.

Hepatitis E Virus and Related Viruses in Animals

Hepatitis E is an acute human liver disease in healthy individuals which may eventually become chronic. It is caused by the hepatitis E virus (HEV) and can have a zoonotic origin. Nearly 57,000 people die yearly from hepatitis E-related conditions. The disease is endemic in both developing and developed countries with distinct epidemiologic profiles. In developing countries, the disease is associated with inadequate water treatment, while in developed countries, transmission is associated with animal contact and the ingestion of raw or uncooked meat, especially liver. All human HEV are grouped into at least four genotypes, while HEV or HEV-related viruses have been identified in an increasing number of domestic and wild animal species. Despite a high genetic diversity, only one single HEV serotype has been described to date for HEV genotypes 1-4. The discovery of new HEV or HEV-related viruses leads to a continuing increase in the number of genotypes. In addition, the genome organization of all these viruses is variable with overlapping open reading frames (ORF) and differences in the location of ORF3. In spite of the role of some domestic and wild animals as reservoir, the origin of HEV and HEV-related viruses in humans and animals is still unclear. This review discusses aspects of the detection, molecular virology, zoonotic transmission and origin of HEV and HEV-related viruses in the context of 'One Health' and establishes a link between the previous and the new taxonomy of this growing virus family.

Zoonotic origin of hepatitis E

The concept of zoonotic viral hepatitis E has emerged a few years ago following the discovery of animal strains of hepatitis E virus (HEV), closely related to human HEV, in countries where sporadic cases of hepatitis E were autochthonous. Recent advances in the identification of animal reservoirs of HEV have confirmed that strains circulating in domestic and wild pigs are genetically related to strains identified in indigenous human cases. The demonstration of HEV contamination in the food chain or pork products has indicated that HEV is frequently a foodborne zoonotic pathogen. Direct contacts with infected animals, consumption of contaminated animal meat or meat products are all potential means of zoonotic HEV transmission. The recent identification of numerous other genetically diverse HEV strains from various animal species poses additional potential concerns for HEV zoonotic infection.

Evidence of hepatitis E infection in swine and humans in the East Region of Romania

OBJECTIVE

Swine hepatitis E virus (HEV) is considered to be a new zoonotic agent due to its close genomic resemblance to the human HEV. The aim of this study was to determine human HEV seroprevalence in eastern Romania and to characterize circulating swine HEV sequences.

METHODS

Serological investigations of human serum samples were done using a commercial ELISA kit (MP Biomedicals). Swine faecal samples were tested to detect the HEV ORF2 sequence by nested reverse transcription PCR.

RESULTS

One hundred and forty-eight human serum samples were tested for anti-HEV IgG of which 22 were found to be positive. Fresh swine faeces (pools) were collected from five farms in eastern Romania. Six out of 19 pooled samples were positive for HEV RNA. Phylogenetic analysis based on alignment of the ORF2 sequence indicated that the Romanian swine HEV isolates belonged to genotype 3.

CONCLUSIONS

This is the first study showing HEV to be present in Romanian pig herds and that the human population is exposed.

Early-life hepatitis e infection in pigs: the importance of maternally-derived antibodies

Passive immunity (PI), acquired through colostrum intake, is essential for piglet protection against pathogens. Maternally-derived antibodies (MDAs) can decrease the transmission of pathogens between individuals by reducing shedding from infected animals and/or susceptibility of naïve animals. Only a limited number of studies, however, have been carried out to quantify the level of protection conferred by PI in terms of transmission. In the present study, an original modeling framework was designed to estimate parameters governing the transmission of infectious agents in the presence and absence of PI. This epidemiological model accounts for the distribution of PI duration and two different forces of infection depending on the serological status of animals after colostrum intake. A Bayesian approach (Metropolis-Hastings algorithm) was used for parameter estimation. The impact of PI on hepatitis E virus transmission in piglets was investigated using longitudinal serological data from six pig farms. A strong impact of PI was highlighted, the efficiency of transmission being on average 13 times lower in piglets with maternally-derived antibodies than in fully susceptible animals (range: 5–21). Median infection-free survival ages, based on herd-specific estimates, ranged between 8.7 and 13.8 weeks in all but one herd. Indeed, this herd exhibited a different profile with a relatively low prevalence of infected pigs (50% at slaughter age) despite the similar proportions of passively immune individuals after colostrum intake. These results suggest that the age at HEV infection is not strictly dependent upon the proportion of piglets with PI but is also linked to farm-specific husbandry (mingling of piglets after weaning) and hygiene practices. The original methodology developed here, using population-based longitudinal serological data, was able to demonstrate the relative impact of MDAs on the transmission of infectious agents.

Development and validation of a genotype 3 recombinant protein-based immunoassay for hepatitis E virus serology in swine

Hepatitis E virus (HEV) is classified within the family Hepeviridae, genus Hepevirus. HEV genotype 3 (Gt3) infections are endemic in pigs in Western Europe and in North and South America and cause zoonotic infections in humans. Several serological assays to detect HEV antibodies in pigs have been developed, at first mainly based on HEV genotype 1 (Gt1) antigens. To develop a sensitive HEV Gt3 ELISA, a recombinant baculovirus expression product of HEV Gt3 open reading frame-2 was produced and coated onto polystyrene ELISA plates. After incubation of porcine sera, bound HEV antibodies were detected with anti-porcine anti-IgG and anti-IgM conjugates. For primary estimation of sensitivity and specificity of the assay, sets of sera were used from pigs experimentally infected with HEV Gt3. For further validation of the assay and to set the cutoff value, a batch of 1100 pig sera was used. All pig sera were tested using the developed HEV Gt3 assay and two other serologic assays based on HEV Gt1 antigens. Since there is no gold standard available for HEV antibody testing, further validation and a definite setting of the cutoff of the developed HEV Gt3 assay were performed using a statistical approach based on Bayes' theorem. The developed and validated HEV antibody assay showed effective detection of HEV-specific antibodies. This assay can contribute to an improved detection of HEV antibodies and enable more reliable estimates of the prevalence of HEV Gt3 in swine in different regions.

Direct contact and environmental contaminations are responsible for HEV transmission in pigs

Hepatitis E virus (HEV) can cause enterically-transmitted hepatitis in humans. The zoonotic nature of Hepatitis E infections has been established in industrialized areas and domestic pigs are considered as the main reservoir. The dynamics of transmission in pig herds therefore needs to be understood to reduce the prevalence of viremic pigs at slaughter and prevent contaminated pig products from entering the food chain. An experimental trial was carried out to study the main characteristics of HEV transmission between orally inoculated pigs and naïve animals. A mathematical model was used to investigate three transmission routes, namely direct contact between pigs and two environmental components to represent within-and between-group oro-fecal transmission. A large inter-individual variability was observed in response to infection with an average latent period lasting 6.9 days (5.8; 7.9) in inoculated animals and an average infectious period of 9.7 days (8.2; 11.2). Our results show that direct transmission alone, with a partial reproduction number of 1.41 (0.21; 3.02), can be considered as a factor of persistence of infection within a population. However, the quantity of virus present in the environment was found to play an essential role in the transmission process strongly influencing the probability of infection with a within pen transmission rate estimated to 2 ⋅ 10^− 6g ge^− 1d^− 1(1 ⋅ 10^− 7; 7 ⋅ 10^− 6). Between-pen environmental transmission occurred to a lesser extent (transmission rate: 7 ⋅ 10^− 8g ge^− 1d^− 1(5 ⋅ 10^− 9; 3 ⋅ 10^− 7) but could further generate a within-group process. The combination of these transmission routes could explain the persistence and high prevalence of HEV in pig populations.

Hepatitis E virus in pork liver sausage, France

We investigated viability of hepatitis E virus (HEV) identified in contaminated pork liver sausages obtained from France. HEV replication was demonstrated in 1 of 4 samples by using a 3-dimensional cell culture system. The risk for human infection with HEV by consumption of these sausages should be considered to be high.

Hepatitis E virus seroprevalence of domestic pigs in Germany determined by a novel in-house and two reference ELISAs

Autochthonous hepatitis E virus (HEV) infections by zoonotic transmission of genotype 3 (GT3) have been reported increasingly from industrialized countries. In this paper the development and validation of an IgG ELISA for the detection of HEV-specific antibodies in domestic pigs is described. Comparison of the diagnostic value of Escherichia coli-expressed HEV-GT3 capsid protein (CP) derivatives revealed a carboxy-terminal derivative as most suitable. Validation of the in-house assay using a commercially available IgG ELISA revealed a high diagnostic specificity and sensitivity. The average HEV seroprevalence of domestic pigs from Germany and the federal state Baden-Wuerttemberg determined by the in-house test was 42.7% and 50.3%, respectively. The seroprevalence in different districts of Baden-Wuerttemberg ranged from 34.9% to 60%, but from 0% to 100% between different herds. These data were compared to those achieved by two commercially available ELISA kits and an in-house ratHEV-based ELISA. In conclusion, the CP-based in-house test proved sensitive and specific, indicating that the ORF3-encoded protein might be dispensable for diagnostics. The novel assay also allowed a parallel analysis by a homologous ratHEV-derived antigen. Thus, the novel IgG ELISA represents a useful tool for future standardized seroprevalence studies in domestic pigs from Germany and other regions of Europe.

High prevalence of hepatitis E in humans and pigs and evidence of genotype-3 virus in swine, Madagascar

Hepatitis E virus (HEV) causes an orofecal disease transmitted through poor hygiene environments, contaminated food (mainly pork products), or by contacts with infected animals. Very little data are currently available regarding the disease in the Southwestern Indian Ocean Islands. We report the first sero- and viro-survey for HEV in human and swine in Madagascar. A seroprevalence rate of 14.1% (60 of 427) was measured in slaughterhouse workers. Seroprevalence to HEV in pigs was estimated to 71.2% (178 of 250), strongly suggesting the existence of a zoonotic cycle. Three out of 250 pig livers (1.2%) tested HEV RNA-positive by quantitative polymerase chain reaction. Phylogenetic analyses based on 1-kb sequences of the ORF 2-3 identified these viruses as HEV genotype 3. Sequences clustered in a distinct Malagasy sub-clade, possibly representative of a new sub-genotype, for which the date of emergence was estimated around 1989. Further studies are needed to confirm other transmission routes of HEV to humans, especially through non-zoonotic cycles.

New models of hepatitis E virus replication in human and porcine hepatocyte cell lines

Hepatitis E virus (HEV) causes acute, enterically transmitted hepatitis in human. It is associated with large epidemics in tropical and subtropical regions where it is endemic or with sporadic cases in non-endemic regions. Unlike other hepatitis viruses, HEV has several animal reservoirs. Phylogenetic studies on HEV human and animal sequences, and the identification of cases of direct transmission from animal to human strongly suggest that HEV is a zoonotic agent. The lack of efficient cell culture models limits studies on molecular and cellular aspects of HEV infection and species barrier crossing. The present study reports on the development of two new in vitro models of HEV replication using a human hepatoma-derived cell line, HepaRG, and a porcine embryonic stem cell-derived cell line, PICM-19. These two cell lines have morphological and functional properties similar to primary hepatocytes. These in vitro culture systems support HEV replication and release of encapsidated RNA. These new models represent a powerful tool for studying the viral replication cycle, species barrier crossing and virulence factors.

High prevalence of Hepatitis E virus in French domestic pigs

The importance of the domestic pig reservoir for Hepatitis E virus (HEV) was assessed by estimating the seroprevalence and prevalence of HEV contaminated livers in French slaughter-aged pigs. 6565 sera and 3715 livers were randomly sampled from 186 pig farms throughout the country. Taking the sampling design into account, the farm-level seroprevalence was 65% (95% CI 57-74) and 31% (95% CI 24-38) of the slaughter-aged pigs had antibodies against HEV. The individual prevalence of HEV RNA positive livers was 4% (95% CI 2-6) and 24% (95% CI 17-31) of the farms had at least 1 positive liver. Most isolates were of genotype 3f (76.7%) with smaller amounts of 3c (18.6%) and 3e (4.6%). The high prevalence of HEV in pigs and the similarities between HEV subtypes from pigs and humans corroborates the possible zoonotic origin of some HEV autochthonous infections.

Zoonotic hepatitis E: animal reservoirs and emerging risks

Hepatitis E virus (HEV) is responsible for enterically-transmitted acute hepatitis in humans with two distinct epidemiological patterns. In endemic regions, large waterborne epidemics with thousands of people affected have been observed, and, in contrast, in non-endemic regions, sporadic cases have been described. Although contaminated water has been well documented as the source of infection in endemic regions, the modes of transmission in non-endemic regions are much less known. HEV is a single-strand, positive-sense RNA virus which is classified in the Hepeviridae family with at least four known main genotypes (1–4) of mammalian HEV and one avian HEV. HEV is unique among the known hepatitis viruses, in which it has an animal reservoir. In contrast to humans, swine and other mammalian animal species infected by HEV generally remain asymptomatic, whereas chickens infected by avian HEV may develop a disease known as Hepatitis-Splenomegaly syndrome. HEV genotypes 1 and 2 are found exclusively in humans while genotypes 3 and 4 are found both in humans and other mammals. Several lines of evidence indicate that, in some cases involving HEV genotypes 3 and 4, animal to human transmissions occur. Furthermore, individuals with direct contact with animals are at higher risk of HEV infection. Cross-species infections with HEV genotypes 3 and 4 have been demonstrated experimentally. However, not all sources of human infections have been identified thus far and in many cases, the origin of HEV infection in humans remains unknown.

The use of Bayesian methods for evaluating the performance of a virus-like particles-based ELISA for serology of hepatitis E virus infection in swine

In the absence of commercial kits for serological studies specifically for hepatitis E virus (HEV) infection of swine, the capsid protein of a swine genotype 3 HEV was expressed using a recombinant baculovirus. This antigen was used in an enzyme-linked immunosorbent assay (ELISA) for detection of anti-HEV antibodies. Estimation of sensitivity and specificity was carried out in comparison with a commercial serological assay using sera from pigs infected experimentally with HEV genotype 3, negative sera from SPF pigs and swine sera collected at slaughterhouses. Since a "gold standard" is not available, a latent-class Bayesian approach for correlated tests was used to estimate the sensitivity and specificity of both tests. External field and experimental data were used to determine the parameters of Beta prior distributions. The estimated mean sensitivity of the commercial test was 0.47 with a 95% credibility interval of 0.39-0.55, whereas the estimated mean sensitivity of the genotype 3-based assay was 0.92 [0.81-0.99]. The estimated specificities were 0.98 [0.93-0.99] and 0.98 [0.95-0.99] for the genotype 3-based test and commercial test, respectively. In conclusion, genotype 3-antigen derived from swine HEV is a better candidate for assessing hepatitis E serology in swine.

[How to investigate and diagnose autochthonous hepatitis E?]

In developed countries, HEV infection was still recently considered as rare, and as an imported disease from endemic areas by travellers. Hepatitis E virus is now recognized mainly as an autochthonous disease in these countries. Although the source and the route of contamination remain uncertain, several cases of food-borne (zoonotic transmission) and blood-borne transmission have been recently reported. The mortality rates in industrialized countries seems to be higher than in endemic areas, since the infection occurs more frequently in elderly people with underlying chronic liver disease (mortality rate approaching 70% in this subgroup of patients). By contrast, whereas mortality rate rises by 20% during pregnancy in developing countries, no death in pregnant woman from developed countries secondary to an autochthonous case has been reported so far. Lastly, HEV infection may be a cause of chronic hepatitis in immunocompromised patients (mostly in solid organ-transplant recipients) which can evolve to cirrhosis.

A national survey of acute hepatitis E in France

BACKGROUND

Few data are available on the incidence, risk factors and contamination pathways involved in acute indigenous hepatitis E in developed countries.

AIMS

To draw up an overall picture of hepatitis E cases, to confirm whether or not the majority of the cases were indigenous and to attempt to identify the risk factors and contamination pathways involved in hepatitis E.

METHODS

This study was performed in the framework of a national network (ANGH) including 96 participating centres. The 19 centres with at least one case of acute HEV reported a total number of 53 cases.

RESULTS

A decreasing South-to-North geographic gradient was observed. A nonspecific clinical profile was observed in many cases. Acute hepatitis E was of indigenous origin in 90% of the patients. The most relevant and/or frequent possible risk factors among the 47 indigenous metropolitan cases were water consumption from a personal water supply, uncooked shellfish consumption and the recent acquisition of a pet pig.

CONCLUSIONS

This national survey confirmed that acute indigenous hepatitis E is an emerging disease in developed countries such as France, and suggests that various risk factors are responsible for acute indigenous hepatitis E contamination in non-endemic countries.

Hepatitis C virus core proteins derived from different quasispecies of genotype 1b inhibit the growth of Chang liver cells

AIM: To investigate the influence of different quasispecies of hepatitis C virus (HCV) genotype 1b core protein on growth of Chang liver cells.

METHODS: Three eukaryotic expression plasmids (pEGFP-N1/core) that contained different quasispecies truncated core proteins of HCV genotype 1b were constructed. These were derived from tumor (T) and non-tumor (NT) tissues of a patient infected with HCV and C191 (HCV-J6). The core protein expression plasmids were transiently transfected into Chang liver cells. At different times, the cell cycle and apoptosis was assayed by flow cytometry, and cell proliferation was assayed by methyl thiazolyl tetrazolium (MTT) assay.

RESULTS: The proportion of S-phase Chang liver cells transfected with pEGFP-N1/core was significantly lower than that of cells transfected with blank plasmid at three different times after transfection (all P < 0.05). The proliferation ratio of cells transfected with pEGFP-N1/core was significantly lower than that of cells transfected with blank plasmid. Among three different quasispecies, T, NT and C191 core expression cells, there was no significant difference in the proportion of S- and G₀/G₁-phase cells. The percentage of apoptotic cells was highest for T (T > NT > C191), and apoptosis was increased in cells transfected with pEGFP-N1/core as the transfection time increased (72 h > 48 h > 24 h).

CONCLUSION: These results suggest that HCV genotype 1b core protein induces apoptosis, and inhibits cell-cycle progression and proliferation of Chang liver cells. Different quasispecies core proteins of HCV genotype 1b might have some differences in the pathogenesis of HCV persistent infection and hepatocellular carcinoma.

Possible zoonotic transmission of hepatitis E from pet pig to its owner

Hepatitis E is transmitted mainly by water or food, but in industrialized countries, all routes of transmission have not been identified. We describe possible zoonotic transmission of hepatitis E virus that involved direct contact between a pet pig and its owner.