Complications of viral influenza

Lessons from a one-year hospital-based surveillance of acute respiratory infections in Berlin- comparing case definitions to monitor influenza

Background

Surveillance of severe acute respiratory infections (SARI) in sentinel hospitals is recommended to estimate the burden of severe influenza-cases. Therefore, we monitored patients admitted with respiratory infections (RI) in 9 Berlin hospitals from 7.12.2009 to 12.12.2010 according to different case definitions (CD) and determined the proportion of cases with influenza A(H1N1)pdm09 (pH1N1). We compared the sensitivity and specificity of CD for capturing pandemic pH1N1 cases.

Methods

We established an RI-surveillance restricted to adults aged ≤ 65 years within the framework of a pH1N1 vaccine effectiveness study, which required active identification of RI-cases. The hospital information-system was screened daily for newly admitted RI-patients. Nasopharyngeal swabs from consenting patients were tested by PCR for influenza-virus subtypes. Four clinical CD were compared in terms of capturing pH1N1-positives among hospitalized RI-patients by applying sensitivity and specificity analyses. The broadest case definition (CD1) was used for inclusion of RI-cases; the narrowest case definition (CD4) was identical to the SARI case definition recommended by ECDC/WHO.

Results

Over the study period, we identified 1,025 RI-cases, of which 283 (28%) met the ECDC/WHO SARI case definition. The percentage of SARI-cases among internal medicine admissions decreased from 3.2% (calendar-week 50-2009) to 0.2% (week 25-2010). Of 354 patients tested by PCR, 20 (6%) were pH1N1-positive. Two case definitions narrower than CD1 but -in contrast to SARI- not requiring shortness of breath yielded the largest areas under the Receiver-Operator-Curve. Heterogeneity of proportions of patients admitted with RI between hospitals was significant.

Conclusions

Comprehensive surveillance of RI cases was feasible in a network of community hospitals. In most settings, several hospitals should be included to ensure representativeness. Although misclassification resulting from failure to obtain symptoms in the hospital information-system cannot be ruled out, a high proportion of hospitalized PCR-positive pH1N1-patients (45%) did not fulfil the SARI case-definition that included shortness of breath or difficulty breathing. Thus, to assess influenza-related disease burden in hospitals, broader, alternative case definitions should be considered.

Mucosal antibody responses are directed by viral burden in children with acute influenza infection

Please cite this paper as: He et al. (2012) Mucosal antibody responses are directed by viral burden in children with acute influenza infection. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2012.00346.x.

Background  Influenza infection causes excess hospitalizations and deaths in younger patients, but susceptibility to severe disease is poorly understood. While mucosal antibodies can limit influenza‐associated infection and disease, little is known about acute mucosal antibody responses to influenza infection.

Objectives  These studies characterize mucosal antiviral antibody production in children during lower respiratory infection (LRI) with H1N1 influenza versus other viral LRI and examine the relationship between mucosal antiviral antibodies and protection against severe disease.

Methods  B lymphocytes were assessed by immunohistochemistry in lung tissue from infants with fatal acute seasonal influenza infection. Nasopharyngeal secretions (NPS) were obtained at presentation from children with acute respiratory illness, including H1N1 (2009) influenza infection. Total and antiviral antibodies, and inflammatory and immune mediators, were quantified by ELISA. Neutralizing activity in NPS was detected using a pseudotyped virus assay. Viral burden was assessed by qPCR.

Results and conclusions  B lymphocytes were abundant in lung tissue of infants with fatal acute influenza LRI. Among surviving children with H1N1 infection, only a small subset (11%) demonstrated H1N1 neutralizing activity in NPS. H1N1 neutralizing activity coincided with high local levels of antiviral IgM, IgG and IgA, greater detection of inflammatory mediators, and higher viral burden (P = 0·016). Patients with mucosal antiviral antibody responses demonstrated more severe respiratory symptoms including greater hypoxia (P = 0·0018) and pneumonia (P = 0·038). These patients also trended toward younger age, longer duration of illness and longer hospital stays. Prophylaxis strategies that heighten neutralizing antibody production in the mucosa are likely to benefit both older and younger children.

The role of viruses in the pathogenesis of peritonsillar abscess

Peritonsillar abscess (PTA) is the most frequent complication of acute tonsillitis and a prevalent cause for acute admission to otorhinolaryngology departments. Our aim was to examine the role of viruses in the pathogenesis of PTA, as this has not previously been considered. We examined both palatine tonsils from 25 patients undergoing acute tonsillectomy for PTA, using PCR-based assays for herpes simplex virus-1 and -2 (HSV-1 and -2), adenovirus, Epstein-Barr virus (EBV), influenza A and B, and respiratory syncytial virus (RSV) A and B. We similarly examined tonsils from 55 patients undergoing elective tonsillectomy due to chronic tonsillar conditions. These patients served as a control group, as they did not have a clinically apparent infection at the time of surgery. Only HSV-1 (5/80, 6.3%), adenovirus (11/80, 13.8%), and EBV (71/80, 88.8%) were detected in our study population. There was no statistically significant difference in the frequency of these viruses across different diagnostic groups. Quantification of EBV load demonstrated no differences between the PTA and the elective tonsillectomy group, nor between the abscessed and non-abscessed tonsil of PTA patients. In summary, our data do not support a significant role for the examined viruses in the pathogenesis of PTA.

Differential effect of prior influenza infection on alveolar macrophage phagocytosis of Staphylococcus aureus and Escherichia coli: involvement of interferon-gamma production

The influenza A virus is one of the main causes of respiratory infection. Although influenza virus infection alone can result in pneumonia, secondary bacterial infection combined with the virus is the major cause of morbidity and mortality. Interestingly, while influenza infection increases susceptibility to some bacteria, including Streptococcus pneumoniae, Staphylococcus aureus (S. aureus), and Haemophilus influenzae, other bacteria such as Escherichia coli (E. coli) and Klebsiella pneumoniae are not associated with influenza infection. The reason for this discrepancy is not known. In this study, it was found that prior influenza virus infection inhibits murine alveolar macrophage phagocytosis of S. aureus but not of E. coli. Here, the mechanism for this inhibition is elucidated: prior influenza virus infection strongly increases interferon gamma (IFN-γ) production. Furthermore, it was shown that IFN-γ differentially affects alveolar macrophage phagocytosis of S. aureus and E. coli. The findings of the present study explain how influenza virus infection increases susceptibility to some bacteria, such as S. aureus, but not others, and provides evidence that IFN-γ might be a promising target for protecting the human population from secondary bacterial infection by influenza.

Progressive osteolysis and surface chondrolysis of the proximal humerus following influenza vaccination

Influenza vaccination is a common annual event among individuals in the United States. Complications, although infrequent, are usually mild and self-limiting. This article describes the case of a 46-year-old man who experienced progressive osteolysis and surface chondrolysis of the proximal humerus following routine influenza vaccination. The patient presented with shoulder pain and limited range of motion 3 weeks following vaccination in the deltoid area. No skin changes were noted, inflammatory markers were normal, and the patient's pain and disability persisted despite nonsteroidal anti-inflammatory drugs and occupational therapy. Plain radiographs revealed a small lytic area involving the greater tuberosity of the humeral head. Magnetic resonance imaging (MRI) showed abnormal uptake and cystic changes involving the greater tuberosity of the humeral head; repeat MRI at 5 months showed progression in the cystic changes. Diagnostic arthroscopy of the shoulder revealed a hyperemic joint capsule and extensive, full-thickness chondrolysis of the humeral head. Cystic biopsy demonstrated inflammatory cells and granulation tissue, consistent with foreign body response. Cultures were negative. Surgical debridement of the cystic areas and resurfacing of the humeral head yielded a good outcome. To our knowledge, this is the first reported complication of influenza vaccination requiring surgical intervention. Physicians need to be aware of the potential for osteolysis and chondrolysis, which may require aggressive forms of management.

Epidemiology and management of common pulmonary diseases in older persons

Pulmonary disease prevalence increases with age and contributes to morbidity and mortality in older patients. Dyspnea in older patients is often ascribed to multiple etiologies such as medical comorbidities and deconditioning. Common pulmonary disorders are frequently overlooked as contributors to dyspnea in older patients. In addition to negative impacts on morbidity and mortality, quality of life is reduced in older patients with uncontrolled, undertreated pulmonary symptoms. The purpose of this review is to discuss the epidemiology of common pulmonary diseases, namely pneumonia, chronic obstructive pulmonary disease, asthma, lung cancer, and idiopathic pulmonary fibrosis in older patients. We will review common clinical presentations for these diseases and highlight differences between younger and older patients. We will also briefly discuss risk factors, treatment, and mortality associated with these diseases. Finally, we will address the relationship between comorbidities, pulmonary symptoms, and quality of life in older patients with pulmonary diseases.

Synergistic TLR2/6 and TLR9 activation protects mice against lethal influenza pneumonia

Lower respiratory tract infections caused by influenza A continue to exact unacceptable worldwide mortality, and recent epidemics have emphasized the importance of preventative and containment strategies. We have previously reported that induction of the lungs' intrinsic defenses by aerosolized treatments can protect mice against otherwise lethal challenges with influenza A virus. More recently, we identified a combination of Toll like receptor (TLR) agonists that can be aerosolized to protect mice against bacterial pneumonia. Here, we tested whether this combination of synthetic TLR agonists could enhance the survival of mice infected with influenza A/HK/8/68 (H3N2) or A/California/04/2009 (H1N1) influenza A viruses. We report that the TLR treatment enhanced survival whether given before or after the infectious challenge, and that protection tended to correlate with reductions in viral titer 4 d after infection. Surprisingly, protection was not associated with induction of interferon gene expression. Together, these studies suggest that synergistic TLR interactions can protect against influenza virus infections by mechanisms that may provide the basis for novel therapeutics.

Therapeutic efficacy of Hypericum perforatum L. extract for mice infected with an influenza A virus

Hypericum perforatum L., a plant used in Chinese herbal medicine, has been proven effective against many viral diseases. In the present study, the therapeutic efficacy of an extract of H. perforatum (HPE) against influenza A virus (IAV) was investigated in mice. Whether HPE would be a promising agent for influenza treatment was evaluated by measuring the protection rate, mean survival days, lung index, and viral titer, as well as the secretion of IL-6, interleukin-10 (IL-10), tumour necrosis factor-α (TNF-α), and interferon-gamma (IFN-γ) in lung tissue and serum on days 3 and 5 post-infection. The results showed that HPE could reduce the lung index and viral titer of mice infected with IAV, decrease mortality, and prolong the mean survival time. HPE decreased the concentration of IL-6 and TNF-α in lung tissue and serum on day 5 post-infection. In contrast, HPE enhanced the lung and serum levels of IL-10 and IFN-γ on the days 3 and 5 post-infection. Our study indicates that HPE has significant therapeutic efficacy for mice infected with IAV. The possible reasons for these results were concluded to be pertaining to up-regulating the expression of IL-10 and IFN-γ, and down-regulating the secretion of IL-6 and TNF-α in lung and serum.

Delay in diagnosis of influenza virus in an elderly hospitalized patient: a fatal outcome

Influenza is a well established cause of seasonal hospitalizations and deaths among older persons. However, influenza is frequently underdiagnosed by physicians, because its clinical presentations are often complex, particularly in elderly patients. We report the case of a 78-year-old woman admitted to the emergency department in January 2008 with fever, vomiting, and a history of asthenia and falls in the preceding three days. Diagnosis of influenza at admission was missed. Influenza was diagnosed by direct fluorescent antibody in a sputum specimen four days later, but the evolution was rapidly unfavorable with fatal respiratory distress syndrome. This case illustrates that, during the influenza season, influenza should be suspected in elderly patients admitted to hospital even if they do not present with classical symptoms. Immunofluorescence testing on sputum specimens can provide a rapid diagnosis and merits further evaluation.

Performance of the QuickVue Influenza A+B rapid test for pandemic H1N1 (2009) virus infection in adults

To investigate the diagnostic accuracy of the QuickVue® Influenza A+B rapid test we conducted a prospective observational study in which this rapid test was compared with a real-time reverse transcription polymerase chain reaction (RT-PCR) for pandemic influenza A H1N1 (2009) infection in Austrian adults. The sensitivity, specificity, and positive and negative predictive values of the QuickVue test compared with the RT-PCR were 26% (95% CI 18–35), 98% (95% CI 92–100), 94% (95% CI 80–99) and 50% (95% CI 42–58), respectively. The prevalence of pandemic H1N1 (2009) virus infection among the 209 patients included in the study was 57%. Our data suggest that a positive QuickVue test provides considerable information for the diagnosis of pandemic influenza A H1N1 (2009) virus infection in young adults but that a negative QuickVue test result should, if relevant for patient management or public health measures, be verified using PCR.

Pandemic H1N1 influenza

The 2009 H1N1 influenza A virus that has targeted not only those with chronic medical illness, the very young and old, but also a large segment of the patient population that has previously been afforded relative protection - those who are young, generally healthy, and immune naive. The illness is mild in most, but results in hospitalization and severe ARDS in an important minority. Among those who become critically ill, 20-40% will die, predominantly of severe hypoxic respiratory failure. However, and potentially in part due to the young age of those affected, intensive care with aggressive oxygenation support will allow most people to recover. The volume of patients infected and with critical illness placed substantial strain on the capacity of the health care system and critical care most specifically. Despite this, the 2009 pandemic has engaged our specialty and highlighted its importance like no other. Thus far, the national and global critical care response has been brisk, collaborative and helpful - not only for this pandemic, but for subsequent challenges in years ahead.

Hospital-acquired viral infection increases mortality in children with severe viral respiratory infection

OBJECTIVE

To investigate the association of method of acquisition (hospital-acquired vs. community-acquired) and mortality in children with severe viral respiratory infection.

DESIGN

Retrospective cohort study.

SETTING

: Pediatric intensive care unit at an urban academic tertiary care children's hospital.

PATIENTS

All patients aged <18 yrs admitted to our pediatric intensive care unit with laboratory-confirmed respiratory syncytial virus, influenza, parainfluenza, or adenovirus infection between October 2002 and September 2008.

INTERVENTIONS

We stratified patients by method of viral acquisition and identified those patients with chronic medical conditions associated with an increased risk of complications from viral illness.

MEASUREMENTS AND MAIN RESULTS

There were 289 patients admitted to the pediatric intensive care unit with laboratory-confirmed viral respiratory infection during the period of study. Fifty-three patients (18%) had hospital-acquired infection and 117 patients (40%) had chronic medical conditions associated with an increased risk of complications from viral illness. Hospital-acquired infection was associated with increased mortality and length of stay (all p < .001). Adjusting for age, chronic medical conditions, severity of illness index, and catheter-associated bloodstream infections, patients with hospital-acquired infection had a 5.8 (95% confidence interval 2.1-15.6) times greater odds (p = .001) of mortality.

CONCLUSIONS

Our results suggest that in children with severe viral respiratory infection, hospital acquisition of infection is associated with increased mortality even after adjusting for chronic medical conditions that predispose to an increased risk of complications from viral illness.

Green tea consumption is inversely associated with the incidence of influenza infection among schoolchildren in a tea plantation area of Japan

Green tea is known to contain antiviral components that prevent influenza infection. A limited number of adult clinical studies have been undertaken, but there is a paucity of clinical evidence concerning children. We conducted an observational study to determine the association between green tea consumption and the incidence of influenza infection among schoolchildren. Anonymous questionnaire surveys were undertaken twice during the influenza season from November 2008 to February 2009 (endemic seasonal type A influenza infection); each survey was conducted for 2663 pupils across all elementary schools in Kikugawa City (a tea plantation area), Japan. Each questionnaire was completed and submitted by 2050 pupils (response rate, 77.0%; age range, 6-13 y). The adjusted OR associated with the consumption of green tea for ≥6 d/wk compared with <3 d/wk was 0.60 [(95% CI = 0.39-0.92); P = 0.02] in cases of influenza confirmed by the antigen test. Meanwhile, the adjusted OR inversely associated with the consumption of 1 cup/d to <3 cups/d (1 cup = 200 mL) and 3-5 cups/d compared with <1 cup/d were 0.62 [(95% CI = 0.41-0.95); P = 0.03] and 0.54 [(95% CI = 0.30-0.94); P = 0.03], respectively. However, there was no significant association with the consumption of >5 cups/d. Our findings thus suggest that the consumption of 1-5 cups/d of green tea may prevent influenza infection in children.

Clinical characteristics and outcomes of hospitalized patients with 2009 H1N1 influenza in a large acute care tertiary hospital, Singapore

This study describes the clinical characteristics and outcomes of hospitalized patients with 2009 H1N1 influenza in a large, acute care, tertiary hospital in Singapore. Of the 265 hospitalized patients with laboratory-confirmed 2009 influenza A (H1N1) during the height of the H1N1 flu pandemic, 13% (35) suffered severe outcomes including a mortality rate of 4.5% (12). Severe outcomes were associated with patients aged 40 years or more, underlying comorbidities, and complicated by pneumonia.

Pneumonia complicating pandemic (H1N1) 2009: risk factors, clinical features, and outcomes

We performed an observational analysis of a prospective cohort of adults hospitalized for pandemic (H1N1) 2009 at 13 Spanish hospitals, from June to November 2009, to determine the risk factors, clinical features, and outcomes of pneumonia. Of 585 patients requiring hospitalization, chest radiography was obtained in 542. A total of 234 (43.1%) patients had pneumonia, of whom 210 underwent bacterial microbiologic studies. Of these patients, 174 (82.8%) had primary viral pneumonia and 36 (17.2%) had concomitant/secondary bacterial pneumonia. Bilateral pneumonia occurred in 48.3% of patients. Streptococcus pneumoniae was the most frequent pathogen among patients with bacterial pneumonia (26 of 36 patients). None of them had received pneumococcal vaccine. Compared with patients without pneumonia, those with pneumonia more frequently had shock during hospitalization (9.8% vs. 1%; p < 0.001), required intensive care unit admission (22.6% vs. 5.8%; p < 0.001), underwent mechanical ventilation (17.9% vs. 3.2%; p < 0.001), and had longer length of hospital stay (median, 7 d vs. 5 d; p < 0.001). In-hospital mortality was higher in patients with pneumonia than in the others (5.2% vs. 0%; p < 0.001). Absence of comorbid conditions (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.32-3.24) was found to be an independent risk factor for pneumonia, whereas early (≤ 48 h) oseltamivir therapy (OR, 0.29; 95% CI, 0.19-0.46) was a protective factor. In conclusion, pneumonia is a frequent complication among adults hospitalized for pandemic (H1N1) 2009 and causes significant morbidity. Mortality in pandemic (H1N1) 2009 is low, but occurs mainly in patients with pneumonia. Early oseltamivir therapy is a protective factor for this complication.

Severe influenza cases in paediatric intensive care units in Germany during the pre-pandemic seasons 2005 to 2008

BACKGROUND

Data on complications in children with seasonal influenza virus infection are limited. We initiated a nation-wide three-year surveillance of children who were admitted to a paediatric intensive care unit (PICU) with severe seasonal influenza.

METHODS

From October 2005 to July 2008, active surveillance was performed using an established reporting system for rare diseases (ESPED) including all paediatric hospitals in Germany. Cases to be reported were hospitalized children < 17 years of age with laboratory-confirmed influenza treated in a PICU or dying in hospital.

RESULTS

Twenty severe influenza-associated cases were reported from 14 PICUs during three pre-pandemic influenza seasons (2005-2008). The median age of the patients (12 males/8 females) was 7.5 years (range 0.1-15 years). None had received vaccination against influenza. In 14 (70%) patients, the infection had been caused by influenza A and in five (25%) by influenza B; in one child (5%) the influenza type was not reported. Patients spent a median of 19 (IQR 12-38) days in the hospital and a median of 11 days (IQR 6-18 days) in the PICU; 10 (50%) needed mechanical ventilation. Most frequent diagnoses were influenza-associated pneumonia (60%), bronchitis/bronchiolitis (30%), encephalitis/encephalopathy (25%), secondary bacterial pneumonia (25%), and ARDS (25%). Eleven (55%) children had chronic underlying medical conditions, including 8 (40%) with chronic pulmonary diseases. Two influenza A- associated deaths were reported: i) an 8-year old boy with pneumococcal encephalopathy following influenza infection died from cerebral edema, ii) a 14-year-old boy with asthma bronchiale, cardiac malformation and Addison's disease died from cardiac and respiratory failure. For nine (45%) patients, possibly permanent sequelae were reported (3 neurological, 3 pulmonary, 3 other sequelae).

CONCLUSIONS

Influenza-associated pneumonia and secondary bacterial infections are relevant complications of seasonal influenza in Germany. The incidence of severe influenza cases in PICUs was relatively low. This may be either due to the weak to moderate seasonal influenza activity during the years 2005 to 2008 or due to under-diagnosis of influenza by physicians. Fifty% of the observed severe cases might have been prevented by following the recommendations for vaccination of risk groups in Germany.

When should a diagnosis of influenza be considered in adults requiring intensive care unit admission? Results of population-based active surveillance in Toronto

Introduction

There is a paucity of data about the clinical characteristics that help identify patients at high risk of influenza infection upon ICU admission. We aimed to identify predictors of influenza infection in patients admitted to ICUs during the 2007/2008 and 2008/2009 influenza seasons and the second wave of the 2009 H1N1 influenza pandemic as well as to identify populations with increased likelihood of seasonal and pandemic 2009 influenza (pH1N1) infection.

Methods

Six Toronto acute care hospitals participated in active surveillance for laboratory-confirmed influenza requiring ICU admission during periods of influenza activity from 2007 to 2009. Nasopharyngeal swabs were obtained from patients who presented to our hospitals with acute respiratory or cardiac illness or febrile illness without a clear nonrespiratory aetiology. Predictors of influenza were assessed by multivariable logistic regression analysis and the likelihood of influenza in different populations was calculated.

Results

In 5,482 patients, 126 (2.3%) were found to have influenza. Admission temperature ≥38°C (odds ratio (OR) 4.7 for pH1N1, 2.3 for seasonal influenza) and admission diagnosis of pneumonia or respiratory infection (OR 7.3 for pH1N1, 4.2 for seasonal influenza) were independent predictors for influenza. During the peak weeks of influenza seasons, 17% of afebrile patients and 27% of febrile patients with pneumonia or respiratory infection had influenza. During the second wave of the 2009 pandemic, 26% of afebrile patients and 70% of febrile patients with pneumonia or respiratory infection had influenza.

Conclusions

The findings of our study may assist clinicians in decision making regarding optimal management of adult patients admitted to ICUs during future influenza seasons. Influenza testing, empiric antiviral therapy and empiric infection control precautions should be considered in those patients who are admitted during influenza season with a diagnosis of pneumonia or respiratory infection and are either febrile or admitted during weeks of peak influenza activity.

Bacteria-specific neutrophil dysfunction associated with interferon-stimulated gene expression in the acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a poorly understood condition with greater than 30% mortality. Massive recruitment of neutrophils to the lung occurs in the initial stages of the ARDS. Significant variability in the severity and duration of ARDS-associated pulmonary inflammation could be linked to heterogeneity in the inflammatory capacity of neutrophils. Interferon-stimulated genes (ISGs) are a broad gene family induced by Type I interferons. While ISGs are central to anti-viral immunity, the potential exists for these genes to evoke extensive modification in cellular response in other clinical settings. In this prospective study, we sought to determine if ISG expression in circulating neutrophils from ARDS patients is associated with changes in neutrophil function. Circulating neutrophil RNA was isolated, and hierarchical clustering ranked patients' expression of three ISGs. Neutrophil response to pathogenic bacteria was compared between normal and high ISG-expressing neutrophils. High neutrophil ISG expression was found in 25 of 95 (26%) of ARDS patients and was associated with reduced migration toward interleukin-8, and altered responses to Staphylococcus aureus, but not Pseudomonas aeruginosa, which included decreased p38 MAP kinase phosphorylation, superoxide anion release, interleukin-8 release, and a shift from necrotic to apoptotic cell death. These alterations in response were reflected in a decreased capacity to kill S. aureus, but not P. aeruginosa. Therefore, the ISG expression signature is associated with an altered circulating neutrophil response phenotype in ARDS that may predispose a large subgroup of patients to increased risk of specific bacterial infections.

Association of bacterial pneumonia and respiratory failure in children with community-acquired influenza infection

OBJECTIVE

To investigate the association of bacterial pneumonia and respiratory failure in children with community-acquired influenza infection presenting to a pediatric intensive care unit.

DESIGN

Retrospective cohort study.

SETTING

Pediatric intensive care unit at an urban academic tertiary-care children's hospital.

PATIENTS

All patients aged <18 yrs admitted to our pediatric intensive care unit with laboratory-confirmed influenza infection between October 2002 and September 2008.

INTERVENTIONS

All patients who met our clinical definitions of respiratory failure and bacterial pneumonia were identified. Patients were stratified by presence or absence of chronic medical conditions associated with an increased risk of influenza-related complications.

MEASUREMENTS AND MAIN RESULTS

There were 59 patients admitted to the pediatric intensive care unit with laboratory-confirmed community-acquired influenza during the period of study. Twenty-four patients (41%) had respiratory failure and 14 patients (24%) met the definition of bacterial pneumonia. The risk of respiratory failure was increased in the presence of bacterial pneumonia (p = .04). Adjusting for age and chronic medical conditions, patients with bacterial pneumonia had a 3.7 times greater odds (p = .04) of respiratory failure.

CONCLUSIONS

Our findings suggest that bacterial pneumonia was associated with increased odds of respiratory failure in both previously healthy children and those with chronic medical conditions. Early aggressive therapy should be considered for patients with severe influenza.

Hospital admissions related to influenza in France during the 2006/2007 epidemic

BACKGROUND

The data available on hospital admissions related to influenza mostly concern in-patients admitted via the emergency department. Severe cases have been collated by intensive care practitioners since 2009. For this survey, we searched French hospital admission databases to estimate the prevalence rate of hospital admissions related to influenza and to record qualitative data.

METHOD

All case studies identified between October 2006 and September 2007 were split into two groups: the first displaying symptoms of clinical influenza and the second suffering from influenza as an associated diagnosis.

RESULTS

We collected 6797 hospital admissions, 2126 of which were closely related to clinical influenza. Fifty percent of cases concerned the elderly and young people. Fifty-six hospital deaths were recorded in which influenza was the underlying cause in 21% of the cases (12). When influenza was an associated diagnosis (44/56), cardiovascular or respiratory diseases were the main causes (26/44).

CONCLUSION

During the same period (2006-2007), the French Sentinel Surveillance identified only 105 hospital admissions related to influenza. Our survey was therefore more exhaustive and was able to record qualitative data. Inclusion of hospital admissions with an associated diagnosis of influenza is debatable because this decreases specificity. The relationship between the principal diagnosis and all the associated diagnoses is difficult to study, although exclusion of this type of hospitalization could significantly underestimate these figures. Despite certain limitations, French hospital admissions databases should complement French Sentinel Surveillance data.

Modulation of human beta-defensin-1 (hBD-1) in plasmacytoid dendritic cells (PDC), monocytes, and epithelial cells by influenza virus, Herpes simplex virus, and Sendai virus and its possible role in innate immunity

hBD comprise a family of antimicrobial peptides that plays a role in bridging the innate and adaptive immune responses to infection. The expression of hBD-2 increases upon stimulation of numerous cell types with LPS and proinflammatory cytokines. In contrast, hBD-1 remains constitutively expressed in most cells in spite of cytokine or LPS stimulation; however, its presence in human PDC suggests it plays a role in viral host defense. To examine this, we characterized the expression of hBD-1 in innate immune cells in response to viral challenge. PDC and monocytes increased production of hBD-1 peptide and mRNA as early as 2 h following infection of purified cells and PBMCs with PR8, HSV-1, and Sendai virus. However, treatment of primary NHBE cells with influenza resulted in a 50% decrease in hBD-1 mRNA levels, as measured by qRT-PCR at 3 h following infection. A similar inhibition occurred with HSV-1 challenge of human gingival epithelial cells. Studies with HSV-1 showed that replication occurred in epithelial cells but not in PDC. Together, these results suggest that hBD-1 may play a role in preventing viral replication in immune cells. To test this, we infected C57BL/6 WT mice and mBD-1((-/-)) mice with mouse-adapted HK18 (300 PFU/mouse). mBD-1((-/-)) mice lost weight earlier and died sooner than WT mice (P=0.0276), suggesting that BD-1 plays a role in early innate immune responses against influenza in vivo. However, lung virus titers were equal between the two mouse strains. Histopathology showed a greater inflammatory influx in the lungs of mBD-1((-/-)) mice at Day 3 postinfection compared with WT C57BL/6 mice. The results suggest that BD-1 protects mice from influenza pathogenesis with a mechanism other than inhibition of viral replication.

Influenza A-induced rhabdomyolysis and acute kidney injury complicated by posterior reversible encephalopathy syndrome

We report a case of Influenza A-induced rhabdomyolysis causing acute kidney injury in a young adult female who required invasive ventilation and renal replacement therapy. This case was further complicated by posterior reversible encephalopathy syndrome. Although this represents an extremely rare neurological complication of Influenza A infection, an appreciation of the condition and its management is important, given the high numbers of critically ill patients recently affected by H1N1 Influenza A in intensive care units in the UK.

Influenza pharmacotherapy: present situation, strategies and hopes

INTRODUCTION

Influenza is a serious health threat for people of all ages. The causative virus is evolving continuously and the risk of an unexpected mutant, which cannot be controlled by seasonal vaccination, is real. New and more effective antiviral drugs are needed.

AREAS COVERED

This review examines the antiviral drugs with confirmed efficacy in combating influenza, as well as newer compounds that are currently undergoing testing and will hopefully be marketed in the near future. A comprehensive, state-of-the-art picture of drug therapy for influenza is presented, including novel solutions and effective strategies for prescribing currently available antiviral drugs, with emphasis on the importance of updated local epidemiological data, clinical assessment and laboratory testing.

EXPERT OPINION

Current anti-influenza drug research is no longer tied solely to viral envelope protein targets like haemagglutinin and neuraminidase. New drugs act on the viral RNA polymerase complex, which is involved in transcription and replication of the viral genome, and can prevent the maturation, replication and dissemination of numerous viral subtypes. Combating this infection and reducing the duration of symptoms also has important socioeconomic implications related to health-care spending (including hospitalization for complications) and sick-leave pay for workers.

Rapid death of duck cells infected with influenza: a potential mechanism for host resistance to H5N1

Aquatic birds are the natural reservoir for most subtypes of influenza A, and a source of novel viruses with the potential to cause human pandemics, fatal zoonotic disease or devastating epizootics in poultry. It is well recognised that waterfowl typically show few clinical signs following influenza A infection, in contrast, terrestrial poultry such as chickens may develop severe disease with rapid death following infection with highly pathogenic avian influenza. This study examined the cellular response to influenza infection in primary cells derived from resistant (duck) and susceptible (chicken) avian hosts. Paradoxically, we observed that duck cells underwent rapid cell death following infection with low pathogenic avian H2N3, classical swine H1N1 and ‘classical' highly pathogenic H5N1 viruses. Dying cells showed morphological features of apoptosis, increased DNA fragmentation and activation of caspase 3/7. Following infection of chicken cells, cell death occurred less rapidly, accompanied by reduced DNA fragmentation and caspase activation. Duck cells produced similar levels of viral RNA but less infectious virus, in comparison with chicken cells. Such rapid cell death was not observed in duck cells infected with a contemporary Eurasian lineage H5N1 fatal to ducks. The induction of rapid death in duck cells may be part of a mechanism of host resistance to influenza A, with the loss of this response leading to increased susceptibility to emergent strains of H5N1. These studies provide novel insights that should help resolve the long-standing enigma of host–pathogen relationships for highly pathogenic and zoonotic avian influenza.

Protective effect of a polyphenolic rich extract from Magnolia officinalis bark on influenza virus-induced pneumonia in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Magnolia officinalis bark is used in traditional Chinese medicine for the treatment of cough, colds, fever, chronic bronchitis and stomach ailments.

AIM OF THE STUDY

To investigate therapeutic effects of polyphenol rich extract from M. officinalis bark (MPE) in influenza virus A-infected mice, and to provide evidence for the inflammation response and immunomodulatory potential during infection.

MATERIALS AND METHODS

Mice were infected with influenza virus A (IVA) and MPE at doses of 10 and 20mg/kg were orally administrated daily for 5 days after challenge. The levels of serum L-6 and TNF-α were determined by ELISA while protein expressions of NF-κB and TLR3 were detected by western blotting analysis.

RESULTS

MPE exhibited significant therapeutical effects on reducing levels of serum NO, IL-6 and TNF-α, inhibiting pneumonia, decreasing lung viral titers and sensitizing IVA-induced apoptosis through down-regulation of NF-κB and TLR3 protein expression in the lung tissue of IVA-infected mice.

CONCLUSIONS

MPE could exhibit preventive and therapeutical effects on IVA-infected mice as a suppressor of the production of inflammatory mediators, NO and pro-inflammatory cytokines, TNF-α and IL-6. These effects appeared to be mediated, at least in part, by an inhibition of TLR3 and NF-κB activation. Therefore, MPE could provide a safe and effective therapeutic approach for influenza and its subsequent viral pneumonia.

Staphylococcus aureus carriage among GPs in The Netherlands

BACKGROUND

The extent to which GPs serve as a reservoir for antibiotic-resistant Staphylococcus aureus is unknown and not well studied.

AIM

To determine the prevalence of nasal S. aureus carriage among GPs in the Netherlands, as well as the antimicrobial resistance and the genotypes of isolated S. aureus.

DESIGN OF STUDY

Observational, point-prevalence, and cross-sectional study.

SETTING

GPs attending the annual conference of the Dutch College of General Practitioners in 2006.

METHOD

Nasal swabs were randomly taken from 395 GPs and analysed for the presence of S. aureus. Antimicrobial susceptibility was determined by a microbroth dilution method and the genotypes by spa typing, which was associated with multilocus sequence typing.

RESULTS

Of the GPs, 129/395 (33%; 95% confidence interval [CI] = 28 to 37%) were carriers of S. aureus. No meticillin-resistant S. aureus (MRSA) was found. Resistance was observed to penicillin (71%; 95% CI = 63 to 79%), fusidic acid (7%; 95% CI = 3 to 13%), and clarithromycin (6%; 95% CI = 3 to 12%). In 72% of the isolates, an MRSA-related genotype of S. aureus was found.

CONCLUSION

The low antibiotic resistance found among S. aureus of GPs suggests that GPs are not a reservoir of antibiotic-resistant S. aureus strains. The relatively high resistance to fusidic acid, which has not previously been described in the Netherlands and is mostly because of antibiotic use, suggests that patients infect GPs and not the other way round. GPs may be at risk for nasal carriage of S. aureus with an MRSA-related genotype.

Clinical epidemiology comparison of H1N1 RT-PCR-positive and RT-PCR-negative pneumonia during the 2009-2010 pandemic in Mansoura University hospitals, Egypt

BACKGROUND

Worldwide, the infectivity and disease burden of the H1N1 pandemic were overestimated because of limited clinical experience concerning patient presentation and outcome of those infected with the novel H1N1 virus.

OBJECTIVE

This study aimed to compare the epidemiologic clinical data among H1N1 RT-PCR-positive and RT-PCR-negative pneumonic patients during the 2009-2010 pandemic in Mansoura University Hospitals, Egypt.

METHODS

A record-based, case-control study was conducted for 43 adult patients admitted to the chest department isolation unit with community-acquired pneumonia during the 2009-2010 H1N1 pandemic after reviewing of 198 suspected and confirmed H1N1 hospitalized cases. Of these patients, 20 cases were confirmed to be H1N1-positive using an RT-PCR detection technique. The remaining 23 patients were RT-PCR-negative. Demographic, clinical, laboratory and radiological data were collected and analyzed using spss version 11.

RESULTS

A review of 198 hospital case records for revealed one main peak of H1N1 influenza during the last week of December 2009. Pneumonic patients who were H1N1-positive were more likely to present with sore throat (P = 0·005), dyspnea (P = 0·002), and gastrointestinal (GIT) complaints (vomiting and diarrhea P = 0·02) when compared to the H1N1-negative group. Also, complications were significantly more frequent (P = 0·01) in the H1N1-confirmed group than in the non-confirmed group. However, no significant differences were found between the groups regarding length of hospital stay, intensive care unit (ICU), and admission or mortality.

CONCLUSION

Sore throat, dyspnea, and presence of GIT complaints increase the suspicion of H1N1 positivity in pneumonia acquired during an H1N1 pandemic. However, H1N1 did not worsen the disease burden of pneumonia.

PPAR-gamma activation as an anti-inflammatory therapy for respiratory virus infections

Newly emerged influenza viruses have attracted extensive attention due to their high infectivity, proinflammatory actions, and potential to induce worldwide pandemics. Frequent mutations and gene reassortments between viruses complicate the development of protective vaccines and antiviral therapeutics. In contrast, targeting the host response for the development of novel cost-effective, broad-based prophylactic or therapeutic agents holds greater promise. Since inflammation often parallels the development of productive immune responses, virus-induced pulmonary inflammation and injury represents an additional challenge to the development of broad-based immunotherapeutics. Excessive inflammatory responses to respiratory viruses, also known as "cytokine storm," are largely due to immune dysregulation that manifests as proinflammatory cytokine secretion. In addition to modulating lipid and glucose metabolism, peroxisome proliferator-activated receptors (PPAR) play important roles in antagonizing core inflammatory pathways such as NF-kappaB, AP1, and STAT. Their role in regulating inflammatory responses caused by pulmonary pathogens is receiving increasing attention, setting the stage for the discovery of novel applications for anti-diabetic and lipid-lowering drugs. This review focuses on the potential use of PPAR-gamma agonists to downregulate the inflammatory responses to respiratory virus-related pulmonary inflammation.

Clinical and laboratory features distinguishing pandemic H1N1 influenza-related pneumonia from interpandemic community-acquired pneumonia in adults

BACKGROUND

Early identification of patients with H1N1 influenza-related pneumonia is desirable for the early instigation of antiviral agents. A study was undertaken to investigate whether adults admitted to hospital with H1N1 influenza-related pneumonia could be distinguished clinically from patients with non-H1N1 community-acquired pneumonia (CAP).

METHODS

Between May 2009 and January 2010, clinical and epidemiological data of patients with confirmed H1N1 influenza infection admitted to 75 hospitals in the UK were collected by the Influenza Clinical Information Network (FLU-CIN). Adults with H1N1 influenza-related pneumonia were identified and compared with a prospective study cohort of adults with CAP hospitalised between September 2008 and June 2010, excluding those admitted during the period of the pandemic.

RESULTS

Of 1046 adults with confirmed H1N1 influenza infection in the FLU-CIN cohort, 254 (25%) had H1N1 influenza-related pneumonia on admission to hospital. In-hospital mortality of these patients was 11.4% compared with 14.0% in patients with inter-pandemic CAP (n=648). A multivariate logistic regression model was generated by assigning one point for each of five clinical criteria: age ≤ 65 years, mental orientation, temperature ≥ 38 °C, leucocyte count ≤ 12 × 10(9)/l and bilateral radiographic consolidation. A score of 4 or 5 predicted H1N1 influenza-related pneumonia with a positive likelihood ratio of 9.0. A score of 0 or 1 had a positive likelihood ratio of 75.7 for excluding it.

CONCLUSION

There are substantial clinical differences between H1N1 influenza-related pneumonia and inter-pandemic CAP. A model based on five simple clinical criteria enables the early identification of adults admitted with H1N1 influenza-related pneumonia.

Laboratory diagnosis, epidemiology, and clinical outcomes of pandemic influenza A and community respiratory viral infections in southern Brazil

Community respiratory viruses (CRVs) are commonly associated with seasonal infections. They have been associated with higher morbidity and mortality among children, elderly individuals, and immunosuppressed patients. In April 2009, the circulation of a new influenza A virus (FLUA H1N1v) was responsible for the first influenza pandemic of this century. We report the clinical and epidemiological profiles of inpatients infected with CRVs or with FLUA H1N1v at a tertiary care hospital in southern Brazil. In addition, we used these profiles to evaluate survivor and nonsurvivor patients infected with FLUA H1N1v. Multiplex reverse transcription-PCR (RT-PCR) and real time RT-PCR were used to detect viruses in inpatients with respiratory infections. Record data from all patients were reviewed. A total of 171 patients were examined over a period of 16 weeks. Of these, 39% were positive for FLUA H1N1v, 36% were positive for CRVs, and 25% were negative. For the FLUA H1N1v- and CRV-infected patients, epidemiological data regarding median age (30 and 1.5 years), myalgia (44% and 13%), need for mechanical ventilation (44% and 9%), and mortality (35% and 9%) were statistically different. In a multivariate analysis comparing survivor and nonsurvivor patients infected with influenza A virus H1N1, median age and creatine phosphokinase levels were significantly associated with a severe outcome. Seasonal respiratory infections are a continuing concern. Our results highlight the importance of studies on the prevalence and severity of these infections and that investments in programs of clinical and laboratory monitoring are essential to detect the appearance of new infective agents.

Frequency of drug-resistant viruses and virus shedding in pediatric influenza patients treated with neuraminidase inhibitors

BACKGROUND

Although influenza virus resistance to the neuraminidase inhibitor zanamivir is reported less frequently than is resistance to the neuraminidase inhibitor oseltamivir in clinical settings, it is unknown whether this difference is due to the limited use of zanamivir or to an inherent property of the drug. We therefore compared the prevalence of drug-resistant viruses and virus shedding in seasonal influenza virus-infected children treated with either oseltamivir or zanamivir.

METHODS

Clinical specimens (throat or nasal swab) were collected from a total of 144 pediatric influenza patients during the 2005-2006, 2006-2007, 2007-2008, and 2008-2009 influenza seasons. Neuraminidase inhibitor-resistant mutants were detected among the isolated viruses by sequencing the viral hemagglutinin and neuraminidase genes. Sensitivity of the viruses to neuraminidase inhibitors was tested by neuraminidase inhibition assay.

RESULTS

In oseltamivir- or zanamivir-treated influenza patients who were statistically comparable in their age distribution, vaccination history, and type or subtype of virus isolates, the virus-shedding period in zanamivir-treated patients was significantly shorter than that in oseltamivir-treated patients. Furthermore, the frequency of zanamivir-resistant viruses was significantly lower than that of oseltamivir-resistant viruses.

CONCLUSION

In comparison with treatment with oseltamivir, treatment of pediatric patients with zanamivir resulted in the emergence of fewer drug-resistant influenza viruses and a shorter virus-shedding period. We conclude that zanamivir shows promise as a better therapy for pediatric influenza patients.

Intranasal vaccination with pneumococcal surface protein A plus poly(I:C) protects against secondary pneumococcal pneumonia in mice

Effective pneumococcal vaccines are required for preventing secondary bacterial pneumonia, a life-threatening condition, during epidemics of influenza. We examined whether nasal administration of a low dose of pneumococcal surface protein A (PspA) plus polyinosinic-polycytidylic acid (poly(I:C)) could protect against a fatal secondary pneumococcal pneumonia after influenza A virus infection in mice. PspA-specific IgG but not IgA level was higher in the airways and blood of mice nasally administered a low dose of PspA plus poly(I:C) than in mice nasally administered PspA alone or poly(I:C) alone. Binding of PspA-specific IgG increased C3 deposition on the bacterial surface. The survival rate during secondary infection was higher in mice immunized with PspA plus poly(I:C) than in mice immunized with poly(I:C) alone. The significant reduction in bacterial density in the lung and blood was associated with increased survival of immunized mice with secondary pneumonia. Passive transfer of sera from mice immunized with PspA plus poly(I:C) increased the survival of mice infected with secondary pneumonia. Our data suggest that an intranasal PspA vaccine has promising protective effects against secondary pneumonia after influenza and that PspA-specific IgG plays a critical role in this protection.

Identification of Unique Blood and Urine Biomarkers in Influenza Virus and Staphylococcus aureus Co-infection: A Preliminary Study

Each year, there are estimated to be approximately 200,000 hospitalizations and 36,000 deaths due to influenza in the United States. Reports have indicated that most deaths are not directly due to influenza virus, but to secondary bacterial pneumonia, predominantly staphylococcal in origin. Here we identify the presence of candidate blood and urine biomarkers in mice with Staphyococcus aureus and influenza virus co-infection. In this pilot study, mice were grouped into four treatments: co-infected with influenza virus and S. aureus, singly infected with influenza virus or S. aureus, and a control group of uninfected mice (PBS treated). Gene expression changes were identified by DNA-microarrays from blood samples taken at day five post infection. Proteomic changes were obtained from urine samples collected at three and five days post infection using 2-D DIGE followed by protein ID by mass spectrometry. Differentially expressed genes and/or proteins were identified as candidate biomarkers for future validation in larger studies.

Influenza vaccination coverage in the 2004/05, 2005/06, and 2006/07 seasons: a secondary data analysis based on billing data of the German associations of statutory health insurance physicians

BACKGROUND

The German Standing Committee on Vaccination recommends annual vaccination for persons in high-risk groups in order to lower the disease burden associated with seasonal influenza. The stated target is 75% vaccination coverage of people over age 60 by the year 2010. We present statistics based on billing data of the German associations of statutory health insurance physicians regarding vaccination coverage for influenza in the three seasons from 2004/05 to 2006/07.

METHODS

We analyzed anonymous data from 14 of the 17 associations of statutory health insurance physicians in Germany. The study population consisted of all persons covered by statutory health insurance in the geographical areas under study (61.5 million persons, or 86% of the total population of these areas). Vaccination coverage was calculated as the number of vaccinated persons divided by the number of persons covered by statutory health insurance.

RESULTS

The influenza vaccination coverage of the overall study population was 19% in 2004/05, 22% in 2005/06, and 21% in 2006/07. The coverage of persons over age 60 was 45% in 2004/05, 50% in 2005/06, and 49% in 2006/07 and was higher in areas that were formerly part of East Germany than in the rest of the country. More than a third of all vaccinated persons were vaccinated in all three seasons, as were almost half of the vaccinated persons over age 60.

CONCLUSION

There was no secular increase in influenza vaccination coverage over the period 2005/06 to 2006/07. The stated target of 75% vaccination coverage for persons over age 60 by the year 2010 would thus seem to represent a major challenge for all persons involved. The analysis of data of the associations of statutory health insurance physicians enables continuous monitoring of influenza vaccination coverage.

Increased risk of hospital admission for influenza in patients with celiac disease: a nationwide cohort study in Sweden

OBJECTIVES

Although earlier studies suggest an increased risk of infectious disease in celiac disease (CD), data on the risk of influenza in patients with CD are limited. We examined the risk of hospital admission for influenza in CD patients, but for comparative reasons also in individuals with small-intestinal inflammation or normal mucosa but positive CD serology.

METHODS

In 2006-2008, we collected duodenal/jejunal biopsy data on CD (Marsh 3: villous atrophy, VA; n=29,008 unique individuals) and inflammation (Marsh 1-2; n=13,200) from all 28 pathology departments in Sweden. A third regional cohort consisted of 3,709 individuals with positive CD serology but normal mucosa (Marsh 0). The biopsies were performed between 1969 and 2008. Through linkage with the Swedish Hospital Discharge Register, we estimated the risk of hospital admission for influenza compared with that of 224,114 age- and sex-matched controls from the general population.

RESULTS

Individuals with CD were at increased risk of hospital admission for influenza (hazard ratio (HR)=2.1; 95% confidence interval (CI)=1.6-2.7; n=81). The absolute risk of influenza was 30/100,000 person-years (excess risk: 16/100,000 person-years). Furthermore, children with CD were at increased risk of influenza (HR=2.5; 95% CI=1.3-4.8). Whereas individuals with inflammation without VA were also at increased risk of influenza (HR=1.9; 95% CI=1.4-2.5), individuals with normal mucosa but positive CD serology were not (HR=1.2; 95% CI=0.5-3.0).

CONCLUSIONS

This study found an increased risk of hospital admission for influenza in patients with CD.

Co-infection of Influenza B and Streptococci causing severe pneumonia and septic shock in healthy women

Background

Since the Influenza A pandemic in 1819, the association between the influenza virus and Streptococcus pneumoniae has been well described in literature. While a leading role has been so far attributed solely to Influenza A as the primary infective pathogen, Influenza B is generally considered to be less pathogenic with little impact on morbidity and mortality of otherwise healthy adults. This report documents the severe synergistic pathogenesis of Influenza B infection and bacterial pneumonia in previously healthy persons not belonging to a special risk population and outlines therapeutic options in this clinical setting.

Case Presentation

During the seasonal influenza epidemic 2007/2008, three previously healthy women presented to our hospital with influenza-like symptoms and rapid clinical deterioration. Subsequent septic shock due to severe bilateral pneumonia necessitated intensive resuscitative measures including the use of an interventional lung assist device. Microbiological analysis identified severe dual infections of Influenza B with Streptococcus pyogenes in two cases and Streptococcus pneumoniae in one case. The patients presented with no evidence of underlying disease or other known risk factors for dual infection such as age (< one year, > 65 years), pregnancy or comorbidity.

Conclusions

Influenza B infection can pose a risk for severe secondary infection in previously healthy persons. As patients admitted to hospital due to severe pneumonia are rarely tested for Influenza B, the incidence of admission due to this virus might be greatly underestimated, therefore, a more aggressive search for influenza virus and empirical treatment might be warranted. While the use of an interventional lung assist device offers a potential treatment strategy for refractory respiratory acidosis in addition to protective lung ventilation, the combined empiric use of a neuraminidase-inhibitor and antibiotics in septic patients with pulmonary manifestations during an epidemic season should be considered.

Impact of aging on viral infections

Older people are more susceptible to a variety of viral infections, including those that induce respiratory disease, resulting in higher morbidity and mortality than younger people. Aging impacts both innate and adaptive arms of the immune system to impair control of viral infections. This review will summarize key findings on how aging impacts immunity to viral infection.

Breaking patterns of environmentally influenced disease for health risk reduction: immune perspectives

BACKGROUND

Diseases rarely, if ever, occur in isolation. Instead, most represent part of a more complex web or "pattern" of conditions that are connected via underlying biological mechanisms and processes, emerge across a lifetime, and have been identified with the aid of large medical databases.

OBJECTIVE

We have described how an understanding of patterns of disease may be used to develop new strategies for reducing the prevalence and risk of major immune-based illnesses and diseases influenced by environmental stimuli.

FINDINGS

Examples of recently defined patterns of diseases that begin in childhood include not only metabolic syndrome, with its characteristics of inflammatory dysregulation, but also allergic, autoimmune, recurrent infection, and other inflammatory patterns of disease. The recent identification of major immune-based disease patterns beginning in childhood suggests that the immune system may play an even more important role in determining health status and health care needs across a lifetime than was previously understood.

CONCLUSIONS

Focusing on patterns of disease, as opposed to individual conditions, offers two important venues for environmental health risk reduction. First, prevention of developmental immunotoxicity and pediatric immune dysfunction can be used to act against multiple diseases. Second, pattern-based treatment of entryway diseases can be tailored with the aim of disrupting the entire disease pattern and reducing the risk of later-life illnesses connected to underlying immune dysfunction. Disease-pattern-based evaluation, prevention, and treatment will require a change from the current approach for both immune safety testing and pediatric disease management.

Immunity and immunopathology to viruses: what decides the outcome?

Many viruses infect humans and most are controlled satisfactorily by the immune system with limited damage to host tissues. Some viruses, however, do cause overt damage to the host, either in isolated cases or as a reaction that commonly occurs after infection. The outcome is influenced by properties of the infecting virus, the circumstances of infection and several factors controlled by the host. In this Review, we focus on host factors that influence the outcome of viral infection, including genetic susceptibility, the age of the host when infected, the dose and route of infection, the induction of anti-inflammatory cells and proteins, as well as the presence of concurrent infections and past exposure to cross-reactive agents.

The impact of matching vaccine strains and post-SARS public health efforts on reducing influenza-associated mortality among the elderly

Public health administrators do not have effective models to predict excess influenza-associated mortality and monitor viral changes associated with it. This study evaluated the effect of matching/mismatching vaccine strains, type/subtype pattern changes in Taiwan's influenza viruses, and the impact of post-SARS (severe acute respiratory syndrome) public health efforts on excess influenza-associated mortalities among the elderly. A negative binomial model was developed to estimate Taiwan's monthly influenza-associated mortality among the elderly. We calculated three winter and annual excess influenza-associated mortalities [pneumonia and influenza (P&I), respiratory and circulatory, and all-cause] from the 1999-2000 through the 2006-2007 influenza seasons. Obtaining influenza virus sequences from the months/years in which death from P&I was excessive, we investigated molecular variation in vaccine-mismatched influenza viruses by comparing hemagglutinin 1 (HA1) of the circulating and vaccine strains. We found that the higher the isolation rate of A (H3N2) and vaccine-mismatched influenza viruses, the greater the monthly P&I mortality. However, this significant positive association became negative for higher matching of A (H3N2) and public health efforts with post-SARS effect. Mean excess P&I mortality for winters was significantly higher before 2003 than after that year [mean +/- S.D.: 1.44+/-1.35 vs. 0.35+/-1.13, p = 0.04]. Further analysis revealed that vaccine-matched circulating influenza A viruses were significantly associated with lower excess P&I mortality during post-SARS winters (i.e., 2005-2007) than during pre-SARS winters [0.03+/-0.06 vs. 1.57+/-1.27, p = 0.01]. Stratification of these vaccine-matching and post-SARS effect showed substantial trends toward lower elderly excess P&I mortalities in winters with either mismatching vaccines during the post-SARS period or matching vaccines during the pre-SARS period. Importantly, all three excess mortalities were at their highest in May, 2003, when inter-hospital nosocomial infections were peaking. Furthermore, vaccine-mismatched H3N2 viruses circulating in the years with high excess P&I mortality exhibited both a lower amino acid identity percentage of HA1 between vaccine and circulating strains and a higher numbers of variations at epitope B. Our model can help future decision makers to estimate excess P&I mortality effectively, select and test virus strains for antigenic variation, and evaluate public health strategy effectiveness.

Role of infection in the development and exacerbation of asthma

Respiratory infections are associated with wheezing illnesses in all ages and may also impact the development and severity of asthma. Respiratory tract infections caused by viruses, Chlamydophila or Mycoplasma have been hypothesized to have significant roles in the pathogenesis of asthma. Progress is being made toward establishing the mechanisms by which these agents can cause acute wheezing and impact the pathophysiology of asthma. Host factors probably contribute to the risk of asthma inception and exacerbation, and these contributions may also vary with respect to early- versus adult-onset disease. This review discusses these various associations as they pertain to the development and exacerbation of asthma.

Seasonal and Pandemic A (H1N1) 2009 influenza vaccination coverage and attitudes among health-care workers in a Spanish University Hospital

Influenza vaccination coverage among health-care workers (HCWs) remains the lowest compared with other priority groups for immunization. Little is known about the acceptability and compliance with the pandemic (H1N1) 2009 influenza vaccine among HCWs during the current campaign. Between 23 December 2009 and 13 January 2010, once the workplace vaccination program was over, we conducted a cross-sectional, questionnaire-based survey at the University Hospital 12 de Octubre (Madrid, Spain). Five hundred twenty-seven HCWs were asked about their influenza immunization history during the 2009–2010 season, as well as the reasons for accepting or declining either the seasonal or pandemic vaccines. Multiple logistic-regression analysis was preformed to identify variables associated with immunization acceptance. A total of 262 HCWs (49.7%) reported having received the seasonal vaccine, while only 87 (16.5%) affirmed having received the pandemic influenza (H1N1) 2009 vaccine. “Self-protection” and “protection of the patient” were the most frequently adduced reasons for acceptance of the pandemic vaccination, whereas the existence of “doubts about vaccine efficacy” and “fear of adverse reactions” were the main arguments for refusal. Simultaneous receipt of the seasonal vaccine (odds ratio [OR]: 0.27; 95% confidence interval [95% CI]: 0.14–0.52) and being a staff (OR: 0.08; 95% CI: 0.04–0.19) or a resident physician (OR: 0.16; 95% CI: 0.05–0.50) emerged as independent predictors for pandemic vaccine acceptance, whereas self-reported membership of a priority group was associated with refusal (OR: 5.98; 95% CI: 1.35–26.5). The pandemic (H1N1) 2009 influenza vaccination coverage among the HCWs in our institution was very low (16.5%), suggesting the role of specific attitudinal barriers and misconceptions about immunization in a global pandemic scenario.

Bench-to-bedside review: bacterial pneumonia with influenza - pathogenesis and clinical implications

Seasonal and pandemic influenza are frequently complicated by bacterial infections, causing additional hospitalization and mortality. Secondary bacterial respiratory infection can be subdivided into combined viral/bacterial pneumonia and post-influenza pneumonia, which differ in their pathogenesis. During combined viral/bacterial infection, the virus, the bacterium and the host interact with each other. Post-influenza pneumonia may, at least in part, be due to resolution of inflammation caused by the primary viral infection. These mechanisms restore tissue homeostasis but greatly impair the host response against unrelated bacterial pathogens. In this review we summarize the underlying mechanisms leading to combined viral/bacterial infection or post-influenza pneumonia and highlight important considerations for effective treatment of bacterial pneumonia during and shortly after influenza.

Anti-influenza virus effects of the aqueous extract from Mosla scabra

ETHNOPHARMACOLOGICAL RELEVANCE

Mosla scabra (Thunb.) C. Y. Wu is a broadly used species in the southeastern China as an antipyretic and antiviral drug for the treatment of colds, fever, inflammation and chronic bronchitis.

AIM OF THE STUDY

To investigate the anti-influenza virus activities of the aqueous extract from Mosla scabra (AEMS), and to provide evidence for the implication of its immunomodulatory potential for the overall protective effect in lethal murine experimental influenza A infection.

MATERIALS AND METHODS

The anti-influenza virus activities of AEMS or ribavirin were evaluated in embryonated eggs and in a mouse infection model and the effects of AEMS on early immune responses during influenza virus infection were evaluated in a mouse infection model.

RESULTS

At the concentration of 0.3-30.0mg/ml, AEMS exhibited both preventive and therapeutical effect on embryonated egg. Oral administration of AEMS to mice infected with influenza virus A (IVA) was highly effective in preventing death, inhibiting pneumonia and reducing lung viral titers. It also significantly enhanced IFN-gamma, IL-2, IL-4 and IL-5 cytokine-producing splenocytes, increased T-cell subsets like CD4(+) and CD4(+)/CD8(+), decreased levels of IL-6 after infection, and provided protective immunity. At a dosage of 4800 mg/kg, almost all treated mice survived, suggesting that AEMS is of low toxicity. However, ribavirin has weaker efficacy compared to AEMS.

CONCLUSIONS

These results showed, for the first time, while both AEMS and ribavirin appeared to have similar efficacy against IVA, AEMS playing a role as an immunomodulator and antiviral inhibitor during influenza virus infection, was considered to be less toxic and may warrant further evaluation as a possible agent for the treatment of influenza.