PubMed Health⌕ Search

Biomedical subjects

Maria Zambon

Publications and source records attributed to Maria Zambon.

At least 19 recordsLinked to original sources
PubMed2006

Programme of the Community Network of Reference Laboratories for Human Influenza to improve Influenza Surveillance in Europe.

All laboratories participating in the Community Network of Reference Laboratories for Human Influenza in Europe (CNRL) co-ordinated by the European Influenza Surveillance Scheme (EISS) should be able to perform a range of influenza diagnostics. This includes direct detection, culture, typing, subtyping and strain characterisation of influenza viruses, diagnostic serology and the creation of archives for clinical specimens and virus isolates. To improve the capacity and quality of the laboratories of the CNRL and to increase the consistency in performance among all 25 European Union countries plus Norway, Romania, and Switzerland, five task groups were set up in February 2005. These task groups developed work programmes in the areas of virus isolation, antibodies, molecular virology, quality control assessment and antiviral susceptibility testing. This report outlines the programmes and the results achieved in the first half-year of operation of the task groups. The action plans are challenging and it is expected that these efforts will lead to considerable improvements in the performance of the laboratories and in the standardisation of methods employed in Europe with regard to routine influenza surveillance and early warning for emerging viruses.

Community Networks↗
PubMed2006

Risk and protective factors for meningococcal disease in adolescents: matched cohort study.

OBJECTIVE: To examine biological and social risk factors for meningococcal disease in adolescents. DESIGN: Prospective, population based, matched cohort study with controls matched for age and sex in 1:1 matching. Controls were sought from the general practitioner. SETTING: Six contiguous regions of England, which represent some 65% of the country's population. PARTICIPANTS: 15-19 year olds with meningococcal disease recruited at hospital admission in six regions (representing 65% of the population of England) from January 1999 to June 2000, and their matched controls. METHODS: Blood samples and pernasal and throat swabs were taken from case patients at admission to hospital and from cases and matched controls at interview. Data on potential risk factors were gathered by confidential interview. Data were analysed by using univariate and multivariate conditional logistic regression. RESULTS: 144 case control pairs were recruited (74 male (51%); median age 17.6). 114 cases (79%) were confirmed microbiologically. Significant independent risk factors for meningococcal disease were history of preceding illness (matched odds ratio 2.9, 95% confidence interval 1.4 to 5.9), intimate kissing with multiple partners (3.7, 1.7 to 8.1), being a university student (3.4, 1.2 to 10) and preterm birth (3.7, 1.0 to 13.5). Religious observance (0.09, 0.02 to 0.6) and meningococcal vaccination (0.12, 0.04 to 0.4) were associated with protection. CONCLUSIONS: Activities and events increasing risk for meningococcal disease in adolescence are different from in childhood. Students are at higher risk. Altering personal behaviours could moderate the risk. However, the development of further effective meningococcal vaccines remains a key public health priority.

Adolescent↗
PubMed2006

Detection of influenza viruses resistant to neuraminidase inhibitors in global surveillance during the first 3 years of their use.

Emergence of influenza viruses with reduced susceptibility to neuraminidase inhibitors (NAIs) develops at a low level following drug treatment, and person-to-person transmission of resistant virus has not been recognized to date. The Neuraminidase Inhibitor Susceptibility Network (NISN) was established to follow susceptibility of isolates and occurrence of NAI resistance at a population level in various parts of the world. Isolates from the WHO influenza collaborating centers were screened for susceptibilities to oseltamivir and zanamivir by a chemiluminescent enzyme inhibition assay, and those considered potentially resistant were analyzed by sequence analysis of the neuraminidase genes. During the first 3 years of NAI use (1999 to 2002), 2,287 isolates were tested. Among them, eight (0.33%) viruses had a >10-fold decrease in susceptibility to oseltamivir, one (0.22%) in 1999 to 2000, three (0.36%) in 2000 to 2001, and four (0.41%) in 2001 to 2002. Six had unique changes in the neuraminidase gene compared to neuraminidases of the same subtype in the influenza sequence database. Although only one of the mutations had previously been recognized in persons receiving NAIs, none were from patients who were known to have received the drugs. During the 3 years preceding NAI use, no resistant variants were detected among 1,054 viruses. Drug use was relatively stable during the period, except for an approximate 10-fold increase in oseltamivir use in Japan during the third year. The frequency of variants with decreased sensitivity to the NAIs did not increase significantly during this period, but continued surveillance is required, especially in regions with higher NAI use.

Antiviral Agents↗
PubMed2005

Serological analysis of serum samples from humans exposed to avian H7 influenza viruses in Italy between 1999 and 2003.

We evaluated the potential for avian-to-human transmission of low pathogenic avian influenza (LPAI) and highly pathogenic avian influenza (HPAI) H7N1 and LPAI H7N3 viruses that were responsible for several outbreaks of influenza in poultry in Italy between 1999 and 2003. A serological survey of poultry workers was conducted by use of a combination of methods. Evidence of anti-H7 antibodies was observed in 3.8% of serum samples collected from poultry workers during the period in 2003 when LPAI H7N3 virus was circulating. These findings highlight the need for surveillance in people occupationally exposed to avian influenza viruses, so that they can be monitored for the risk of avian-to-human transmission during outbreaks of avian influenza caused by both LPAI and HPAI viruses.

Agricultural Workers' Diseases↗
PubMed2005

First external quality assurance of antibody diagnostic for SARS-new coronavirus.

To confirm an infection with the new coronavirus (SARS-CoV) causing the severe acute respiratory syndrome (SARS) diagnostic assays for detection of SARS-CoV specific antibody are necessary. To evaluate the diagnostic performance of laboratories an external quality assurance (EQA) study was performed in 2004. Participating laboratories (9/20) correctly detected anti-SARS antibodies in serum samples without false positive results in an immunofluorescence assay. In contrast, only 4/13 laboratories detected most of the anti-SARS antibody positive samples without false positive results using enzyme immunoassays (EIA) and/or immunoblot. The overall results clearly demonstrate that serological diagnosis of SARS-CoV remains at an early stage of development, with further technical improvements required, particularly with respect to the use of SARS specific EIAs.

Antibodies, Viral↗
PubMed2005

Subcellular localization of the severe acute respiratory syndrome coronavirus nucleocapsid protein.

The coronavirus nucleocapsid (N) protein is a viral RNA-binding protein with multiple functions in terms of virus replication and modulating cell signalling pathways. N protein is composed of three distinct regions containing RNA-binding motif(s), and appropriate signals for modulating cell signalling. The subcellular localization of severe acute respiratory syndrome coronavirus (SARS-CoV) N protein was studied. In infected cells, SARS-CoV N protein localized exclusively to the cytoplasm. In contrast to the avian coronavirus N protein, overexpressed SARS-CoV N protein remained principally localized to the cytoplasm, with very few cells exhibiting nucleolar localization. Bioinformatic analysis and deletion mutagenesis coupled to confocal microscopy and live-cell imaging, revealed that SARS-CoV N protein regions I and III contained nuclear localization signals and region II contained a nucleolar retention signal. However, cytoplasmic localization was directed by region III and was the dominant localization signal in the protein.

Amino Acid Sequence↗
PubMed2005

Neuraminidase inhibitor susceptibility network position statement: antiviral resistance in influenza A/H5N1 viruses.

The emerging epidemic of H5N1 avian influenza virus with spillover into the human population in Asia has provoked intense concern globally about the potential of these particularly pathogenic viruses to evolve with the capacity for human-to-human transmission with a consequent pandemic. The availability of antiviral drugs with activity against influenza A viruses and the recognition of drug-resistant variants to these drugs prompted the following report by a select group of the global experts--members of the Neuraminidase Inhibitor Susceptibility Network--on the best use of the available drugs, both for prophylaxis and treatment. The editors of Antiviral Therapy are pleased to be able to provide this document in an expeditious manner.

Acetamides↗
PubMed2004

Cleavage and serum reactivity of the severe acute respiratory syndrome coronavirus spike protein.

Severe acute respiratory syndrome (SARS) coronavirus (SCoV) spike (S) protein is the major surface antigen of the virus and is responsible for receptor binding and the generation of neutralizing antibody. To investigate SCoV S protein, full-length and individual domains of S protein were expressed on the surface of insect cells and were characterized for cleavability and reactivity with serum samples obtained from patients during the convalescent phase of SARS. S protein could be cleaved by exogenous trypsin but not by coexpressed furin, suggesting that the protein is not normally processed during infection. Reactivity was evident by both flow cytometry and Western blot assays, but the pattern of reactivity varied according to assay and sequence of the antigen. The antibody response to SCoV S protein involves antibodies to both linear and conformational epitopes, with linear epitopes associated with the carboxyl domain and conformational epitopes associated with the amino terminal domain. Recombinant SCoV S protein appears to be a suitable antigen for the development of an efficient and sensitive diagnostic test for SARS, but our data suggest that assay format and choice of S antigen are important considerations.

Animals↗
PubMed2004

Restrictions to the adaptation of influenza a virus h5 hemagglutinin to the human host.

The binding specificities of a panel of avian influenza virus subtype H5 hemagglutinin (HA) proteins bearing mutations at key residues in the receptor binding site were investigated. The results demonstrate that two simultaneous mutations in the receptor binding site resulted in H5 HA binding in a pattern similar to that shown by human viruses. Coexpression of the ion channel protein, M2, from most avian and human strains tested protected H5 HA conformation during trafficking, indicating that no genetic barrier to the reassortment of the H5 surface antigen gene with internal genes of human viruses existed at this level.

Adaptation, Physiological↗
PubMed2003

Influenza.

Although most influenza infections are self-limited, few other diseases exert such a huge toll of suffering and economic loss. Despite the importance of influenza, there had been, until recently, little advance in its control since amantadine was licensed almost 40 years ago. During the past decade, evidence has accrued on the protection afforded by inactivated vaccines and the safety and efficacy in children of live influenza-virus vaccines. There have been many new developments in vaccine technology. Moreover, work on viral neuraminidase has led to the licensing of potent selective antiviral drugs, and economic decision modelling provides further justification for annual vaccination and a framework for the use of neuraminidase inhibitors. Progress has also been made on developing near-patient testing for influenza that may assist individual diagnosis or the recognition of widespread virus circulation, and so optimise clinical management. Despite these advances, the occurrence of avian H5N1, H9N2, and H7N7 influenza in human beings and the rapid global spread of severe acute respiratory syndrome are reminders of our vulnerability to an emerging pandemic. The contrast between recent cases of H5N1 infection, associated with high mortality, and the typically mild, self-limiting nature of human infections with avian H7N7 and H9N2 influenza shows the gaps in our understanding of molecular correlates of pathogenicity and underlines the need for continuing international research into pandemic influenza. Improvements in animal and human surveillance, new approaches to vaccination, and increasing use of vaccines and antiviral drugs to combat annual influenza outbreaks are essential to reduce the global toll of pandemic and interpandemic influenza.

Antiviral Agents↗
PubMed2003

Boosting immunity to influenza H5N1 with MF59-adjuvanted H5N3 A/Duck/Singapore/97 vaccine in a primed human population.

In 1997, influenza A/Hong Kong/97 (H5N1) emerged as a potential human threat. In 1999, a randomised study comparing two doses of MF59-adjuvanted and non-adjuvanted influenza A/Duck/Singapore/97 (H5N3) surface-antigen vaccine found non-adjuvanted vaccine was poorly immunogenic. Addition of MF59 significantly boosted antibody to H5N1 to levels associated with protection. At 16 months, we undertook a follow-up study to assess the effect of H5N3 revaccination. Geometric mean titres (GMTs) of antibody by haemagglutination-inhibition (HI), microneutralisation (MN) and single radial haemolysis (SRH) indicated that protective antibody titres did not exist at 16 months after two-dose priming. Twenty-one days after revaccination, there was significant boosting of antibody compared to GMTs achieved 21 days after two-dose priming in the original study (P<0.001). MF59 significantly increased GMTs of antibody when compared to non-adjuvanted vaccine (P<0.001).

Adjuvants, Immunologic↗