Animals ; Disease Models, Animal ; Hepatitis, Viral, Animal ; virology ; Humans ; Mice ; Murine hepatitis virus ; genetics ; pathogenicity ; physiology

Animals ; Genotype ; Hepatitis E ; veterinary ; virology ; Hepatitis E virus ; genetics ; Hepatitis, Viral, Animal ; virology ; Prevalence

Rift Valley fever (RVF) is an acute, febrile zoonotic disease that is caused by the RVF virus (RVFV). RVF is mainly prevalent on the Arabian Peninsula, the African continent, and several islands in the Indian Ocean near southeast Africa. RVFV has been classified by the World Organisation for Animal Health (OIE) as a category A pathogen. To avoid biological safety concerns associated with use of the pathogen in RVFV neutralization assays, the present study investigated and established an RVFV pseudovirus-based neutralization assay. This study used the human immunodeficiency virus (HIV) lentiviral packaging system and RVFV structural proteins to successfully construct RVFV pseudoviruses. Electron microscopy observation and western blotting indicated that the size, structure, and shape of the packaged pseudoviruses were notably similar to those of HIV lentiviral vectors. Infection inhibition assay results showed that an antibody against RVFV inhibited the infective ability of the RVFV pseudoviruses, and an antibody neutralization assay for RVFV detection was then established. This study has successfully established a neutralization assay based on RVFV pseudoviruses and demonstrated that this method can be used to effectively evaluate antibody neutralization.
Africa ; Animals ; Blotting, Western ; HIV ; Indian Ocean ; Islands ; Methods ; Microscopy, Electron ; Product Packaging ; Rift Valley fever virus ; Rift Valley Fever ; Zoonoses

OBJECTIVESTo establish an animal model of HCV transgenic mice to elucidate the pathogenesis of hepatitis C virus infection and function of the viral structural proteins.

METHODSStructural gene of HCV were amplified and recombined into eukaryotic expression vectors, pcDNA4HisMax and pMT/BiP/V5-His A, after their expressive activity was confirmed to detect the structural protein in the transfected COS7 and S2 cells by Western blot. The fertilized expression element, which contained CMV or pMT promoter, structural gene of HCV and polyadenylation signal sequence, was microinjected into 1736 C57BL/6 mouse fertilized ova. The ova were then replanted into the oviducts of 69 pseudopregnant recipient mice.

RESULTSTwenty-five recipient mice were impregnated and later produced 105 newborns; 49 of them died from unknown causes and 57 survived. After the specific HCV structural genes were identified by PCR and Southern blot hybridization, 26 founders were obtained; among them 10 were stable expression mice and 16 were the inducible ones. The rate of founders developed from implanted embryos was only 1.50%. Through hybridization with normal mice, 58 hybrid mice have been obtained at present.

CONCLUSIONTwo kinds of different transgenic mice of HCV were developed; one is of stable expression, and the other is inducible. This transgenic mice model may create an opportunity for studying the function of the structural gene of HCV and elucidate its pathogenicity.

Animals ; Disease Models, Animal ; Gene Expression Regulation, Viral ; Hepacivirus ; genetics ; Hepatitis C ; Mice ; Mice, Transgenic ; Viral Structural Proteins ; genetics

This article describes the nomenclature, history and genetic evolution of duck hepatitis A virus, and updates the epidemiology, clinical symptom and surveillances of duck virus hepatitis A. It also summarizes the present status and progress of duck virus hepatitis A and illustrated the necessity and urgency of its research, which provides rationale for the control of duck hepatitis A virus disease in China.
Animals ; Ducks ; virology ; Hepatitis Virus, Duck ; classification ; genetics ; isolation & purification ; Hepatitis, Viral, Animal ; virology ; Picornaviridae Infections ; veterinary ; virology

Duck hepatitis B virus (DHBV) belongs to the Avihepadnavirus genus of the Hepadnaviridae, and it not only has the same replication pattern, but also has the similar genomic and antigenic structures to Hepatitis B virus (HBV). The genome of DHBV is a partially double-stranded closed circular DNA. The genome consists of three distinct open reading frames (ORFs): ORF-PreS/S, ORF-PreC/C and ORF-P, which all locate on the negative DNA strand and encode four separate proteins. The ORF-PreS/S encodes envelope proteins L and S, and the ORF-PreC/C and ORF-P encode capsid proteins C and polymerase proteins P, respectively. The characteristics of genome structure,viral proteins features and functions were described in this review in order to provide useful information for the further study of DHBV and the duck model infected by DHBV.
Animals ; Ducks ; Hepadnaviridae Infections ; veterinary ; virology ; Hepatitis B Virus, Duck ; chemistry ; genetics ; isolation & purification ; Hepatitis, Viral, Animal ; virology ; Open Reading Frames ; Protein Structure, Tertiary ; Viral Proteins ; chemistry ; genetics

Animals ; DNA, Viral ; genetics ; isolation & purification ; Ducks ; Hepatitis B Virus, Duck ; genetics ; isolation & purification ; Hepatitis, Viral, Animal ; virology ; Organic Chemicals ; Polymerase Chain Reaction ; methods ; Sensitivity and Specificity

OBJECTIVETo establish a highly expressing and replicating hepatitis B virus (HBV) genome transgenic mouse models for screening anti-HBV drugs and investigating the pathogenesis of hepatitis B.

METHODSElongated HBV genome as the investigated gene was transducted into the pronuclei of the fertilized eggs of mice by the technique of microinjection, then the eggs were transplanted into the oviducts of the pseudopregnant mice. All the newborn mice were screened and identified by PCR and Southern blot detecting genomic DNA in tail tissue, then the positive mice were examined plasma HBsAg, HBeAg by ELISA and plasma HBV DNA by Southern blot.

RESULTSAmong the 61 offsprings, 18 were positive for tail tissue HBV DNA examination, 7 of which were positive for replication and expression detection.

CONCLUSIONTransgenic mice with elongated HBV genome possess high efficiency of replication and expression, which can be used for further investigation.

Animals ; DNA Replication ; DNA, Viral ; genetics ; Disease Models, Animal ; Genome, Viral ; Hepatitis B ; virology ; Hepatitis B Surface Antigens ; genetics ; Hepatitis B e Antigens ; genetics ; Hepatitis B virus ; genetics ; physiology ; Mice ; Mice, Transgenic ; genetics ; Virus Replication

The rapid mutation and widely spread of duck hepatitis A virus (DHAV) lead to the vast economic loss of the duck industry. To prepare and evaluate bivalent inactivated vaccine laboratory products of DHAV, 6 strains were screened from 201 DHAV-1 strains and 38 DHAV-3 strains by using serotype epidemiological analysis in most of the duck factory. Vaccine candidate strains were selected by ELD50 and LD50 tests in the 6 strains. Continuously passaged, the 5th passaged duck embryos bodies grinding fluid was selected as vaccine virus seeds. The virus seeds were treated with formaldehyde and water in oil in water (W/O/W) emulsions, making into three batches of two bivalent inactivated vaccine laboratory products. The safety test, antibody neutralization test, challenged protection and cross immune protection experiment suggested that the vaccines possessed good safety, and neutralizing antibodies were detected at 7th day and the challenged protection rate reached 90% to 100% at the 14th and 21st day. Moreover, immune duration of ducklings lasted more than five weeks. However, cross-immunity protection experiments with DHAV-SH and DHAV-FS only had 20%-30%. The two bivalent inactivated vaccine laboratory products of duck viral hepatitis were effective and reliable, providing a new method as well as a new product for DHAV prevention and control.
Animals ; Antibodies, Neutralizing ; blood ; Ducks ; virology ; Hepatitis Virus, Duck ; Hepatitis, Viral, Animal ; prevention & control ; virology ; Neutralization Tests ; Picornaviridae Infections ; prevention & control ; veterinary ; Poultry Diseases ; prevention & control ; virology ; Vaccines, Inactivated ; immunology ; Viral Hepatitis Vaccines ; immunology

BACKGROUNDTo determine the feasibility of inhibition of duck hepatitis B virus (DHBV) DNA replication by antisense phosphorothioate oligodeoxynucleotides corresponding to DHBV transcription region.

METHODSThe authors designed three antisense phosphorothioate oligodeoxynucleotides which correspond to DHBV PreS1,PreS2 and S antigen gene promotors respectively. The DNA replication level was detected with Southern blot method and cpm calculation.

RESULTSPrimary duck hepatocyte culture was treated with 1.5 micromol/L antisense oligodeoxynucleotides in vitro, all the antisense fragments caused a firm inhibition of viral DNA replication and the inhibition rates were 61.5%, 69.3% and 62.4%, respectively. In vivo, the animals were treated with 10 microgram/g PreS1 antigen gene promotor antisense oligodeoxynucleotides per day for 6 days and a very strong inhibition rate of 87.9% was obtained.

CONCLUSIONSThe results demonstrated the potential clinical application of antisense phosphorothioate oligodeoxynucleotides in clinics.

Animals ; DNA Replication ; drug effects ; DNA, Viral ; drug effects ; Ducks ; Hepadnaviridae Infections ; virology ; Hepatitis B Surface Antigens ; blood ; Hepatitis B Virus, Duck ; genetics ; physiology ; Hepatitis, Viral, Animal ; virology ; Oligodeoxyribonucleotides, Antisense ; pharmacology ; Protein Precursors ; blood ; Virus Replication ; drug effects