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Objective:To analyze the neutralization properties of different genotypes and mutants of severe fever with thrombocytopenia syndrome virus (SFTSV).Methods:Pseudoviruses of SFTSV of different genotypes and mutants were constructed using VSVΔG-Fluc*G backbone. Neutralization assays were established based on the pseudoviruses. DNA vaccines for different SFTSV genotypes were prepared. Serum samples were collected from guinea pigs immunized with the DNA vaccines. Neutralizing antibodies in serum samples from immunized guinea pigs and naturally infected patients were detected using neutralization assays and analyzed.Results:The pseudoviruses of five genotypes and 43 mutants were successfully constructed and the neutralization assays based the pseudoviruses were successfully established after optimizing the reaction parameters. The dilution multiple corresponding to the inhibition rate of neutralizing antibody to half of the pseudovirus infection was taken as the titer of neutralizing antibody by the reduction in pseudovirus reporter gene. The neutralization antibody titers in naturally infected patients and immunized guinea pigs were respectively in the ranges of 1∶100-1∶43 000 and 1∶100-1∶2 500 when detected with the reference HB29 pseudovirus. The neutralization antibody titers ranged from 1∶100-1∶2 500 after immunization with different genotypes of DNA vaccines. No significant statistical difference in neutralization antibody titer was observed among different genotypes or mutant strains.Conclusions:The neutralization properties of different genotypes and mutants showed no significant change, which would be very useful for developing vaccines.
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Objective@#To investigate the presence of hepatitis E virus (HEV) RNA and HEV antigen (HEV-Ag) and to evaluate the infectivity of HEV in urine through a SPF rabbit model of HEV infection.@*Methods@#Serum, fecal and urine samples collected from SPF rabbits with HEV infection were tested for viral and biochemical markers using real-time RT-PCR and ELISA. Liver and kidney biopsies were performed for observing histopathological changes and immunohistochemical staining. Rabbits were challenged with HEV isolated in urine samples to evaluate the infectivity.@*Results@#Rabbit R1# that was injected with rabbit HEV presented viremia, fecal shedding of HEV, high serum level of HEV-Ag, elevated aspartate transaminase (AST) and alanine transaminase (ALT) and typical symptoms of hepatitis. Urine samples of rabbit R1# continued to be positive for HEV RNA and HEV-Ag. Ratios of HEV-Ag to RNA in urine samples of rabbit R1# were significantly higher than those in serum and feces samples. The parameters quantified in routine urinalysis remained within the normal ranges in rabbit R1#. However, pathological changes and the presence of HEV-Ag were observed in kidney tissues. Furthermore, serum and fecal samples that were collected from one of the two rabbits injected with rabbit R1# urine-derived HEV were HEV positive and the virus strains isolated form feces remained infective to rabbits.@*Conclusion@#HEV infection may result in kidney injury and the urine may pose a risk of transmission. HEV-Ag detection in urine may be valuable for the diagnosis of ongoing HEV infection.
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Objective:Selected virulence factors more than and high virulent Aeromonas hydrophia strain made into inactivated vaccine,to study the immunization effect of inactivated vaccine.Methods:Crucian were vaccinated with formalin-killed vaccine via in-traperitoneal injection.Controls were injected with the same volumes of saline.Then the antibody titres, histopathology and relative percent survival were analyzed from samples of both groups.Results: The antibody in the indirect agglutination reaction could be detected in vaccinated fish once a weeks after immunization and reached highest level 6 weeks after immunization.The histopathology analysis indicated that the vaccine had a good protective effect on crucian target organs.Vaccinated fish showed 100%relative percent survival and the immune period would be 6 month.Conclusion:The vaccine in this study has a significant protective effect on crucian and may be used as effective fish vaccines against bacterial septicemia.