Serological Evidence of Hepatitis E Virus Infection in Brazilian Equines

Hepatitis E virus (HEV) infection has been demonstrated in various animal species; those recognized as potential zoonotic reservoirs pose a considerable risk to public health. In Brazil, HEV-3 is the only genotype identified in humans and swine nationwide, in a colony-breeding cynomolgus monkey and, recently, in bovines and capybara. There is no information regarding HEV exposure in the equine population in Brazil. This study aimed to investigate anti-HEV antibodies and viral RNA in serum samples from horses slaughtered for meat export and those bred for sport/reproduction purposes. We used a commercially available ELISA kit modified to detect species-specific anti-HEV, using an anti-horse IgG-peroxidase conjugate and evaluating different cutoff formulas and assay precision. Serum samples (n = 257) were tested for anti-HEV IgG and HEV RNA by nested RT-PCR and RT-qPCR. The overall anti-HEV seroprevalence was 26.5% (68/257) without the detection of HEV RNA. Most municipalities (53.3%) and farms (58.8%) had positive horses. Animals slaughtered for human consumption had higher risk of HEV exposure (45.5%) than those bred for sports or reproduction (6.4%) (p < 0.0001). The statistical analysis revealed sex and breeding system as possible risk-associated factors. The first serological evidence of HEV circulation in Brazilian equines reinforces the need for the surveillance of HEV host expansion in a one-health approach.

Detection of Hepatitis E Virus in Rabbits and Rabbit Meat from Slaughterhouses in Hebei Province of China

Background: Hepatitis E virus (HEV) is a zoonotic pathogen. HEV has been found to be widely prevalent in rabbits. Its isolates are classified into HEV-3, rabbit subgenotype (HEV-3ra). The routes of human infection with HEV-3ra remain unclear; however, foodborne transmission is possible when asymptomatically infected animals enter the food chain. The prevalence of HEV infection in slaughtered rabbits and the presence of HEV in rabbit meat were evaluated in this study. Materials and Methods: In three slaughterhouses in Hebei province, China, samples of rabbit blood were collected during the slaughter process, and muscle, liver, and cavity juice were collected from the rabbit carcasses. Anti-HEV antibody in serum samples was detected using enzyme-linked immunosorbent assay. HEV RNA was tested in all samples by reverse transcription nested PCR (RT-nested PCR). The final amplicons of RT-nested PCR were sequenced and phylogenetically analyzed. Results: Of the 459 serum samples, 50 [10.9%, 95% confidence interval (CI): 8.1-13.7] were positive for anti-HEV antibody, and 17 (3.7%, 95% CI: 2.0-5.4) were positive for HEV RNA. HEV RNA was detected in 7 of 60 liver samples (11.7%, 95% CI: 3.3-20) and 2 cavity juice samples from semi-eviscerated carcasses, but was not detected in any muscle sample from either the eviscerated or semi-eviscerated carcasses. All the detected HEV strains belonged to HEV-3ra and related most closely with the rabbit HEV sequence previously reported in China. Conclusion: A portion of rabbits were in the viremia period of HEV infection at the slaughter age, resulting in the possibility of HEV carriage by rabbit carcass, particularly semi-eviscerated carcass containing liver. These findings suggest a potential risk of HEV transmission from raw rabbit products entering the food chain, whereas the presence of HEV appeared to be lower in the eviscerated carcass than in the semi-eviscerated carcass.

Farm biosecurity measures to prevent hepatitis E virus infection in finishing pigs on endemically infected pig farms

Hepatitis E virus (HEV) can be transmitted from pigs to humans and cause liver inflammation. Pigs are a major reservoir of HEV and most slaughter pigs show evidence of infection by presence of antibodies (ELISA) or viral RNA (PCR). Reducing the number of HEV infected pigs at slaughter would likely reduce human exposure, yet how this can be achieved, is unknown. We aimed to identify and quantify the effect of biosecurity measures to deliver HEV negative batches of pigs to slaughter. A case-control study was performed with Dutch pig farms selected based on results of multiple slaughter batches. Case farms delivered at least one PCR and ELISA negative batch to slaughter (PCR^-ELISA^-), indicating absence of HEV infection, and control farms had the highest proportion of PCR and/or ELISA positive batches (PCR⁺ELISA⁺), indicating high within-farm transmission. Data about biosecurity and housing were collected via a questionnaire and an audit. Variables were selected by regularization (LASSO regression) and ranked, based the frequency of variable selection. The odds ratios (OR) for the relation between case-control status and the highest ranked variables were determined via grouped logistic regression. Thirty-five case farms, with 10 to 60% PCR^-ELISA^- batches, and 38 control farms with on average 40% PCR⁺ELISA⁺ batches, were included. Rubber and steel floor material in fattening pens had the highest ranking and increased the odds of a PCR^-ELISA^- batch by 5.87 (95%CI 3.03-11.6) and 7.13 (95%CI 3.05-16.9) respectively. Cleaning pig driving boards weekly (OR 1.99 (95%CI 1.07-3.80)), and fly control with predatory flies (OR 4.52 (95%CI 1.59-13.5)) were protective, whereas a long fattening period was a risk. This study shows that cleaning and cleanability of floors and fomites and adequate fly control are measures to consider for HEV control in infected farms. Yet, intervention studies are needed to confirm the robustness of these outcomes.

Hepatitis E Virus Infection in Patients with Chronic Inflammatory Bowel Disease Treated with Immunosuppressive Therapy

BACKGROUND

Medical treatment of inflammatory bowel disease (IBD) has evolved significantly, and treatment with immunomodulators is recommended. These medications may alter the patient's immune response and increase the risk of opportunistic infections. Our aim was to evaluate the prevalence and the incidence of acute or chronic HEV infection in IBD patients under immunomodulatory treatment.

PATIENTS AND METHODS

We conducted a retrospective, multicenter, observational study between 2017 and 2018. IBD outpatients hospitalized for the infusion of immunomodulators were included in 16 French centers. During their daily hospitalization, blood samples were drawn for HEV serology (IgM and IgG) and HEV RNA detection.

RESULTS

A total of 488 patients were included, of which 327 (67%) patients had Crohn's disease and 161 (33%) ulcerative colitis. HEV IgM was detected in 3 patients, but HEV RNA was undetectable in all patients. The HEV IgG seroprevalence rate was 14.2%. IgG-positive patients were older at sampling (p = 0.01) and IBD diagnosis (p = 0.03), had higher seafood consumption (p = 0.01) and higher doses of azathioprine (p = 0.03). Ileal and upper digestive tract involvement was more frequent in IgG-positive patients (p = 0.009), and ileocolic involvement was more frequent in IgG-negative patients (p = 0.01). Under multivariate analysis, age > 50 years [OR: 2.21 (1.26, to 3.85), p = 0.004] was associated with previous HEV infection.

CONCLUSION

Systematic screening for HEV infection is not needed among IBD patients on immunomodulatory medications. However, in the event of abnormal liver test findings, HEV should be part of the classic diagnostic assessment.

Hepatitis E Virus (HEV): Identification of Subtypes 3b and 3m in Wild Boar Population in Liguria Region, Italy

The wild boar is an important natural reservoir for the zoonotic transmission of the hepatitis E virus (HEV) around the world. In particular, HEV genotypes 3 and 4 are an emerging problem in industrialized countries, as the number of wild boars has increased, and their territory is ever closer to farms and populated areas. This study describes the HEV prevalence and geographic circulation among wild boar populations in the Ligurian region (Italy) during the period 2019-2022. Liver samples from 849 wild boars were analyzed for HEV RNA using real-time RT-PCR; positive samples were then subjected to sequencing and phylogenetic analysis. Overall, 6.7% of the wild boars were positive for HEV RNA; however, in the last two years, the percentage of positive animals almost doubled. Phylogenetic analysis showed that wild boar HEV sequences belonged to genotype 3 and clustered within subtypes 3a and 3c, and, for the first time in Italy, subtypes 3b and 3m were identified. Interestingly, 13 sequences could not be assigned to a recognized subtype. Furthermore, the results showed different circulations of identified subtypes across the territory. These findings increase the knowledge of HEV-3 heterogeneity in Italy and describe the role of wild boars in maintaining an active viral circulation in the environment.

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.

Identification and genetic diversity of hepatitis E virus in domestic swine from Slovakia

Background

Hepatitis E virus (HEV) is agent causing hepatitis worldwide. Originally considered to be limited to developing countries, this virus was also detected in developed countries. In recent years an increasing number of reports indicate that farmed domestic pigs are widely infected with HEV in several European countries. The HEV status in Slovakia is still missing.

Results

In this study, the circulation of HEV among domestic swine in Slovakia and genetic diversity of the virus was studied. Overall HEV RNA was detected in 53/388 (13.7, 95% CI: 10.40–17.48%) pig rectal swabs in five production stages (age categories) with statistically significant differences among all the stages. The highest HEV prevalence was observed in weaners 24/81 (29.6, 95% CI: 19.99–40.81%) and then significantly declined in growers and fatteners. No HEV was detected in suckling piglets and sows. Twenty-eight partial sequences of ORF1 (242 bp) and seventeen of ORF2 (304 bp) were analysed. Phylogenetic analysis and p-distance comparisons confirmed in both ORFs that all Slovak HEV sequences belong to the genotype HEV-3, major clade 3abchij with higher identity to 3a and 3i subtypes. Three sequences were outside of all lastly updated HEV-3 subtypes.

Conclusion

This is the first report to fill the information gap about HEV infection in pigs in Slovakia. The results suggested a lower prevalence of HEV in Slovak pig farms than observed in other European countries. While most HEV isolates were typed as HEV-3 clade 3abchij, three sequences were unclassified.

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.

Hepatitis E Virus Occurrence in Pigs Slaughtered in Italy

Simple Summary

Hepatitis E is now recognized as an emerging zoonotic disease in Europe caused by an RNA virus (HEV) and foodborne is the main route of transmission. Human cases have been linked to the consumption of contaminated pig liver sausages, raw venison, or undercooked wild boar meat. The zoonotic genotype HEV-3 is widespread in pigs at farm level but little information is available on the occurrence of HEV-positive pigs at the slaughterhouse. The aim of this study was to investigate the prevalence of HEV-positive pigs during slaughtering, to understand which biological samples (feces and organs) were more frequently HEV positive. Our results showed that pigs positive for HEV can be slaughtered and that the percentage of positive animals depends on the age of animals. The other main result is the presence of the virus in the plasma of animals, which may contribute to the contamination of meat (muscle). Nevertheless, muscles are rarely contaminated by HEV-RNA compared to liver, which is the organ of replication.

Abstract

In Europe, foodborne transmission has been clearly associated to sporadic cases and small clusters of hepatitis E in humans linked to the consumption of contaminated pig liver sausages, raw venison, or undercooked wild boar meat. In Europe, zoonotic HEV-genotype 3 strains are widespread in pig farms but little information is available on the prevalence of HEV positive pigs at slaughterhouse. In the present study, the prevalence of HEV-RNA positive pigs was assessed on 585 animals from 4 abattoirs located across Italy. Twenty-one pigs (3.6%) tested positive for HEV in either feces or liver by real-time RT-PCR. In these 21 pigs, eight diaphragm muscles resulted positive for HEV-RNA. Among animals collected in one abattoir, 4 out of 91 plasma tested positive for HEV-RNA. ELISA tests for the detection of total antibodies against HEV showed a high seroprevalence (76.8%), confirming the frequent exposure of pigs to the virus. The phylogenetic analyses conducted on sequences of both ORF1 and ORF2 fragments, shows the circulation of HEV-3c and of a novel unclassified subtype. This study provides information on HEV occurrence in pigs at the slaughterhouse, confirming that muscles are rarely contaminated by HEV-RNA compared to liver, which is the most frequently positive for HEV.

Seroprevalence of hepatitis E virus among blood donors on Corsica, France, 2017

Background

Hepatitis E virus (HEV) is an emerging zoonotic pathogen and an important cause of acute viral hepatitis in European countries. Corsica Island has been previously identified as a hyperendemic area for HEV.

Aim

Our aim was to characterise the prevalence and titres of IgG antibodies to HEV among blood donors on Corsica and establish a model of the annual force of infection.

Methods

Between September 2017 and January 2018, 2,705 blood donations were tested for anti-HEV IgG using the Wantai HEV IgG enzyme immunoassay.

Results

The overall seroprevalence was 56.1%. In multivariate analysis, seroprevalence was higher in men than in women (60.0% vs 52.2%; p < 0.01), increased with age and was significantly higher among donors born on Corsica (60.6% vs 53.2%; p < 0.01). No significant difference was observed between the five districts of the island. IgG anti-HEV titres were mostly low (70% of positive donors had titres < 3 IU/mL). In Corsican natives, increasing seroprevalence by age could be explained by models capturing a loss of immunity (annual probability of infection: 4.5%; duration of immunity: 55 years) or by age-specific probabilities of infection (3.8% for children, 1.3% for adults).

Conclusion

We confirmed the high HEV seroprevalence on Corsica and identified three aspects that should be further explored: (i) the epidemiology in those younger than 18 years, (ii) common sources of contamination, in particular drinking water, that may explain the wide exposure of the population, and (iii) the actual protection afforded by the low IgG titres observed and the potential susceptibility to secondary HEV infection.

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.

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.

Occurrence of HEV-RNA in Italian Regional Pork and Wild Boar Food Products

Hepatitis E is an emerging threat in industrialized countries. The foodborne transmission linked to consumption of pork and game meat is considered the main source of autochthonous infection. In Europe, small outbreaks have been reported linked to the consumption of pork liver sausages and wild boar meat. Based on previous findings and on increasing evidence of pork and game meat as a vehicle for HEV infections, the present study investigated the occurrence of HEV in 99 pork and 63 wild boar sausages and salami sold in Southern Italy. The HEV genome was detected in four wild boar sausages. Sequencing from 2 wild boar sausages confirmed that the HEV strains detected belonged to HEV-3 genotype, not assigned to any defined subtype. Data obtained confirmed the possible occurrence of HEV in pork products and in game. Although the detection rate is low, these products are frequently consumed raw after curing, whose effect on virus viability is still unknown.

Seroprevalence Study of Anti-HEV IgG among Different Adult Populations in Corsica, France, 2019

Hepatitis E virus (HEV) is a major cause of acute hepatitis worldwide. In France, hyperendemic areas including Corsica have an anti-HEV Immunoglobulin G (IgG) prevalence higher than 50%. The aim of this study was to determine the seroprevalence of anti-HEV IgG in three adult populations in Corsica and the risk factors associated with antibody detection. Between 2017 and 2019, a total of 930 individuals, including 467 blood donors, 393 students or university staff members and 70 patients from general practice, were tested for the presence of anti-HEV IgG using the Wantai HEV IgG enzyme immunoassay kit and filled a questionnaire. The association between seropositivity and potential risk factors was tested with univariate and multivariate analyses. Out of the 930 samples, 52.3% (486/930) were seropositive—54.4% (254/467) among blood donors, 47.6% (187/393) among university students and 64.3% (45/70) among patients of general practice. Three main risk factors were identified: (i) skinning and butchering (Adjusted Odds Ratio aOR = 2.76, 95% confidence interval [95% CI] [1.51–5.37]; p-value < 10⁻³), (ii) consumption of a local pork live raw sausage (fittonu) (aOR = 1.95 95% CI [1.45–2.64]; p-value = 10⁻⁵), and (iii) increasing age (p-value = 0.003). Seropositivity rates between the different populations were homogeneous after age stratification. This cross-sectional study indicates a high anti-HEV IgG seroprevalence in the Corsican adult population, not significantly different between women and men and increasing with age. This serosurvey also showed homogeneity regarding the exposure to HEV among three different types of populations. Finally, we confirmed the endemicity of Corsica with respect to HEV and identified a strong association between consumption of figatellu/fittonu and the practice of skinning and butchering with the detection of anti-HEV IgG.