Use of electrophoresis of RNA from human rotavirus to establish the identity of strains involved in outbreaks in a tertiary care nursery

During two nosocomial outbreaks in a tertiary care nursery, 22 of 102 infants had infections due to human rotavirus (HRV). The time sequence and proximity of the infected infants in the nursery rooms had suggested infant-to-infant spread of a single HRV strain in each outbreak. Polyacrylamide gel electrophoresis of virus permitted demonstration of four different HRV electropherotypes (strains) during the first outbreak period and seven during the second. One of the strains was detected during both outbreaks. All strains had fast-migrating RNA segments 10 and 11. Infant-to-infant spread of at least two different viruses apparently occurred in each outbreak period. Thus, electrophoretic analysis showed that infants in a tertiary care center can be infected with at least 10 different HRV strains within two months, that multiple HRV strains can spread independently and in parallel to different infants as part of a "single" outbreak, and that secondary spread of individual strains can be traced with considerable accuracy.     

An outbreak of gastroenteritis associated with acute rotaviral infection in schoolchildren

In April 1988 a large outbreak of group C rotavirus infection associated with acute gastroenteritis occurred among schoolchildren and their teachers simultaneously at seven elementary schools in Fukui city, Japan. Of 3,102, 675 (21.8%) became ill. Clinical symptoms were mild, predominantly abdominal pain and vomiting, with diarrhea reported in only 27.6%. The outbreak subsided within 2 d. No pathogenic bacteria were found in fecal specimens; the virus particles detected by electron microscopy were morphologically indistinguishable from conventional infantile rotavirus. Immune electron microscopy showed that these virions formed large aggregates with convalescent serum and with the reference serum specific to group C rotavirus. Polyacrylamide gel electrophoresis showed similar RNA patterns for virus from this outbreak and typical group C rotavirus.     

Rotavirus antigenemia in patients with acute gastroenteritis

Although rotavirus infections are generally considered to be confined to the intestine, recent reports suggest that extraintestinal disease occurs. We studied whether rotavirus infection was associated with antigenemia during a major outbreak of gastroenteritis in the Kingston metropolitan area, during July-August 2003. Rotavirus antigen was identified in 30 of 70 acute-phase serum samples (including from 2 deceased individuals) but in only 1 of 53 control samples. Serum antigen levels were inversely associated with time since symptom onset and were directly associated with antigen levels in stool (P = .02). Serum antigen levels were significantly elevated during primary infections (acute-phase serum immunoglobulin G [IgG] titers, <25), compared with those in subsequent infections (acute-phase serum IgG titers, > or = 25) (P = .02). Antigenemia was common in this outbreak and might provide a mechanism to help explain rare but well-documented reports of findings of extraintestinal rotavirus. In situations in which stool samples are not readily available (i.e., patients with severe dehydration or those recently recovered or deceased), serum testing by enzyme immunoassay offers a new and practical diagnostic tool.     

An outbreak of rotavirus infection among adults in an institution for rehabilitation: long-term residence in a closed community as a risk factor for rotavirus illness

An outbreak of group A rotavirus infection resulted in gastroenteritis among disabled adults in an isolated rehabilitation institution in Kobe, Japan. Of the 95 residents, 16 were diagnosed with rotavirus illness. The causative agent was a single strain of typical human group A rotavirus belonging to VP7 serotype G2, VP4 genotype P[4], and NSP4 genotype A. Mean duration of stay was significantly longer for residents with rotavirus illness (22.1+/-11.8 years) than for residents without the disease (13.5+/-10.6 years; P=0.01). Age, sex, disability and location of resident rooms displayed no significant relationships with illness. These observations suggest that long-term residence in a closed community, which might be related to absence of immuno-stimulation, represents a risk factor for rotavirus illness.     

Two sequential outbreaks of rotavirus gastroenteritis: evidence for symptomatic and asymptomatic reinfections

In two sequential outbreaks of rotavirus gastroenteritis that occurred in a kibbutz in southern Israel (the Negev), 32 persons (9% of the population) were ill in the first and 45 (13% of the population) in the second. Excretion of virus, changes in titers of rotavirus-specific serum IgG, or both implicated rotavirus in 72% of the illnesses in outbreak 1 and in 56% of the illnesses in outbreak 2. In both outbreaks the age-specific morbidity rate decreased with increasing age. Half (six of 12) of the children six to 27 months of age who were ill with rotavirus in outbreak 1 were ill with rotavirus again in outbreak 2, whereas two were asymptomatically infected; older children who were ill in outbreak 1 were not ill in outbreak 2. Serotype determination by enzyme-linked immunosorbent assay using monoclonal antibodies to VP7 implicated a serotype 3 virus in outbreak 1 and a serotype 1 virus in outbreak 2.     

Rotavirus infections in newborns: an epidemiological and clinical study

An outbreak of rotavirus infections among newborns at Karolinska Hospital, Stockholm, which has been going on for greater than 2 years has been followed with clinical and epidemiological investigations. About one third of the babies born in the hospital were infected at the age of 3 days. The clinical symptoms were mild, 8.8% of the rotavirus positive babies had loose stools compared to 1.9% of those who did not excrete the virus. An epidemiological survey in the neonatal intensive care unit suggested that rotavirus was introduced into the unit by babies admitted from the obstetric wards. The main reservoir of rotavirus was the babies and rotavirus was not found among staff or mothers. In the beginning hygienic measures seemed to be effective but after some weeks the colonization rate again increased. Electropherotyping of samples collected during different periods showed that one single rotavirus electropherotype belonging to the subgroup 1 of human rotavirus was found throughout the outbreak.     

An epidemic of rotavirus-associated gastroenteritis in a nursing home for the elderly

92 cases of acute gastroenteritis were registered among 256 individuals during an outbreak in a nursing home for the elderly, the majority of patients being between 70 and 90 years of age. Most cases appeared in 4 of the 8 wards; 66% of the inmates of these wards became ill. Characteristic symptoms were initial nausea and vomiting followed by diarrhoea and low fever. A number of patients were severely ill. One patient died. Rotavirus infection was diagnosed by virus detection and/or antibody titre rise during the acute phase of the illness in 13 of 16 patients examined. At the end of the outbreak, high titres of complement-fixing antibodies against rotavirus (greater than or equal to 64) were detected in serum from 21/22 patients convalescing from the disease, as compared to only 5/45 individuals with no signs of disease. It is tentatively suggested that the outbreak became extensive and rather severe because of lowered immunity against rotavirus infection among the elderly.     

Immune protection of infants against rotavirus gastroenteritis by a serotype 1 reassortant of bovine rotavirus WC3

The safety and protective efficacy of a serotype 1 reassortant of bovine rotavirus WC3, disignated strain WI79-9, was evaluated in a double-blind placebo-controlled trial. Rotavirus reassortant WI79-9 contains a gene segment 9 coding for the surface structural protein vp7 of a human serotype 1 rotavirus, with all other gene segments derived from WC3 rotavirus, which had previously been shown to be safe and immunogenic in infants. Infants 2-11 months of age were given two doses of vaccine (10(7.3) plaque-forming units/dose) or of placebo 28 days apart. Adverse reactions to the vaccine were not detected. The incidence of serum plaque reduction neutralization antibody responses to two doses of vaccine was serotype 6, 97%; serotype 3, 68%; and serotype 1, 22%. Active surveillance during the subsequent rotavirus season revealed 8 cases of rotavirus gastroenteritis in 39 placebo control infants and no cases in 38 WI79-9 vaccine recipients (protection = 100%, P = .003). Six cases of rotavirus gastroenteritis were caused by type 1 and two by type 3 virus. Although vaccination with WI79-9 affected only the incidence of rotavirus gastroenteritis, the vaccinated infants exhibited a significantly reduced incidence of total days of diarrhea, fever, and illness associated with gastroenteritis in general.     

Nosocomial conjunctivitis caused by adenovirus type 4

An outbreak of conjunctivitis caused by adenovirus type 4 (AV 4) occurred in hospital personnel who had contact with a patient with AV 4 pneumonia. Nine ill individuals were identified. AV 4 infection was demonstrated in all by isolation of AV 4 and/or a fourfold or greater rise in serum titer of specific neutralizing antibody. The incubation period was seven to 10 days, and the illness lasted five to seven days. Infectious virus was regularly present in the affected eyes for one week but not usually for more than 10 days after the onset of symptoms. Visual disturbance persisted for at least five months in one patient, who developed subepithelial deposits. The outbreak occurred after isolation procedures were abandoned in the care of the patient. No secondary case appeared. Isolation of patients with adenovirus pneumonia and barrier nursing are recommended as practical means of preventing nosocomial adenoviral infection and its consequences.     

Uncontrolled nosocomial rotavirus transmission during a community outbreak

Between Jan. 11 and March 31, 1983, 60 pediatric patients were diagnosed with rotavirus gastroenteritis. Of these cases 24 were community acquired, 29 were nosocomial, and 7 were of undetermined origin. Despite intensive infection control efforts, nosocomial transmission continued as long as patients with community-acquired cases were admitted. The use of disinfectants and germicides that were ineffective against rotavirus may have contributed to the continued nosocomial spread during a community outbreak.     

Rescue of noncultivatable human rotavirus by gene reassortment during mixed infection with ts mutants of a cultivatable bovine rotavirus.

Fastidious human rotaviruses that did not undergo productive infection in tissue culture were rescued by genetic reassortment during mixed infection with a temperature-sensitive (ts) mutant of a cultivatable bovine rotavirus. In this manner, the genes of the fastidious rotavirus that restricted growth in vitro were replaced by the corresponding genes from a tissue culture-adapted rotavirus. We recovered genetically reassorted viruses that grew to high titer and were neutralized specifically by hyperimmune guinea pig type 1 or type 2 human rotavirus antiserum. Preliminary RNA analysis of these clones disclosed that they were indeed viruses with reassorted genes.     

Rotavirus infection in elderly patients

In the course of an outbreak of non-bacterial diarrhoea in a group of elderly patients in a rehabilitation ward, rotavirus was detected by electron-microscopy in five of 11 stool specimens (45.5%) from symptomatic elderly patients. This suggests that although rotavirus is usually thought of as a cause of gastro-enteritis in children it should also be considered as a cause of non-bacterial diarrhoea in elderly patients and stool specimens examined for its presence. Rotavirus gastro-enteritis appears to be a highly contagious disease but appropriate measures can limit its spread.     

Human-rhesus reassortant rotavirus vaccines: safety and immunogenicity in adults, infants, and children

Human-rhesus reassortant rotavirus vaccines derived from rhesus rotavirus and human rotavirus serotypes 1, 2, or 4 were administered to adults, children, and infants after they had been given sodium bicarbonate buffer. Over 70% of infants and children developed antibody responses to or shed the candidate vaccine viruses. Individuals with prevaccination serum neutralization antibody titers less than or equal to 1:160 had significantly (P less than .0001) higher response rates than did individuals with prevaccination titers greater than or equal to 1:320. Similarly, shedding of vaccine viruses occurred significantly (P = .03) more often in children than adults and was inversely correlated with prevaccination antibody titers. No illnesses were observed in adults, and the vaccines were well tolerated in children. An increased rate of low-grade, transient fever (38.0-38.8 C) was noted only in children given serotype 2 vaccine, compared with controls (P = .006). No significant differences in the average number of unformed stools passed during the seven days after vaccination were noted in vaccinees versus controls. These vaccine strains are currently undergoing further evaluation in expanded clinical trials.     

Incidence and genetic diversity of group C rotavirus among adults

Fecal samples from a 1-year prospective study were investigated to establish the role of group C rotavirus infections in acute diarrhea in Swedish adults (>15 years old). Rotaviruses were found in samples from 3% of the patients, and, in 35% of these, group C rotavirus was detected. Clinical symptoms of group C rotavirus infection were generally milder than those of group A rotavirus infection. Gene 8 (vp7) from 12 group C isolates, including strains from the prospective study, a military outbreak, and a sporadic case, was sequenced. The gene was found to be extremely conserved, with identities of 99.1%-100% at the amino acid level. This study has systematically investigated the prevalence and genetic diversity of group C rotavirus in adults. The data confirm the extreme sequence conservation within human group C rotavirus strains and suggest that symptomatic group C rotavirus infections occur more frequently in adults than has been previously recognized.     

Genomic epidemiology of the Escherichia coli O104:H4 outbreaks in Europe, 2011

The degree to which molecular epidemiology reveals information about the sources and transmission patterns of an outbreak depends on the resolution of the technology used and the samples studied. Isolates of Escherichia coli O104:H4 from the outbreak centered in Germany in May-July 2011, and the much smaller outbreak in southwest France in June 2011, were indistinguishable by standard tests. We report a molecular epidemiological analysis using multiplatform whole-genome sequencing and analysis of multiple isolates from the German and French outbreaks. Isolates from the German outbreak showed remarkably little diversity, with only two single nucleotide polymorphisms (SNPs) found in isolates from four individuals. Surprisingly, we found much greater diversity (19 SNPs) in isolates from seven individuals infected in the French outbreak. The German isolates form a clade within the more diverse French outbreak strains. Moreover, five isolates derived from a single infected individual from the French outbreak had extremely limited diversity. The striking difference in diversity between the German and French outbreak samples is consistent with several hypotheses, including a bottleneck that purged diversity in the German isolates, variation in mutation rates in the two E. coli outbreak populations, or uneven distribution of diversity in the seed populations that led to each outbreak.     

Conservation of amino acid sequence of VP8 and cleavage region of 84-kDa outer capsid protein among rotaviruses recovered from asymptomatic neonatal infection.

Within the past few years, rotavirus strains were recovered from four discrete prolonged outbreaks of infection in newborn nurseries in which affected infants failed to develop significant symptoms. The virus strains recovered from each outbreak belonged to a different human rotavirus serotype and thus each of the four human rotavirus serotypes was associated with asymptomatic infection of neonates. Marked conservation of sequence was observed among the fourth genes of the nursery rotavirus strains in a previous study using RNA X RNA hybridization, while a different conserved set of fourth gene sequences was identified among virulent human rotaviruses representing the four known serotypes. In the present study, this sequence dimorphism was further evaluated by comparing the sequence of the region of the fourth gene of virulent and asymptomatic human rotaviruses that codes for the VP8 protein, downstream cleavage sites, and the NH2 terminus of VP5. The corresponding sequences of a simian rotavirus were also determined. The fourth segment (+) strand RNA has a 5' conserved nontranslated sequence of nine nucleotides and encodes a VP8 protein of 240 amino acids in human rotavirus strains and 241 amino acids in simian rotavirus strains. Human and simian rotaviruses exhibit many similarities in this region of their genome, including identical NH2-terminal amino acid sequences, conservation of arginine at the two trypsin cleavage sites, and the position of a cysteine residue. Alignment of amino acid sequences of the VP8 protein, the downstream cleavage region, and the NH2 terminus of VP5 of asymptomatic and virulent human rotavirus strains indicates a high degree of homology (96% or more) among the asymptomatic viruses (serotypes 1, 2, 3, and 4), while homology between asymptomatic strains and virulent viruses is considerably less (68-72%). A high degree of conservation of amino acid sequence (92-97%) is also observed among three of the virulent strains (serotypes 1, 3, and 4). At 48 positions in the protein sequence of VP8, the cleavage region, and the NH2 terminus of VP5, an amino acid is conserved among asymptomatic rotaviruses, while a different amino acid is conserved among virulent rotaviruses. Notably, three of these differences are located within the cleavage region between VP8 and VP5. These findings suggest that the fourth genes of virulent and asymptomatic human rotavirus strains represent two lines of divergent evolution from a common ancestor. Also, it is possible that this sequence dimorphism may be responsible in part for the difference in virulence between these two groups of human rotaviruses.     

2019-2020年湖北部分地区G9P[8]型人轮状病毒基因特征北大核心CSCD

目的对人A组轮状病毒进行检测及分离鉴定,并研究其各基因片段的遗传进化关系。方法2019-2020年对湖北武汉市和襄阳市临床腹泻病人的粪便样品进行采集,共319份。设计特异性轮状病毒VP6基因引物,RT-PCR检测轮状病毒的感染情况。将阳性样品接种于MA104细胞进行轮状病毒的分离。RT-PCR特异性扩增VP6基因和特异性间接免疫荧光对其进行病毒鉴定及病毒增殖检测;并进一步通过RT-PCR扩增轮状病毒的11个基因片段,在线工具Rota C V2.0对测序结果进行分型分析。Mega软件对其全基因组序列进行遗传进化分析。结果轮状病毒感染阳性标本共69份,阳性率为21.63%。成功分离获得11株人轮状病毒,主要衣壳蛋白VP7和VP4基因型均为G9P[8]型。其中3株轮状病毒归属于类Wa株毒株,基因型图谱为G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1。8株毒株在Wa-like的基因型中具有DS-1-like的NSP4为E2基因型特征。基因型图谱为G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1。结论G9P[8]型人轮状病毒毒株在2019-2020年湖北部分地区占主导趋势,且其NSP4基因以E2基因型为主要流行形式。     

Clinical and immunological studies of rotavirus vaccines

The RIT 4237 bovine rotavirus vaccine has served as a useful model for rotavirus vaccination, but the vaccine will not be further developed or tested. The main problem encountered with this vaccine was its poor "take" rate in developing countries. The reasons for this are unclear, and it is not known whether other bovine rotavirus vaccines are more efficacious in this respect. WC-3 bovine rotavirus vaccine will shortly be tested at several sites in developing countries. The rhesus rotavirus vaccine RRV-1 does not appear by itself to be a practical vaccine either. It has induced only moderate protection against human rotavirus serotypes other than the vaccine type. However, the fact that RRV-1 vaccine has induced substantial protection against severe diarrhoea caused by serotype 3 rotavirus, even in young infants, is promising and supports the concept that serotype-specific neutralizing antibodies play a role in protection against human rotavirus disease. Based on this concept, it has been possible to develop reassortant rhesus rotaviruses in which one RNA segment of human rotavirus, which encodes the expression of VP7 antigen, has been incorporated (Kapikian et al., 1986; 1987). Such rhesus-human reassortant rotaviruses, representing serotypes 1, 2 and 4 of human rotavirus and serotype 3 of rhesus rotavirus, can be combined to make a tetravalent vaccine that might induce neutralizing antibodies against each of the main serotypes of human rotavirus. Although its efficacy is unproven, such a combination vaccine is presently regarded as the most promising candidate rotavirus vaccine for the prevention of human rotavirus disease.