Prevalence of hepatitis E virus antibodies in individuals exposed to swine in Mato Grosso, Brazil

Seroprevalence of hepatitis E virus in patients with chronic liver disease

INTRODUCTION

The seroprevalence of hepatitis E virus (HEV) in patients with chronic liver disease (CLD) is little known in Brazil. Studies have suggested that HEV may harmfully influence the course of CLD, with a higher risk of progression to cirrhosis.

OBJECTIVE

To estimate the prevalence of the anti-HEV antibody (IgG) in patients with CLD and to describe demographic data and risk factors, as well as clinical-laboratory and ultrasound parameters.

PATIENTS AND METHODS

Cross-sectional study that included 227 patients with CLD followed at a referral outpatient clinic from June 2022 to March 2023. The patients were investigated clinically and tested for liver functions, anti-HEV IgG and, in positive cases, for HEV-RNA. Ultrasonography of the upper abdomen was also carried out.

RESULTS

Investigation of 227 patients (50 with hepatitis B, 49 with nonalcoholic fatty liver disease, 33 with hepatitis C, 17 with alcoholic liver disease, 16 with schistosomiasis and 62 with mixed disease), 55.5% were female, with an average age of 57 ± 13 years; 37.9% had liver cirrhosis. Seven patients (3.08%) presented anti-HEV positive and HEV-RNA negative. Ultrasound identified association between anti-HEV and contact with pigs, presence of gynecomastia or palmar erythema, lower platelet count, higher APRI and FIB-4 values, and splenomegaly.

CONCLUSION

Although the prevalence of anti-HEV in patients with CLD was low in this study, the antibody was observed more frequently in cases with a history of contact with pigs and with clinical-laboratory or imaging evidence of more advanced chronic liver disease.

Higher Risk of HEV Transmission and Exposure among Blood Donors in Europe and Asia in Comparison to North America: A Meta-Analysis

Background and aims: The increasing number of diagnosed hepatitis E virus (HEV) infections in Europe has led to the implementation of the testing of blood products in various countries. Many nations have not yet implemented such screening. To assess the need for HEV screening in blood products worldwide, we conducted a systematic review and meta-analysis assessing HEV RNA positivity and anti-HEV seroprevalence in blood donors. Methods: Studies reporting anti-HEV IgG/IgM or HEV RNA positivity rates among blood donors worldwide were identified via predefined search terms in PubMed and Scopus. Estimates were calculated by pooling study data with multivariable linear mixed-effects metaregression analysis. Results: A total of 157 (14%) of 1144 studies were included in the final analysis. The estimated HEV PCR positivity rate ranged from 0.01 to 0.14% worldwide, with strikingly higher rates in Asia (0.14%) and Europe (0.10%) in comparison to North America (0.01%). In line with this, anti-HEV IgG seroprevalence in North America (13%) was lower than that in Europe (19%). Conclusions: Our data demonstrate large regional differences regarding the risk of HEV exposure and blood-borne HEV transmission. Considering the cost–benefit ratio, this supports blood product screening in high endemic areas, such as Europe and Asia, in contrast to low endemic regions, such as the U.S.

Hepatitis E Virus Research in Brazil: Looking Back and Forwards

Hepatitis E virus (HEV) has emerged as a public health concern in Brazil. From the first identification and characterization of porcine and human HEV-3 strains in the 2000s, new HEV subtypes have been identified from animal, human, and environmental isolates. As new potential animal reservoirs have emerged, there is a need to compile evidence on the zoonotic dissemination of the virus in animal hosts and the environment. The increasing amount of seroprevalence data on sampled and randomly selected populations must be systematically retrieved, interpreted, and considered under the One Health concept. This review focused on HEV seroprevalence data in distinct animal reservoirs and human populations reported in the last two decades. Furthermore, the expertise with experimental infection models using non-human primates may provide new insights into HEV pathogenesis, prevention, and environmental surveillance.

Systematic Review of Hepatitis E Virus in Brazil: A One-Health Approach of the Human-Animal-Environment Triad

Simple Summary

Hepatitis E virus (HEV) is an important causative agent of acute and chronic hepatitis worldwide. Originally identified in epidemics associated with flooding in Asia, it nowadays shows very distinct genetic and epidemiological patterns. While HEV genotypes (HEV-) 1 and 2 are associated with the original outbreaks (waterborne diseases), HEV-3 and HEV-4 present a zoonotic pattern (associated with consumption of meat from infected animals), HEV-5 and 6 have been found only in wild boar in Japan, and HEV-7 and 8 have been detected in camels and dromedary seldom affecting humans. Brazil, with a precarious sanitary structure and being an important world meat producer, was the focus of this study in order to identify patterns of occurrence of HEV. After reviewing scientific studies, it was identified that the only genotype found in Brazil is HEV-3 and the area where there were more reports was the South region of the country. This is the region that produces more pork. These results indicate that HEV-3 is widespread in the country and sanitary surveillance is essential in the national production of pigs, as well as the implementation of monitoring protocols in hospitals.

Abstract

Brazil is the fifth largest country in the world with diverse socioeconomic and sanitary conditions, also being the fourth largest pig producer in the world. The aim of the present systematic review was to collect and summarize all HEV published data from Brazil (from 1995 to October 2020) performed in humans, animals, and the environment, in a One Health perspective. A total of 2173 papers were retrieved from five search databases (LILACs, Mendeley, PubMed, Scopus, and Web of Science) resulting in 71 eligible papers after application of exclusion/inclusion criteria. Data shows that HEV genotype 3 (HEV-3) was the only retrieved genotype in humans, animals, and environment in Brazil. The South region showed the highest human seroprevalence and also the highest pig density and industry, suggesting a zoonotic link. HEV-1 and 2 were not detected in Brazil, despite the low sanitary conditions of some regions. From the present review we infer that HEV epidemiology in Brazil is similar to that of industrialized countries (only HEV-3, swine reservoirs, no waterborne transmission, no association with low sanitary conditions). Hence, we alert for the implementation of HEV surveillance systems in swine and for the consideration of HEV in the diagnostic routine of acute and chronic hepatitis in humans.

Sero-molecular epidemiology of hepatitis E virus in pigs and human contacts in Ghana

BACKGROUND

Hepatitis E virus (HEV) is among the leading causes of viral hepatitis in most developing countries. Zoonotic acquisition of HEV genotype 3 from swine has come into focus more recently. Available studies on HEV in Ghana and other countries in the region do not provide enough information towards understanding the epidemiology of HEV in human and animal populations. Towards this end, we conducted a comparative cross-sectional study to determine the seroprevalence and risk factors associated with HEV exposure, both in swine and humans working on pig farms in typical local settings. The presence of viral RNA in human and swine samples was also evaluated, along with classification of viral sequences from HEV-positive samples.

METHODS

Structured questionnaires soliciting information on pigs reared, as well as socio-demographic information including age, sex and educational background of humans was collected. A total of 10 ml and 5 ml of whole blood was collected from pigs and human participants respectively. ELISA and real-time RT-PCR were performed on the sera for the qualitative detection of IgG antibodies to hepatitis E virus and viral RNA, respectively.

RESULTS

Five hundred and forty-four (544) human participants including 264 swine contacts and 280 swine non-contacts were enrolled in the study. Although the proportion of HEV IgG antibodies was higher in contact groups (114; 54.3%) than non-contact groups (96; 45.7%), a multivariate analysis did not show any significant difference. No HEV RNA was detected in human samples. Similarly, 720 pigs were sampled from 18 farms located in five regions in Ghana. Twenty-three (23) of the pigs (3.2, 95%CI = 2.0-4.8) were positive for HEV RNA by real-time RT-PCR testing. Sequences obtained from HEV-positive samples were found to share high sequence identities with each other and clustered with other genotype 3 viruses indicating the existence of circulating zoonotic genotype 3 viruses on farms. Although we did not find evidence of pig to human transmission of HEV genotype 3, the presence of this genotype in pigs shows the potential for possible zoonotic transmission in African farm settings and buttresses the importance of active surveillance for the infection among at risk populations.

Serologic evidence of the circulation of the hepatitis E virus and the prevalence of antibodies against hepatitis A in an indigenous population in northern Argentina

In 2005 a universal vaccination program against hepatitis A was introduced in Argentina. Nevertheless, there are still some unvaccinated marginal population groups. There are no data about the seroprevalence of hepatitis E in the northern region of Argentina mainly because of lack of awareness of this emergent pathogen. We aimed to determine the seroprevalence of hepatitis A, and hepatitis E in an indigenous population in northern Argentina. One hundred and twenty six (126) donor serum samples collected near San Salvador de Jujuy were analyzed for anti-HAV IgG and HEV IgG and IgM, alkaline phosphatase and transaminase values. Volunteers were interviewed about their living conditions, animal farming, consumption of tap water or river water, and level of education. Seroprevalence of specific anti-HAV antibodies was high (80.2%, 95% confidence interval, 72.1-86.7%) in children under 5 years of age, indicating early infection in life. Seroprevalence of anti-HEV antibodies was 5.6% (95% CI: 2.3-11.2%), being slightly higher than the values found in healthy patients from other regions of the country. Although we could not characterize the genotype of the circulating HEV strain, the clear epidemiological difference between seroprevalence of HAV and HEV in a community with poor sanitary conditions suggest that the circulating HEV strains spread through a different transmission route than HAV. Furthermore a significant correlation between anti-HEV IgG and swine farming was found (p<0.05), which supports a zoonotic transmission path. We reassessed the epidemiological pattern of HAV infection and reported evidence of HEV infection for the first-time in a community belonging to the Guarani ethnic group, highlighting the need to include hepatitis E testing in routine diagnostics in the region.

Hepatitis E virus seroprevalence in patients with chronic hepatitis C at a university hospital in Brazil

Aim: We investigated the prevalence of anti-hepatitis E virus (HEV) antibodies in patients with chronic hepatitis C and the relationship with liver injury stage. Materials & methods: In total, 451 patients were included and the presence of anti-HEV antibodies was evaluated by ELISA. Results: Anti-HEV IgG antibodies were detected in 45 (10.0%) patients and anti-HEV IgM were detected in two IgG-positive patients (4.4%). The distributions of liver fibrosis, steatosis, inflammatory activity, homeostasis model assessment of insulin resistance and liver enzyme levels were similar between HEV-positive and HEV-negative patients. However, HEV-positive patients had a higher mean age (p = 0.030). The seroprevalence by age group increased from 2.2 (18–30 years) to 53.3% (>60 years). HEV infection was not related to advanced fibrosis. Conclusion: This investigation showed that the seroprevalence of HEV among patients with chronic hepatitis C is similar to that of blood donors in the same region.

Detection and characterization of hepatitis E virus genotype 3 in HIV-infected patients and blood donors from southern Brazil

BACKGROUND

Hepatitis E virus genotype 3 (HEV-3) infection usually causes self-limited acute hepatitis. In immunosuppressed patients, HEV-3 infection can rapidly progress to chronic hepatitis and cirrhosis. In southern Brazil, data on HEV seroprevalence are scarce.

METHODS

Testing for HEV RNA and antibodies (anti-HEV) was performed for 320 HIV-infected patients followed at the HIV/AIDS Service of the Federal University of Rio Grande between 2012 and 2013, as well as 281 blood donor samples obtained in 2015. Variables associated with anti-HEV positivity were assessed by multivariable logistic regression analysis.

RESULTS

HIV and blood donor groups showed similar HEV seroprevalence (6.7% and 7.1%, respectively). Risk factors associated with anti-HEV detection were older age, marital status, a higher number of sexual partners, poor sanitation, and alcohol use (HIV group), and living in a rural area (blood donors). HEV RNA was detected in eight serum samples from HIV-infected patients and in one blood donor, who was also positive for anti-HEV IgM and IgG.

CONCLUSIONS

The prevalence rates of HEV infection were comparable between HIV-seropositive patients who were not severely immunocompromised and blood donors. The blood donor's HEV isolate showed high similarity with swine HEV strains from Brazilian herds in the same region, thus indicating a potential risk of foodborne and parenteral transmission via blood transfusion.

Emerging zoonotic viral infections of occupational health importance

Emerging viral infections represent a public health risk pointed out by the spreading of pathogens with potential zoonotic risk. Moreover, the risk of zoonosis has probably been underestimated in occupational settings. A literature review between 2007 and 2018 was performed to identify evidences concerning the epidemiological associations between some emerging viruses and occupational diseases. Observational studies and case-reports were selected and analyzed. West Nile Virus (WNV) disease, Crimean-Congo Hemorrhagic Fever (CCHF) disease and Hepatitis E virus (HEV) infection were included in the review for their potential zoonotic transmission. The most important risk factor for acquiring WNV infection and CCHF infection is the exposure to infected mosquitoes and ticks, respectively; therefore, outdoor workers are at risk of infection. HEV is responsible for epidemics and endemics of acute hepatitis in humans, that can become infected through waterborne, foodborne and zoonotic transmission routes. A total of 10, 34 and 45 eligible studies for WNV, CCHF virus (CCFHV) and HEV, respectively, were analyzed by year, country, study design, risk group and outcomes. The occupational risk groups mainly included farm and agricultural workers, veterinarians, slaughterers, animal handlers, healthcare workers and soldiers. These findings support the need to develop effective interventions to prevent transmission of emerging viruses.

Hepatitis E virus infection in swine workers: A meta-analysis

Hepatitis E virus (HEV) infects both humans and animals. Swine has been confirmed to be the principal natural reservoir, which raises a concern that HEV infection would be substantially increasing among swine workers. The present study calculated the pooled prevalence of IgG antibodies against HEV among swine workers and the general population in previous cross-sectional studies. We conducted a meta-analysis comparing the prevalence of HEV infection between swine workers and the general population, including local residents, blood donors and non-swine workers. Through searches in three databases (PubMed and OVID in English, and CNKI in Chinese) and after study selection, a total of 32 studies from 16 countries (from 1999 through 2018) were included in the meta-analysis. A random-effect model was employed in the study; an I ² statistic assessed heterogeneity, and the Egger's test detected publication bias. The comparative prevalence of anti-HEV IgG was pooled from the studies. Compared to the general population, the prevalence ratio (PR) for swine workers was estimated to be 1.52 (95% CI 1.38-1.76) with the I ² being 71%. No publication bias was detected (p = 0.40). A subgroup analysis further indicated increased prevalence of anti-HEV IgG in the swine workers in Asia (PR = 1.49, 95% CI: 1.35-1.64), in Europe (PR = 1.93, 95% CI: 1.49-2.50) and in all five swine-related occupations, including swine farmers, butchers, meat processors, pork retailers and veterinarians (PR ranged between 1.19 and 1.75). In summary, swine workers have a relatively higher prevalence of past HEV infection, and this finding is true across swine-related occupations, which confirms zoonotic transmission between swine and swine workers.

Hepatitis E seroprevalence in the Americas: A systematic review and meta-analysis

BACKGROUND & AIMS

While hepatitis E virus infections are a relevant topic in Europe, knowledge about epidemiology of hepatitis E virus infections in the USA and Latin America is still limited. Aim of this study was to estimate anti-hepatitis E virus IgG seroprevalence in the Americas and to assess whether low socioeconomic status is associated with hepatitis E virus exposure.

METHODS

We performed a systematic review and meta-analysis. Literature search was performed in PubMed for articles published 01/1994-12/2016. Prevalence was estimated using a mixed-effects model and reported in line with PRISMA reporting guidelines.

RESULTS

Seroprevalence was significantly higher in the USA than in Latin America, independently of assay, patient cohort, methodological quality or study year (OR: 1.82 (1.06-3.08), P = .03). Patients in the USA had a more than doubled estimated seroprevalence (up to 9%, confidence interval 5%-15.6%) than those in Brazil (up to 4.2%, confidence interval 2.4%-7.1%; OR: 2.27 (1.25-4.13); P = .007) and Mixed Caribbean (up to 1%, OR: 8.33 (1.15-81.61); P = .04). A comparison with published data from Europe demonstrated that anti-hepatitis E virus seroprevalence in the USA and Europe did not differ significantly (OR: 1.33 (0.81-2.19), P = .25), while rate in South America was significantly lower than that in Europe (OR: 0.67 (0.45-0.98), P = .04).

CONCLUSIONS

Hepatitis E virus is common in the USA. Surprisingly, the risk of hepatitis E virus exposure was low in many South American countries. Seroprevalence did not differ significantly between Europe and the USA. Hence, hepatitis E virus is not limited to countries with low sanitary standards, and a higher socioeconomic status does not protect populations from hepatitis E virus exposure.

Hepatitis E virus in South America: The current scenario

Hepatitis E virus (HEV) is one of the most frequent causes of acute viral hepatitis of enteric transmission worldwide. In South America the overall epidemiology has been little studied, and the burden of the disease remains largely unknown. A research of all scientific articles about HEV circulation in South America until November 2017 was carried out. Human seroprevalences of HEV varied according to the studied population: blood donors presented prevalence rates ranging from 1.8% to 9.8%, while reports from HIV-infected individuals, transplant recipients and patients on hemodialysis showed higher prevalence rates. Only 2 cases of chronic hepatitis in solid-organ transplant patients from Argentina and Brazil have been described. Detection of HEV in the swine population is widely prevalent in the region. Anti-HEV antibodies have also been recently documented in wild boars from Uruguay. Although scarce, studies focused on environmental and food HEV detection have shown viral presence in these kind of samples, highlighting possible transmission sources of HEV in the continent. HEV genotype 3 was the most frequently detected in the region, with HEV genotype 1 detected only in Venezuela and Uruguay. HEV is widely distributed throughout South America, producing sporadic cases of acute hepatitis, but as a possible agent of chronic hepatitis. Finding the virus in humans, animals, environmental samples and food, show that it can be transmitted through many sources, alerting local governments and health systems to improve diagnosis and for the implementation of preventive measures.

Detection of hepatitis E virus genotype 3 in pigs from subsistence farms in the state of Mato Grosso, Brazil

Hepatitis E is a zoonotic disease, recognized as an important global public health concern. In this study, molecular detection of the ORF1 and ORF2 genomic regions of the hepatitis E virus (HEV) was carried out in fecal and serum samples from pigs in subsistence farms of Mato Grosso, Brazil. Fragments of the ORF2 region were amplified in 8% (12/150) of fecal samples, with 53.3% (8/15) of farms having positive results. Of the 12 positive samples, fragments of the ORF1 region were amplified in 33.3% (4/12) of these. Molecular characterization confirmed the phylogenetic groupings as HEV subtypes 3d, 3 h, and 3i. The results revealed that meat from pigs that was originally meant for personal consumption is being traded in marketplaces in metropolitan Cuiabá, thereby creating a source of transmission to consumers in Mato Grosso. The environmental conditions must be taken into account when investigating the presence and transmission of HEV.

Prevalence of hepatitis E virus RNA and antibodies in a cohort of kidney transplant recipients in Central Brazil

OBJECTIVE

To assess the prevalence of hepatitis E virus (HEV) RNA and antibodies among kidney transplant recipients (KTR) in Central Brazil. The presence of chronic HEV infection was also investigated.

METHODS

A cohort study was conducted among 316 KTR treated at a referral center for kidney transplantation in Goiânia, Brazil. All serum samples were tested for the presence of HEV RNA (real-time PCR) and anti-HEV IgG/IgM (ELISA). Anti-HEV-positive samples were confirmed using an immunoblot test. HEV chronicity was investigated in a subgroup of patients with elevated alanine aminotransferase (ALT >40IU/l) through HEV RNA detection in additional serum samples collected 3 and 6 months apart.

RESULTS

A seroprevalence of 2.5% (95% confidence interval 1.2-5.1%) was found for anti-HEV IgG. There was no difference in characteristics between the anti-HEV IgG seropositive and seronegative KTR groups. Anti-HEV IgM was detected in only one patient (0.3%). All KTR were negative for HEV RNA.

CONCLUSIONS

These results show that HEV infection is infrequent in KTR in Central Brazil, with low seroprevalence rates of past and recent infection, and also an absence of active and chronic HEV infections.

Hepatitis E in southern Vietnam: Seroepidemiology in humans and molecular epidemiology in pigs

Viral pathogens account for a significant proportion of the burden of emerging infectious diseases in humans. The Wellcome Trust-Vietnamese Initiative on Zoonotic Infections (WT-VIZIONS) is aiming to understand the circulation of viral zoonotic pathogens in animals that pose a potential risk to human health. Evidence suggests that human exposure and infections with hepatitis E virus (HEV) genotypes (GT) 3 and 4 results from zoonotic transmission. Hypothesising that HEV GT3 and GT4 are circulating in the Vietnamese pig population and can be transmitted to humans, we aimed to estimate the seroprevalence of HEV exposure in a population of farmers and the general population. We additionally performed sequence analysis of HEV in pig populations in the same region to address knowledge gaps regarding HEV circulation and to evaluate if pigs were a potential source of HEV exposure. We found a high prevalence of HEV GT3 viral RNA in pigs (19.1% in faecal samples and 8.2% in rectal swabs) and a high HEV seroprevalence in pig farmers (16.0%) and a hospital-attending population (31.7%) in southern Vietnam. The hospital population was recruited as a general-population proxy even though this particular population subgroup may introduce bias. The detection of HEV RNA in pigs indicates that HEV may be a zoonotic disease risk in this location, although a larger sample size is required to infer an association between HEV positivity in pigs and seroprevalence in humans.

Hepatitis E virus infection in patients with acute non-A, non-B, non-C hepatitis in Central Brazil

Hepatitis E virus (HEV) infection has a worldwide distribution and represents an important cause of acute hepatitis. This study aims to investigate the occurrence of HEV infection and factors associated with this infection in patients with acute non-A, non-B, non-C hepatitis in Central Brazil. From April 2012 to October 2014, a cross-sectional study was conducted among 379 patients with acute non-A, non-B, non-C hepatitis in the City of Goiania, Central Brazil. Serum samples of all patients were tested for serological markers of HEV infection (anti-HEV IgM and IgG) by ELISA. Positive samples were confirmed using immunoblot test. Anti-HEV IgM and IgG positive samples were tested for HEV RNA. Of the 379 serum samples, one (0.3%) and 20 (5.3%) were positive for anti-HEV IgM and IgG, respectively. HEV RNA was not found in any sample positive for IgM and/or IgG anti-HEV. After multivariate analysis, low education level was independently associated with HEV seropositivity (p = 0.005), as well as living in rural area, with a borderline p-value (p = 0.056). In conclusion, HEV may be responsible for sporadic self-limited cases of acute hepatitis in Central Brazil.

Hepatitis E Virus: A Cross-Sectional Serological and Virological Study in Pigs and Humans at Zoonotic Risk within a High-Density Pig Farming Area

An increase in autochthonous hepatitis E virus (HEV) infections has been recorded in Italy suspected to be zoonotically transmitted from pigs; this study was carried out to determinate the seroprevalence and risk factors associated with hepatitis HEV exposition, both in swine and humans working in pig farms, located within a high-density pig farming area in Piedmont region, north-western Italy. The presence of viral RNA in human and swine samples was also evaluated, and phylogenetic analysis was performed on HEV-positive samples. Forty-two swine farms were sampled; 142 workers were enrolled in the study and classified into two groups: (i) 69 workers with occupational contact with swine (including veterinarians and farmers) recruited in the 42 sampled farms; (ii) 73 without occupational contact with swine. Forty-one of 42 (97%) swine farms resulted positive to enzyme-linked immunosorbent assay test for HEV antibodies (Abs). Overall seroprevalence in swine was 50% (441/879), with seropositivity rate higher in sows (333/469, 71%). HEV RNA in stool samples was detected in animals from 13 of 42 tested farms (31%), and a higher positivity resulted in weaners (40/246, 16.3%). Phylogenetic analysis classified all HEV isolates within genotype 3 (subtypes 3f, 3e, 3c). All humans were negative for HEV viral genome in blood. Five of 142 sera were positive for IgG anti-HEV with an overall prevalence of 3.52% with no statistically significant differences in prevalence rates between workers at zoonotic risk and the control group (5.7% versus 1.3%). In contrast, a significant difference (OR 10.1) was observed within the subgroup including subjects exposed for short periods (veterinarians) compared with those who worked for long periods (farmers) suggesting a correlation between the time of exposure and the likelihood of HEV infection. Reporting HEV infection is not mandatory in Italy, but a constant epidemiological surveillance should be ensured to clarify the epidemiology of this disease.

Hepatitis A and E seroprevalence and associated risk factors: a community-based cross-sectional survey in rural Amazonia

BACKGROUND

Hepatitis A virus (HAV) and hepatitis E virus (HEV) are both transmitted by the faecal-oral route, and represent common causes of acute hepatitis in developing countries. The endemicity of HAV infection has shifted from high to moderate in Brazil. Human cases of HEV infection seem to be rare, although the virus has been detected in swine livestock and effluents of slaughterhouses. This study was to determine the epidemiology of hepatitis A and E in one of the largest agricultural settlements in the Amazon Basin of Brazil.

METHODS

Serum samples collected from 397 individuals aged between 5 and 90 years during a population-based cross-sectional survey were tested for anti-HAV and anti-HEV antibodies. Associated risk factors and spatial clustering of HAV and HEV seropositivity were also analyzed.

RESULTS

The overall rate of HAV seropositivity was 82.9% (95% confidence interval (CI), 79.2-86.6%). Multilevel logistic regression analysis identified increasing age (in years; odds ratio (OR), 1.097; 95% CI, 1.050-1.147; P < 0.001) and crowding (OR, 1.603; 95% CI, 1.054-2.440; P = 0.028) as significant risk factors for HAV seropositivity. Anti-HEV IgG was detected in 50/388 settlers (12.9%, 95% CI, 9.5-16.2%). Anti-HEV IgM was detected in 7/43 (16.3%) anti-IgG positive samples, and 4 of them had a confirmed result by immunoblot. Increasing age was the only significant determinant of HEV seropositivity (OR, 1.033; 95% CI, 1.016-1.050; P < 0.001). No significant spatial clustering of HAV and HEV seropositivity was detected in the area.

CONCLUSIONS

Both HAV and HEV are endemic, with differing rates of infection in children and adults in this rural setting of the Brazilian Amazon. Anti-HEV prevalence was considerably higher than those previously reported in Brazil. The detection of HEV- specific IgM antibodies in four asymptomatic individuals is highly suggestive of the circulation of HEV in this rural population.

Infection by Brazilian and Dutch swine hepatitis E virus strains induces haematological changes in Macaca fascicularis

BACKGROUND

Hepatitis E virus (HEV) has been described as an emerging pathogen in Brazil and seems to be widely disseminated among swine herds. An autochthonous human case of acute hepatitis E was recently reported. To obtain a better understanding of the phenotypic profiles of both human and swine HEV strains, a experimental study was conducted using the animal model, Macaca fascicularis.

METHODS

Six cynomolgus monkeys (Macaca fascicularis) were inoculated intravenously with swine HEV genotype 3 that was isolated from naturally and experimentally infected pigs in Brazil and the Netherlands. Two other monkeys were inoculated with HEV genotype 3 that was recovered from Brazilian and Argentinean patients with locally acquired acute and fulminant hepatitis E. The haematological, biochemical, and virological parameters of all animals were monitored for 67 days.

RESULTS

Subclinical hepatitis was observed in all monkeys after inoculation with HEV genotype 3 that was recovered from the infected swine and human patients. HEV RNA was detected in the serum and/or faeces of 6 out of the 8 cynomolgus monkeys between 5 and 53 days after inoculation. The mild inflammation of liver tissues and elevations of discrete liver enzymes were observed. Seroconversions to anti-HEV IgM and/or IgG were detected in 7 animals. Reactivities to anti-HEV IgA were also detected in the salivary samples of 3 animals. Interestingly, all of the infected monkeys showed severe lymphopenia and a trend toward monocytosis, which coincided with elevations in alanine aminotransferase and antibody titres.

CONCLUSIONS

The ability of HEV to cross the species barrier was confirmed for both the swine (Brazilian and Dutch) and human (Argentinean) strains, thus reinforcing the zoonotic risk of hepatitis E in South America. Cynomolgus monkeys that were infected with HEV genotype 3 developed subclinical hepatitis that was associated with haematological changes. Haematological approaches should be considered in future studies of HEV infection.