SPF家兔尿液中戊型肝炎病毒传染性的研究

Infectivity of hepatitis E virus in SPF rabbit urine

目的研究家兔尿液中戊型肝炎病毒（HEV）的存在情况，评价尿液中排出的HEV是否具有传染性。方法使用兔型HEV毒株攻击SPF家兔，建立家兔HEV感染模型，采用实时荧光RT-PCR试剂和ELISA抗原、抗体检测试剂检测血清、粪便和尿液样品中的各病毒标志物和血清中的生化指标。到期解剖感染家兔，取肝脏和肾脏组织，进行组织病理和免疫组化检查。使用家兔阳性尿液攻击家兔，评价尿液的传染性。结果HEV抗原和核酸能够从感染家兔R1#的尿液、血清和粪便中持续检出，转氨酶也检测到异常，家兔呈现典型的急性感染的特点。尿液中HEV抗原与核酸的比值显著高于血清和粪便，尿液中虽然未检测到有异常的生化指标，但肾脏组织病理改变比较典型。将阳性尿液感染2只家兔，其中1只血清和粪便中能检出病毒核酸，并且分离该粪便中的病毒能再次感染家兔。结论家兔HEV感染能够导致肾脏损伤，并且感染后的尿液有传染性。尿液中的HEV抗原可以作为诊断HEV感染有意义的指标。

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.MethodsSerum, 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. ResultsRabbit 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. ConclusionHEV 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.