Detection and characterization of hepatitis E virus in domestic pigs of different ages in Portugal

Serological and Molecular Survey of Hepatitis E Virus in Small Ruminants from Central Portugal

Hepatitis E virus (HEV) is currently recognized as an emerging problem and a growing concern for public health in developed countries, with HEV infections mainly attributable to foodborne transmission of HEV-3. The zoonotic HEV genotype 3 infects a wide range of mammalian hosts, with swine considered as the primary host. This study investigates the occurrence of HEV among small ruminants in Portugal. The primary aim of the present research was to evaluate the circulation and the potential for HEV infection among sheep and goats. A total of 400 bile samples and 493 blood samples were collected from sheep and goats at a slaughterhouse in the center region of Portugal, between January 2022 and March 2023. The HEV RNA detection in bile samples was performed using a nested broad-spectrum RT-PCR targeting the ORF1 region. Serological analysis to detect anti-HEV antibodies was conducted using a commercial double-antigen sandwich multi-species ELISA. The HEV RNA was not detected in any bile samples using the nested broad-spectrum RT-PCR. Serological analysis revealed an overall HEV antibody seroprevalence of 2% (10/493, 95% CI: 0.98-3.70) among the small ruminants, namely 2.2% in goats and 2.0% in sheep. Curiously, no statistically significant association among the factors, age, sex and species and HEV seroprevalence was observed. Although HEV RNA was not detected in the bile of sheep and goats, this study the evidence of seroprevalence in these small ruminant species. Further research could provide additional insights into the factors influencing HEV transmission dynamics in small ruminants in Portugal and its potential implications for public health.

Detection of hepatitis E virus genotype 3 in an Algerian mouse (Mus spretus) in Portugal

Virus monitoring in small mammals is central to the design of epidemiological control strategies for rodent-borne zoonotic viruses. Synanthropic small mammals are versatile and may be potential carriers of several microbial agents. In the present work, a total of 330 fecal samples of small mammals were collected at two sites in the North of Portugal and screened for zoonotic hepatitis E virus (HEV, species Paslahepevirus balayani). Synanthropic small mammal samples (n = 40) were collected in a city park of Porto and belonged to the species Algerian mouse (Mus spretus) (n = 26) and to the greater white-toothed shrew (Crocidura russula) (n = 14). Furthermore, additional samples were collected in the Northeast region of Portugal and included Algerian mouse (n = 48), greater white-toothed shrew (n = 47), wood mouse (Apodemus sylvaticus) (n = 43), southwestern water vole (Arvicola sapidus) (n = 52), Cabrera's vole (Microtus cabrerae) (n = 49) and Lusitanian pine vole (Microtus lusitanicus) (n = 51). A nested RT-PCR targeting a part of open reading frame (ORF) 2 region of the HEV genome was used followed by sequencing and phylogenetic analysis. HEV RNA was detected in one fecal sample (0.3%; 95% confidence interval, CI: 0.01-1.68) from a synanthropic Algerian mouse that was genotyped as HEV-3, subgenotype 3e. This is the first study reporting the detection of HEV-3 in a synanthropic rodent, the Algerian mouse. The identified HEV isolate is probably the outcome of either a spill-over infection from domestic pigs or wild boars, or the result of passive viral transit through the intestinal tract. This finding reinforces the importance in the surveillance of novel potential hosts for HEV with a particular emphasis on synanthropic animals.

Prevalence of Paslahepevirus balayani in commercial swine food products from Spain

Paslahepevirus balayani (formerly known as hepatitis E virus) is an emerging cause of foodborne disease in Europe, transmitted mainly by the consumption of raw or undercooked pork. Since little is known about the presence of the virus in several pork products that are eaten uncooked, our aim was to evaluate the prevalence of Paslahepevirus balayani in groups of commercial pork products intended for human consumption subjected to different processing techniques. A total of 1265 samples of pork products from Spain were divided into four groups and tested for the presence of Paslahepevirus balayani RNA: unprocessed pig and wild boar meat frozen at -20 °C (n = 389), dry-cured pork products (n = 391), dry-cured and salted pork products (n = 219), and boiled products (n = 266) (none of these products contained pork liver). Five samples were positive for Paslahepevirus balayani RNA (overall prevalence: 0.4%; 95% CI: 0.17% - 0.92%). All positive samples were from unprocessed meat stored at -20 °C, with a prevalence in this group of 1.3% (95% CI: 0.42-3.44); two samples came from pigs (1.1%; 95% CI: 0.13-3.81) and three from wild boar (1.5%; 95% CI: 0.31-4.28). None of the pork samples in the other groups was positive. In conclusion, Paslahepevirus balayani was found in unprocessed swine products form Spain, but not in processed products intended to be consumed undercooked, demonstrating that transmission of this zoonotic virus by eating these pork products should be more seriously considered.

Prevalence, Genetic Diversity, and Quantification of the RNA Genome of the Hepatitis E Virus in Slaughtered Pigs in Serbia

The goal of this study conducted in Serbia was to detect HEV in pig liver samples from slaughterhouses, retail outlets, and environmental swabs over the course of a year. All positive HEV samples were measured and expressed as HEV gene copy numbers per gram of sample, and a representative number of samples were sequenced using the Sanger approach. A total of 45 HEV-positive samples were re-amplified using nested RT-PCR employing CODEHOP primers targeting ORF2 (493 nucleotides). The average prevalence of the HEV genotype 3 in all pig liver samples from the slaughterhouses was 29%, while HEV prevalence was 44% in liver samples from animals younger than 3 months. HEV RNA was found in thirteen out of sixty (22%) environmental swab samples that were taken from different surfaces along the slaughter line. Our findings confirmed seasonal patterns in HEV prevalence, with two picks (summer and winter periods) during the one-year examination. Among HEV-positive samples, the average viral particles for all positive liver samples was 4.41 ± 1.69 log10 genome copies per gram. Phylogenetic analysis revealed the majority of HEV strains (43/45) from Serbia were grouped in the HEV-3a subtype, while two strains were classified into the HEV-3c subtype, and one strain could not be classified into any of the HEV-3 subtypes.

Hepatitis E Virus in Livestock-Update on Its Epidemiology and Risk of Infection to Humans

Hepatitis E virus (HEV) is a public health problem worldwide and an important food pathogen known for its zoonotic potential. Increasing numbers of infection cases with human HEV are caused by the zoonotic transmission of genotypes 3 and 4, mainly by consuming contaminated, undercooked or raw porcine meat. Pigs are the main reservoir of HEV. However, it should be noted that other animal species, such as cattle, sheep, goats, and rabbits, may also be a source of infection for humans. Due to the detection of HEV RNA in the milk and tissues of cattle, the consumption of infected uncooked milk and meat or offal from these species also poses a potential risk of zoonotic HEV infections. Poultry infected by avian HEV may also develop symptomatic disease, although avian HEV is not considered a zoonotic pathogen. HEV infection has a worldwide distribution with different prevalence rates depending on the affected animal species, sampling region, or breeding system.

Hepatitis E Virus in the Iberian Peninsula: A Systematic Review

One of the most frequent causes of acute viral hepatitis is hepatitis E virus (HEV) causing 20 million infections worldwide each year and 44,000 deaths. Studies on HEV in the Iberian Peninsula have been increasing through time with HEV infection being identified in humans and animals. The aim of the present systematic review was to compile and evaluate all the published data on HEV from studies performed in humans, animals and environmental samples in the Iberian Peninsula. The electronic databases Mendeley, PubMed, Scopus, and Web of Science were thoroughly searched, and research published up until February 01, 2023 were included. Resulting in a total of 151 eligible papers by full reading and application of PRISMA exclusion/inclusion criteria. Overall, the present review shows that several HEV genotypes, namely HEV-1, 3, 4, and 6 as well as Rocahepevirus, are circulating in humans, animals, and in the environment in the Iberian Peninsula. HEV-3 was the most common genotype circulating in humans in Portugal and Spain, as expected for developed countries, with HEV-1 only being detected in travelers and emigrants from HEV endemic regions. Spain is the biggest pork producer in Europe and given the high circulation of HEV in pigs, with HEV-3 being primarily associated to zoonotic transmission through consumption of swine meat and meat products, in our opinion, the introduction of an HEV surveillance system in swine and inclusion of HEV in diagnostic routines for acute and chronic human hepatitis would be important. Additionally, we propose that establishing a monitoring mechanism for HEV is crucial in order to gain a comprehensive understanding of the prevalence of this illness and the various strains present in the Iberian Peninsula, as well as their potential impact on public health.

Survey of Zoonotic Diarrheagenic Protist and Hepatitis E Virus in Wild Boar (Sus scrofa) of Portugal

Enteropathogenic parasites and viruses have been frequently reported in swine and can infect a wide range of mammals, including humans. Among the wide variety of parasites infecting swine, diarrhoeagenic protists are among those that cause significant morbidity. Hepatitis E virus (HEV) has also been reported both in domestic pigs and wild boar and is known to have an important public health significance. These agents share the fecal−oral transmission route, but data on their fecal shedding and circulation pathways are still lacking or incomplete. Hence, the aim of the present study was to characterize the presence of microeukaryotes and HEV in the wild boar of Portugal. Wild boar stool samples (n = 144) were obtained during the official hunting seasons (October to February) in 2018/2019, 2019/2020, and 2021/2022 and tested for Cryptosporidium spp., Balantioides coli, Giardia duodenalis, Blastocystis sp., Enterocytozoon bieneusi and HEV by molecular assays, followed by sequencing and phylogenetic analysis. We have detected Cryptosporidium scrofarum (1.4%, 95% CI: 0.2−4.9), B. coli (14.6%, 95% CI: 9.2−21.4), Blastocystis ST5 (29.2%, 95% CI: 21.9−37.2) and HEV genotype 3 (2.8%, 95% CI: 0.7−6.9; subgenotypes 3e and 3m). Co-infections were observed in thirteen animals where two were positive for both HEV and B. coli, one was positive for both C. scrofarum and Blastocystis ST5, and ten were positive for both B. coli and Blastocystis ST5. Giardia duodenalis and E. bieneusi were not detected in the surveyed wild boar population. As far as we know, this is the first report describing protist infections by Cryptosporidium spp., B. coli, and Blastocystis sp., as well as the first identification of the emerging HEV genotype 3m in wild boar of Portugal. The present work shows that potentially zoonotic protozoa and HEV are circulating in wild boar populations in Portugal. Awareness and epidemic-surveillance network implementation measures targeting wild boar are needed to prevent the spread of these pathogenic agents to humans.

Screening for hepatitis E virus genotype 3 in red deer (Cervus elaphus) and fallow deer (Dama dama), Portugal, 2018-2020

Hepatitis E virus (HEV) genotype 3 is the most prevalent HEV genotype in Europe causing mostly asymptomatic infections in humans, but can also sporadically cause severe acute hepatitis, chronic liver disease, chronic hepatitis in immunocompromised patients and extra-hepatic manifestations. Although much is today known about the swine reservoir, no information is available on the occurrence of HEV from widely distributed deer species in Portugal. Here, we investigated the presence and characterized HEV in free-living deer in Portugal by screening stools from red deer (Cervus elaphus) (n = 95) and fallow deer (Dama dama) (n = 35) for HEV by a broad-spectrum nested RT-PCR, followed by sequencing and phylogenetic analysis. Two red deer females, sampled in central Portugal, showed to be shedding HEV (2.1%; 95% confidence interval: 0.58-7.35). Sequencing and genetic characterization showed that these two deer HEV sequences were 98.96% identical to each other, being both of HEV genotype 3 subgenotype 3e. The increasing numbers and distribution of deer in Portugal and the zoonotic features of the circulating HEV genotype 3 subgenotype 3e highlights the importance of continued surveillance directed to food-borne diseases, especially those involving wild animals and deer in particular.

Long-term surveillance for hepatitis E virus in an Italian two-site farrow-to-finish swine farm

In humans, hepatitis E virus (HEV) is responsible for an acute enterically transmitted hepatitis, which can become chronic in immune-compromised patients. Genotypes 3 and 4 (HEV-3 and HEV-4) are zoonotic, and domestic pigs and wild boar are the main reservoirs. The occurrence of autochthonous cases in Europe, which have been increasing over the last 10 years, has been associated with food-borne zoonotic transmission of HEV-3, mainly linked to consumption of undercooked or raw pork products (sausages containing liver) and wild boar meat. Zoonotic HEV-3 strains are widespread on pig farms, but little information is available on the dynamic of HEV-3 infection within farms, among pigs. The aims of this study were to evaluate the prevalence of the infection among pigs of different ages along the production chain by the zoonotic HEVs, and to evaluate how long the virus may persist in the farm environment. The presence of HEV-RNA was investigated by real-time reverse transcription PCR (RT-PCR) in 281 test faecal pools over 19 months (2017-2019) on a two-site farrow-to-finish farm (about 1,000 sows), in Northern Italy. A total of 67/281 test faecal pools (23.8%) resulted positive for the presence of HEV-RNA (site 1: 59/221, 26.7%; site 2: 8/60, 13.3%). Nucleotide sequencing revealed a unique HEV-3 viral variant circulating during 19 months of surveillance. The same HEV-3 strain was detected in the same farm on 2012, indicating the persistence of the same virus over 7 years, and highlighting the role of the environment as a continuous source of infection on pig farms. The results confirmed the circulation of the zoonotic genotype HEV-3 in pigs before slaughtering.

Presence of hepatitis E virus in commercially available pork products

An increasing number of hepatitis E virus (HEV) infections in industrialized countries have been foodborne and linked to the consumption of undercooked pork products. To date, data on the prevalence of HEV in pork products sold in the United States is limited and no standard processing method exists for the detection of HEV in foods. In order to develop a processing method for the detection of HEV in pork products, ground pork and pork liver were selected for method development. Murine norovirus (MNV) was used as a process control. A filtration step prior to RNA detection was shown to reduce the level of PCR inhibitors in ground pork and an additional ultracentrifugation process was successful in removing PCR inhibitors in pork liver. MNV RNA was detected in ground pork and liver samples inoculated with 4.7 log₁₀ PFU/g and 3.0 log₁₀ PFU/g, respectively. Using the developed method for viral RNA detection in ground pork and pork liver, 20 packages of ground pork (six 1 g sub-samples per package) and 14 pork livers (four 1 g sub-samples per liver) were screened for the presence of HEV RNA. Fifteen out of 119 (12.6%) ground pork samples tested positive for HEV RNA and 13 out of 20 packages (65%) contained at least one positive sample. Twenty-five of 56 (45%) of pork liver samples were positive for HEV RNA and 6 of 14 livers (43%) had all sub-samples test positive for HEV RNA. Overall, the results indicate ground pork and pig liver as a potential source of HEV.

Evaluation of a non-invasive screening approach to determine hepatitis E virus status of pig farms

BACKGROUND

Identifying pig farms infected with hepatitis E virus (HEV) is a key aspect to implement surveillance programmes for this emerging zoonotic agent. Detection of HEV in blood has several drawbacks, including animal handling, economic costs and animal stress. The objective of this study was to evaluate the effectiveness of a non-invasive screening approach for determining the HEV status of pig farms under different management systems.

METHODS

Forty stool samples randomly collected from the pen floor of 17 intensive pig farms and the yard of nine extensive ones were tested for HEV RNA. The invasive method used to confirm the HEV status of the farm was HEV RNA analysis of serum samples randomly collected from 40 animals on each farm.

RESULTS

Twenty-one HEV-positive farms were detected by invasive and non-invasive methods. No positive serum or stool samples were detected on five intensive farms. A high intertest agreement (K=1; P<0.00001) was observed between both methodologies, showing the stool screening approach a 100 per cent of sensitivity and specificity with respect to the invasive method. Likewise, a significant negative relationship was observed between the HEV within-farm prevalence and the number of the first HEV-positive stool sample found (Spearman's rho=-0.64; P=0.0004). This negative relationship was higher in intensively managed farms.

CONCLUSION

This non-invasive screening approach could be reliably applied in a large-scale surveillance programme for determining the HEV status of pig farms under different management systems.

Assessment of the Presence of Hepatitis E virus in Surface Water and Drinking Water in Portugal

Hepatitis E virus (HEV) is a non-enveloped single-stranded positive-sense RNA virus, belonging to the Hepeviridae family, resistant to environmental conditions, and transmitted by the consumption of contaminated water. This virus is responsible for both sporadic and epidemic outbreaks, leading to thousands of infections per year in several countries, and is thus considered an emerging disease in Europe and Asia. This study refers to a survey in Portugal during 2019, targeting the detection and eventual quantification of enteric viruses in samples from surface and drinking water. Samples positive for HEV RNA were recurrently found by reverse transcription quantitative PCR (RT-qPCR), in both types of matrix. The infectivity of these samples was evaluated in cultured Vero E6 cells and RNA from putative viruses produced in cultures evidencing cytopathic effects and was subjected to RT-qPCR targeting HEV genomic RNA. Our results evidenced the existence of samples positive either for HEV RNA (77.8% in surface water and 66.7% in drinking water) or for infectious HEV (23.0% in surface water and 27.7% in drinking water). These results highlight the need for effective virological control of water for human consumption and activities.

Occurrence of Hepatitis E Virus in Pigs and Pork Cuts and Organs at the Time of Slaughter, Spain, 2017

Zoonotic hepatitis E, mainly caused by hepatitis E virus (HEV) genotype (gt) 3, is a foodborne disease that has emerged in Europe in recent decades. The main animal reservoir for genotype 3 is domestic pigs. Pig liver and liver derivates are considered the major risk products, and studies focused on the presence of HEV in pig muscles are scarce. The objective of the present study was to evaluate the presence of HEV in different organs and tissues of 45 apparently healthy pigs from nine Spanish slaughterhouses (50% national production) that could enter into the food supply chain. Anti-HEV antibodies were evaluated in serum by an ELISA test. Ten samples from each animal were analyzed for the presence of HEV RNA by reverse transcription real-time PCR (RT-qPCR). The overall seroprevalence obtained was 73.3% (33/45). From the 450 samples analyzed, a total of 26 RT-qPCR positive samples were identified in the liver (7/45), feces (6/45), kidney (5/45), heart (4/45), serum (3/45), and diaphragm (1/45). This is the first report on detection of HEV RNA in kidney and heart samples of naturally infected pigs. HEV RNA detection was negative for rib, bacon, lean ham, and loin samples. These findings indicate that pig meat could be considered as a low risk material for foodborne HEV infection.

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.

Short communication: detection and molecular characterization of hepatitis E virus in domestic animals of São Tomé and Príncipe

As in most of the African continent, the status of hepatitis E virus (HEV) infection in domestic animals in São Tomé and Príncipe, an archipelago off the western equatorial coast of Central Africa, is also completely unknown. In the present study, we investigated the presence of HEV among domestic animals in São Tomé and Príncipe. A total of 93 stool samples from different animal species (goat, cow, pig, chicken, duck, and monkey) were tested for HEV RNA using two real-time RT-PCR assays, followed by a nested RT-PCR assay for sequencing and phylogenetic analysis. A total of six samples (1 cow stool and 5 pig stools) were found to be positive for HEV RNA of which one pig stool was positive by broad spectrum nested RT-PCR. Phylogenetic analysis showed that the retrieved sequence clustered within HEV subgenotype 3f, similar to zoonotic strains of European countries and posing interesting questions on past introduction of European HEV into São Tomé and Príncipe archipelago. This is the first report describing the presence and molecular characterization of HEV in São Tomé and Príncipe.

Hiding in Plain Sight? It's Time to Investigate Other Possible Transmission Routes for Hepatitis E Virus (HEV) in Developed Countries

Historically in developed countries, reported hepatitis E cases were typically travellers returning from countries where hepatitis E virus (HEV) is endemic, but now there are increasing numbers of non-travel-related ("autochthonous") cases being reported. Data for HEV in New Zealand remain limited and the transmission routes unproven. We critically reviewed the scientific evidence supporting HEV transmission routes in other developed countries to inform how people in New Zealand may be exposed to this virus. A substantial body of indirect evidence shows domesticated pigs are a source of zoonotic human HEV infection, but there is an information bias towards this established reservoir. The increasing range of animals in which HEV has been detected makes it important to consider other possible animal reservoirs of HEV genotypes that can or could infect humans. Foodborne transmission of HEV from swine and deer products has been proven, and a large body of indirect evidence (e.g. food surveys, epidemiological studies and phylogenetic analyses) support pig products as vehicles of HEV infection. Scarce data from other foods suggest we are neglecting other potential sources of foodborne HEV infection. Moreover, other transmission routes are scarcely investigated in developed countries; the role of infected food handlers, person-to-person transmission via the faecal-oral route, and waterborne transmission from recreational contact or drinking untreated or inadequately treated water. People have become symptomatic after receiving transfusions of HEV-contaminated blood, but it is unclear how important this is in the overall hepatitis E disease burden. There is need for broader research efforts to support establishing risk-based controls.

Hepatitis E Virus Genotype 1 Cases Imported to Portugal from India, 2016

Hepatitis E in industrialized countries is mainly associated with genotype 3 hepatitis E virus (HEV) and normally causes a sporadic self-limiting disease in immunocompetent individuals. Unlike genotype 3, genotypes 1 and 2 circulate in developing countries, produce severe disease and occur in the epidemic form. Hepatitis E occurring in travellers returning from endemic areas in developing countries is not a novel epidemiological occurrence, however the vast majority of cases remain to be genetically studied. The present study describes two cases of severe acute hepatitis E that required hospitalization for 6 and 9 days in two individuals of Indian nationality that had recently migrated to Portugal to work. The retrieved HEV sequences both belonged to genotype 1 and had a high degree of nucleotide sequence identity, clustering with strains isolated in India and Nepal, in 2013 and 2014. Confirmed HEV genotypes of increased pathogenicity like genotype 1 are being introduced into otherwise naïve populations of industrialized countries such as European countries with consequences difficult to predict. As far as we know the present study is the first in Portugal to describe and genetically characterize imported cases of hepatitis E infection caused by HEV genotype 1.

An overview of 20 years of studies on the prevalence of human enteric viruses in shellfish from Galicia, Spain

Galicia (NW Spain) has 1490 km of coastline, and its particular topography, characterized by the presence of fiord-like inlets, called rías, with an important primary production, makes this region very favourable for shellfish growth and culture. In fact, Galicia is one of the most important mussel producers in the world. Due to its proximity to cities and villages and the anthropogenic activities in these estuaries, and despite the routine official controls on the bivalve harvesting areas, contamination with material of faecal origin is sometimes possible but, current regulation based on Escherichia coli as an indicator micro-organism has been revealed as useful for bacterial contaminants, this is not the case for enteric viruses. The aim of this review is to offer a picture on the situation of different harvesting areas in Galicia, from a virological standpoint. A recompilation of results obtained in the last 20 years is presented, including not only the data for the well-known agents norovirus (NoV) and hepatitis A virus (HAV) but also data on emerging viral hazards, including sapovirus (SaV), hepatitis E virus (HEV) and aichivirus (AiV). Epidemiological differences related to diverse characteristics of the harvesting areas, viral genotype distribution or epidemiological links between environmental and clinical strains will also be presented and discussed. The presentation of these historical data all together could be useful for future decisions by competent authorities for a better management of shellfish growing areas.

A comprehensive study of hepatitis E virus infection in pigs entering a slaughterhouse in Slovenia

Hepatitis E is a zoonotic viral disease of pigs with increasing public health concern in industrialized countries. Presented broad study of hepatitis E virus (HEV) presence in pigs in Slovenia is the first attempt to overview the HEV situation in pigs entering a slaughterhouse and, further, to analyse the possibility of HEV entering into the food supply chain. 2433 samples from 811 clinically healthy pigs were collected at four slaughterhouses in Slovenia. Sampling covered three different age groups of pigs and three different types of samples (faeces, bile and liver) important for tracing HEV in a pig population. In addition, 63 swab samples were collected systematically from three different sites on the slaughter line, as well as 22 samples of minced meat and 30 bratwurst samples. All the samples were screened for the presence of HEV nucleic acids by specific real-time RT-PCR assay. In the group of three month old pigs 13.7% of faeces, 13.0% of bile and 2.1% of liver samples were HEV positive. In the group of six months old pigs only 0.25% of liver and 0.25% of bile samples were positive. In the category of sows, no positive samples were found. Two out of 63 swab samples collected on the slaughter line were HEV positive. All tested samples of minced meat and bratwurst were negative. The phylogenetic analysis of 50 HEV positive samples, with comparison of 366 nucleotides in ORF1 region, revealed high diversity of identified strains of HEV in pigs, belonging into subtypes 3a, 3b, 3c and 3e.

High hepatitis E virus antibody positive rates in dogs and humans exposed to dogs in the south-west of China

Hepatitis E (HE) is a zoonotic viral disease caused by hepatitis E virus (HEV). The objective of this study was to investigate the prevalence of HEV infection among dogs and humans exposed to dogs in the south-west region of China. A total of 4,490 dog serum samples and 2,206 relative practitioner serum samples were collected from 18 pet hospitals and dog farms in Yunnan, Sichuan and Guizhou province, and the anti-HEV IgG antibodies were detected by ELISA. The results showed that the total positive rate of anti-HEV antibodies was 36.55% with the highest rate in city stray dogs, and the differences in distinct species and growth phases were significant. The positive rate of anti-HEV antibody in veterinarian and farm staff-related practitioners was significantly higher than the general population. The finding of the present survey suggested that high HEV seroprevalence in dogs and humans exposed to dogs in the south-west area of China poses a significant public health concern. It is urgent to improve integrated strategies to detect, prevent and control HEV infection in dogs and humans exposed to dogs in this area.

Seroprevalence of Hepatitis E Virus Antibodies in Portuguese Children

BACKGROUND

Hepatitis E virus (HEV) has become a growing public health concern in industrialized countries. Most of the HEV seroprevalence studies have focused on adult populations, and reports regarding HEV seroepidemiology among children are scarce in these countries. The aims of this work were to perform a nationwide seroprevalence study on HEV infection in Portuguese children and to compare the HEV seropositivity in this 2015 children cohort with results in sera performed 20 years earlier.

METHODS

Sera (N = 352) from children collected in 2015 from all regions of Portugal were screened for anti-HEV IgG and IgM using the commercial enzyme-linked immunosorbent assay recomWell HEV IgG/IgM (2015 version; Mikrogen, Neuried, Germany), and positive samples were retested by immunodot assay recomLine HEV IgG/IgM (2015 version; Mikrogen, Neuried, Germany). For the comparative assessment of HEV seropositivity of the 2 children cohorts, children's sera (N = 71) archived since 1995 were screened for anti-HEV IgG and results were compared with that of the 2015 cohort, matched by sex, age and region.

RESULTS

Anti-HEV antibodies were detected in 4 children giving an overall HEV seroprevalence in the 2015 cohort of 1.1%. A healthy 10-15-year-old female was found positive for anti-HEV IgM indicating a current or recent HEV infection. No statistically significant difference was observed in HEV seroprevalence regarding gender, age group and region of residence. Comparison of the HEV seropositivity of the 2 children cohorts showed a statistical significant decrease with time (P = 0.024).

CONCLUSIONS

This is the first national study of HEV seroprevalence in Portuguese children and the first to demonstrate a decrease of anti-HEV antibodies in this age group over time.

From the epidemiology of hepatitis E virus (HEV) within the swine reservoir to public health risk mitigation strategies: a comprehensive review

Hepatitis E virus (HEV) is the causative agent of hepatitis E in humans, an emerging zoonosis mainly transmitted via food in developed countries and for which domestic pigs are recognised as the main reservoir. It therefore appears important to understand the features and drivers of HEV infection dynamics on pig farms in order to implement HEV surveillance programmes and to assess and manage public health risks. The authors have reviewed the international scientific literature on the epidemiological characteristics of HEV in swine populations. Although prevalence estimates differed greatly from one study to another, all consistently reported high variability between farms, suggesting the existence of multifactorial conditions related to infection and within-farm transmission of the virus. Longitudinal studies and experimental trials have provided estimates of epidemiological parameters governing the transmission process (e.g. age at infection, transmission parameters, shedding period duration or lag time before the onset of an immune response). Farming practices, passive immunity and co-infection with immunosuppressive agents were identified as the main factors influencing HEV infection dynamics, but further investigations are needed to clarify the different HEV infection patterns observed in pig herds as well as HEV transmission between farms. Relevant surveillance programmes and control measures from farm to fork also have to be fostered to reduce the prevalence of contaminated pork products entering the food chain.

Hepatitis E Virus in Pork and Variety Meats Sold in Fresh Markets

Swine is an economically important livestock, yet pork consumption and close contact with pigs are associated with the risk of hepatitis E virus (HEV) infection. Limited data on the prevalence of HEV in Southeast Asia have mainly examined farm animals. To investigate the potential zoonotic transmission of HEV from dietary consumption of pork and variety meats (i.e., offal or organ meats), we obtained 1090 liver, 559 pork meat, and 556 intestine samples from fresh markets in the Bangkok metropolitan area between November 2014 and February 2015. The presence of HEV was assessed using reverse-transcription polymerase chain reaction. Concurrently, 720 bile and 553 fecal samples from a slaughterhouse were also examined. Overall, HEV RNA was found in 0.23 % of the market samples and 3.93 % of the slaughterhouse samples. Fecal and bile samples were more likely to test positive compared to liver, pork, and intestine samples (p < 0.001). Phylogenetic analysis showed that all HEV sequences obtained in this study formed a cluster closely related to genotype 3f. Pork and variety meats derived from pigs are commonly sold in fresh markets throughout Southeast Asia. Here, a relatively low HEV prevalence from pork and variety meats sold in Bangkok was found. Additional studies will be required to further assess potential dietary transmission of HEV elsewhere in the region.

Prevalence of hepatitis E virus antibodies in workers occupationally exposed to swine in Portugal

The concept of zoonotic hepatitis E in industrialized countries has emerged with the discovery of swine strains of hepatitis E virus (HEV) genotype 3, closely related to human HEV. Different routes of zoonotic HEV transmission have been recognized, including contact with infected pigs. Workers occupationally exposed to swine (WOES) have been considered a risk group for HEV infection, but contradictory results have been reported. In the present study, we searched for anti-HEV IgG in WOES (butchers, slaughterhouse workers, veterinarians and pig farmers; n = 114) and in the general population (n = 804) in order to investigate the potential occupational risk of zoonotic HEV infection in this work group. A significantly higher (p = 0.008) anti-HEV IgG seroprevalence was found in WOES (30.7 %) when compared with the general population (19.9 %). Multivariate analysis showed that having professions with exposure to pigs for more than 16.5 years was a risk factor for being positive for anti-HEV IgG (aOR of 5.4, 95 % CI 1.9-15.6, p = 0.002). To our knowledge, this is the first study on the prevalence of anti-HEV IgG in WOES in Portugal, also showing increased probability for infection in this group.

Hepatitis E Virus in Sylvatic and Captive Wild Boar from Portugal

Hepatitis E virus (HEV) is a zoonotic agent today considered a major Public Health issue in industrialized countries. HEV strains belonging to zoonotic genotype 3 are widely present in swine, being today considered important reservoirs for human disease. Unlike in swine, only scarce data are available on the circulation of HEV in wild boar. This study describes the detection and molecular characterization of HEV in livers from sylvatic wild boar hunted in Portugal and destined for consumption. Additionally, the detection of HEV in stools of a confined wild boar population also destined for consumption is also described. A total of 80 liver samples collected during the hunting season of 2011/2012 and 40 stools collected in February 2012 from a wild boar breeding farm in Portugal were tested by a nested broad-spectrum RT-PCR assay targeting open reading frame (ORF) 1. Twenty livers (25.0%) and 4 stools (10%) were positive for HEV. Phylogenetic analysis showed that all strains clustered with sequences classified as HEV genotype 3 subgenotype e. To our knowledge, this is the first report documenting the occurrence and molecular analysis of HEV in sylvatic and captive wild boar destined for human consumption in Portugal. This report demonstrates for the first time the circulation of HEV in wildlife reservoirs of Portugal adding knowledge to the epidemiology of HEV in wild boar populations.

Hepatitis E virus genotype 3 in mussels (Mytilus galloprovinciallis), Spain

Coastal waters can become contaminated with both human waste from sewage treatment plants and runoff following manure application. Thus, shellfish produced close to land can bioaccumulate enteric viruses of human and animal origin, including zoonotic hepatitis E virus that infect both human and swine. The goal of this study was to evaluate the presence of HEV in shellfish from Galicia (NW Spain), a densely populated region with a strong tradition of swine farming, and one of the most important regions in the world for mussel production. We tested 81 mussel batches by RT-qPCR followed by conventional broad-spectrum nested RT-PCR and phylogenetic analysis. We have obtained 12 positive samples by RT-qPCR (14.81%) with HEV contamination levels ranging from 6.7 × 10(1) to 8.6 × 10(4) RNA copies/g digestive tissue. Phylogenetic analysis based on a 330 nt region of the ORF 1 showed that all sequenced isolates belonged to the zoonotic genotype 3 subgenotype e, being closely related to strains of human and swine origin. Results show that shellfish may be a potential route for HEV transmission to humans.

A Public Health initiative on hepatitis E virus epidemiology, safety and control in Portugal--study protocol

BACKGROUND

The discovery of autochthonous hepatitis E in industrialized countries has changed the understanding of hepatitis E virus (HEV) infection in these regions, now known to be mainly due to zoonotic transmission of genotype 3. The foodborne route of transmission via consumption of contaminated meat from HEV infected pigs is well documented as well as the direct occupational exposure to animal reservoirs. Accumulating evidence also points to an emerging potential threat to blood safety after the identification of viremic blood donors and the documentation of HEV-contaminated blood or blood products. Moreover, the origin of several iatrogenic cases remains unclear and porcine-derived pharmaceutic products have been suspected as a cause. Severe morbidity following HEV infection in patients receiving immunosuppressive therapy and in those with severe immunodeficiency from other causes has been recently recognized as a serious consequence of this infection in industrialized countries. In Portugal no large-scale HEV seroprevalence study has been undertaken, no professional risk groups have been identified, and the risk of blood donation from HEV silent infected donors is unknown. The present paper describes seroepidemiological and molecular approaches to answer these questions.

METHODS/DESIGN

To address these issues a study protocol was designed that will approach: i) the seroprevalence of HEV among the Portuguese general population; ii) HEV infection among butchers and slaughterhouse workers (occupational risk); iii) the silent HEV infection in Portuguese blood donors (HEV transfusion-associated risk); iv) the potential HEV contamination of porcine-derived pharmaceutical products. Commercial enzyme immunoassays and real-time/conventional RT-PCR assays will be used.

DISCUSSION

This study is the first evaluation of the seroepidemiological status to HEV infection of the Portuguese population, the first to potentially identify professional risk groups, and to evaluate the safety of blood and blood products and porcine-derived pharmaceutics in Portugal. It will generate valuable data applicable for preventive and control measures against HEV infection (e.g., introduction of systematic screening of blood donors, control of blood products or porcine derived pharmaceutical products), thus helping to manage the burden of this viral disease.

Effect of swine hepatitis E virus on the livers of experimentally infected Mongolian gerbils by swine hepatitis E virus

Previous studies have shown that hepatitis E virus (HEV) can be transmitted between rats, pigs, cattle, rabbits, chicken, cats, and deer. Because wild and domestic rodents have anti-HEV antibodies, they are considered potential reservoirs of HEV. In the current study, Mongolian gerbils were experimentally infected with swine hepatitis E virus and the effects of this infection were investigated. After inoculation with HEV, the liver-to-body weight ratio increased at 7 dpi. Mongolian gerbils demonstrated significant increase (p<0.05) in Aspartate Transaminase (AST), alanine transaminase (ALT) and total bilirubin (T-BIL) concentrations in the sera, and HEV IgG was detected at 21 days post-inoculation (dpi). Real-time PCR revealed that the copies of HEV RNA in the liver were detected at 7 dpi, and peaked at 28 dpi at a concentration of 7.73 logs g(-1). Using both light and electron microscopy, hepatic lesions were observed in the HEV inoculated animals. In the experimental group, characteristic viral hepatitis lesions were prominent in the liver. HEV antigen was detected in the liver by immunohistochemistry, and HEV ORF3 antigen was detectable in liver by Western blot. These results clearly demonstrate that viral load of HEV in livers was dynamic, and ultrastructural hepatic injury in HEV infected Mongolian gerbils and anti-HEV IgG positive seroconversion were observed during infection.

Age-related and regional differences in the prevalence of hepatitis E virus-specific antibodies in pigs in Germany

An increasing number of acute autochthonous human hepatitis E virus (HEV)-infections was noticed in Germany and other developed countries, most likely the result of a zoonotic virus transmission from pig, wild boar and deer. Currently there is still a lack of profound data concerning the actual prevalence of HEV-specific antibodies in domestic pig herds in Germany, in particular for regions with high pig density, and its age-dependency. 2273 domestic pig sera were collected in 2011 mainly from Bavaria, North Rhine-Westphalia and Lower Saxony from areas having a high pig density. Initially, 420 randomly selected pig sera were tested in three commercially available and in two in-house HEV-antibody ELISAs. 43.6% (183/420) to 65.5% (275/420) of the sera were demonstrated to be reactive against human pathogenic HEV genotypes 1 and/or 3. The majority of sera reacted only weakly or not at all with the rat HEV antigen with very few sera showing a stronger reactivity to this antigen compared to the genotype 3 antigen. The results of all three HEV-IgG tests, i.e. the PrioCHECK(®) HEV Ab porcine ELISA kit, the ID Screen(®) Hepatitis E Indirect Multi-species ELISA kit and the genotype 3 in-house ELISA were in good accordance. Therefore, the remaining sera were tested using the PrioCHECK(®) HEV Ab porcine ELISA kit. Samples with a borderline result were finally determined by application of the conjugate-modified recomLine HEV IgG assay. A total of 1065 of the 2273 sera (46.9%) were found to be anti-HEV IgG-positive. While 38.4% (306/796) of fatteners (age between 3 and 9 months) exhibited HEV-specific antibodies, 51.4% (759/1477) of sows (age older than 9 months) exhibited anti-HEV antibodies (P<0.001). Fatteners kept in Southern Germany had a significantly higher HEV IgG prevalence compared to fatteners kept in the high pig density federal states North Rhine-Westphalia and Lower Saxony but also in German federal states with a low pig density. In conclusion, the present study clearly demonstrates that a high percentage of domestic pigs in Germany have had contact with HEV. Seroprevalence depends on the pig's age and herd origin with the most significant regional variations for fatteners. The presence of anti-HEV-free herds may indicate that it is feasible to establish and sustain HEV-free pig herds. HEV seroprevalence still depends on the assay used for testing. This demonstrates an urgent need for test validation.

Acute hepatitis E complicated by Guillain-Barre syndrome in Portugal, December 2012--a case report

Autochthonous hepatitis E virus (HEV) infection has been increasingly reported in Europe and the United States, mostly arising from genotype 3 and less frequently genotype 4. We report here on a patient with HEV genotype 3a infection complicated by Guillain-Barré syndrome in Portugal in December 2012. We draw attention to the diagnosis of autochthonous HEV infection and to its rare, but important, neurological complications.