Characterization of an influenza B virus isolated from a fatal case of myocarditis in a pediatric patient in Italy

Influenza B is one of the infective agents that can cause rapid and fatal myocarditis in children. Here, we describe a fatal case of myocarditis in a previously healthy child, after infection with an influenza B/Victoria-lineage virus during the 2022-23 epidemic season in Italy. Influenza B virus was isolated also in a second case, a younger family member showing only a mild influenza-like illness. Genotypic and phenotypic analyses have been performed on both virus samples and results showed that HA1 sequences were identical and genetically and antigenically related to other B viruses circulating in 2022-23 season in Italy. However, a D129N substitution was found in the receptor binding domain of the HA of the two viruses, not detected in other circulating viruses in Italy but only in a proportion of those circulating in other European countries. Phenotypic analyses assessed the susceptibility towards either neuraminidase inhibitors and baloxavir. Annual influenza vaccination remains one of the best interventions to prevent complications such as myocarditis, particularly in children.

Identification of Anti-Influenza A Compounds Inhibiting the Viral Non-Structural Protein 1 (NS1) Using a Type I Interferon-Driven Screening Strategy

There is an urgent need to identify efficient antiviral compounds to combat existing and emerging RNA virus infections, particularly those related to seasonal and pandemic influenza outbreaks. While inhibitors of the influenza viral integral membrane proton channel protein (M2), neuraminidase (NA), and cap-dependent endonuclease are available, circulating influenza viruses acquire resistance over time. Thus, the need for the development of additional anti-influenza drugs with novel mechanisms of action exists. In the present study, a cell-based screening assay and a small molecule library were used to screen for activities that antagonized influenza A non-structural protein 1 (NS1), a highly conserved, multifunctional accessory protein that inhibits the type I interferon response against influenza. Two potential anti-influenza agents, compounds 157 and 164, were identified with anti-NS1 activity, resulting in the reduction of A/PR/8/34(H1N1) influenza A virus replication and the restoration of IFN-β expression in human lung epithelial A549 cells. A 3D pharmacophore modeling study of the active compounds provided a glimpse of the structural motifs that may contribute to anti-influenza virus activity. This screening approach is amenable to a broader analysis of small molecule compounds to inhibit other viral targets.

Haemagglutination inhibition and virus microneutralisation serology assays: use of harmonised protocols and biological standards in seasonal influenza serology testing and their impact on inter-laboratory variation and assay correlation: A FLUCOP collaborative study

Introduction

The haemagglutination inhibition assay (HAI) and the virus microneutralisation assay (MN) are long-established methods for quantifying antibodies against influenza viruses. Despite their widespread use, both assays require standardisation to improve inter-laboratory agreement in testing. The FLUCOP consortium aims to develop a toolbox of standardised serology assays for seasonal influenza. Building upon previous collaborative studies to harmonise the HAI, in this study the FLUCOP consortium carried out a head-to-head comparison of harmonised HAI and MN protocols to better understand the relationship between HAI and MN titres, and the impact of assay harmonisation and standardisation on inter-laboratory variability and agreement between these methods.

Methods

In this paper, we present two large international collaborative studies testing harmonised HAI and MN protocols across 10 participating laboratories. In the first, we expanded on previously published work, carrying out HAI testing using egg and cell isolated and propagated wild-type (WT) viruses in addition to high-growth reassortants typically used influenza vaccines strains using HAI. In the second we tested two MN protocols: an overnight ELISA-based format and a 3-5 day format, using reassortant viruses and a WT H3N2 cell isolated virus. As serum panels tested in both studies included many overlapping samples, we were able to look at the correlation of HAI and MN titres across different methods and for different influenza subtypes.

Results

We showed that the overnight ELISA and 3-5 day MN formats are not comparable, with titre ratios varying across the dynamic range of the assay. However, the ELISA MN and HAI are comparable, and a conversion factor could possibly be calculated. In both studies, the impact of normalising using a study standard was investigated, and we showed that for almost every strain and assay format tested, normalisation significantly reduced inter-laboratory variation, supporting the continued development of antibody standards for seasonal influenza viruses. Normalisation had no impact on the correlation between overnight ELISA and 3-5 day MN formats.

Multiplex Real-Time Reverse-Transcription Polymerase Chain Reaction Assays for Diagnostic Testing of Severe Acute Respiratory Syndrome Coronavirus 2 and Seasonal Influenza Viruses: A Challenge of the Phase 3 Pandemic Setting

BACKGROUND

Pandemic coronavirus disease 2019 (COVID-19) disease represents a challenge for healthcare structures. The molecular confirmation of samples from infected individuals is crucial and therefore guides public health decision making. Clusters and possibly increased diffuse transmission could occur in the context of the next influenza season. For this reason, a diagnostic test able to discriminate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from influenza viruses is urgently needed.

METHODS

A multiplex real-time reverse-transcription polymerase chain reaction (PCR) assay was assessed using 1 laboratory protocol with different real-time PCR instruments. Overall, 1000 clinical samples (600 from samples SARS-CoV-2-infected patients, 200 samples from influenza-infected patients, and 200 negative samples) were analyzed.

RESULTS

The assay developed was able to detect and discriminate each virus target and to intercept coinfections. The limit of quantification of each assay ranged between 5 and 10 genomic copy numbers, with a cutoff value of 37.7 and 37.8 for influenza and SARS-CoV-2 viruses, respectively. Only 2 influenza coinfections were detected in COVID-19 samples.

CONCLUSIONS

This study suggests that multiplex assay is a rapid, valid, and accurate method for the detection of SARS-CoV-2 and influenza viruses in clinical samples. The test may be an important diagnostic tool for both diagnostic and surveillance purposes during the seasonal influenza activity period.

Co-circulation of the two influenza B lineages during 13 consecutive influenza surveillance seasons in Italy, 2004-2017

BACKGROUND

Since 1985, two antigenically distinct lineages of influenza B viruses (Victoria-like and Yamagata-like) have circulated globally. Trivalent seasonal influenza vaccines contain two circulating influenza A strains but a single B strain and thus provide limited immunity against circulating B strains of the lineage not included in the vaccine. In this study, we describe the characteristics of influenza B viruses that caused respiratory illness in the population in Italy over 13 consecutive seasons of virological surveillance, and the match between the predominant influenza B lineage and the vaccine B lineage, in each season.

METHODS

From 2004 to 2017, 26,886 laboratory-confirmed influenza cases were registered in Italy, of which 18.7% were type B. Among them, the lineage of 2465 strains (49%) was retrieved or characterized in this study by a real-time RT-PCR assay and/or sequencing of the hemagglutinin (HA) gene.

RESULTS

Co-circulation of both B lineages was observed each season, although in different proportions every year. Overall, viruses of B/Victoria and B/Yamagata lineages caused 53.3 and 46.7% of influenza B infections, respectively. A higher proportion of infections with both lineages was detected in children, and there was a declining frequency of B/Victoria detections with age. A mismatch between the vaccine and the predominant influenza B lineage occurred in eight out of thirteen influenza seasons under study. Considering the seasons when B accounted for > 20% of all laboratory-confirmed influenza cases, a mismatch was observed in four out of six seasons. Phylogenetic analysis of the HA1 domain confirmed the co-circulation of both lineages and revealed a mixed circulation of distinct evolutionary viral variants, with different levels of match to the vaccine strains.

CONCLUSIONS

This study contributes to the understanding of the circulation of influenza B viruses in Italy. We found a continuous co-circulation of both B lineages in the period 2004-2017, and determined that children were particularly vulnerable to Victoria-lineage influenza B virus infections. An influenza B lineage mismatch with the trivalent vaccine occurred in about two-thirds of cases.

Moderate influenza vaccine effectiveness against A(H1N1)pdm09 virus, and low effectiveness against A(H3N2) subtype, 2018/19 season in Italy

Background: Influenza vaccines are updated every year to match the vaccine strains with currently circulating viruses; consequently influenza vaccine effectiveness (IVE) has to be assessed annually.Research design and methods: A test-negative case-control study was conducted within the context of the Italian sentinel influenza surveillance network to estimate IVE by age group, virus subtype, and vaccine brand in medically attended laboratory-confirmed influenza.Results: In Italy, the 2018/19 influenza season was characterized by the co-circulation of influenza A(H1N1)pdm09 and A(H3N2) viruses. The adjusted IVE estimate in preventing influenza was moderate (44.8%, 95% CI: 18.8 to 62.5) against A(H1N1)pdm09, whereas there was no evidence of effectiveness (1.8%, 95% CI: -37.8 to 30.1) in persons affected by A(H3N2). IVE against A(H1N1)pdm09 decreased with age ranging from 65.7% to 13.1% among children/adolescents and elderly, respectively; moreover results suggest that Vaxigrip Tetra® was more effective against A(H1N1)pdm09 compared to Fluarix Tetra® [62.5% (95% CI: 34.3 to 78.6) vs 24.5% (95% CI: -40.6 to 59.6)]. Low effectiveness (35.2%, 95% CI: -50.8 to 72.1) against A(H3N2) was detected only in the elderly immunized with Fluad®.Conclusions: Findings suggest that influenza vaccines were low to moderately effective, probably due to a mismatch between circulating and vaccine strains.

Immunogenicity of modified vaccinia virus Ankara expressing the hemagglutinin stalk domain of pandemic (H1N1) 2009 influenza virus

BACKGROUND

Vaccination offers protection against influenza, although current vaccines need to be reformulated each year. The development of a broadly protective influenza vaccine would guarantee the induction of heterosubtypic immunity also against emerging influenza viruses of a novel subtype. Vaccine candidates based on the stalk region of the hemagglutinin (HA) have the potential to induce broad and persistent protection against diverse influenza A viruses.

METHODS

Modified vaccinia virus Ankara (MVA) expressing a headless HA (hlHA) of A/California/4/09 (CA/09) virus was used as a vaccine to immunize C57BL/6 mice. Specific antibody and cell-mediated immune responses were determined, and challenge experiments were performed by infecting vaccinated mice with CA/09 virus.

RESULTS

Immunization of mice with CA/09-derived hlHA, vectored by MVA, was able to elicit influenza-specific broad cross-reactive antibodies and cell-mediated immune responses, but failed to induce neutralizing antibodies and did not protect mice against virus challenge.

CONCLUSION

Although highly immunogenic, our vaccine was unable to induce a protective immunity against influenza. A misfolded and unstable conformation of the hlHA molecule may have affected its capacity of inducing neutralizing antiviral, conformational antibodies. Design of stable hlHA-based immunogens and their delivery by recombinant MVA-based vectors has the potential of improving this promising approach for a universal influenza vaccine.

Protective immunity against influenza in HLA-A2 transgenic mice by modified vaccinia virus Ankara vectored vaccines containing internal influenza proteins

BACKGROUND

The emergence of novel strains of influenza A viruses with hemagglutinins (HAs) that are antigenically distinct from those circulating in humans, and thus have pandemic potential, pose concerns and call for the development of more broadly protective influenza vaccines. In the present study, modified vaccinia virus Ankara (MVA) encoding internal influenza antigens were evaluated for their immunogenicity and ability to protect HLA-A2.1 transgenic (AAD) mice from infection with influenza viruses.

METHODS

MVAs expressing NP (MVA-NP), M1 (MVA-M1) or polymerase PB1 (MVA-PB1) of A/California/4/09 (CA/09) virus were generated and used to immunize AAD mice. Antibodies and CD8+T cell responses were assessed by ELISA and ELISPOT, respectively, and challenge experiments were performed by infecting vaccinated mice with CA/09 virus.

RESULTS

CD8+T cells specific to immunodominant and subdominant epitopes on the internal influenza proteins were elicited by MVA-based vectors in AAD mice, whereas influenza-specific antibodies were detected only in MVA-NP-immunized mice. Both M1- and NP-based MVA vaccines, regardless of whether they were applied individually or in combination, conferred protection against lethal influenza virus challenge.

CONCLUSION

Our data further emphasize the promising potential of MVA vector expressing internal antigens toward the development of a universal influenza vaccine.

A heat-inactivated H7N3 vaccine induces cross-reactive cellular immunity in HLA-A2.1 transgenic mice

BACKGROUND

Cross-reactive immunity against heterologous strains of influenza virus has the potential to provide partial protection in individuals that lack the proper neutralizing antibodies. In particular, the boosting of memory CD8+ T cell responses to conserved viral proteins can attenuate disease severity caused by influenza virus antigenic variants or pandemic strains. However, little is yet known about which of these conserved internal antigens would better induce and/or recall memory CD8+ T cells after in vivo administration of an inactivated whole virus vaccine.

METHODS

We explored the CD8 + T cell responses to selected epitopes of the internal proteins of an H7N3 influenza virus that were cross-reactive with A/PR/8/34 virus in HLA-A2.1 transgenic (AAD) mice.

RESULTS

CD8+ T cells against dominant and subdominant epitopes were detected upon infection of mice with live H7N3 virus, whereas immunization with non-replicating virus elicited CD8+ T cell responses against mostly immunodominant epitopes, which were rapidly recalled following infection with A/PR/8/34 virus. These vaccine-induced T cell responses were able to reduce the lung viral load in mice challenged intranasally with the heterologous influenza virus.

CONCLUSIONS

A single immunization with non-replicating influenza virus vaccines may be able to elicit or recall cross-reactive CD8+ T cell responses to conserved immunodominant epitopes and, to some extent, counteract an infection by heterologous virus.

Generation of switched memory B cells in response to vaccination in Down syndrome children and their siblings

BACKGROUND

Immunodeficiency is an integral aspect of Down syndrome, as demonstrated by the increased susceptibility to infection of affected. Mortality is still higher than in general population, with respiratory infections among the major causes of death. As more people with Down syndrome are living today than ever before, it is indispensable to develop strategies to prevent and cure the associated disorders. Vaccination is the most successful instrument of preventive medicine. Special seasonal influenza and pneumococcal vaccination strategies have been designed for individuals with risk conditions of all ages. Down syndrome individuals are not included in the high-risk categories.

METHODS

We enrolled in our study 15 children with Down syndrome and their siblings, vaccinated for the first time with seasonal influenza vaccine and receiving a booster dose of a glyco-conjugated pneumococcal vaccine. We compared the immunological features and response to vaccination measuring serum antibody titers and frequency of specific memory B cells.

RESULTS

We confirm that a severe reduction of switched memory B cells is always associated to Down syndrome. After primary vaccination Down syndrome children generate significantly less specific switched memory B cells than their siblings. The response to a booster dose of vaccine is instead comparable in both groups. The production of specific antibodies was equally effective in Down syndrome and controls both after primary and secondary immunization.

CONCLUSIONS

Down syndrome individuals should be considered a high risk group, because of their increased susceptibility to infection and reduced number of switched memory B cells. Tailored vaccination protocols are needed in order to reduce their burden of infections throughout life.

Human infection with highly pathogenic A(H7N7) avian influenza virus, Italy, 2013

During an influenza A(H7N7) virus outbreak among poultry in Italy during August–September 2013, infection with a highly pathogenic A(H7N7) avian influenza virus was diagnosed for 3 poultry workers with conjunctivitis. Genetic analyses revealed that the viruses from the humans were closely related to those from chickens on affected farms.

Safety and immunogenicity of co-administered MF59-adjuvanted 2009 pandemic and plain 2009-10 seasonal influenza vaccines in rheumatoid arthritis patients on biologicals

Rheumatoid arthritis (RA) patients under immunosuppressive therapy are particularly susceptible to infections, mainly of the respiratory tract, thus vaccination may represent a strategy to reduce their incidence in this vulnerable population. In the 2009-10 influenza season, the safety and immunogenicity of co-administered non-adjuvanted seasonal and MF59-adjuvanted pandemic influenza vaccines were evaluated in this study in 30 RA patients under therapy with anti-tumour necrosis factor (TNF)-α agents or Abatacept and in 13 healthy controls (HC). Patients and HC underwent clinical and laboratory evaluation before (T0), 1 (T1) and 6 months (T2) after vaccinations. No severe adverse reactions, but a significant increase in total mild side effects in patients versus HC were observed. Both influenza vaccines fulfilled the three criteria of the Committee for Proprietary Medicinal Products (CPMP). Seroconversion rate for any viral strain in patients and HC was, respectively, 68 versus 45 for H1-A/Brisbane/59/07, 72 versus 81 for H3-A/Brisbane/10/07, 68 versus 54 for B/Brisbane/60/08 and 81 versus 54 for A/California/7/2009. A slight increase in activated interferon (IFN)-γ-, TNF-α- or interleukin (IL)-17A-secreting T cells at T1 compared to T0, followed by a reduction at T2 in both patients and HC, was registered. In conclusion, simultaneous administration of adjuvanted pandemic and non-adjuvanted seasonal influenza vaccines is safe and highly immunogenic. The largely overlapping results between patients and HC, in terms of antibody response and cytokine-producing T cells, may represent further evidence for vaccine safety and immunogenicity in RA patients on biologicals.

Modified vaccinia virus Ankara expressing the hemagglutinin of pandemic (H1N1) 2009 virus induces cross-protective immunity against Eurasian 'avian-like' H1N1 swine viruses in mice

Objectives

To examine cross-reactivity between hemagglutinin (HA) derived from A/California/7/09 (CA/09) virus and that derived from representative Eurasian “avian-like” (EA) H1N1 swine viruses isolated in Italy between 1999 and 2008 during virological surveillance in pigs.

Design

Modified vaccinia virus Ankara (MVA) expressing the HA gene of CA/09 virus (MVA-HA-CA/09) was used as a vaccine to investigate cross-protective immunity against H1N1 swine viruses in mice.

Sample

Two classical swine H1N1 (CS) viruses and four representative EA-like H1N1 swine viruses previously isolated during outbreaks of respiratory disease in pigs on farms in Northern Italy were used in this study.

Setting

Female C57BL/6 mice were vaccinated with MVA/HA/CA/09 and then challenged intranasally with H1N1 swine viruses.

Main outcome measures

Cross-reactive antibody responses were determined by hemagglutination- inhibition (HI) and virus microneutralizing (MN) assays of sera from MVA-vaccinated mice. The extent of protective immunity against infection with H1N1 swine viruses was determined by measuring lung viral load on days 2 and 4 post-challenge.

Results and Conclusions

Systemic immunization of mice with CA/09-derived HA, vectored by MVA, elicited cross-protective immunity against recent EA-like swine viruses. This immune protection was related to the levels of cross-reactive HI antibodies in the sera of the immunized mice and was dependent on the similarity of the antigenic site Sa of H1 HAs. Our findings suggest that the herd immunity elicited in humans by the pandemic (H1N1) 2009 virus could limit the transmission of recent EA-like swine HA genes into the influenza A virus gene pool in humans.

Investigation of an imported case of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection in Florence, Italy, May to June 2013

On 31 May 2013, the first case of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection in Italy was laboratory confirmed in a previously healthy adult man, who developed pneumonia with moderate respiratory distress after returning from a holiday in Jordan. Two secondary cases were identified through contact tracing, among family members and colleagues who had not previously travelled abroad. Both secondary cases developed mild illness. All three patients recovered fully.

Monitoring the susceptibility to oseltamivir of Influenza A(H1N1) 2009 virus by nested-PCR and pyrosequencing during the pandemic and in the season 2010-2011

For the early detection of the H275Y mutation as a marker of oseltamivir resistance in A(H1N1) pandemic strains, a sensitive and specific pyrosequencing assay was developed. This assay analyses a region 99nts long, encompassing the H275Y site, amplified by a nested PCR. Seventy-five respiratory specimens, obtained from 62 patients during the pandemic and in the 2010-2011 influenza season, in Tuscany, were tested. Resistant strains were demonstrated in 10 patients. In three other patients, resistant and sensitive variants were found. This pyrosequencing assay may be a useful method for monitoring the spread of resistant influenza H1N1 2009 strains.

Multicentre observational study of the natural history of left-sided acute diverticulitis

BACKGROUND

The natural history of acute diverticulitis (AD) is still unclear. This study investigated the recurrence rate, and the risks of emergency surgery, associated stoma and death following initial medical or surgical treatment of AD.

METHODS

The Italian Study Group on Complicated Diverticulosis conducted a 4-year multicentre retrospective and prospective database analysis of patients admitted to hospital for medical or surgical treatment of AD and then followed for a minimum of 9 years. The persistence of symptoms, recurrent episodes of AD, new hospital admissions, medical or surgical treatment, and their outcome were recorded during follow-up.

RESULTS

Of 1046 patients enrolled at 17 centres, 743 were eligible for the study (407 recruited retrospectively and 336 prospectively); 242 patients (32·6 per cent) underwent emergency surgery at accrual. After a mean follow-up of 10·7 years, rates of recurrence (17·2 versus 5·8 per cent; P < 0·001) and emergency surgery (6·9 versus 1·3 per cent; P = 0·021) were higher for medically treated patients than for those treated surgically. Among patients who had initial medical treatment, age less than 40 years and a history of at least three episodes of AD were associated with an increased risk of AD recurrence. There was no association between any of the investigated parameters and subsequent emergency surgery. The risk of stoma formation was below 1 per cent and disease-related mortality was zero in this group. The disease-related mortality rate was 0·6 per cent among patients who had surgical treatment.

CONCLUSION

Long-term risks of recurrent AD or emergency surgery were limited and colectomy did not fully protect against recurrence.

Molecular surveillance of pandemic influenza A(H1N1) viruses circulating in Italy from May 2009 to February 2010: association between haemagglutinin mutations and clinical outcome

Haemagglutinin sequences of pandemic influenza A(H1N1) viruses circulating in Italy were examined, focusing on amino acid changes at position 222 because of its suggested pathogenic relevance. Among 169 patients, the D222G substitution was detected in three of 52 (5.8%) severe cases and in one of 117 (0.9%) mild cases, whereas the D222E mutation was more frequent and evenly distributed in mild (31.6%) and severe cases (38.4%). A cluster of D222E viruses among school children confirms reported human-to-human transmission of viruses mutated at amino acid position 222.

Transmission of hemagglutinin D222G mutant strain of pandemic (H1N1) 2009 virus

A pandemic (H1N1) 2009 virus strain carrying the D222G mutation was identified in a severely ill man and was transmitted to a household contact. Only mild illness developed in the contact, despite his obesity and diabetes. The isolated virus reacted fully with an antiserum against the pandemic vaccine strain.

First case in Italy of acquired resistance to oseltamivir in an immunocompromised patient with influenza A/H1N1v infection

A pandemic influenza A/H1N1v strain with the neuraminidase H274Y mutation was detected in nasal secretions of a 2-year-old leukemic patient with influenza-like illness after 18 days of treatment with oseltamivir. At baseline, no drug-resistant virus was found, while 4 days after treatment initiation a mixture of wild-type and mutated virus was detected. After treatment interruption, the wild type influenza virus re-emerged and became prevalent in nasal secretions after a few days, suggesting the lower fitness of the mutated virus strain. The patient slowly improved concurrently with a decrease in virus load, which resulted negative 42 days after diagnosis. No other drug-resistant influenza A/H1N1v virus strains have been detected in Italy (up to the end of November 2009) since the first case of the novel A/H1N1v virus was identified in the country (May 2009).

Influenza vaccine administration in rheumatoid arthritis patients under treatment with TNFalpha blockers: safety and immunogenicity

Twenty-eight patients with low-moderate, stable rheumatoid arthritis (RA), under treatment with tumor necrosis factor (TNF) alpha blockers, were immunized at least once with non-adjuvanted trivalent influenza vaccine during three consecutive influenza seasons. Antibodies toward A influenza antigens significantly increased and reached protective levels, still detectable 6 months after vaccination, both in RA patients and healthy controls. Response to B antigen instead was only observed from the second year for healthy controls and in the third year for patients. No significant difference in disease activity and anti-nuclear antibodies was observed as a consequence of vaccine administration, whereas T regulatory cells showed a significant increase 30 days after immunization in RA patients. This study confirms safety of influenza vaccine administration in RA patients treated with TNFalpha blockers. The cohort follow-up revealed the overcoming of poor B vaccine antigen immunogenicity via repeated vaccinations. Finally, protective antibody response was still observed 6 months after vaccination.

Molecular analysis of avian H7 influenza viruses circulating in Eurasia in 1999-2005: detection of multiple reassortant virus genotypes

Avian influenza infections by high and low pathogenicity H7 influenza viruses have caused several outbreaks in European poultry in recent years, also resulting in human infections. Although in some cases the source of H7 strains from domestic poultry was shown to be the viruses circulating in the wild bird reservoir, a thorough characterization of the entire genome of H7 viruses from both wild and domestic Eurasian birds, and their evolutionary relationships, has not been conducted. In our study, we have analysed low pathogenicity H7 influenza strains isolated from wild and domestic ducks in Italy and southern China and compared them with those from reared terrestrial poultry such as chicken and turkey. Phylogenetic analysis demonstrated that the H7 haemagglutinin genes were all closely related to each other, whereas the remaining genes could be divided into two or more phylogenetic groups. Almost each year different H7 reassortant viruses were identified and in at least two different years more than one H7 genotype co-circulated. A recent precursor in wild waterfowl was identified for most of the gene segments of terrestrial poultry viruses. Our data suggest that reassortment allows avian influenza viruses, in their natural reservoir, to increase their genetic diversity. In turn this might help avian influenza viruses colonize a wider range of hosts, including domestic poultry.

Evolutionary Analysis of HA and NS1 Genes of H5N1 Influenza Viruses in 2004–2005 Epidemics

H5N1 avian influenza viruses circulating in early 2004 in eastern Asia appeared to be under strong purifying selection, except for the hemagglutinin (HA) and nonstructural 1 (NS1) genes, where few amino acid positions were found under positive selection pressure. To evaluate whether the widespread circulation of the H5N1 viruses in the following years was accompanied by a change in the evolution of the HA and NS1, phylogenetic and positive selection analyses were performed on 89 HA and 57 NS1 sequences. Results showed that the number of HA positively selected sites decreased compared to 2004; no selection pressure for NS1 was found. These findings suggest a possible change in the adaptation of the H5N1 virus to birds.

Prevalence of antibodies against A and B influenza viruses in South-Western Papua New Guinea

Influenza viruses remain a major cause of respiratory disease in both developed and developing countries. Nevertheless, there is little information on the prevalence of this respiratory infection in many developing countries, such as Papua New Guinea, since most of the available data originate from studies carried out in industrialized countries. In the present study, a serosurvey among residents of 47 remote villages of Papua New Guinea was conducted to evaluate the intensity of exposure to human influenza A and B viruses. The data obtained confirm the co-circulation of these antigenic variants, reported having circulated in the Southern Hemisphere. Variations in seroprevalence of influenza A and B virus infection were found within the study area.

[Vaginal swab in pediatric age]

Vaginal secretion sampling in young patients. The aim of the study was to evaluate whether different instrumental tools (the classical cotton swab, the urethral cotton swab, the balloon shape cotton swab and cyto-brush) yield different sampling success in young patients presenting with suspected vulvovaginitis. The study was conducted in a randomised prospective way on 100 children with symptoms of vulvovaginal infection (age range: 4 months -8 years ) seen at the Clinic of Paediatric Gynaecology of the Department of Obstetric and Gynaecology, "V.Buzzi" Children's Hospital, Milano (Italy). Children's compliance and the number of samples which had to be discontinued, because of children's intolerance have allowed the evaluation of each tools. Each of these tools was tested on 25 young patients. The vaginal secretion sampling was not possible on 8 patients out of 25 with cyto-brush (32%), on 7 out of 25 with the balloon shape cotton swab (28%), on 4 out of 25 with the classical cotton swab (16%) and only 1 out of 25 with the urethral cotton swab (4%). In conclusion all the instruments tested allow sampling of vaginal secretion in young children, but the reaction and compliance of the patients has been best with the otologic cotton swab.

Smoking and weight control behaviors

OBJECTIVE

To examine the association between weight control and tobacco use in young women.

METHODS

Smoking status and weight and eating related issues, endorsement of the belief "smoking helps to control weight" dieting status (DEBQ-R), current and ideal weight and current height were assessed in 144 students.

RESULTS

Smoker (S) restrained eaters (RE) scored higher on dietary restraint than nonsmoker (NS) RE. In the smoking questionnaire, S-RE selected a significantly higher number of items concerning hunger, eating and weight than S unrestrained eaters (URE). S-RE had a greater level of endorsement of the belief: "smoking helps to control weight" than NS-URE. The subjects who marked those items had significantly higher scores in the DEBQ-R and were more likely to be RE than those who marked none of them.

CONCLUSION

Our findings suggest that among young women who smoke and diet there might be a risk group that smokes as a weight control strategy.

Interspecies transmission of an H7N3 influenza virus from wild birds to intensively reared domestic poultry in Italy

Since the "bird flu" incident in Hong Kong SAR in 1997, several studies have highlighted the substantial role of domestic birds, such as turkeys and chickens, in the ecology of influenza A viruses. Even if recent evidence suggests that chickens can maintain several influenza serotypes, avian influenza viruses (AIVs) circulating in domestic species are believed to be introduced each time from the wild bird reservoir. However, so far the direct precursor of influenza viruses from domestic birds has never been identified. In this report, we describe the antigenic and genetic characterization of the surface proteins of H7N3 viruses isolated from wild ducks in Italy in 2001 in comparison to H7N3 strains that circulated in Italian turkeys in 2002-2003. The wild and domestic avian strains appeared strictly related at both phenotypic and genetic level: homology percentages in seven of their genes were comprised between 99.8% (for PB2) and 99.1% (for M), and their NA genes differed mainly because of a 23-aminoacid deletion in the NA stalk. Outside this region of the molecule, the NAs of the two virus groups showed 99% similarity. These findings indicate that turkey H7N3 viruses were derived "in toto" from avian influenza strains circulating in wild waterfowl 1 year earlier, and represent an important step towards the comprehension of the mechanisms leading to interspecies transmission and emergence of potentially pandemic influenza viruses.

[Comprehensive treatment of obesity and its prevention]

Obesity is associated to chronic metabolic entities affecting the quality of life and life expectancy. An early treatment, if efficient, can overcome most of the problems. The normalisation of body composition, of energy reserves and their distribution, as well as the minimisation of weight dependent metabolic upsets and the establishment of therapeutic priorities, according to the repercussions of obesity, are important factors for the treatment of this disease. Prevention is important and its basis is teaching and the setting in healthy life style with modification of the food habits and the incorporation of physical work into everyday activities. Diet therapy, physical activity, pharmacotherapy, surgery education and psychology are the forms proposed for the treatment and prevention of obesity.

Characterization of the non-linear rate-dependency of QT interval in humans

AIMS

Repolarization has rate-dependent and rate-independent components. A function considering such components separately was validated in canine Purkinje fibres and applied to the QT/RR relation in humans.

METHODS AND RESULTS

Action potential duration (APD) was measured in Purkinje fibres during steady-state pacing at different cycle lengths (CL) and after prolonged quiescence (APD(0)). The APD/CL relationship was expressed by this function: APD=APD(max)(*)CL(S)/(CL(50)(S)+CL(S)), where APD(max) (APD extrapolated at infinite CL) is a rate-independent measure of repolarization, CL(50) (CL at which 50% of APD(max) is achieved) and S evaluates the rate dependency of APD. The same function was used to fit the QT/RR relation in 46 normal subjects (20 males, 26 females) and in 7 amiodarone-treated subjects undergoing a bicycle stress test. RR and QT (V(5)) were measured at the end of each load step; QT(c) (Bazett's formula) was obtained at rest. The APD/CL and QT/RR relations were equally well expressed by the function with high correlation coefficients (R>or=0.90). In Purkinje fibres, APD(max) was 461+/-37 ms, CL(50) was 394+/-54 ms and S was 0.98+/-0.11. APD(max) and APD(0) correlated (R=0.96) and were similar. The corresponding values in humans were: QT(max) 432+/-63 ms, RR(50) 345+/-60 ms and S 2.6+/-0.8. While QT(c) and QT(max) were longer in females, RR(50) and S were similar between genders. Amiodarone increased QT(c), QT(max) and RR(50) and decreased S. In QT(max) and QT(c) distributions generated by pooling data from treated and untreated subjects, 86% of treated subjects were correctly identified by QT(max) and 28% by QT(c).

CONCLUSIONS

Canine and human repolarization showed a saturating dependency on cycle length, described by the proposed function. Gender and amiodarone independently affected QT(max), RR(50) and S: therefore they might reflect specific ionic mechanisms. Finally, QT(max) identified drug-induced repolarization abnormalities in individual subjects better than QT(c).

Changes of autonomic cardiac profile after a 3-week integrated body weight reduction program in severely obese patients

The autonomic control of the heart is abnormal in obese subjects due to a prevalence of sympathetic over parasympathetic limb of the autonomic balance. We evaluated the effects of a short-term (3 weeks) integrated body weight reduction program (consisting of energy restricted diet and high-intensity exercise training) on heart rate variability (HRV) in severely obese, normotensive patients. The HRV was evaluated both in the time and frequency domain over a 18-hour Holter recording period obtained before and at the end of the third week. Three-week body weight reduction program reduced BMI (from 41.4 +/- 4.6 to 39.5 +/- 4.3 kg/m2, -4.6%, p<0.0001) and heart rate (from 77.8 +/- 8.6 to 73.6 +/- 8.7 b/min, p=0.0003). Significant changes in the autonomic profile were observed both in the time and frequency domain (SD of RR interval, SDRR: +16.1%; mean squared successive difference: (MSSD) +16.7%; percentage of RR intervals differing more than 50 msec from the preceding one, pNN50: +31.8%; low frequency oscillation, LF: +17.1%; high frequency oscillation, HF: +/- 18.2%). In conclusion, this study demonstrates that a short-term, integrated body weight reduction program is able to favorably modify the autonomic profile in a population of normotensive, severely obese subjects. The reduction of heart rate and the increase in parasympathetic activity may consistently contribute to a reduction of the risk of cardiovascular morbidity and of sudden cardiac death, still high in this patients' group.

[Antihypertensive therapy in the elderly: results of large trials]

The aim of this review was to evaluate if antihypertensive treatment in elderly hypertensive patients is able to lower the incidence of cardiovascular events when compared to hypertensive controls who received placebo. All trials agree in that the greater blood pressure reduction in hypertensive patients randomized to active treatment is associated with a minor incidence of cerebrovascular, cardiac and all cardiovascular events in comparison to placebo-treated control groups. Therefore the chronic antihypertensive treatment makes more good than bad. All antihypertensive agents have been used for the treatment of arterial hypertension in the elderly and all have shown a good efficacy and tolerability, even if, as in the adult hypertensives, the combination of two or more agents is necessary in the great majority of hypertensive patients to reach the target blood pressure. Because life expectancy is progressively longer and the prevalence of hypertension, in particular isolated systolic hypertension, is age-dependent, it is clinically relevant to investigate if there is an upper limit for the benefit of antihypertensive therapy. The results so far available suggest a benefit up to the age of 80 years, while an ongoing study is aimed at evaluating the benefit of antihypertensive therapy in patients > 80 years. Finally, according to our personal point of view, there are sufficient data to sustain the indication of a diastolic blood pressure reduction between 80 and 90 mmHg, while the indication to a reduction in systolic blood pressure below 140 mmHg is less strong and supported.