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W D Cubitt

Publications and source records attributed to W D Cubitt.

At least 19 recordsLinked to original sources
PubMed2004

Pathology of astrovirus associated diarrhoea in a paediatric bone marrow transplant recipient.

Human astrovirus infection often causes outbreaks of self limiting diarrhoea, but may also infect patients who are immunodeficient or immunocompromised. Although there are previous publications relating to various aspects of astroviruses, there is a minimal amount of literature on the histopathological features of gastrointestinal astrovirus infection in humans. We report the histopathological findings, including immunohistochemical and electron microscopic features, of astrovirus infection in a bone marrow transplant recipient aged 4 years with diarrhoea. The appearance of a small intestinal biopsy did not suggest graft versus host disease, but demonstrated villous blunting, irregularity of surface epithelial cells, and an increase in lamina propria inflammatory cell density. Immunohistochemical staining with a murine astrovirus group specific monoclonal antibody demonstrated progressively more extensive staining in the duodenal and jejunal biopsies, predominantly restricted to the luminal surface and cytoplasm of surface epithelial cells, most marked at the villus tips. Electron microscopic examination demonstrated viral particles within the cytoplasm of enterocytes, focally forming paracrystalline arrays.

Astroviridae Infections↗
PubMed2003

Retrospective screening for hepatitis C in a tertiary paediatric referral centre.

The true prevalence of hepatitis C virus in children in the UK is not known and targeted screening is not standard practice despite an anticipated rise in new cases due to vertical transmission. An extension of the Department of Health's 'look-back' exercise was undertaken in order to determine the prevalence of hepatitis C virus in high-risk patient groups who were transfused with blood and/or blood products before 1991. Five hundred and ninety-five patients transfused between 1971-91 were traced and offered counselling and testing. Blood samples from 405 were analysed for the presence of HCV antibodies and/or HCV RNA by RT-PCR and eight patients were found to be positive. The HCV seroprevalence rate in this cohort was 1.97% and the HCV genome detection rate was 1.72%. In view of the long-term complications from this infection and the availability of potentially effective anti-viral agents, we feel that targeted screening is of value in this setting.

Adolescent↗
PubMed2001

Characterisation of a South African human astrovirus as type 8 by antigenic and genetic analyses.

Human astroviruses (HAstV) can, on the basis of immunoassays using type-specific rabbit antisera, be classified into eight serotypes that correlate with genotypes. Very few isolates of HAstV type 8 have been described and there is a paucity of data available with regard to the antigenic and genetic relationships between HAstV type 8 (HAstV-8) and HAstV types 1 (HAstV-1) to 7 (HAstV-7). A wild-type HAstV from a South African paediatric patient with diarrhoea was analysed antigenically, by immune electron microscopy and enzyme immunoassay, and genetically in selected regions of the ORF1a, ORF1b and ORF2 and characterised as a HAstV-8. This HAstV-8 strain exhibited greatest homology with HAstV-4 in the 5' end of the capsid gene and ORF1a and 1b, and greatest homology with HAstV-5 in the 3' end of the capsid region. This study confirms, by both antigenic and genetic analyses, that HAstV-8 represents a distinct antigenic and genotype and is the first report of a HAstV-8 from a hospitalised paediatric patient with diarrhoea in southern Africa.

Amino Acid Sequence↗
PubMed2000

Characterisation of rotaviruses from children treated at a London hospital during 1996: emergence of strains G9P2A[6] and G3P2A[6].

Rotavirus strains from 171 patients treated in 1996 at a children's hospital in London were characterised. Use of a panel of typing monoclonal antibodies for serotypes G1-4 identified 105 (61%) of the strains. The majority, 90 strains (86%), were serotype G1. Characterisation of G (VP7) and P (VP4) types using reverse transcription-polymerase chain reaction was more efficient, and 167 of 171 (98%) of the strains were identified this way. The predominant strains were G1P1A[8] (55%) and G4P1A[8] (17%), which are prevalent throughout the world; however, a significant number of cases were associated with genotypes not recorded previously in the United Kingdom. There were 21 (13%) cases associated with G9P2A[6] and 11 (6%) cases associated with G3P2A[6]. The majority (seven of 10) cases of infection in children older than 3 years of age were caused by these two genotypes. A majority (15/21) of G9P2A[6] strains were recovered from children admitted to the hospital, and five children were sufficiently dehydrated to necessitate intravenous rehydration.

Antibodies, Monoclonal↗
PubMed2000

HCV prevalence in pregnant women in the UK.

The objective of the study was to assess the prevalence and epidemiology of hepatitis C virus (HCV) infection in pregnant women in the North Thames region, and in the UK in general. Demographic data were linked to neonatal samples prior to anonymization and testing by anti-HCV EIA, and with RIBA 3 confirmation. Risk factors for maternal infection were explored. Area-specific seroprevalence rates were multiplied into population sizes to estimate HCV prevalence in pregnant women in the UK. A total of 241/126,009 samples were confirmed anti-HCV positive, and a further 40 were indeterminate, representing a seroprevalence of 0.19-0.22%; 51% of maternal HCV infections were in UK-born women (71% of the population), and 22% in women from continental Europe (5% of the population). Among European-born women, HCV prevalence was associated with birth in continental Europe, partner not being notified at birth registration, partner born in a different region to the mother, and inner city residence. Four of the 241 anti-HCV positive samples (1.7%) were also anti-HIV-1 positive. It was estimated that each year an estimated 1150 out of 730,000 pregnancies in the UK would involve a woman infected with HCV (uncertainty range 660-1850), a prevalence of 0.16% (0.09-0.25%). On the basis of reported rates of mother-to-child transmission of HCV, this would represent approximately 70 paediatric HCV infections per year.

Adolescent↗
PubMed1999

Application of electronmicroscopy, enzyme immunoassay, and RT-PCR to monitor an outbreak of astrovirus type 1 in a paediatric bone marrow transplant unit.

During 1997, an extensive outbreak of astrovirus occurred in a unit where paediatric patients were being treated for leukaemias and inherited immune deficiency disorders. Prolonged shedding of virus for many months following infection was demonstrated in three patients who had undergone bone marrow transplantation. Comparison of reverse transcription-polymerase chain reaction (RT-PCR), enzyme immunoassay (EIA), and electronmicroscopy (EM) to monitor the outbreak showed that many subclinical infections, mainly in children aged > 3 years could only be detected by RT-PCR. Use of RT-PCR revealed that several patients were infected earlier and shed virus for longer than by using EM or EIA. The virus responsible for the outbreak was identified as HAstV-1 and was shown to have a sequence that differed from a strain obtained in 1988.

Astroviridae Infections↗
PubMed1999

Prevalence of antibodies to astrovirus types 1 and 3 in children and adolescents in Norfolk, Virginia.

OBJECTIVE: To determine the prevalence of antibody to human astrovirus types 1 (HAstV-1) and 3 (HAstV-3) in children. METHODS: Sera from children hospitalized in Norfolk, VA, for noninfectious conditions were collected for a 1-month period every 6 months from 1993 to 1996 and tested by enzyme immunoassay for antibody to HAstV-1 and HAstV-3 with the use of baculovirus-expressed recombinant capsid proteins as antigens. RESULTS: The seroprevalence of 393 infants and children to HAstV-1 decreased from 67% in infants <3 months of age to 7% by 6 to 8 months of age, consistent with loss of transplacental antibodies. Children acquired HAstV-1 antibody with a peak prevalence of 94% at 6 to 9 years of age (P < 0.001). Antibodies to HAstV-3 exhibited a lower prevalence, with 26% positive at <3 months, 0% at 6 to 11 months and 42% by 6 to 9 years of age. HAstV-1 seroprevalence in children O to 2 months of age decreased from 89% in November, 1993, to 40% in November, 1996 (P = 0.009). CONCLUSIONS: Astrovirus type-specific antibody prevalence can be measured by baculovirus-expressed capsid antigens in an enzyme immunoassay. Children developed antibody to HAstV-1 (94%) and to HAstV-3 (42%) by 6 to 9 years of age indicating frequent exposure to these enteric viruses in infancy and early childhood.

Adolescent↗
PubMed1999

Comparative studies of human rotavirus serotype G8 strains recovered in South Africa and the United Kingdom.

Epidemiological studies on the VP7 serotype prevalence of human rotaviruses in South Africa and the United Kingdom identified several strains which could not be serotyped as G1-G4 by monoclonal antibodies. Further analysis of these strains with a G8-specific monoclonal antibody and with probes for human rotaviruses confirmed them as G8 rotaviruses. These G8 strains exhibited a high degree of sequence identity when compared with each other and with other rotavirus G8 strains. Five South African strains were further characterized as VP6 subgroup I, but with a long RNA electropherotype, which is similar to the G8 strains previously isolated in Finland. In the UK strains, one was VP6 subgroup II with a long RNA electropherotype (similar to the Italian G8 strain). The other two were subgroup I with a short RNA electropherotype. None of these strains exhibited the super-short RNA electropherotype described in the prototype G8 strains recovered from Indonesia (69M).

Amino Acid Sequence↗
PubMed1999

Detection of antibodies to hepatitis C virus in dried blood spot samples from mothers and their offspring in Lahore, Pakistan.

Dried blood spot samples from mothers and their offspring attending the obstetric and pediatric departments of two hospitals in Lahore, Pakistan, were tested for antibodies to hepatitis C virus (HCV). The seroprevalence of HCV in the women was 6.7% (95% confidence interval [CI], 4.3 to 9.1), and that in the children was 1.3% (95% CI, 0.34 to 2.26). Four anti-HCV immunoglobulin G (IgG)-positive children had mothers that were anti-HCV IgG negative, which suggested that their infection was community acquired.

Adolescent↗
PubMed1998

Prevalence of antibodies to the Hawaii strain of human calicivirus as measured by a recombinant protein based immunoassay.

The evaluation of an enzyme immunoassay using recombinant Hawaii virus-like particles (rHV-LPs) with a panel of sera which had been screened previously for antibodies to Norwalk virus (NV) and Mexico virus (MxV) is described. The assay was also applied to study the epidemiology of Hawaii virus. Adult volunteers challenged with the prototype (genogroup II, human calicivirus) HV developed significant IgG responses (16-32 fold rises) following challenge whereas adults challenged or naturally infected with NV (genogroup I) did not. Lesser antibody responses (4-8 fold rises) were demonstrated in volunteers challenged with Snow Mountain agent (SMA) and patients infected by SRSV 'UK3' and 'UK4' strains, indicating a degree of antigenic relatedness among viruses within genogroup II. Comparison of the seroprevalence of IgG antibodies to rHV, rMxV and rNV in 338 children in London showed that infections with genogroup II viruses are prevalent and occur earlier in life than NV. Many young children had antibodies to MxV but not HV indicating that genogroup II viruses have both conserved and antigenically distinct epitopes. A serological study on 566 Canadians aged between 9 and 79 years showed that the prevalence of antibodies to rHV rose with age from 65-100% and from 53-100% for NV. Measurement of antibody response in a heart transplant patient infected with an MxV-like virus showed significant responses to both rMxV and rHV. Continuous monitoring of the patient over two years showed that antibody levels declined rapidly to prechallenge levels after a year.

Adolescent↗
PubMed1997

Sapporo-like human caliciviruses are genetically and antigenically diverse.

The Sapporo-like human caliciviruses (HuCVs) comprise one of three genogroups of HuCVs associated with acute gastroenteritis. Phylogenetic analysis has shown that Sapporo-like HuCVs are related more closely to animal caliciviruses than to other known HuCVs. We produced 3.2 kb cDNA fragments from the 3' end to three Sapporo-like HuCVs that were associated with acute gastroenteritis in children (Houston/86, Houston/90, and London/92). Sequence analysis of the 3.2 kb cDNAs showed that two of the three viruses had a genomic organization similar to that of other Sapporo-like strains and the third strain (London/92) lacked an open reading frame overlapping the 5' end of the capsid gene. Alignment of the capsid sequences of these three strains showed 44-78% amino acid identity among the three strains. Phylogenetic analysis of the aligned sequences indicated the three strains are related but each belongs to a distinct genetic cluster. The genetic differences are associated with antigenic differences in that an enzyme immune assay (EIA) specific for the prototype Sapporo/82 strain detected the Houston/86 strain, but not the Houston/90 and London/92 strains. In vitro transcription and translation of viral cDNA containing the predicted capsid gene of Houston/90 resulted in a protein of 63 K, which is immunoprecipitated by sera from children infected with the strain. Genetically and antigenically distinct strains in the Sapporo-like HuCVs have not been described previously and the occurrence of such diverse strains in the same community likely increases the importance of these strains as a cause of illness in children.

Amino Acid Sequence↗
PubMed1997

Propagation of human astrovirus in the PLC/PRF/5 hepatoma cell line.

Astroviruses are associated with gastroenteritis in humans and many diseases in animals. Human astroviruses (HAstVs) cannot be propagated readily or isolated in conventional cell cultures. The presence of trypsin supports HAstV growth in selected cell cultures such as the continuous colonic carcinoma cell line (CaCo-2). This study reports on the propagation of cell culture adapted reference strains of HAstV, and the direct isolation of HAstV from stool specimens in the human hepatoma cell line PLC/PRF/5.

Antigens, Viral↗
PubMed1997

A method for the detection and confirmation of antibodies to hepatitis C virus in dried blood spots.

This study describes the development and evaluation of a cost effective test rationale for the detection of anti-HCV in dried blood spots. Samples were screened using an 'in house' IgG ELISA that incorporated the recombinant proteins c22-3, c200 and NS5. Confirmation of specific antibody to HCV was by a modification of the immunoblot RIBA 3.0. An extensive panel of well evaluated anti-HCV positive and negative samples from the UK and South Africa were used to assess the sensitivity and specificity of the two tests. One third of the anti-HCV positive samples had been typed. All anti-HCV positive samples were detected by the 'in house' screening EIA. Test/negative optical density ratios showed that more than 95% of reactive samples produced values greater than 5.0. Antibodies to HCV could be detected in a wide range of samples derived from asymptomatic and symptomatic patients and of different genotypes, with similar sensitivity. The presence of anti-HCV could be confirmed by RIBA 3.0 in samples with low reactivity but not in anti-HCV negative samples. Furthermore the immunoblot assay successfully increased specificity by screening out false reactive EIA samples that might occur in an epidemiological survey of a multi-ethnic population.

Adult↗
PubMed1996

Study on occurrence of human calicivirus (Mexico strain) as cause of sporadic cases and outbreaks of calicivirus-associated diarrhoea in the United Kingdom, 1983-1995.

The use of a recently developed EIA using antisera raised against purified baculovirus expressed recombinant Mexico virus (rMx) capsid protein is described for screening for human calicivirus in stools. The results show that MX-like viruses have been circulating in the UK periodically since 1983 and were an occasional cause of sporadic cases of diarrhoea in infants and outbreaks of infection among elderly patients in hospitals and old people's homes. Further evidence is presented that some strains of caliciviruses with characteristic surface morphology (HuCVs) and some with an indistinct appearance, small round structured viruses (SRSVs) are antigenically related to MxV. Tests on SRSVs from four unrelated outbreaks typed as UK3 failed to react in the Mx EIA or recombinant Norwalk virus (rNV) EIA. A 2-month survey of 206 children treated in two London hospitals for diarrhoea showed that only one was positive for MxV, a child known to be infected with HIV-1. None of the samples reacted in the rNV EIA.

Adult↗
PubMed1996

Historical background and classification of caliciviruses and astroviruses.

Infections caused by caliciviruses, i.e., vesicular exanthema virus of swine were recognised as a major cause of economic loss in the 1930s. However, it was not until the application of electronmicroscopy in the 1970s that caliciviruses and astroviruses were recognised and proven to be a cause of diarrhoea and vomiting. The following review briefly describes the steps which have led to the development of diagnostic tests and enabled the characterization of several members of the Caliciviridae and Astroviridae. In the past five years this has culminated in the sequencing of their genomes and the expression of viral proteins. This in turn has led to the development of improved diagnostic tests e.g., RT-PCR and enzyme immunoassays, and may pave the way towards producing effective vaccines in the future.

Animals↗
PubMed1996

Genetic and antigenic diversity of human caliciviruses (HuCVs) using RT-PCR and new EIAs.

RT-PCR using primers from conserved regions of calicivirus genomes, followed by sequencing, permits characterization of genetic variation within the family. EIAs based on baculovirus-expressed viral capsid proteins and hyperimmune antisera against the capsid proteins were developed to detect HuCV antigens and antibodies. Serologic surveys using recombinant Norwalk virus (rNV) and recombinant Mexico virus (rMX, a SMA-like virus) EIAs showed that infections by HuCVs are common and that children acquire antibodies to HuCVs at an early age in both developed and developing countries. Three HuCV genogroups have been described that are represented by Norwalk virus (NV), Snow Mountain agent (SMA), and Sapporo virus, although recently accumulated sequences of HuCV strains indicate these genogroups can be further divided. These genogroups also correspond to distinct antigenic groups based on the results of the recombinant EIAs. The three genogroups co-circulate and have a worldwide distribution, although the SMA genogroup seems to be predominant currently. Application of these new assays for further characterization of the genetic and antigenic properties of HuCVs remains an important task for HuCV research.

Antibodies, Viral↗
PubMed1996

Seroprevalence of astrovirus types 1 and 6 in London, determined using recombinant virus antigen.

We have developed a microimmunofluorescence test (IF) which uses cells infected with a recombinant baculovirus which expresses the capsid proteins of astrovirus types 1 or 6. The IF test was sensitive and specific and the results for human astrovirus type 1 (HAst-1) were comparable to those obtained by immune electronmicroscopy and radioimmunoassay. Application of the test to a panel of 273 sera collected from patients and staff at two childrens hospitals in London showed that over 50% of the population were infected by HAst-1 between the age of 5 and 12 months rising to 90% by 5 years, whereas human astrovirus type 6 (HAst6) was relatively uncommon (10-30%) in all age groups.

Adult↗