Human immunodeficiency virus

Infection of enterocytes by HIV is well documented and has been implicated as the cause of so-called HIV enteropathy, where both morphological and functional abnormalities of the gut have been described in the absence of any other detectable pathogen (Bartlett et al 1992, Ullrich et al 1989). The clinical importance of HIV enteropathy is probably limited certainly, 'pathogen-negative' diarrhoea is comparatively short-lived and associated with a good prognosis (Blanshard & Gazzard 1995).

Discussion

Desselberger You talked of genotypes, clades and lineages could you clarify what you mean exactly by these terms Koopmans For genotype, I like to use an arbitrary definition of genotype, which is 80 amino acid diversity of the complete capsid sequence. I don't use 'clades', but David Matson may be able to clarify the meaning of this term. Matson The issue is a bit complex. 'Clade' is a more generic term. A 'genotype' is a specific term that we sometimes use when we can't use 'serotype' it is a...

What the future will hold

The discovery of many novel viral agents of gastroenteritis has allowed us to consider the role that each may play in endemic disease of children and in outbreaks. For children, rotavirus emerges as the most common cause of severe gastroenteritis and has become the target for prevention and control with vaccines. So far, the other common pathogens of children astroviruses, enteric adenoviruses and caliciviruses appear to cause illness that is either less common or less severe. Consequently,...

Other enteric viruses

Several other enteric viruses have been associated with HIV-related diarrhoea. Grohmann et al (1993) carefully examined stool specimens from patients with diarrhoea and control patients without diarrhoea. Samples were examined by electron microscopy, PAGE and enzyme immunoassay (EIA) for rotavirus, adenovirus, calicivirus and picobirnavirus. Paired sera were also analysed for antibodies to Norwalk and picobirnavirus. Overall, virus was detected in 35 of patients with diarrhoea and 12 without...

G9 rotaviruses

Human G9 rotavirus strains were first detected in the USA in 1983 and then a decade later in the USA and Bangladesh as epidemic strains (Ramachandran et al 1998, Unicomb et al 1999). They were first detected in the UK in 1995 96, carrying a P 6 VP4 (Table 4 Iturriza-Gomara et al 2000c, Cubitt et al 2000). Those strains decreased in incidence towards 1997 98 but seemed to be replaced by G9P 8 strains. It is likely that the P 8 gene has been picked up by natural reassortment with the...

Other rotavirus vaccines

A presentation on rotavirus vaccines would not be complete if it did not consider the prospects for other rotavirus vaccines that may fill the void left by the withdrawal of the rhesus rotavirus-based vaccine. Table 2 summarizes the status of the various rotavirus vaccines that have been evaluated in efficacy trials in infants and young children. Evaluation of monovalent bovine or rhesus rotavirus vaccine has been discontinued because of the variable efficacy of these immunogens. The...

References

Appleton H, Higgins PG 1975 Viruses and gastroenteritis in infants. Lancet 1 1297 Bishop RF, Davidson GP, Holmes IH, Ruck BJ 1973 Virus particles in epithelial cells of duodenal mucosa from children with acute non-bacterial gastroenteritis. Lancet 2 1281 1283 Chiba S, Estes MK, Nakata S, Calisher CH (eds) 1997 Viral Gastroenteritis. Arch Virol 142(supplement 12) 1 311 Ciba Foundation 1976 Acute diarrhoea in childhood (Ciba Found Symp 42). Elsevier Excerpta Medica North Holland, Amsterdam Ciba...

Genetic diversity of strains recovered from humans

We have used the POL-based genotyping method since 1994 for typing of outbreak strains and since May 1996 for typing of strains from sporadic cases from the epidemiological studies. In these years we have observed that genogroup (GG) II strains by far outnumber the GGI strains, although the TABLE 5 Distribution of GGI and GGII strains from 1996-1999 as detected in outbreaks or in population-based studies, and number of different genotypes detected per year for the different study populations...

A

I Case-control 1 21 00 888 AR 22 or 10 MCOs 4 11 00 326 , AR 8e or 10 MCOs 4 11 00 326 , AR 8e or Total background and vaccine related cases projected annually per 100,000 infants < 12 months of age. Date of CDC presentation of study, cpp _ F3sldtiv6 risk dExcess cases projected annually for entire U.S. cohort of estimated 4 million infants < 12 months of age. ePer 100,000 vaccinees. Total background and vaccine related cases projected annually per 100,000 infants < 12 months of age. Date...

Genotyping as a tool for molecular epidemiological studies

In the absence of an in vitro culture system for these viruses, antigenic typing has been limited to studies with solid-phase immune EM (SPIEM), and more recently with recombinant capsid protein-based ELISA (Lewis et al 1995, Jiang et al 1996). Clearly, the human caliciviruses are antigenically quite variable, but little is known about the role of this variability in their epidemiology, e.g. are there differences in virulence or transmissibility, are certain variants associated with specific...

Ethical considerations for developing countries

A meeting at the WHO in Geneva, 9 11 February 2000, considered the future directions for rotavirus vaccine research in developing countries (World Health Organization 2000). Ethical considerations were a feature of this meeting. Some of the issues that were addressed in this regard included whether a vaccine withdrawn from the US market could be used in developing countries. Should testing a vaccine with known adverse risks that can be fatal be supported What safeguards would be necessary Was...

Unresolved issues regarding rotavirus vaccine and intussusception

The CDC data regarding the clustering of cases particularly during the first week after the first dose of vaccine are significant and important, and this needs to be studied further. However, the key question that has even greater public health importance and which has not been answered satisfactorily relates to the attributable risk, if any, of RRV-TV among the one million infants who were vaccinated. How many cases of intussusception did the RRV-TV vaccine cause in excess of the background...

General discussion I

Desselberger It has already been mentioned that there is no reverse genetics system for rotaviruses. On the other hand, we have had fascinating insights from John Patton into the replication of rotavirus. Why do you think that a reverse genetics system for rotaviruses has not yet been established Patton Development of a reverse genetics system has been complicated by both the lack of fundamental information on how rotaviruses package and replicate their genomes and technical difficulties in...

Multiplicity of rotavirus receptors

Despite the advances in the molecular and structural biology of these viruses, little is known about the rotavirus cell receptors. A number of glycoconjugates have been shown to bind to, and to block the infectivity of, SA-dependent animal rotavirus strains, and some of them have been suggested to play a role as possible receptors, like GM3 gangliosides in newborn piglet intestine (Rolsma et al 1998), GM1 in LLC-MK2 cells (Superti & Donelli 1991), and 300-330 kDa glycoproteins in murine...

Pathogenesis of rotavirus gastroenteritis

Estes, Gagandeep Kang, Carl Q.-Y. Zeng, Sue E. Crawford and Max Ciarlet 'Division of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA Abstract. The outcome of intestinal infection with rotaviruses is more complex than initially appreciated, and it is affected by a complex interplay of host and viral factors. Rotaviruses infect intestinal enterocytes, and the early events in infection are mediated by virus epithelial cell interactions. Diarrhoea may...

Transmission dynamics

Although some of the genetic mechanisms underlying rotavirus diversity are known, the transmission dynamics of rotaviruses effecting this diversity in TABLE 5 G and P types of human rotavirus strains commonly found in animal rotavirus strains Cats, dogs, monkeys Pigs, horses Calves Nakagomi et al 1989 Arch. Virol. 106 145-150 Mochizuki et al 1997 J. Clin. Microbiol. 35 1272-1275 Gouvea & Santos 1999 Vaccine 17 1291-1292 Santos et al 1999 J. Clin. Microbiol. 37 2734-2736 Snodgrass et al 1990...

Was there an epidemic of intussusception because of vaccine use

Our initial doubts about the overall risk of this vaccine arose from evaluation of published data from CDC which failed to reveal a striking increase in the overall number of cases of intussusception that would have been anticipated from the extremely high odds ratios, noted above, that were presented for the first week following vaccination. For example, CDC reported the occurrence of three cases of intussusception in 9802 vaccinees in a California managed care study, which translated to an...

Detection of NLV and SLV by consensus RTPCR

Several groups have developed RT-PCR-based detection methods following the cloning of prototype NLV strains. The first round RT-PCR assays, however, were suboptimal, as they had been optimized using one or a few prototype strains (Moe et al 1994). When it became clear that NLVs were highly variable (Lew et al 1994, Green et al 1993, Wang et al 1994, Ando et al 1994), we developed a single-round generic NLV-specific primer pair by empirically selecting primers targeting a highly conserved region...

Biological features of the viruses

The viruses that cause gastroenteritis in humans represent an extraordinary diversity of organisms that have probably evolved over distinct and divergent pathways (Table 3). First, the recognized viruses belong in four different families that have as their most basic building blocks different nucleic acids blueprints DNA for the adenoviruses, positive sense single-stranded RNA for the caliciviruses and astroviruses, (and toroviruses and enteroviruses entero 22 ), and double-stranded RNA for the...

General discussion II

Matson I have a comment about heterotypic protection to rotavirus. We did a study in daycare centres where kids were monitored for two rotavirus seasons, with at least one weekly stool specimen (O'Ryan et al 1994). We only detected G1 and G3 viruses. Then we looked at the antibody levels using an epitope-specific antibody assay for G1 G4, and the monoclonals we used were neutralizing monoclonals used for typing. We found that as the children had an increasing number of infections, children...

Conclusion

CMV enterocolitis remains an important cause of AIDS-related diarrhoea. Fortunately, the introduction of HAART has dramatically reduced the morbidity and mortality associated with this disease. The role of non-CMV enteric infection in HIV-related diarrhoea remains uncertain with the possible exception of adenovirus infection. Conclusive evidence is unlikely to become available in the post-HAART era. Dr R.C.G. Pollok is a Wellcome Trust Research Fellow. References Albrecht H, Stellbrink HJ,...

The need for a rotavirus vaccine

Since the golden age of viral gastroenteritis commenced in the early 1970s, many viruses have been implicated as etiological agents of diarrhoeal illnesses. However, rotaviruses reign as the number one cause of severe diarrhoeal disease worldwide, surpassing the enteric adenoviruses, astroviruses, caliciviruses and bacterial agents. Thus, the need for a rotavirus vaccine is clear and compelling, with the goal being the prevention of severe rotavirus diarrhoea during the first two years of life...

Results and discussion

Rotavirus pathogenesis is complex and involves several mechanisms The outcome of an infection with rotavirus is clearly dependent on both host and viral factors, and these factors can affect one or more of the several stages of pathogenesis (Table 1). Host factors have been dissected by analysis of the outcome of infection in animals inoculated with well-defined viral strains. Both natural and experimental rotavirus infections are characterized by viral replication in enterocytes in the small...

Viruses

Chichester New York Weinheim Brisbane Singapore Toronto Copyright 2001 John Wiley & Sons Ltd Print ISBN 0-471-49663-4 elSBN 0-470-84653-4 Copyright Novartis Foundation 2001 Published in 2001 by John Wiley & Sons Ltd, Baffins Lane, Chichester, West Sussex P019 1UD, England National 01243779777 International (+44) 1243 779777 e-mail (for orders and customer service enquiries) cs-books wiley.co.uk Visit our Home Page on http www.wiley.co.uk or http www.wiley.com All Rights Reserved. No part...

Integrin mediates the cell attachment of the NAresistant RRV variant nar3

The initial interaction of nar3 with the cell surface is likely to be with integrin a2 1, through the DGE integrin binding domain present in VP5, since (i) antibodies to the a2 subunit reduce by 30 the infectivity of both wtRRV and nar3, but only block the cell attachment of nar3 (ii) MAbs to a2 block the attachment of the GST-VP5 fusion protein but not that of GST-VP8 (Fig. 3) (iii) GST-VP5 specifically displaces up to 75 of the cell binding of nar3, while a GST-VP5 mutant polypeptide in which...

A model for the early interactions of rotaviruses with MA104 cells

Rotavirus Vp4 Vp8 Vp5

As a summary of the data presented here, we propose the following working model (Fig. 5), which takes into account the currently available information (a) Wild type RRV interacts primarily with a SA-containing cell receptor through the VP8 domain of VP4. The identity of the SA-containing molecule has not been determined, although good candidates are ganglioside GM3 (Guo et al 1999, Rolsma et al 1998), or the SA present in the integrin molecules (see below). The SA-binding domain of VP8 is...

An

N-term NTPase 3A VPg Protease Polymerase Cap& id and 3' small ORF FIG. 2. Diagrammatic representation of the organization of ORFs in the two genera of human enteric caliciviruses. The 5' region of the genome encodes the viral non-structural proteins as part of a larger polyprotein precursor. The 3' region (subgenomic region) of the genome encodes the viral capsid structural protein and a 3'-terminal small basic protein of unknown function. otherwise antigenically indistinguishable from NV...

Adenovirus

Adenovirus has previously been reported to cause infection in other immuno-suppressed patient groups, including individuals with primary immunodeficiency and bone marrow transplant patients (Hierholzer 1992). Dionisio et al (1997) reported increasing stool carriage of subgenus F type 40 adenovirus with increasing immunosuppression amongst HIV patients. Adenovirus colitis was first described by Janoff et al (1991) in five HIV patients with diarrhoea. Adenovirus was identified by electron...

Animal rotaviruses

The diversity of co-circulating rotaviruses in any one region is mainly driven by a constant sequence of point mutations and reassortment events (see above). A further mechanism to explain the great variability of human isolates is the possible transmission to humans of animal rotaviruses, either as whole viruses (Das et al 1993) or by contributing individual genes in a reassortant event FIG. 2. Phylogenetic tree constructed from nt sequences of the VP7 gene (nt 417 784) of the rotavirus...

Astrovirus infectious RNA and a determinant of infectivity

We have demonstrated that RNA extracted from virions is infectious (Geigenmuller et al l997a). That is, when purified viral RNA is introduced into BHK cells by transfection, progeny virus particles are produced and can be used to infect Caco-2 cells, in the presence of trypsin, to levels comparable to wild-type. This two-step, two-cell-line procedure is necessary since BHK cells are easily transfectable and will support astrovirus infection once RNA is introduced into the cells, while Caco-2...

Conclusions

From the studies so far, caliciviruses are increasingly recognized as an important public health problem, with very high incidence rates in people of all age groups. By molecular epidemiological studies, we are now beginning to unravel the epidemiology of the different lineages of calicivirus. To advance our understanding of transmission routes and the mechanism behind the appearance of 'epidemic' strains a standardized international surveillance system is needed, which allows for rapid strain...

Contents

Symposium on Gastroenteritis Viruses, held at the Novartis Foundation, London, 16-18 May 2000 Editors Derek Chadwick (Organiser) and Jamie A. Goode This Symposium is based on aproposal made by Ulrich Desselberger Roger I. Glass, Joseph Bresee, Baoming Jiang, Jon Gentsch, Tamie Ando, Rebecca Fankhauser, Jacqueline Noel, Umesh Parashar, Blair Rosen and Stephan S. Monroe Gastroenteritis viruses an overview 5 Discussion 19 B. V.Venkataram Prasad, S. Crawford, J. A. Lawton, J. Pesavento, M. Hardy...

Epidemiology

In temperate climates rotavirus infections occur in strict seasonal peaks during late autumn winter spring (Brandt et al 1983, Haffejee 1995, Bishop 1996) whereas in subtropical and tropical regions rotavirus infections are more evenly spread (Cook et al 1990, Ahmed et al 1991). The winter spring outbreaks in infants and young children are based on a strong endemicity of the virus. Spread from West to East during a season has been observed in the USA (Anonymous 1997) and in Europe (Koopmans...

Genetic instability

At the first Calicivirus conference in Atlanta, USA, 1999, Dr Tamie Ando presented his analysis of currently used diagnostic RT-PCR primers and showed that the proportion of positives had gradually declined over the years, suggesting that the more recently detected caliciviruses were slightly different. In a similar analysis of our data, we have not observed such a decline, although the consensus sequence of Lordsdale-like strains found in 1999 differs by as much as 3 (nucleotides in polymerase...

H

L. 237 Holmes, K. V. 43, 60, 62, 63, 99, 194, 218, 253, 258, 269, 270, 271, 272,273, 274 Kang, G. 82 Kapikian, A. Z. 23, 44, 120, 121, 150,1S3, 173, 174,175,177,192, 251, 252, 255, 270, 271,274, 304 Kiang, D. 219 K pmans, M. P. 21, 38, 99,100,115,149, 150, 178,195,197, 214, 215, 216, 217, 245, 246, 247, 253, 256, 269, 272, 273, 285, 286, 287, 302

Integrin 3 functions as a coreceptor for rotaviruses

The relevance of 3 integrin for rotavirus infection was established by the fact that antibodies to this integrin subunit reduced by 50 the infectivity of RRV, nar3 and Wa rotaviruses. In accordance to this finding, when vitronectin, a 3 integrin ligand, was pre-incubated with cells, it specifically blocked rotavirus infectivity up to 70 (Guerrero et al 2000b). Since integrins a2 1, a4 1 and aX 2 have been suggested to play a role during rotavirus entry (Coulson et al 1997), we performed...

Infectious intestinal disease in The Netherlands

The epidemiology of NLV infections in people who are sufficiently ill to visit their physician has been assessed in a physician-based case-control study that started in May of 1996, and ended May 1999 (de Wit et al 1997, 2001). Cases and controls were recruited through physicians that participate in the NIVEL network, covering approximately 1 of the population of The Netherlands. Detailed questionnaires were used to establish risk factors for acquisition of infection with a broad range of...

Investigation of animal caliciviruses related to Norwalklike caliciviruses

Until recently, the NLVs were considered to be pathogens with humans as the sole host. However, recent publications from Japan and the UK reported the presence of NLVs in some pigs and in some historic stool samples from calves (Sugieda et al 1998, Liu et al 1999, Dastjerdi et al 1999). The calf viruses, named Newbury agent and Jena virus, had been shown to be pathogenic for young calves under FIG. 3. Distribution of genotypes of NLV in outbreaks of gastroenteritis reported to municipal health...

Molecular epidemiology of human astroviruses

Holmes*f and Gael M. Belliot* * Viral Gastroenteritis Section, 'Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, A tlanta, GA 30333, USA, f Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA, and A tlanta Research and Education Foundation, A tlanta, GA 30033, USA Abstract. Human astroviruses (HAstVs) are associated with 5 9 percent of cases of gastroenteritis in young...

Molecular epidemiology of human enteric caliciviruses in The Netherlands

Marion Koopmans, Jan Vinje, Erwin Duizer, Matty de Wit and Yvonne van Duijnhoven Research Laboratory for Infectious Diseases and Center for Infectious Diseases Epidemiology, National Institute of Public Health and the Environment, Bilthoven, The Netherlands .Abstract. Caliciviruses are among the most common causes of gastroenteritis in people of all age groups. These antigenetically and genetically diverse viruses have been grouped into two genera within the family Caliciviridae, designated...

Natural rotavirus infection induces protection against disease caused by reinfection but protection is often incomplete

Natural infection of newborns causes protection against moderate-to-severe, but not mild, disease caused by reinfection Evidence that natural rotavirus infection induces protection against disease caused by reinfection was provided first by Ruth Bishop and colleagues (Bishop et al TABLE 1 Capacity of rotavirus infection of newborns ( < 1 month of age) to protect against rotavirus disease associated with subsequent infection during childhood TABLE 1 Capacity of rotavirus infection of newborns...

Natural rotavirus infection induces protection against disease caused by reinfection but protection is often shortlived

Whereas children commonly develop symptomatic rotavirus infections with the same rotavirus serotype one year after a primary rotavirus infection, it is TABLE 3 Capacity of one, two or three natural rotavirus infections to protect against symptomatic reinfection TABLE 3 Capacity of one, two or three natural rotavirus infections to protect against symptomatic reinfection Protection against infection or disease( ) uncommon for children to be symptomatically infected with the same rotavirus...

Norwalklike viruses

The prototype virus for this genus is the Norwalk virus (NV), the first human virus to be described with an aetiological association with non-bacterial gastroenteritis (Kapikian et al 1972). The NV was the cause of an outbreak of gastroenteritis amongst adults and children in an elementary school in Norwalk, Ohio, USA. NV was visualized in human stool samples by immune electron microscopy using convalescent serum from a volunteer who had been experimentally infected with a faecal filtrate from...

Participants

Arias Instituto de Biotecnolog a, UNAM, Apt. Postal 510-3, Col. Miraval, Cuernavaca, Morelos 62250, Mexico Ruth Bishop Department of Gastroenterology and Clinical Nutrition, Royal Children's Hospital, Flemington Road, Melbourne, Victoria 3052, Australia David Brown Enteric and Respiratory Virus Laboratory, Central Public Health Laboratory, Public Health Laboratory Service, 61 Colindale Avenue, London NW9 5DF, UK Mike Carter School of Biological Sciences, University of Surrey,...

Recent advances in virion and genome structure

A great deal of progress has been made in the molecular characterization of the human caliciviruses over the past decade. The aetiological role of NLVs as the primary cause of adult viral gastroenteritis is established, furthermore NLVs are now recognized as the major cause of food-borne viral gastroenteritis. One of the major obstacles to research is the lack of a cell culture system, which has driven researchers to investigate other caliciviruses to study as model systems. In particular...

Sapporolike viruses

It is now clearly established that human enteric caliciviruses which display the classic surface structure have a fundamentally different genome organization to the NLVs (Liu et al 1995). They are also phylogenetically distinct from NLVs and have been assigned to a separate genus (Berke et al 1997, Noel et al 1997). The classic caliciviruses were first described in the UK (Madeley & Cosgrove 1976), but it was not until some years later that the prototype Sapporo virus was identified...

Sapporo London Parkville Genotypes

Distribution of genotypes of NLV (top) and SLV (bottom) in cases of gastroenteritis detected during a physician-based study in The Netherlands from 1996 1998. For genotype designations see Table 1. in the community study, as was noted earlier from Sweden and the UK, suggesting that these strains are less virulent (Vinje et al 2000a). In the near future we will analyse the epidemiological database in combination with genotyping information for such genotype-specific characteristics. The...

Rotavirus evolution

What are the explanations for this enormous diversity Rotaviruses evolve, in principle, by three different mechanisms point mutations, reassortment and intramolecular recombination (rearrangement). The point mutation rate of rotaviruses was measured in vitro and found to be approximately 5x10_5 per nucleotide site (Blackhall et al 1996), i.e. per replication of one genome (of approximately 18.55 kbp size) on average one mutation occurs. This mutation rate is in close agreement with that of...

Supportive interventions in acute diarrhoea

Fluid requirements change dramatically during the early neonatal period and through childhood into adult life (Fig. 1). Fluid requirements (related to body weight) are greatest during infancy and thus it is this period when the child is most susceptible to fluid losses. Dehydration is a state in which total body water is decreased and in acute diarrhoeal illnesses results from both (i) increased fluid losses from the gastrointestinal tract and when there is fever, increased insensible losses...

Subgenomic RNA s

Genome organization of human astrovirus serotype 1 (Oxford strain). Human astroviruses isolated directly in Caco-2 cells contain an additional 45 nt in ORF'la (Willcocks et al 1994b) at (Q). Initiation and termination codons are indicated by black arrowheads and asterisks, respectively. The first potential initiation codon in ORF'lb is shown by (A). The ribosomal frameshift signal located in the 70 nt overlap region between ORF'la and -lb is indicated by ( 2). Motifs, including the...

The molecular biology of human caliciviruses

Virus Group, Mailpoint 814, Division of Cell and Molecular Medicine, University of Southampton Medical School, Southampton S016 6YD, UK .Abstract. Within the last decade molecular analyses of the genome of Norwalk-like viruses (NLVs) have confirmed that this important group of infectious agents belongs to the Caliciviridae family. NLVs have a positive-sense, single-stranded RNA genome of approximately 7700 nucleotides excluding the polyadenylated tail. The genome encodes three open reading...

Viruses causing diarrhoea in AIDS

Digestive Disease Research Centre, St Bartholomew's & The Royal London School of Medicine andDentistry, Turner St, London E1 2AD, UK Abstract. Opportunistic viral enteritis is an important gastrointestinal manifestation of HIV related disease. Cytomegalovirus (CMV) is a well established aetiological agent of disease in the gastrointestinal tract in this group. CMV enteritis may affect any region of the bowel, most commonly the colon. Diagnosis and management of these infections may be...

Structural studies on gastroenteritis viruses

Crawfordf, J. A. Lawton*1, J. Pesavento*, M. Hardyf2, and M. K. Estesf * Verna and Maars McLean Department of Biochemistry and Molecular Biology, and f Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Pla a, Houston, TX 77030, USA A bstract. There are many recent advances in our understanding of the structure-function relationships in rotavirus, a major pathogen of infantile gastroenteritis, and Norwalk virus, a causative...

Caliciviruses

The application of electron microscopy to the examination of stool samples from patients with diarrhoeal disease resulted in the discovery of the viruses associated with gastroenteritis. Whilst rotaviruses and enteric adenoviruses have obvious and distinguishable morphological features there was considerable confusion about the role of 'small round viruses' found in stool samples from patients with nonbacterial gastroenteritis. An interim classification scheme described in 1982 FIG. 1. Electron...

The future of RRVTV

It is clear that the developing countries of the world will not use the rotavirus vaccine as long as the ACIP recommendation for its withdrawal remains in force. How can this barrier be removed There are three possible options that need consideration (i) a recommendation for routine use of the vaccine would remove the barrier, but the prospect of this option being selected is highly unlikely and appears not possible at present, based on the currently available data (ii) a 'permissive...

Rotavirus features relevant to vaccine development

Rotaviruses are 70 nm in diameter, non-enveloped and possess a distinctive double-shelled outer capsid. Within the inner shell is a third layer, the core, which contains the viral genome comprised of 11 segments of double-stranded (ds)RNA. During coinfection with different rotavirus strains, the segmented genomes readily undergo genetic reassortment. With regard to vaccine development, the two outer capsid proteins, VP4 and VP7, deserve special attention (Kapikian & Chanock 1996). VP7, a...

Rotavirus epidemiology and surveillance

Ulrich Desselberger, Miren Iturriza-Gomara and Jim J. Gray Clinical Microbiology and Public Health Laboratory, Addenbrooke's Hospital, Cambridge, CB22QW, UK Abstract. There is extensive antigenic and genomic diversity among co-circulating human rotaviruses. They are differentiated into groups, subgroups and types. There are at least 7 groups (A G) and 4 subgroups within group A. To distinguish types within group A, a dual classification system has been established with the glycoprotein VP7...

Gastrointestinal CMV infection

The pathogenic role of CMV infection is well established. Although retinitis is the most common manifestation of infection, GI infection of the oesophagus, stomach, small bowel and colon occurs in 5 15 of patients during the course of HIV infection (Jacobson & Mills 1988). Although CMV may infect any part of the GI tract the most common site of infection is the colon (Mentec et al 1994). The spectrum of symptomatology associated with CMV colitis is wide. Chronic or intermittent diarrhoea in...

Summary

New techniques for isolation in cell cultures of human enterotropic coronaviruses and toroviruses from diarrhoeal stools will elucidate the importance of these agents in human enteric diseases. Sensitive and specific diagnostic tests are becoming available to analyse the roles of these two types of viruses in human enteric diseases and to compare the viruses associated with different outbreaks of disease. Experiments that focus on the interactions between viral envelope glycoproteins and their...

Magnification of relative risk by comparing unequal groups

A greatly magnified rate ofintussusception for the vaccinated group was created by the 'window analysis' because CDC compared vastly unequal person-year values which artificially inflate the time denominator for the non-vaccinated group. In this way, the initial clustering of cases during the first week after vaccination is assumed to persist at the same elevated rate even though such data are not available, and were, in fact clearly ruled out. For example, in data presented by CDC at the...

Enteric nervous system

The effects of rotavirus infection on polarized epithelial cells. Data from Jourdan et al (1998), Brunet et al (2000), Lundgren et al (2000) and Obert et al (2000). in a neuraminidase-independent fashion infect polarized epithelial cells efficiently through both the apical and basolateral surfaces. Rotavirus strains whose infectivity is reduced by treatment of cells with neuraminidase (e.g. RRV, SA11, bovine NCDV, porcine OSU) only infect polarized epithelial cells efficiently through...

Molecular biology of astroviruses selected highlights

Matsui, David Kiang, Nancy Ginzton, Teri Chew and Ute Geigenmuller-Gnirke Department of Medicine, Division of Gastroenterology, Stanford University School of Medicine, Stanford, CA 94305-5487, and Veterans Affairs Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304, USA Abstract. Human astrovirus, the prototype of the Astroviridae family, is a non-enveloped positive-strand RNA virus with distinctive morphology. Initially named for a characteristic 5 6 point star...

Development of a reporter cell line for astrovirus detection

The CDC has identified as a priority the need for 'simple detection methods that are more sensitive and more specific than the current EIA' (Glass et al 1996). Such methods would permit larger scale epidemiological studies and improve understanding of astrovirus infection and immunity. To enhance detection of astrovirus, we propose development of a reporter cell line. Such cell lines have been described for several other viruses (Rocancourt et al 1990, Kimpton & Emerman 1992, Stabell &...

Wildtype rotavirus and intussusception

Because of the association of the vaccine with intussusception and its withdrawal from use, earlier studies that had examined the relationship between naturally occurring rotavirus infection and intussusception have taken on special importance. In 1978, in Japan, rotavirus was detected in stools of 11 (37 ) of 30 children (6 49 months old) with intussusception a serologic response was observed in five of seven rotavirus-positive children (Konno et al, 1978). It was concluded that human...

Enteric infections with coronaviruses and toroviruses

Department of Microbiology, B-175, University of Colorado health Sciences Center, 4200 East 9 th Avenue, Denver, CO 20862, USA Abstract. Many enteric viruses are difficult or impossible to propagate in tissue culture. Coronaviruses and toroviruses are large, enveloped, plus-strand RNA viruses in the order Nidovirales that cause enteric disease in young pigs, cows, dogs, mice, cats and horses. Two different serogroups of mammalian coronaviruses cause frequent respiratory infections in humans,...

Early events of rotavirus infection the search for the receptors

Guerrero1, Ernesto M ndez, Selene Zarate, Pavel Isa, Rafaela Espinosa, Pedro Romero and Susana L pez Departamento de Gen tica y Fisiolog a Molecular, Instituto de Biotecnolog a, Universidad NacionalAut noma de Mexico, Cuernavaca, Morelos 62250, Mexico Abstract. The entry of rotaviruses into epithelial cells seems to be a multistep process. Infection competition experiments have suggested that at least three different interactions between the virus and cell surface...

Epidemiologic considerations

Calicivirus Under Microscope

The disease burden of acute gastroenteritis Acute gastroenteritis is often considered to be exclusively a problem of children in developing countries. These children have 5 10 episodes of gastroenteritis each - NLV Enterovirus 22 FIG. 1. Viral agents of gastroenteritis as seen by direct electron microscopy. Bar 100 nm. year during their first 5 years of life and, though many of these are mild, some episodes can lead to malnutrition, dehydration and death Bern et al 1992 . In the developing...

Structural studies on Norwalk virus capsids

Norwalk virus, a member of the Caliciviridae, is a prototype human calicivirus that causes epidemic acute gastroenteritis Kapikian et al 1996 . Human caliciviruses have been very difficult to adapt to cell culture systems. The lack of a cell culture system or a practical animal model has to some extent limited the progress in understanding the molecular characteristics of the virus and its replication strategies. However, the successful cloning of the Norwalk virus genome and its expression...

RNA replication

Plication Rotavirus

Characterization of subviral particles purified from infected cells has indicated that the synthesis of dsRNA occurs simultaneously with the packaging of mRNA FIG. 1. Model for assembly of core pentamers with replicase activity. The RNA polymerase, VP1, and capping enzyme, VP3, interact with viral mRNA to form a pre-core complex that lacks replicase activity. In the viroplasm, the complex then interacts with VP2 dimers, NSP2 octamers, and NSP5 multimers producing a structure that represents one...

The interaction of rotavirus with its host cell is a multistep process

Parallel Force Systems

Several lines of evidence suggest that rotaviruses need to interact with more than one cell surface molecule to enter the cell, using during this process different FIG. 1. Distinctive structural features of the outer shell protein VP4. The trypsin cleavage region is indicated by an arrow, which defines the boundary between VP8 and VP5. In VP8, the haemagglutination domain HA aa 93 to 208 is shadowed the asterisks below this domain indicate aa 155 and 188 190, which are important in the SA...

Structural studies on rotavirus

Rotavirus Dlp

The biochemistry and molecular biology of rotaviruses are well characterized Estes 1996 . Rotaviruses belong to the family of viruses called Reoviridae. The rotavirus particle contains multiple protein layers enclosing the genome that consists of 11 segments of double-stranded ds RNA. Each segment codes for one protein with the exception of segment 11 that codes for two proteins. Out of the 12 proteins, six are structural and six are non-structural. The outer capsid layer is made of VP7 and...

Gastroenteritis viruses an overview

Glass, Joseph Bresee, Baoming Jiang, Jon Gentsch, Tamie Ando, Rebecca Fankhauser, Jacqueline Noel, Umesh Parashar, Blair Rosen and Stephan S. Monroe Viral Gastroenteritis Section, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30333, USA Abstract. Acute gastroenteritis is among the most common illnesses of humankind, and its associated morbidity and mortality are greatest among those at the extremes of age, children and the elderly. In developing countries,...

Rotavirus RNA replication and gene expression

Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 7 Center Drive, MSC 0720, Room 117, Bethesda, MD 20892, USA Abstract. Rotavirus mRNAs are capped but non-polyadenylated and serve as templates for both the synthesis of viral proteins and the segmented dsRNA genome. Viral proteins involved in RNA replication include the RNA polymerase VP1 , the core scaffold protein VP2 and the non-structural RNA-binding proteins NSP2 and...

Diagnostic advances

In the field of viral gastroenteritis, advances in our understanding of the epidemiology and clinical importance of each virus have required the Nucleic acid Genome organisation Characterisation Wheel-shaped rota , dsRNA 11 segments triplet capsid Small round structured ss RNA 3 ORFs viruses SRSV with calices Small round virus Small round virus Small round virus Groups A,B,C Group A has 2 subgroups I, II multiple serotypes, classified on the basis of two outer capsid proteins P and G...