RESUMO
In the absence of commercial kits for serological studies specifically for hepatitis E virus (HEV) infection of swine, the capsid protein of a swine genotype 3 HEV was expressed using a recombinant baculovirus. This antigen was used in an enzyme-linked immunosorbent assay (ELISA) for detection of anti-HEV antibodies. Estimation of sensitivity and specificity was carried out in comparison with a commercial serological assay using sera from pigs infected experimentally with HEV genotype 3, negative sera from SPF pigs and swine sera collected at slaughterhouses. Since a "gold standard" is not available, a latent-class Bayesian approach for correlated tests was used to estimate the sensitivity and specificity of both tests. External field and experimental data were used to determine the parameters of Beta prior distributions. The estimated mean sensitivity of the commercial test was 0.47 with a 95% credibility interval of 0.39-0.55, whereas the estimated mean sensitivity of the genotype 3-based assay was 0.92 [0.81-0.99]. The estimated specificities were 0.98 [0.93-0.99] and 0.98 [0.95-0.99] for the genotype 3-based test and commercial test, respectively. In conclusion, genotype 3-antigen derived from swine HEV is a better candidate for assessing hepatitis E serology in swine.
Assuntos
Proteínas do Capsídeo , Ensaio de Imunoadsorção Enzimática/métodos , Anticorpos Anti-Hepatite/sangue , Vírus da Hepatite E/imunologia , Hepatite E/veterinária , Doenças dos Suínos/diagnóstico , Suínos/virologia , Animais , Antígenos Virais/genética , Baculoviridae/genética , Teorema de Bayes , Proteínas do Capsídeo/genética , Vetores Genéticos , Hepatite E/diagnóstico , Vírus da Hepatite E/genética , Sensibilidade e Especificidade , Estatística como Assunto , Doenças dos Suínos/imunologia , Virossomos/genéticaRESUMO
Hepatitis E virus (HEV) is responsible for large waterborne epidemics of acute hepatitis in endemic regions and for sporadic autochthonous cases in non endemic regions. Although the water vector has been thoroughly documented in endemic regions, very little is known about the modes of contamination occurring in non endemic regions. Unlike the other hepatitis viruses, HEV has an animal reservoir. Several lines of evidence, such as the results of phylogenic analysis and studies on direct contamination via infected food products, have suggested that some cases of animal to human transmission occur. However, all the possible sources of human contamination in non endemic areas have not yet been defined, and this point needs to be investigated. The high genetic variability of HEV, which might be an important factor, involved in zoonotic contamination processes, also needs a surveillance plan.
Assuntos
Hepatite E/transmissão , Zoonoses/transmissão , Animais , Reservatórios de Doenças/veterinária , Hepatite E/epidemiologia , Hepatite E/imunologia , Vírus da Hepatite E/imunologia , Vírus da Hepatite E/patogenicidade , Vírus da Hepatite E/fisiologia , Humanos , Estágios do Ciclo de Vida , Vacinas contra Hepatite Viral/uso terapêutico , Zoonoses/epidemiologiaRESUMO
Accumulating evidence suggests that hepatitis E virus (HEV) infection is an emerging disease in regions where HEV is nonendemic. In France, the prevalence of anti-HEV antibodies in the general population has never been studied. Using blood donors' samples, we have found a prevalence of 3.20%, which is similar to that of other industrialized countries.
Assuntos
Doadores de Sangue , Anticorpos Anti-Hepatite/sangue , Vírus da Hepatite E/imunologia , Hepatite E/epidemiologia , Adulto , Feminino , França/epidemiologia , Hepatite E/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos SoroepidemiológicosRESUMO
Hepatitis E is transmitted mainly by water or food, but in industrialized countries, all routes of transmission have not been identified. We describe possible zoonotic transmission of hepatitis E virus that involved direct contact between a pet pig and its owner.
Assuntos
Vírus da Hepatite E/isolamento & purificação , Hepatite E/transmissão , Doenças dos Suínos/transmissão , Zoonoses , Adulto , Animais , Animais Domésticos , Anticorpos Antivirais/sangue , Reservatórios de Doenças/veterinária , Reservatórios de Doenças/virologia , Amplificação de Genes , Genótipo , Hepatite E/veterinária , Hepatite E/virologia , Vírus da Hepatite E/classificação , Vírus da Hepatite E/imunologia , Humanos , Fígado/enzimologia , Fases de Leitura Aberta , Filogenia , RNA Viral/química , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Especificidade da Espécie , Suínos , Doenças dos Suínos/virologiaRESUMO
A full-length cDNA clone of an Encephalomyocarditis virus (EMCV) strain (2887A) isolated from aborted swine fetus was constructed and sequenced. Sequence comparison showed more than 99% nucleotide and amino acid sequence identity with two other EMCV strains, EMCV-PV21 and -R. However, the 2887A genomic sequence showed only about 84% nucleotide identity and 96% amino acid identity with EMCV-B, -D and -PV2 variants. RNA synthesized by in vitro transcription of this cDNA clone was infectious upon transfection of BHK21 cells, as shown by cytopathic effects and identification by neutralization test, and by propagation of the virus released into the culture media. The transcript RNA led to the production of infectious particles despite the presence of two nongenomic nucleotide residues at the 5' end, the short poly(C) tract (C(10)TCTC(3)TC(10)), the short poly(A) tail (7A), and the presence of six nongenomic nucleotides at the 3' end. The rescued virus was also found to be highly pathogenic for mice by intra-peritoneal inoculation producing a fatal disease indistinguishable from that of wild-type virus. An important finding concerning the molecular basis of infectivity was that the in vitro synthesized EMCV RNA transcript is infectious, although it contains a very short poly(A). The availability of the infectious cDNA clone of the reproductive failure strain of EMCV should prove to be useful for studying the molecular basis of the pathogenicity of EMCV in pig.