北京地区2007-2008年G9型A组人轮状病毒VP7和VP4基因分析

目的 了解北京地区2007-2008年检测到的G9型A组人轮状病毒外壳蛋白VP7和VP4的基因特征.方法 选取经过轮状病毒核酸杂交方法检测为G9型轮状病毒的12份儿童腹泻患儿的粪便标本,应用针对VP7全长基因的特异引物对进行RT-PCR扩增,对所获得的VP7全长基因进行克隆和测序,将所获得的序列与GenBank中的G9型原型病毒株和近期流行株的VP7基因进行序列和种系进化分析;经巢式PCR对G9型的VP4进行P基因分型.结果 12株G9型轮状病毒经VP7基因的序列比较分析得到确认.P基因分型结果显示北京地区近年来存在G9P[8]和G9P[6]型两种组合的轮状病毒感染.序列和种系进化分析发现北京G9型株VP7基因与世界范围内近期流行的G9型株一样都属于进化分支Ⅲ,彼此间的核苷酸和氨基酸同源性较高,而与国内最早报道的G9型T203进化关系较远,且北京G9P[8]和G9P[6]型株分别与国内近期报道的新疆G9P[8]和G9P[6]型株及相应的武汉G9型株VP7基因,在氨基酸位点上存在一些共同的氨基酸残基取代.结论 北京地区近年存在G9P[8]和G9P[6]两种不同基因组合的G9型轮状病毒感染,需要进一步加强对G9型轮状病毒的分子流行病学监测.     

昆明地区22株人轮状病毒VP7及NSP4基因分析

目的研究昆明地区轮状病毒（RV）不同VP7血清型及NSP4基因变异与腹泻的流行及症状严重程度的关系。方法对2002年和2003年分离于昆明地区的RV，用PCR分型法对四种主要的VP7血清型进行分型，并对从150份RV腹泻标本VP7血清型为G1、G3、（34型RV株中挑出的14份一般腹泻株和8份重症腹泻株的NSP4基因序列进行了分析，与来自GenBank Database的4株人RV（Wa、KUN、AU-1、Hochi）和3株动物RV（EW、OSU、SA11）以及中国不同地区流行株NSP4的基因变异情况进行了比较。结果2002年昆明地区RV流行株以G1型为主，2003年RV腹泻株以G3型为主；昆明地区RV流行株间的氨基酸同源性高达98．9％～99．4％，22株流行株全都属于Wa组；NSP4变异与地域及VP7血清型无关；NSP4基因变异与RV腹泻临床症状严重程度不相关（P〉0．05）。结论不同年份相同季节不同地域流行的RVVP7血清型变异较大，而NSP4基因的相对保守性及其免疫原性使其有可能成为发展疫苗的候选基因。     

VP7、VP4与轮状病毒装配及分子流行病学

A组轮状病毒是全球婴幼儿腹泻的主要病原,其外壳蛋白VP7和VP4在病毒黏附、穿入细胞、血凝及诱导产生中和抗体中具有重要的作用,它们还分别决定血清型G型和P型,VP4又以基因序列不同而分型,称为P[]基因型,而且由其决定的分子病学流行特点不断发生变化。文中对A组轮状病毒VP7和VP4以上几方面的研究加以综述。     

宁波地区新生儿轮状病毒VP7基因序列分析

目的研究宁波地区新生儿轮状病毒流行株VP7基因的分子生物学特点以及遗传变异规律。方法通过聚丙烯酰胺凝胶电泳(PAGE)检测新生儿病毒性腹泻便样中的轮状病毒核酸;选择特殊电泳带型样品通过逆转录聚合酶链反应(RT-PCR)扩增VP7全基因并测序;测序结果利用DNAstar和Blast软件进行比对。结果通过PAGE发现11份样品中有9份阳性样品,其中带型为4-2-3-2的有7份,带型为3-2-2-2和4-2-1-2的各1份。3种带型各选一株进行VP7基因的扩增并测序,测序结果经分析发现,06NB3和06NB9与G1型标准株Wa的核苷酸同源性为84.4%和91.5%,氨基酸同源性分别为87.4%和94.8%,06NB2与G3型标准株YO的核苷酸同源性为95.3%,氨基酸的同源性为96.6%。结论宁波地区在新生儿中有A组轮状病毒流行,其电泳带型以典型的4-2-3-2为主,也可见特殊带型。06NB3和06NB9的VP7基因片段属G1型,06NB2则属于G3型。06NB3与国内外近几年流行的G1型毒株基因序列有较大差异,06NB9和06NB2则差异较小。     

武汉市儿童医院婴幼儿腹泻轮状病毒的VP4型别分析

目的研究武汉市儿童医院腹泻门诊A组轮状病毒VP4基因的分子流行病学特征. 方法利用聚丙烯酰胺凝胶电泳,将检测出的A组轮状病毒阳性样利用多重RT-PCR技术对VP4基因进行分型研究. 结果武汉地区793份腹泻患儿粪便样本经检测轮状病毒阳性257例,阳性率为32.4%.其中P [8]型232例(90.3%),P [4]型3例(1.2%),P [8]与P [4]混合感染15例(5.8%),尚有7例(2.7%)未能分出型别.对检测结果按采样时间、年龄和性别分布分别进行了分析. 结论武汉地区A组轮状病毒以P[8]型为主要流行基因型,患儿以6月至1岁为主,男女性别差异不大,武汉地区婴幼儿腹泻A组轮状病毒VP4基因分型研究将为轮状病毒疫苗的研制提供基础.     

福州地区2009-2014年腹泻儿童轮状病毒特征

目的 了解轮状病毒在福州地区腹泻儿童中的流行情况.方法 收集2009-2014年5岁以下腹泻住院儿童粪便标本,用ELISA法检测轮状病毒抗原,RT-PCR法确定基因型别.对G9轮状病毒阳性标本的VP7基因全长测序及进化分析.结果 福州地区腹泻儿童轮状病毒高峰期在10～12月,呈单峰流行态势.G9轮状病毒在2011年后成为福州地区优势流行型别,毒株VP7基因核苷酸序列相似性92.5％～100％,毒株间有较高的同源性,进化分析都属于G9第3亚型.结论 G9轮状病毒在福州地区流行强度逐渐加强,目前已成为优势流行型别.毒株同源性高,属G9型3亚型.     

宁波市食源性腹泻患者中3种相关病毒的检测与分型

目的了解腹泻患者中食源性相关病毒感染情况与流行特征,为防控病毒性胃肠炎提供依据。方法采集2 129份食源性腹泻患者粪便标本,用实时荧光定量PCR法检测轮状病毒、诺如病毒和甲型肝炎病毒核酸;用NSP4和VP1基因对轮状病毒和诺如病毒流行株分别测序。结果检出轮状病毒核酸52份,阳性率为2.44%,以A组感染为主;检出诺如病毒核酸113份,阳性率为5.31%,以Ⅱ型为主。VP1基因将诺如病毒分为GⅠ.2、GⅡ.6和GⅡ.17 3个型;A组轮状病毒均带NSP4毒力基因。全年均可检出病毒,秋冬季是发病高峰;全人群均可检出,5岁~及其以下年龄组的阳性率高于18岁~年龄组,差异有统计学意义(P0.05)。结论检测发现A组轮状病毒和GⅡ.17型诺如病毒是本市病毒性胃肠炎主要流行病原。病原感染途径多样、带毒者多、人群普遍易感、全年均可检出,本市人群随时有暴发疫情的可能。应加强关注,强化检测,以减少疾病的流行。     

青海省67份轮状病毒结构蛋白VP7基因分型和分布情况

目的 研究2016-2017年青海地区腹泻患者轮状病毒基因分型及流行病学分布。方法 收集门诊及住院部腹泻的粪便标本238份,采用实时荧光PCR法对轮状病毒A组进行检测,阳性标本进行VP7基因扩增和测序。结果 238份粪便标本中,通过实时荧光PCR 检测到轮状病毒A组阳性67份,阳性率为28.15%（67/238）;对67份轮状病毒A阳性标本进行VP7蛋白检测和测序,测序后得到29份核苷酸序列,用Clustral X Bootstap NJ Tree软件构件进化树,分析发现2016年3月-2017年12月青海轮状病毒以G9P8型为主,共26株,占89.66% (26/29),G2P4型2株(2/28),G3P8型1株(1/28), 轮状病毒腹泻发病高发季节为9-12月,其中以12月份检出最高,占总数的61.19%（41/67）。病人以成人为主,成人和5岁以下儿童比例为1.73[DK]∶1。结论 2016-2017年青海地区轮状病毒以流行病毒株G9P8型为主。     

辽宁省首次检出G9型A组轮状病毒

目的了解辽宁省A组轮状病毒的感染情况,为轮状病毒的预防控制提供科学依据。方法采集辽宁省沈阳、大连、丹东、阜新4个市门诊及住院疑似病毒性腹泻患者粪便标本135份,采用酶联免疫吸附试验(ELISA)检测轮状病毒抗原,阳性标本用逆转录-聚合酶链反应(RT-PCR)扩增A组轮状病毒VP7基因和VP4基因,RT-PCR产物进行核苷酸碱基序列的测定和比对,并构建VP7基因遗传进化树。结果 135份粪便标本中,共检测出A组轮状病毒阳性标本21份;A组轮状病毒G基因分型:G9型15株,G3型2株,G2型1株,G1型1株,未分型2株;P基因型分型:P[8]型20株,P[4]型1株;G/P基因型组合以G9P[8]为主共15株,G3P[8]2株,G1P[8]1株,G2P[4]1株,G/P[8]2株。结论辽宁省首次检出G9型A组轮状病毒,主要流行G/P基因型组合为G9P[8]。     

重庆地区婴幼儿轮状病毒腹泻VP7型别分析

目的：研究重庆地区1998－2000年度秋冬季婴幼儿轮状病毒腹泻分子流行病学,方法：采用逆转录－聚合酶链反应（RT－PCR）扩增婴幼儿腹泻便样中的编码轮状病毒VP7蛋白的全基因片段（1062bp),再用巢式－聚合酶链反应（net-PCR)对扩增得到的VP7基因进行分型,同时利用核苷酸序列分析方法进行分型。结果：在1998－1999年度130例婴幼儿腹泻便样中VP7基因阳性者50例（38．46％）,其中G1型占88％（44／50）,G3型占8％（4／50）,混合型占4％（2／50）,均为G1＋G3型,而1999－2000年度轮状病毒流行季节采集的112 标本中VP7基因扩增阳性者38例（33．93％）,其中G3型占78．95％（30／38）,G1型占13．16％（5／38）,混合型占7．89％（3／38）,均为G1＋G3型,苷酸序列分型结果与PCR分型结果一致。结论：重庆地区 1998－1999年度轮状病毒流行季节中流行的轮状病毒以G1型为主,而1999－2000年度轮状病毒流行季节中G3型为主,在连续两年的监测中出现轮状病毒血清型的转变。     

Genotypic linkages of VP4, VP6, VP7, NSP4, NSP5 genes of rotaviruses circulating among children with acute gastroenteritis in Thailand

Rotavirus is the main cause of acute viral gastroenteritis in infants and young children worldwide. Surveillance of group A rotavirus has been conducted in Chiang Mai, Thailand since 1987 up to 2004 and those studies revealed that group A rotavirus was responsible for about 20-61% of diarrheal diseases in hospitalized cases. In this study, we reported the continuing surveillance of group A rotavirus in 2005 and found that group A rotavirus was detected in 43 out of 147 (29.3%) stool samples. Five different G and P genotype combinations were detected, G1P[8] (27 strains), G2P[4] (12 strains), G9P[8] (2 strains), G3P[8] (1 strain), and G3P[10] (1 strain). In addition, analysis of their genotypic linkages of G (VP7), P (VP4), I (VP6), E (NSP4), and H (NSP5) genotypes demonstrated that the rotaviruses circulating in Chiang Mai, Thailand carried 3 unique linkage patterns. The G1P[8], G3P[8], and G9P[8] strains carried their VP6, NSP4, NSP5 genotypes of I1, E1, H1, respectively. The G2P[4] strains were linked with I2, E2, H2 genotypes, while an uncommon G3P[10] genotype carried unique genotypes of I8, E3 and H6. These findings provide the overall picture of genotypic linkage data of rotavirus strains circulating in Chiang Mai, Thailand.     

Diversity in VP3, NSP3, and NSP4 of rotavirus B detected from Japanese cattle

Bovine rotavirus B (RVB) is an etiological agent of diarrhea mostly in adult cattle. Currently, a few sequences of viral protein (VP)1, 2, 4, 6, and 7 and nonstructural protein (NSP)1, 2, and 5 of bovine RVB are available in the DDBJ/EMBL/GenBank databases, and none have been reported for VP3, NSP3, and NSP4. In order to fill this gap in the genetic characterization of bovine RVB strains, we used a metagenomics approach and sequenced and analyzed the complete coding sequences (CDS) of VP3, NSP3, and NSP4 genes, as well as the partial or complete CDS of other genes of RVBs detected from Japanese cattle. VP3, NSP3, and NSP4 of bovine RVBs shared low nucleotide sequence identities (63.3–64.9% for VP3, 65.9–68.2% for NSP3, and 52.6–56.2% for NSP4) with those of murine, human, and porcine RVBs, suggesting that bovine RVBs belong to a novel genotype. Furthermore, significantly low amino acid sequence identities were observed for NSP4 (36.1–39.3%) between bovine RVBs and the RVBs of other species. In contrast, hydrophobic plot analysis of NSP4 revealed profiles similar to those of RVBs of other species and rotavirus A (RVA) strains. Phylogenetic analyses of all gene segments revealed that bovine RVB strains formed a cluster that branched distantly from other RVBs. These results suggest that bovine RVBs have evolved independently from other RVBs but in a similar manner to other rotaviruses. These findings provide insights into the evolution and diversity of RVB strains.     

Evidence of discordant genetic linkage in the VP4, VP6, VP7 and NSP4 encoding genes of rotavirus strains from adolescent and adult patients with acute gastroenteritis

The vast diversity within rotavirus strains circulating in the developing countries continues to be a major challenge for the efficacy of currently used preset rotavirus vaccines. The sequence analysis and phylogeny of multiple genes of rotavirus strains enable identification of reassortant strains and their human or animal origin. The objective of this study was to monitor the genetic linkage between the rotavirus VP4(P), VP6(I), VP7(G) and NSP4(E) encoding genes. The G, P, I and E genotypes of a total of 80 rotavirus strains isolated from adolescent and adult cases of acute gastroenteritis at the two time points [1993–1996 (n = 67) and 2004–2007 (n = 13)] were determined by nucleotide sequencing and phylogenetic analysis. The rotavirus strains from the 1990s and 2000s revealed common combinations of genotypes (G1–P[8]–I1–E1, G2–P[4]–I2–E2, G3–P[8]–I1–E1 and G4–P[8]–I1–E1) in 47.8% and 30.8%, unusual combinations of the same genotypes (G2–P[8]–I2–E2, G9–P[6]–I1–E1, G9–P[6]–I1–E2, G9–P[6]–I2–E1 and G4–P[4]–I1–E2, G1–P[4]–I2–E1, G9–P[4]–I1–E1) in 7.5% and 23% and mixed infections of different G and P genotypes in 31.3% and 46.2%, respectively. Discordance in the association of I with E, G with I and E and P with I and E genotypes was found to be contributed respectively by 23.8–38.5%, 40.3–69.8% and 49.3–61.5% of the rotavirus strains at the two time points.The data suggest relatively high occurrence of intergenogroup reassortment in circulating rotavirus strains emphasizing the need for continuous surveillance and whole genome sequence based characterization of rotavirus strains for better understanding of their evolution and ecology.     

Diversity of human rotavirus VP6, VP7, and VP4 in Lagos State,Nigeria

This study investigated the diversity of rotavirus strains recovered from young children in Lagos, Nigeria, during December 1996-January 1997. In total, 287 children, aged 1-60 month(s), presenting with diarrhoea to the Gbaja Health Centre of Massey Street Children Hospital and the Lagos University Teaching Hospital, were included in the study. Rotavirus-positive specimens were characterized by monoclonal antibody enzyme-linked immunosorbent assay (ELISA) for VP6 subgroup and VP7 serotype and by polymerase chain reaction (PCR) for VP4 genotype and VP7 strains (that were non-reactive to ELISA). Of 84 samples tested for VP6 subgroup epitope, subgroup II was predominant (51%) with only a few subgroup I strains (4%), while many could not be typed at all (45%). For the VP7 serotypes, G1 was the most prevalent strain (45%), followed by G3 strains (5%). Neither G2 nor G4 strains were found, although mixed G1/G2 has been reported for the first time in Nigeria. Of strains that were non-reactive to ELISA, 29 (34%) could not be typed by PCR for G type. A subset of 23 samples was selected on the basis of RNA electropherotype, VP7 serotype, and included nine strains of VP7 that were non-reactive to ELISA. VP4 genotype of this subset was determined by PCR, and the most prevalent genotype was P[6] (30%), followed by P[8] (26%). Only one P[4] strain was identified. This study has shown the diversity of rotavirus strains circulating in West Africa.     

Identification of a multi-reassortant G12P[9] rotavirus with novel VP1, VP2, VP3 and NSP2 genotypes in a child with acute gastroenteritis

The G12 rotavirus genotype is globally emerging to cause severe gastroenteritis in children. Common G12 rotaviruses have either a Wa-like or DS-1-like genome constellation, while some G12 strains may have unusual genome composition. In this study, we determined the full-genome sequence of a G12P[9] strain (ME848/12) detected in a child hospitalized with acute gastroenteritis in Italy in 2012. Strain ME848/12 showed a complex genetic constellation (G12-P[9]-I17-R12-C12-M11-A12-N12-T7-E6-H2), likely derived from multiple reassortment events, with the VP1, VP2, VP3 and NSP2 genes being established as novel genotypes R12, C12, M11 and N12, respectively. Gathering sequence data on human and animal rotaviruses is important to trace the complex evolutionary history of atypical RVAs.     

Rotavirus enterotoxin NSP4 has mucosal adjuvant properties

Rotavirus nonstructural protein 4 (NSP4) is a protein with pleiotropic properties. It functions in rotavirus morphogenesis, pathogenesis, and is the first described viral enterotoxin. Since many bacterial toxins function as potent mucosal adjuvants, we evaluated whether baculovirus-expressed recombinant simian rotavirus SA11 NSP4 possesses adjuvant activity by co-administering NSP4 with keyhole limpet hemocyanin (KLH), tetanus toxoid (TT) or ovalbumin (OVA) as model antigens in mice. Following intranasal immunization, NSP4 significantly enhanced both systemic and mucosal immune responses to model immunogens, as compared to the control group, in an antigen-specific manner. Both full-length and a cleavage product of SA11 NSP4 had adjuvant activity, localizing this activity to the C-terminus of the protein. NSP4 forms from virulent and avirulent porcine rotavirus OSU strain, and SA11 NSP4 localized within a 2/6-virus-like particle (VLP) also exhibited adjuvant effects. These studies suggest that the rotavirus enterotoxin NSP4 can function as an adjuvant to enhance immune responses for a co-administered antigen.     

Sequence and phylogenetic analysis of the VP6 and NSP4 genes of human rotavirus strains: Evidence of discordance in their genetic linkage

NSP4 and VP6 genes of a total of 118 rotavirus strains detected in adolescent and adult cases of acute gastroenteritis (AGE) in 1993–1996 and 2004–2007 were characterized to determine their diversity and genetic linkage. Eighty-two percent and 89% of the strains showed amplification of NSP4 and VP6 genes respectively in RT-PCR. Sequencing and phylogenetic analysis of the VP6 genes showed distribution of genogroups in the lineages I-1 (1.4%), I-2 (50.7%) and II-4 (47.9%) in the 1990s and I-2 (73.5%) and II-4 (26.5%) in 2000s, indicating diversity in genogroups at both time points. Amino acid divergence within the genogroup II strains from 1990s and genogroup I strains from the 2000s was noteworthy (4.7–6.7%). Sequencing and phylogenetic analysis of the NSP4 genes showed almost equal distribution (45.0–55.0%) of genotypes A and B however, higher amino acid divergence within the genotype B strains (up to 9.3%) than in genotype A strains (up to 2.9%) at the two-time points. Nearly 70% of the strains showed NSP4-A–VP6-I or NSP4-B–VP6-II genetic linkage. The discordance in the linkage noted in 29.7% of the strains was predominated by NSP4-B and VP6-I combination and appeared strikingly high in the infections caused by unusual and mixed rotavirus strains. This is the first report to describe the phylogenetic analysis of rotavirus NSP4 and VP6 genes and their discordance in adolescent and adult cases with AGE from India. The extensive diversity within the rotavirus genes and their relationship revealed by this study emphasizes the need for evaluation of the rotavirus vaccines being used currently.