Tracing Hepatitis E Virus in Pigs From Birth to Slaughter

Seroprevalence survey of Hepatitis E Virus in Domestic Pigs in Guangdong, China

The Hepatitis E virus (HEV) causes acute and chronic Hepatitis E and is a global public health concern. HEV genotypes 3 (HEV-3) and 4 (HEV-4) are common to humans and animals, and domestic pigs and wild boars have been identified as the main reservoirs. However, limited information is available on the status of HEV infection in pigs, particularly in the Guangdong Province, China. This study aimed to investigate the seroprevalence of HEV in pig farms within the Guangdong Province. A total of 1568 serum samples were collected from 25 farms and tested for anti-HEV IgG antibodies. Enzyme-linked immunosorbent assay (ELISA) results revealed that 57.53% (902/1568) of serum samples from 24 farms (24/25, 96%) were positive for anti-HEV IgG antibodies. Year, season, region, and age were all linked risk factors for HEV in Guangdong, with season and region showing more significant impacts. The results showing a high seroprevalence of HEV confirmed its circulation among domestic pigs in the Guangdong Province, China. The presence of this antibody indicates that HEV infection was or is present on farms, posing a risk of zoonotic transmission of HEV from pigs to exposed workers and from pork or organs to consumption.

Porcine-derived pancreatic enzyme replacement therapy may be linked to chronic hepatitis E virus infection in cystic fibrosis lung transplant recipients

OBJECTIVES

In high-income countries hepatitis E virus (HEV) is an uncommonly diagnosed porcine-derived zoonoses. After identifying disproportionate chronic HEV infections in persons with cystic fibrosis (pwCF) postlung transplant, we sought to understand its epidemiology and potential drivers.

DESIGN

All pwCF post-transplant attending our regional CF centre were screened for HEV. HEV prevalence was compared against non-transplanted pwCF and with all persons screened for suspected HEV infection from 2016 to 2022 in Alberta, Canada. Those with chronic HEV infection underwent genomic sequencing and phylogenetic analysis. Owing to their swine derivation, independently sourced pancreatic enzyme replacement therapy (PERT) capsules were screened for HEV.

RESULTS

HEV seropositivity was similar between transplanted and non-transplanted pwCF (6/29 (21%) vs 16/83 (19%); p=0.89). Relative to all other Albertans investigated for HEV as a cause of hepatitis (n=115/1079, 10.7%), pwCF had a twofold higher seropositivity relative risk and this was four times higher than the Canadian average. Only three chronic HEV infection cases were identified in all of Alberta, all in CF lung transplant recipients (n=3/29, 10.3%). Phylogenetics confirmed cases were unrelated porcine-derived HEV genotype 3a. Ninety-one per cent of pwCF were taking PERT (median 8760 capsules/person/year). HEV RNA was detected by RT-qPCR in 44% (47/107) of PERT capsules, and sequences clustered with chronic HEV cases.

CONCLUSION

PwCF had disproportionate rates of HEV seropositivity, regardless of transplant status. Chronic HEV infection was evident only in CF transplant recipients. HEV may represent a significant risk for pwCF, particularly post-transplant. Studies to assess HEV incidence and prevalence in pwCF, and potential role of PERT are required.

Hepatitis A Virus and Hepatitis E Virus as Food- and Waterborne Pathogens-Transmission Routes and Methods for Detection in Food

Foodborne viruses are an important threat to food safety and public health. Globally, there are approximately 5 million cases of acute viral hepatitis due to hepatitis A virus (HAV) and hepatitis E virus (HEV) every year. HAV is responsible for numerous food-related viral outbreaks worldwide, while HEV is an emerging pathogen with a global health burden. The reported HEV cases in Europe have increased tenfold in the last 20 years due to its zoonotic transmission through the consumption of infected meat or meat products. HEV is considered the most common cause of acute viral hepatitis worldwide currently. This review focuses on the latest findings on the foodborne transmission routes of HAV and HEV and the methods for their detection in different food matrices.

Evaluation of Non-Invasive Sampling Methods for Detection of Hepatitis E Virus Infected Pigs in Pens

Pigs are a reservoir of hepatitis E virus (HEV), which causes hepatitis in humans. To study the epidemiology of HEV in pig farms, sampling methods are currently used that cause discomfort to pigs, such as rectal sampling. In line with the 3Rs principle, we aimed to evaluate non-invasive methods to detect pens with HEV-shedding pigs. Twenty-eight pens of one farm were sampled cross-sectionally. Individual rectal swabs (IRS) were collected to determine prevalence within pens. Four pen-level samples were compared: a pool of IRS per pen (P), boot socks (BS), oral fluid (OF) and pooled faecal droppings (FD). Each sample was tested by RT-PCR and the sensitivity and specificity of each method was determined by Bayesian latent class analysis. According to IRS, 19/28 pens were HEV positive. BS had a sensitivity of 95% and detected HEV in pens with 10% of pigs shedding; however, specificity was below 30%. FD were comparably accurate to P, with a sensitivity and specificity of 94% and 86%, respectively. BS sampling is thus advised to detect early shedding of HEV or pen contamination, and FD to determine the duration of shedding. This study demonstrates that non-invasive sampling can replace rectal swabs in research on HEV in pigs.

Molecular and serological investigation of Hepatitis E virus in pigs slaughtered in Northwestern Italy

BACKGROUND

Hepatitis E Virus (HEV) is recently considered an emerging public health concern. HEV genotypes 1 and 2 are widely distributed and pathogenic only for humans. In contrast, HEV, genotypes 3 and 4 are observed in swine, deer, wild boars and rabbits and can also be transmitted to humans. The presence of HEV in the liver, muscle, faeces, blood, and bile was detected by real-time RT-PCR in 156 pigs belonging to twenty different farms, ranging from 1 to 8 months of age. The phylogenetic analysis was performed on the viral strain present in the positive biological matrix, with the lowest Ct. HEV-IgG and HEV-IgM in the sera were analysed by two different ELISA kits.

RESULTS

Twenty-one pigs, i.e., 13.46% of them (21/156, 95% CI: 8.53%-19.84%), tested positive for HEV in at least one biological matrix by real-time RT-PCR, while phylogenetic analysis revealed the presence of HEV subtypes 3f and 3c. Pig serums analysed by ELISA showed an overall prevalence of 26.92% (42/156, 95% CI: 20.14%-34.60%) for HEV-IgG, whereas the 28.95% (33/114, 95% CI: 20.84%-38.19%) of them tested negative resulted positive for the HEV-IgM.

CONCLUSIONS

The faeces are the biological matrix with the highest probability of detecting HEV. The best concordance value (Kappa Kohen index) and the highest positive correlation (Phi index) were observed for the correlation between bile and liver, even when the number of positive liver samples was lower than the positive bile samples. This finding may suggest that a higher probability of HEV occurs in the bile, when the virus is present in the liver, during the stages of infection. Finally, the presence of HEV in muscle was observed in 11 pigs, usually used for the preparation of some dishes, typical of the Italian tradition, based on raw or undercooked meat. Therefore, their consumption is a possible source of infection for final consumer.

Metagenomic Analysis of RNA Fraction Reveals the Diversity of Swine Oral Virome on South African Backyard Swine Farms in the uMgungundlovu District of KwaZulu-Natal Province

Numerous RNA viruses have been reported in backyard swine populations in various countries. In the absence of active disease surveillance, a persistent knowledge gap exists on the diversity of RNA viruses in South African backyard swine populations. This is the first study investigating the diversity of oral RNA virome of the backyard swine in South Africa. We used three samples of backyard swine oral secretion (saliva) collected from three distantly located backyard swine farms (BSFs) in the uMgungundlovu District, KwaZulu-Natal, South Africa. Total viral RNA was extracted and used for the library preparation for deep sequencing using the Illumina HiSeq X instrument. The FASTQ files containing paired-end reads were analyzed using Genome Detective v 1.135. The assembled nucleotide sequences were analyzed using the PhyML phylogenetic tree. The genome sequence analysis identified a high diversity of swine enteric viruses in the saliva samples obtained from BSF2 and BSF3, while only a few viruses were identified in the saliva obtained from BSF1. The swine enteric viruses belonged to various animal virus families; however, two fungal viruses, four plant viruses, and five unclassified RNA viruses were also identified. Specifically, viruses of the family Astroviridae, according to the number of reads, were the most prevalent. Of note, the genome sequences of Rotavirus A (RVA) and Rotavirus C (RVC) at BSF2 and RVC and Hepatitis E virus (HEV) at BSF3 were also obtained. The occurrence of various swine enteric viruses in swine saliva suggests a high risk of diarrhoeic diseases in the backyard swine. Of note, zoonotic viruses in swine saliva, such as RVA, RVC, and HEV, indicate a risk of zoonotic spillover to the exposed human populations. We recommend the implementation of biosecurity to ensure sustainable backyard swine farming while safeguarding public health.

High prevalence of acute hepatitis E virus infection in pigs in Dutch slaughterhouses

Hepatitis E is caused by hepatitis E virus (HEV), one of the causes of acute viral hepatitis. Domestic pigs are considered as the main reservoir of HEV-3. The recently reported high prevalence of HEV in liver- and meat products on the Dutch market warranted a cross-sectional prevalence study on HEV infection among 5-6 months old pigs slaughtered in the Netherlands (n = 250). For this, liver, caecum content and blood samples were analyzed for the presence of genomic HEV RNA by RT-PCR. In addition, a serological test was performed to detect HEV IgG. Background information was retrieved on the corresponding farms to evaluate potential risk factors for HEV at pig slaughter age. HEV IgG was detected in sera from 167 pigs (67.6 %). HEV RNA was detected in 64 (25.6 %) caecum content samples, in 40 (16.1 %) serum samples and in 25 (11.0 %) liver samples. The average level of viral contamination in positive samples was log₁₀ 4.6 genome copies (gc)/g (range 3.0-8.2) in caecum content, log₁₀ 3.3 gc/ml (range 2.4-5.9) in serum and log₁₀ 3.2 gc/0.1 g (range 1.7-6.2) in liver samples. Sequence analyses revealed HEV-3c only. Ten times an identical strain was detected in two or three samples obtained from the same pig. Each animal in this study however appeared to be infected with a unique strain. The presence of sows and gilts and welfare rating at the farm of origin had a significant effect (p < 0.05) on the distribution over the four groups representing different stages of HEV infection based on IgG or RNA in caecum and/or serum. The observed proportion of tested pigs with viremia (16 %) was higher than in other reported studies and was interestingly often observed in combination with a high number of HEV genome copies in liver and caecum content as detected by RT-qPCR. Data provided will be useful for risk assessment for food safety of pork products, will provide baseline data for future monitoring of HEV infections in pigs and new thoughts for mitigation strategies.

Repeated cross-sectional sampling of pigs at slaughter indicates varying age of hepatitis E virus infection within and between pig farms

Humans can become infected with hepatitis E virus (HEV) by consumption of undercooked pork. To reduce the burden of HEV in humans, mitigation on pig farms is needed. HEV is found on most pig farms globally, yet within-farm seroprevalence estimates vary considerably. Understanding of the underlying variation in infection dynamics within and between farms currently lacks. Therefore, we investigated HEV infection dynamics by sampling 1711 batches of slaughter pigs from 208 Dutch farms over an 8-month period. Four farm types, conventional, organic, and two types with strict focus on biosecurity, were included. Sera were tested individually with an anti-HEV antibody ELISA and pooled per batch with PCR. All farms delivered seropositive pigs to slaughter, yet batches (resembling farm compartments) had varying results. By combining PCR and ELISA results, infection moment and extent per batch could be classified as low transmission, early, intermediate or late. Cluster analysis of batch infection moments per farm resulted in four clusters with distinct infection patterns. Cluster 1 farms delivered almost exclusively PCR negative, ELISA positive batches to slaughter (PCR⁻ELISA⁺), indicating relatively early age of HEV infection. Cluster 2 and 3 farms delivered 0.3 and 0.7 of batches with intermediate infection moment (PCR⁺ELISA⁺) respectively and only few batches with early infection. Cluster 4 farms delivered low transmission (PCR⁻ELISA⁻) and late infection (PCR⁺ELISA⁻) batches, demonstrating that those farms can prevent or delay HEV transmission to farm compartments. Farm type partly coincided with cluster assignment, indicating that biosecurity and management are related to age of HEV infection.

Co-Circulation of Different Hepatitis E Virus Genotype 3 Subtypes in Pigs and Wild Boar in North-East Germany, 2019

Hepatitis E is a major cause of acute liver disease in humans worldwide. The infection is caused by hepatitis E virus (HEV) which is transmitted in Europe to humans primarily through zoonotic foodborne transmission from domestic pigs, wild boar, rabbits, and deer. HEV belongs to the family Hepeviridae, and possesses a positive-sense, single stranded RNA genome. This agent usually causes an acute self-limited infection in humans, but in people with low immunity, e.g., immunosuppressive therapy or underlying liver diseases, the infection can evolve to chronicity and is able to induce a variety of extrahepatic manifestations. Pig and wild boar have been identified as the primary animal reservoir in Europe, and consumption of raw and undercooked pork is known to pose a potential risk of foodborne HEV infection. In this study, we analysed pig and wild boar liver, faeces, and muscle samples collected in 2019 in Mecklenburg-Western Pomerania, north-east Germany. A total of 393 animals of both species were investigated using quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR), conventional nested RT-PCR and sequence analysis of amplification products. In 33 animals, HEV RNA was detected in liver and/or faeces. In one individual, viral RNA was detected in muscle tissue. Sequence analysis of a partial open reading frame 1 region demonstrated a broad variety of genotype 3 (HEV-3) subtypes. In conclusion, the study demonstrates a high, but varying prevalence of HEV RNA in swine populations in Mecklenburg-Western Pomerania. The associated risk of foodborne HEV infection needs the establishment of sustainable surveillance and treatment strategies at the interface between humans, animals, and the environment within a One Health framework.

Study of Animal Mixing and the Dynamics of Hepatitis E Virus Infection on a Farrow-to-Finish Pig Farm

In Europe, swine are a livestock reservoir for Hepatitis E virus genotype 3 (HEV-3). Consumption of food containing HEV-3 can cause zoonotic human infection, though risk is reduced by heat treatment. Implementing controls that limit infection in slaughter pigs may further reduce foodborne transmission risk but knowledge of infection dynamics on commercial farms is limited. This study addressed this knowledge gap and in particular investigated the influence of group mixing. Faeces were collected from grower (n = 212) and fattener (n = 262) pigs on a farrow-to-finish farm on four occasions. HEV RNA was detected on all occasions, and prevalence was higher in growers (85.8%) than fatteners (26.0%; p < 0.001). HEV-positive samples were also collected from the wider farm environment (n = 67; 64.7% prevalence), indicating potential sources for HEV re-circulation within the herd. Timing of infection in a cohort was also investigated. HEV was absent from all piglet faeces (n = 98) and first detected at weaner stage (25.7% prevalence), but only in groups weaned earlier or comprising pigs from many different litters. Farrowing sow faeces (n = 75) were HEV-negative but antibodies were detected in blood from two sows. Results suggest that multiple factors influence HEV infection dynamics on pig farms, and potential foci for further study into practical control solutions are highlighted.

Genetic Diversity of Hepatitis E Virus Type 3 in Switzerland-From Stable to Table

Simple Summary

The main hosts of hepatitis E virus (HEV) genotype 3 are porcine species. Transmission of the virus to humans, for example via undercooked meat, may cause acute or chronic hepatitis. To determine sources and routes of infection, comparing the viruses present in humans to the ones present in main hosts is a helpful tool. However, it requires knowledge of the genetic diversity of the circulating viruses. Therefore, we tested Swiss pigs and wild boars for HEV and determined the virus subtype and part of its genome. In addition, we determined the HEV subtype present in 11 positive meat products. One pig liver from the slaughterhouses (0.3%) and seven livers from a carcass collection (13%) as well as seven wild boar livers (5.8%) were found HEV positive. The same virus subtypes were found in Swiss pigs, wild boars, and meat products. Most of the viruses belonged to a Swiss-specific cluster within the subtype 3h. In addition, one pig liver and one wild boar liver were found positive for 3l and two meat products from Germany for 3c. Our data indicate that Switzerland has its “own” HEV viruses that circulate independent from the rest of Europe.

Abstract

Hepatitis E caused by hepatitis E viruses of the genotype 3 (HEV-3) is a major health concern in industrialized countries and due to its zoonotic character requires a “One Health” approach to unravel routes and sources of transmission. Knowing the viral diversity present in reservoir hosts, i.e., pigs but also wild boars, is an important prerequisite for molecular epidemiology. The aim of this study was to gain primary information on the diversity of HEV-3 subtypes present along the food chain in Switzerland, as well as the diversity within these subtypes. To this end, samples of domestic pigs from slaughterhouses and carcass collection points, as well as from hunted wild boars, were tested for HEV RNA and antibodies. HEV positive meat products were provided by food testing labs. The HEV subtypes were determined using Sanger and next generation sequencing. The genetic analyses confirmed the predominance of a Swiss-specific cluster within subtype HEV-3h in pigs, meat products, and wild boars. This cluster, which may result from local virus evolution due to the isolated Swiss pig industry, supports fast differentiation of domestic and imported infections with HEV.

A Systematic Review on the Effectiveness of Pre-Harvest Meat Safety Interventions in Pig Herds to Control Salmonella and Other Foodborne Pathogens

This systematic review aimed to assess the effectiveness of pre-harvest interventions to control the main foodborne pathogens in pork in the European Union. A total of 1180 studies were retrieved from PubMed^® and Web of Science for 15 pathogens identified as relevant in EFSA's scientific opinion on the public health hazards related to pork (2011). The study selection focused on controlled studies where a cause-effect could be attributed to the interventions tested, and their effectiveness could be inferred. Altogether, 52 studies published from 1983 to 2020 regarding Campylobacter spp., Clostridium perfringens, Methicillin-resistant Staphylococcus aureus, Mycobacterium avium, and Salmonella spp. were retained and analysed. Research was mostly focused on Salmonella (n = 43 studies). In-feed and/or water treatments, and vaccination were the most tested interventions and were, overall, successful. However, the previously agreed criteria for this systematic review excluded other effective interventions to control Salmonella and other pathogens, like Yersinia enterocolitica, which is one of the most relevant biological hazards in pork. Examples of such successful interventions are the Specific Pathogen Free herd principle, stamping out and repopulating with disease-free animals. Research on other pathogens (i.e., Hepatitis E, Trichinella spiralis and Toxoplasma gondii) was scarce, with publications focusing on epidemiology, risk factors and/or observational studies. Overall, high herd health coupled with good management and biosecurity were effective to control or prevent most foodborne pathogens in pork at the pre-harvest level.

Hepatitis E Virus Genotype 7 RNA and Antibody Kinetics in Naturally Infected Dromedary Calves, United Arab Emirates

Orthohepevirus A genotype 7 is a novel zoonotic variant of hepatitis E virus. To clarify infection in the animal reservoir, we virologically monitored 11 dromedary dam–calf pairs. All calves became infected during the first 6 months of life and cleared the virus after an average of 2 months. Dams did not become infected.

Hepatitis E Virus in the Food of Animal Origin: A Review

Hepatitis E virus (HEV) is a cosmopolitan foodborne pathogen. The viral agent infects humans through the consumption of contaminated food (uncooked or undercooked). Most cases of infection are asymptomatic and for this reason, this pathology is considered underdiagnosed. Domestic and wild animals are considered natural reservoirs: that is, domestic pig, wild boar, sheep, goat, deer, rabbit, and so on. Therefore, various work categories are at risk: that is, veterinarians, farmers, hunters, slaughterhouse workers, and so on. In these last decades, researchers found a high percentage of positivity to the molecular viral detection in several food matrices included: ready-to-eat products, processed meat products, milk, and shellfish. This review aims to provide an international scenario regarding HEV ribonucleic acid (RNA) detection in several foodstuffs. From this investigative perspective, the study aims to highlight various gaps of the current knowledge about technologies treatments' impact on viral loads. The purpose was also to provide an innovative point of view "One Health"-based, pointing out the strategic role of environmental safety.

Infection dynamics and persistence of hepatitis E virus on pig farms - a review

Background

Hepatitis E virus (HEV) genotype 3 and 4 is a zoonosis that causes hepatitis in humans. Humans can become infected by consumption of pork or contact with pigs. Pigs are the main reservoir of the virus worldwide and the virus is present on most pig farms.

Main body

Though HEV is present on most farms, the proportion of infected pigs at slaughter and thus the level of exposure to consumers differs between farms and countries. Understanding the cause of that difference is necessary to install effective measures to lower HEV in pigs at slaughter. Here, HEV studies are reviewed that include infection dynamics of HEV in pigs and on farms, risk factors for HEV farm prevalence, and that describe mechanisms and sources that could generate persistence on farms. Most pigs become infected after maternal immunity has waned, at the end of the nursing or beginning of the fattening phase. Risk factors increasing the likelihood of a high farm prevalence or proportion of actively infected slaughter pigs comprise of factors such as farm demographics, internal and external biosecurity and immunomodulating coinfections. On-farm persistence of HEV is plausible, because of a high transmission rate and a constant influx of susceptible pigs. Environmental sources of HEV that enhance persistence are contaminated manure storages, water and fomites.

Conclusion

As HEV is persistently present on most pig farms, current risk mitigation should focus on lowering transmission within farms, especially between farm compartments. Yet, one should be aware of the paradox of increasing the proportion of actively infected pigs at slaughter by reducing transmission insufficiently. Vaccination of pigs may aid HEV control in the future.

Hepatitis E virus genome detection in commercial pork livers and pork meat products in Germany

The hepatitis E virus (HEV) is one of the most common causes of hepatitis worldwide. HEV is also widespread in many developed countries, where the number of infections is steadily increasing. In those countries, the virus is transmitted mainly through consumption of undercooked or raw food or through contact with animals. Especially, pigs serve as a main reservoir of HEV. Here, we investigated the prevalence of HEV RNA in pork livers and pork meat products to assess the actual risk of HEV infection through food consumption in Germany. A total of 131 pork products were collected from grocery stores and butcher shops between October 2019 and February 2020 and screened for HEV RNA using nested PCR and subsequent sequencing. Overall, 10% of the samples were positive for HEV, including pork livers (5%), spreadable liver sausages (13%) and liver pâté samples (15%). Sequence analyses indicated that the large majority of HEV strains belonged to subtype HEV-3c, representing the most frequent subtype in Germany. One sample belonged to subtype HEV-3f. Further sequence analysis revealed large sequence variation between the samples; however, most of the mutations identified were synonymous. Although infectivity of the virus was not tested, the results suggest a considerable risk of HEV infection through food consumption. Therefore, preventive measures should be taken according to a One Health approach.

Wild Boar as a Sylvatic Reservoir of Hepatitis E Virus in Poland: A Cross-Sectional Population Study

The most important wildlife species in the epidemiology of hepatitis E virus (HEV) infections are wild boars, which are also the main reservoir of the virus in a sylvatic environment. The aim of the study was a serological and molecular assessment of the prevalence of HEV infections in wild boars in Poland. In total, 470 pairs of samples (wild boar blood and livers) and 433 samples of faeces were tested. An ELISA (ID.vet, France) was used for serological analysis. For the detection of HEV RNA, real-time (RT)-qPCR was employed. The presence of specific anti-HEV IgG antibodies was found in 232 (49.4%; 95%CI: 44.7–54%) sera, with regional differences observed in the seroprevalence of infections. HEV RNA was detected in 57 (12.1%, 95%CI: 9.3–15.4%) livers and in 27 (6.2%, 95%CI: 4.1–8.9%) faecal samples, with the viral load ranging from 1.4 to 1.7 × 10¹¹ G.C./g and 38 to 9.3 × 10⁷ G.C./mL, respectively. A correlation between serological and molecular results of testing of wild boars infected with HEV was shown. HEV infections in wild boars appeared to be common in Poland.

Increased risk of hepatitis E virus infection in workers occupationally exposed to sheep

Hepatitis E virus (HEV) is an enteric RNA virus from the family Hepeviridae with five genotypes (genotypes 1-4 and 7) known to infect humans. HEV infection is known to have a zoonotic swine origin in industrialized countries. The role of pigs and wild boars as major reservoirs for human infection is today well-established; however, the list of new animal reservoirs is ever-expanding as new HEV strains are continuously being found in a broad host range. The recent detection of HEV in sheep stools brings concerns on the possibility of HEV transmission from these animals to humans, particularly in those occupationally exposed. The present work investigated the potential occupational risk of HEV infection in shepherds and sheep milk cheesemakers-workers occupationally exposed to ovine (WOEOs; N = 96)-from a region of the Centre of Portugal ('Serra da Estrela') based on the differences of anti-HEV IgG seroprevalence rates between these professionals and the general population (N = 192). The presence of HEV-specific antibodies in sheep (N = 90) from the same region was also evaluated. The HEV seroprevalence in WOEOs (29.3%) was found to be significantly higher (p = .0198) when compared with population controls (16.1%) which suggests an increased risk for HEV infection in these workers. HEV-specific antibodies were also found in 16.6% of the studied sheep showing that HEV circulates in these animals. Further studies are needed to confirm the zoonotic potential of sheep HEV.

Increasing Hepatitis E Virus Seroprevalence in Domestic Pigs and Wild Boar in Bulgaria

Simple Summary

Hepatitis E virus (HEV) is a lesser-known hepatitis virus, but its worldwide spread is undisputed and has increased in recent years. The zoonotic spread of HEV, mainly due to genotype (gt) 3, emerged in developed countries in the past decade. In addition, transmission via contaminated meat from pigs and boars was also established. Detailed analysis of viral dynamics and distribution is needed in order to identify associated risk factors. The aim of the current study is to present new and additional data on the HEV distribution among pigs, and for the first-time, also among the wild boar population in Bulgaria.

Abstract

(1) Background: Hepatitis E virus (HEV) is a causative agent of acute viral hepatitis, predominantly transmitted by the fecal–oral route. In developed countries, HEV is considered to be an emerging pathogen since the number of autochthonous cases is rising. Hepatitis E is a viral disease with a proven zoonotic potential for some of its genotypes. The main viral reservoirs are domestic pigs and wild boar. Consumption of undercooked meat, as well as occupational exposure, are key factors for the spread of HEV. In order to evaluate the risks of future viral evolution, a detailed examination of the ecology and distribution of the virus is needed. The aim of the present study is to investigate the prevalence of anti-HEV IgG Ab in domestic pigs and wild boar in Bulgaria; (2) Methods: In this study, during the period of three years between 2017 and 2019, 433 serum samples from 19 different pig farms and 1 slaughterhouse were collected and analyzed. In addition, 32 samples from wild boar were also collected and analyzed during the 2018–2019 hunting season. All samples were analyzed by commercial indirect ELISA; (3) Results: Overall, HEV seroprevalence was 60% (95% CI 42.7–77.1) in domestic pigs and 12.5% (4/32) in wild boar. The observed seroprevalence of the slaughter-aged pigs was 73.65% (95% Cl 58.7–87.3). Prevalence in domestic pigs was significantly higher in the samples collected during 2019 (98% (95% Cl 96.1–99.9)) compared to those collected during 2017 (45.33% (95% CI 2.7–87.3)) and 2018 (38.46% (95% CI 29.1–49.7.); (4) Conclusions: Our findings suggest that domesticated pigs and wild boar might be the reason for the increased HEV transmission across Bulgaria. The genotypic characterization of HEV found in pigs, wild boar and humans will give a more accurate view of the zoonotic transmission of this virus.

In silico mapping of microbial communities and stress responses in a porcine slaughterhouse and pork products through its production chain, and the efficacy of HLE disinfectant

The use of shotgun metagenomic sequencing to understand ecological-level spread of microbes and their genes has provided new insights for the prevention, surveillance and control of microbial contaminants in the slaughterhouse environment. Here, microbial samples were collected from products and surrounding areas though a porcine slaughter process; shotgun metagenomic DNA-sequencing of these samples revealed a high community diversity within the porcine slaughterhouse and pork products, in zones originating from animal arrival through to the sale zones. Bacteria were more prevalent in the first zones, such as arrival- and anesthesia-zones, and DNA viruses were prevalent in the scorching-and-whip zone, animal products and sale zone. Data revealed the dominance of Firmicutes and Proteobacteria phyla followed by Actinobacteria, with a clear shift in the relative abundance of lactic acid bacteria (mainly Lactobacillus sp.) from early slaughtering steps to Proteobacteria and then to viruses suggesting site-specific community compositions occur in the slaughterhouse. Porcine-type-C oncovirus was the main virus found in slaughterhouse, which causes malignant diseases in animals and humans. As such, to guarantee food safety in a slaughterhouse, a better decipher of ecology and adaptation strategies of microbes becomes crucial. Analysis of functional genes further revealed high abundance of diverse genes associated with stress, especially in early zones (animal and environmental surfaces of arrival zone with 57,710 and 40,806 genes, respectively); SOS responsive genes represented the most prevalent, possibly associated with genomic changes responsible of biofilm formation, stringent response, heat shock, antimicrobial production and antibiotic response. The presence of several antibiotic resistance genes suggests horizontal gene transfer, thus increasing the likelihood for resistance selection in human pathogens. These findings are of great concern, with the suggestion to focus control measures and establish good disinfection strategies to avoid gene spread and microbial contaminants (bacteria and viruses) from the animal surface into the food chain and environment, which was achieved by applying HLE disinfectant after washing with detergent.

Evaluation of High-Pressure Processing in Inactivation of the Hepatitis E Virus

Hepatitis E virus (HEV) causes acute hepatitis with approximately 20 million cases per year globally. Based on genetic diversity, HEV is classified into different genotypes, with genotype 3 (HEV-3) being most prevalent in Europe and North America. The transmission of HEV-3 has been shown to be zoonotic and mainly associated with the consumption of raw or undercooked pork products. Herein, we investigated the efficacy of high-pressure processing (HPP) in inactivation of HEV-3 using a cell culture system. HPP has been indicated as a promising non-thermal pathogen inactivation strategy for treatment of certain high-risk food commodities, without any noticeable changes in their nature. For this purpose, we treated HEV-3 in media with different conditions of HPP: 400 MPa for 1 and 5 min, as well as 600 MPa for 1 and 5 min, at ambient temperature. All four HPP treatments of HEV in media were observed to result in a 2-log reduction in HEV load, as determined by the amounts of extracellular HEV RNA produced at 14-day post-infection, using the A549/D3 cell culture system. However, application of the same treatments to artificially contaminated pork pâté resulted in 0.5 log reduction in viral load. These results indicate that the efficacy of HPP treatment in the inactivation of HEV-3 is matrix-dependent, and independent of maximum pressure between 400 and 600 MPa and hold time between 1 and 5 min. Based on the obtained results, although the HPP treatment of pork pâté reduces the HEV-3 load, it might not be sufficient to fully mitigate the risk.

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.

Detection and genomic characterization of hepatitis E virus genotype 3 from pigs in Ghana, Africa

BACKGROUND

Hepatitis E virus (HEV) is a major cause of human hepatitis worldwide. Zoonotic genotypes of the virus have been found in diverse animal species with pigs playing a major role. Putative risk of zoonotic infection from livestock particularly swine in Sub-Saharan Africa including Ghana is poorly understood due to scarcity of available data, especially HEV sequence information.

METHODS

Serum samples were collected from cattle, sheep, goats and pigs from Kumasi in the Ashanti region of Ghana. Samples were subjected to nested RT-PCR screening and quantification of HEV RNA-positive samples using real-time RT-PCR and the World Health Organization International Standard for HEV. Testing of all pig samples for antibodies was done by ELISA. Sanger sequencing and genotyping was performed and one representative complete genome was generated to facilitate genome-wide comparison to other available African HEV sequences by phylogenetic analysis.

RESULTS

A total of 420 samples were available from cattle (n = 105), goats (n = 124), pigs (n = 89) and sheep (n = 102). HEV Viral RNA was detected only in pig samples (10.1%). The antibody detection rate in pigs was 77.5%, with positive samples from all sampling sites. Average viral load was 1 × 10⁵ (range 1.02 × 10³ to 3.17 × 10⁵) International Units per mL of serum with no statistically significant differences between age groups (≤ 6 month, > 6 months) by a T-test comparison of means (t = 1.4272, df = 7, p = 0.1966). Sequences obtained in this study form a monophyletic group within HEV genotype 3. Sequences from Cameroon, Ghana, Burkina Faso and Madagascar were found to share a most recent common ancestor; however this was not the case for other African HEV sequences.

CONCLUSION

HEV genotype 3 is highly endemic in pigs in Ghana and likely poses a zoonotic risk to people exposed to pigs. HEV genotype 3 in Ghana shares a common origin with other virus strains from Sub-Saharan Africa.

Epidemiology of hepatitis E virus infection in a cohort of 4023 immunocompromised patients

OBJECTIVES

The prevalence of active, chronic, and former hepatitis E virus (HEV) infections was investigated in a cohort of immunocompromised patients. The association with transfusion transmitted HEV was evaluated, and the HEV seroprevalence was compared with that in healthy blood donors.

STUDY DESIGN AND METHODS

Serum samples from 4023 immunocompromised patients at Rigshospitalet, Denmark were retrospectively tested for HEV RNA and anti-HEV IgG. HEV RNA-positive patients were followed up by HEV testing, clinical symptoms, and transfusion history. Factors associated with anti-HEV were explored by multivariable logistic regression analysis. Samples from 1226 blood donors were retrospectively tested for anti-HEV IgG.

RESULTS

HEV RNA was detected in six patients (0.15%) with no indications of chronic HEV infection. HEV RNA prevalence rates among recipients of allogeneic haematopoietic stem cell transplantation (allo-HSCT) and solid organ transplantation (SOT) were 0.58% and 0.21%, respectively. Transfusion transmitted infections were refuted, and transfusion history was not associated with anti-HEV positivity. The difference in HEV seroprevalence between patients (22.0%) and blood donors (10.9%) decreased when adjusting for age and sex (odds ratio 1.20, 95% confidence interval 0.97-1.48).

CONCLUSIONS

HEV viremia among allo-HSCT and SOT recipients suggests that clinicians should be aware of this diagnosis. The lack of association of blood transfusion with anti-HEV positivity supports food-borne transmission as the main transmission route of HEV common to both patients and blood donors.