High genetic diversity of hepatitis E virus in swine in São Paulo State, Brazil / Diversidade genética do vírus da hepatite E em suínos no estado de São Paulo, Brasil

A hepatite E é uma zoonose emergente que afeta diversas espécies de mamíferos, inclusive o ser humano. É ocasionada por um vírus da espécie Orthohepevirus A que possui diversos genótipos e subgenótipos. No Brasil é descrito o genótipo HEV-3, cujo principal reservatório é o porco doméstico. Testes moleculares e sorológicos demonstram o HEV-3 em diferentes estados, tanto em animais quanto em humanos. No estado de São Paulo, existem diversos estudos sobre a epidemiologia da hepatite E em humanos, mas faltam informações sobre o HEV-3 em suínos. Assim, o objetivo deste trabalho foi verificar a ocorrência de HEV por meio da técnica de RT-PCR e posterior sequenciamento em um banco de amostras de fezes de suínos colhidas entre 2008 e 2009, na região metropolitana de Campinas. Das 89 amostras analisadas, foi possível detectar o HEV-3 em sete e, pela reconstrução filogenética, foram encontrados os subgenótipos HEV-3b, HEV-3h, e HEV-3j. Uma amostra disponível no GenBank, proveniente de São Paulo, que ainda não havia sido subgenotipada, foi agrupada ao HEV-3i. Os subgenótipos HEV-3j e HEV-3i ainda não tinham sido relatados no país. O estudo demonstra uma grande diversidade genética do HEV no estado de São Paulo e reforça o caráter zoonótico da HEV-3.(AU)

High frequency of hepatitis E virus infection in swine from South Brazil and close similarity to human HEV isolates

Abstract Hepatitis E virus is responsible for acute and chronic liver infections worldwide. Swine hepatitis E virus has been isolated in Brazil, and a probable zoonotic transmission has been described, although data are still scarce. The aim of this study was to investigate the frequency of hepatitis E virus infection in pigs from a small-scale farm in the rural area of Paraná State, South Brazil. Fecal samples were collected from 170 pigs and screened for hepatitis E virus RNA using a duplex real-time RT-PCR targeting a highly conserved 70 nt long sequence within overlapping parts of ORF2 and ORF3 as well as a 113 nt sequence of ORF2. Positive samples with high viral loads were subjected to direct sequencing and phylogenetic analysis. hepatitis E virus RNA was detected in 34 (20.0%) of the 170 pigs following positive results in at least one set of screening real-time RT-PCR primers and probes. The swine hepatitis E virus strains clustered with the genotype hepatitis E virus-3b reference sequences in the phylogenetic analysis and showed close similarity to human hepatitis E virus isolates previously reported in Brazil.

Molecular detection of hepatitis E virus in feces and slurry from swine farms, Rio Grande do Sul, Southern Brazil / Detecção molecular do vírus da hepatite E em fezes e chorume de propriedades suinícolas, Rio Grande do Sul, Sul do Brasil

Hepatitis E virus (HEV) is highly disseminated among swine herds worldwide. HEV is also a threat to public health, since particularly genotypes 3 and 4 may cause acute hepatitis in human beings. No previous studies were done on the occurrence of HEV in environmental samples in Rio Grande do Sul, Brazil. In the present study, reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to detect the presence of HEV in swine feces and in effluents from slurry lagoons in farms located in the municipality of Teutônia, inside the area of swine husbandry in the state. Pooled fecal samples from the floor of pig barns from 9 wean-to-finish farms and liquid manure samples were collected from the slurry lagoons from 8 of these farms. From the pooled fecal samples, 8/9 were positive for the HEV ORF1 gene by RT-PCR; all the slurry lagoon samples were positive for HEV RNA (100%). The identity of the HEV ORF1 amplicons was confirmed by sequencing belonging to HEV genotype 3, which was previously shown to be circulating in South America.

O vírus da hepatite E (HEV) é altamente disseminado entre rebanhos suínos no mundo todo. O HEV é também uma ameaça à saúde pública, já que os genótipos 3 e 4 podem causar hepatite aguda em seres humanos. Não há estudos anteriores sobre a ocorrência de HEV em amostras ambientais no Rio Grande do Sul. No presente estudo, empregou-se transcrição reversa e reação em cadeia da polimerase (RT-PCR) para detectar a presença de HEV em fezes de suínos e efluentes de lagoas de chorume em fazendas localizadas no município de Teutônia, representativo da região de maior produção de suínos no estado. Pools de amostras fecais foram coletadas a partir do chão de galpões de suínos provenientes de 9 propriedades de terminação; outra amostra de esterco líquido foi coletada das lagoas de chorume de 8 dessas fazendas. A partir das amostras fecais reunidas, 8/9 foram positivas para o gene ORF1 de HEV por PCR convencional; todas as amostras de lagoas de chorume foram positivas para RNA de HEV (100%). A identificação dos produtos de amplificação de HEV ORF1 foi confirmada por sequenciamento pertencente ao HEV genótipo 3, o qual foi previamente detectado na América do Sul.

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

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

Molecular analysis of swine hepatitis E virus from north India.

Background & objectives: Hepatitis E is the main cause of enterically transmitted non-A, non-B hepatitis in developing countries. In the developed countries such as the USA, Japan and Taiwan, the viruses infecting humans and swine share the same genotype with a high sequence similarity. Genotype 1 circulates in humans whereas genotype 4 in pigs in India. The present study was designed to investigate the presence of anti-HEV antibodies and HEV-RNA in swine population from north India, to investigate the genotype prevalent in it, and to compare it with other swine and human HEV strains from India. Methods: A total of 67 serum samples were collected from pigs of age period (1-6 months) from Indian Veterinary Research Institute (IVRI), Izatnagar, Bareily and subjected to anti-HEV IgG and HEV RNA detection. A phylogenetic tree was constructed using the neighbor-joining method and evaluated using the interior branch test method with MEGA 4 software. Results: Anti-HEV IgG and HEV RNA was found in 38.8 and 4.5 per cent of swine samples studied respectively. The above samples were observed to be of genotype 4e. The three new sequences had nucleotide similarity with other swine sequences in genotype 4 ranging from 80-98 per cent. Interpretation & conclusions: The three sequences observed in the present study showed nucleotide similarity with other swine sequences from southern and western India. The present study suggests that genotype 4 ‘e’ is prevalent in the north India.

Presencia de anti-VHE en un estudio de cohorte de porcinos ¿reservorio animal de hepatitis E en Chile? / Presence of anti hepatitis E virus antibodies in swine

Background: Swine hepatitis E virus (HEV) has a cross-reaction with human anti-HEV antibodies. Therefore, pigs could be an animal reservoir, rendering hepatitis E as a zoonosis. The spread of this infection among infected pigs across countries would be possible through trading. Previously, using an anti-human conjugate, we detected anti-HEV antobodies in adult pigs in Chile. Aim: To detect anti-HEV (ELISA) in a cohort of swine at different ages. Material and Methods: Two hundred pigs aged 42 to 360 days, divided in 20 groups of 10 animals were tested. Anti-HEV was detected by ELISA using anti-pig IgG horseradish peroxidase instead of anti-human conjugates. Results: Anti-HEV were detected in one animal aged 90 days, two animals aged 120 days, one animal aged 260 days and 2 animals aged 360 days, five pregnant sows and two old hogs. This represents a total of 14 animals or 7 percent of the sample. Conclusions: There is a significant prevalence of anti-HEV in pigs from 90 days of birth, suggesting that these swine are aprobable reservoir.

Serological evidence of hepatitis E virus infection in different animal species from the Southeast of Brazil

Serological evidence of hepatitis E virus infection (HEV) has been observed in both humans and different animal species living in non-endemic areas, suggesting that animals could be important reservoir for virus transmission to man. Antibodies to HEV have been detected in some Brazilian population groups. Nevertheless, sporadic cases of acute HEV infection have never been reported. We collected 271 serum samples from several domestic animals and also from pig handlers from Southeast of Brazil in order to investigate the seroprevalence of HEV infection. Anti-HEV IgG was detected in cows (1.42 percent), dogs (6.97 percent), chickens (20 percent), swines (24.3 percent), and rodents (50 percent), as well as in pig handlers (6.3 percent). The recognition of swine HEV infections in pigs in many countries of the world led us to investigate a larger sample of pigs (n = 357) from the same Brazilian region with ages ranging from 1 to > 25 weeks. IgG anti-HEV was detected in 100 percent of 7-day old pigs. Following a gradual decline between weeks 2 and 8 (probably due to loss of maternal IgG), the prevalence then steady increased until it reached 97.3 percent of animals older than 25 weeks. Besides the detection of anti-HEV antibodies in different animal species, the results showed that swine HEV infection seems to be almost universal within this Brazilian pig population. This is the first report that shows evidences of HEV circulation in Brazilian animal species and pig handlers.