A trivalent vaccine candidate against hepatitis E virus,norovirus, and astrovirus

Hepatitis E virus (HEV), norovirus (NoV), and astrovirus (AstV) are enterically-transmitted viral pathogens causing epidemic or endemic hepatitis (HEV) and gastroenteritis (NoV and AstV) respectively in humans, leading to significant morbidity and mortality worldwide. While a recombinant subunit vaccine against HEVs is available in China, there is no commercial vaccine or antiviral against NoV or AstV. We report here our development of a trivalent vaccine against the three viral pathogens through our new polymer vaccine technology. All HEV, NoV, and AstV are non-enveloped RNA viruses covered by a protein capsid, featuring surface protruding (P) proteins that are responsible for virus–host interaction. These dimeric P proteins elicit neutralizing antibody and are good targets for subunit vaccine development. The trivalent subunit vaccine was developed by fusion of the dimeric P domains of the three viruses together that formed tetramers. This trivalent vaccine elicited significantly higher antibody responses in mice against all three P domains than those induced by a mixture of the three free P domains (mixed vaccine). Furthermore, the post-immune antisera of the trivalent vaccine showed significantly higher neutralizing titers against HEV infection in cell culture and higher blocking activity against NoV binding to HBGA ligands than those of the post-immune sera of the mixed vaccine. Thus, the trivalent vaccine is a promising vaccine candidate against HEV, NoV, and AstV.     

ELISA法、荧光免疫法及PCR检测婴幼儿腹泻常见病毒

目的 了解不同方法学检测婴幼儿腹泻常见病毒的检测结果差异及一致性情况.方法 采用酶联免疫吸附试验(ELISA)、免疫荧光法(四联法)及聚合酶链式反应(PCR)技术筛查深圳市福田区引起临床婴幼儿急性腹泻的轮状病毒(RV)、肠道腺病毒(EAdV)、诺如病毒(NV)和星状病毒(AstV)的抗原,并将检测结果数据进行对比.结果酶免法与荧光免疫法检测数据对比:对RV,NV,EAdV的抗原阳性检出率差异有统计学意义(P＜0.05),对AstV抗原阳性检出率差异无统计学意义(P＜0.05);两种方法对RV的检测结果具有较好的一致性(Kappa值为0.558),对NV,EAdV和AstV的检测结果一致性较差(Kappa值分别为0.142,-0.025和0.361);ELISA法和PCR检测数据对比:ELISA法除对EAdV阳性检出率低于PCR外,对其他3种病毒的阳性检出率均高于PCR,且经x2检验显示两种方法对4种病毒的阳性检出率差异均有统计学意义(P＜0.05).两种方法对RV,NV,AstV的检测结果具有很好的一致性(Kappa值均＞0.75),对EAdV的检测结果一致性较好(Kappa值为0.537);荧光免疫法(四联法)和PCR检测数据对比:除AstV外,两种方法对其他3种病毒的阳性检出率差异均有统计学意义(P＜0.05).对RV的检测结果具有很好的一致性(Kappa值为0.764),对EAdV的检测结果一致性较好(Kappa值为0.452),NV和AstV的检测结果一致性差(Kappa值分别为0.181和-0.017).结论 ELISA法和荧光免疫法(四联法)对腹泻病毒的检测,除轮状病毒外,其它病毒检测结果的一致性较差,只可用于腹泻病原的初步筛查,确认必须进一步做培养或分子诊断;ELISA法、荧光免疫法(四联法)与PCR三者间的阳性检出率差异均有统计学意义,ELISA法与PCR检测结果的一致性明显较好.以PCR检测结果作为评估标准,ELISA法对四种腹泻病毒抗原的检测灵敏度、特异性及准确性均优于荧光免疫法,荧光免疫法检测结果的假阳性率较高.     

上海市浦东新区2012-2013年病毒性腹泻检测情况分析

目的 了解上海市浦东新区2012-2013年间常见病毒性腹泻的病原学特征,为腹泻病的防控提供依据.方法 收集2012-2013年上海市浦东新区14家监测医院腹泻患者的粪便标本,采用实时荧光定量-聚合酶链式反应(real-time PCR)检测轮状病毒、诺如病毒GⅠ型、诺如病毒GⅡ型、星状病毒、扎如病毒和肠腺病毒.结果 共检测粪便样本4 214份.1 255份样本检出至少1种病毒核酸,核酸阳性检出率为29.78％.轮状病毒、诺如病毒GⅠ型、诺如病毒GⅡ型、扎如病毒、星状病毒以及肠腺病毒的检出率分别为7.6％、1.4％、18.6％、1.6％、1.5％和1.1％.各年龄组均有病毒检出,其中年龄最小的为1岁,最大为92岁,分别为感染轮状病毒和诺如病毒.病毒性腹泻感染不存在男女差异,但不同年龄组的病毒性腹泻感染有差异.不同病毒病原的感染存在不同的高峰期,但主要集中在秋冬季.结论 诺如病毒和轮状病毒是浦东地区病毒性腹泻的主要病原.应该加强对病毒性腹泻的监测,尤其是诺如病毒和轮状病毒.     

A novel virus of the late blight pathogen, Phytophthora infestans, with two RNA segments and a supergroup 1 RNA-dependent RNA polymerase

Double-stranded RNA representing four distinct electrophoretic patterns was found in a screen of Phytophthora infestans isolates. Two dsRNAs that always appeared together were sequenced. RNA 1, which was 3160 nt plus a poly (A) tail, contained a single deduced ORF with the potential to encode a polyprotein of 977 aa with motifs characteristic of supergroup I viral RdRps. The 2776 nt, polyadenylated RNA2 contained an ORF with a potential to encode a polyprotein of 847 aa including a possible trypsin-like serine protease, and a second putative ORF of unknown function. An alternative form of RNA2, in which a 19-nt stretch was replaced by a 9-nt sequence, was detected in 4 of 17 clones sequenced. Based on genome structure and phylogenetic analysis, this virus did not fit into any known virus family and we tentatively named it Phytophthora infestans RNA virus 1 (PiRV-1).     

Acute encephalopathy in an immunocompromised boy with astrovirus-MLB1 infection detected by next generation sequencing

We report a case of an immunodeficient 4-year-old boy with acute encephalopathy possibly related to human astrovirus-MLB1 infection. The astrovirus-MLB1 genome was identified in his stool, serum, cerebrospinal fluid, urine, and throat swabs by next generation sequencing. We present additional evidence showing human astroviruses are important infectious agents, regardless of their clades, involving the central nervous system in immunocompromised hosts.     

Molecular epidemiology and genetic diversity of human astrovirus in South Korea from 2002 to 2007

The present study was conducted to survey the prevalence and genotypic distribution of human astrovirus (HAstV) circulating in South Korea. Of 160,027 patients with acute gastroenteritis, 2,057 (1.3%) were positive for HAstV antigen. We determined the genotypes of 187 HAstV strains collected from laboratories across the country. Genetic analysis revealed genotype 1 to be the most prevalent, accounting for 72.19% of the strains, followed by genotypes 8 (9.63%), 6 (6.95%), 4 (6.42%), 2 (3.21%) and 3 (1.60%). Our findings indicate that HAstV is less common but, even so, a potentially important viral agent of gastroenteritis in South Korea, with significant genetic diversity among circulating HAstV strains.     

Novel human astrovirus strains showing multiple recombinations within highly conserved ORF1b detected from hospitalized acute watery diarrhea cases in Kolkata,India

Human astroviruses (HAstVs) associated with acute watery diarrhea among hospitalized infants, children and adults as sole or mixed infection, were earlier reported from Kolkata, India. Further, novel recombinations have been detected through sequencing of the highly conserved ORF1b (RdRp) region of seven human astrovirus strains in Kolkata, India. Primers were designed and the ORF1b region was amplified by RT-PCR and sequenced. To examine the evolutionary pressures influencing the evolution of human astroviruses we implemented evolutionary genetics analysis. Maximum recombination break points detected in Kolkata strain IDH1300 were 8 and a single break point location was detected at 1205nt position. Partition-wise phylogenetic analyses of the IDH1300 Kolkata strain did not show close homology to the reference strains. Further phylogenetic analyses of full length ORF1b region of the seven human astrovirus strains showed that they formed a close cluster with each other and displayed a separate lineage in comparison to reference human astrovirus strains worldwide. This study shows the emergence of novel recombinant human astrovirus strains in Kolkata, India, warranting stringent surveillance to monitor the genetic diversity of human astrovirus strains infecting different age groups.     

Astrovirus enteritis in a chronic lymphocytic leukemia patient treated with fludarabine monophosphate

 We report on a case of severe astrovirus gastroenteritis in a chronic lymphocytic leukemia (CLL) patient treated with fludarabine monophosphate (FAMP). Astrovirus was detected in stools using both an immunoenzymatic assay and an electronic microscopy analysis. Treatment consisted in symptomatic care and the outcome was favorable. Astrovirus infection might constitute a common etiology of gastroenteritis in patients with hematologic malignancies that have been severely immunocompromised with FAMP or other purine analogues, and therefore should be more systematically investigated. Received: March 22, 1999 / Accepted: June 22, 1999     

昆明市幼儿病毒性腹泻病原学监测分析

目的了解云南省昆明市病毒性腹泻的病原谱特征,探索其流行规律,以期为病毒性腹泻患儿临床治疗及制定有针对性的防控措施提供参考。方法采集2018年1月至2019年12月因腹泻就诊的昆明市5岁以下患儿粪便标本,用实时荧光定量PCR方法进行核酸检测,检测轮状病毒、诺如病毒、腺病毒、星状病毒及札如病毒,并分析各种病毒的流行病学特征。结果共收集病例418例,男性患儿258例,女性患儿160例,男女性别比1.61∶1,男性患儿检出率为69.38%,女性患儿检出率为63.75%,男女检出率之比为1.09∶1。患儿主要集中在散居儿童及人口集中的托幼机构。感染科腹泻病毒核酸检出率高达83.43%。腹泻幼儿年龄主要集中在<2岁年龄段,1~<2岁年龄组轮状病毒核酸检出率男性达83.33%,女性达86.54%。轮状病毒、诺如病毒在冬春季流行;札如病毒、星状病毒、腺病毒春季高发;腺病毒在夏季高发。结论昆明市5岁以下婴幼儿病毒性腹泻仍以轮状病毒及诺如病毒为主要病原体,尤其要防范冬春季腹泻病高发期轮状病毒及诺如病毒引起的暴发及流行。应针对不同病毒发病高峰时间,制定有针对性的防控方案,采用不同的应对措施。