Respiratory viral infections in adults with and without chronic obstructive pulmonary disease

Viral etiology of acute exacerbations of COPD in Hong Kong

INTRODUCTION

Viral respiratory infections may precipitate acute exacerbations of COPD (AECOPD). However, little is known about viral etiology related to AECOPD in Asia. We aimed to study the viral etiology of AECOPD in Hong Kong.

METHODS

Patients admitted to an acute hospital in Hong Kong with AECOPD were recruited prospectively from May 1, 2004, to April 30, 2005. Nasopharyngeal aspirate was collected and assessed by polymerase chain reaction (PCR) and viral culture. Spirometry was performed in the stable phase at 2 to 3 months after hospital discharge.

RESULTS

There were 262 episodes of AECOPD among 196 patients (mean age, 75.7 +/- 7.7 years [+/- SD]; 160 men). Mean FEV(1) was 39.6 +/- 18.9% of predicted normal, and FEV(1)/FVC ratio was 58.0 +/- 15.2%. Fifty-eight episodes (22.1%) yielded positive viral PCR results. The viruses identified were influenza A (7.3%), coronavirus OC43 (4.6%), rhinovirus (3.1%), influenza B (2.7%), and respiratory syncytial virus (2.3%). The diagnostic yield of viral identification by PCR was 2.7 times higher than that based on conventional viral culture. The rates of identifying a positive viral etiology by PCR were similar among the subjects with FEV(1) >or= 50%, >or= 30 to 50%, and < 30% of predicted normal. Viral infection appeared to have no effect on subsequent readmissions or mortality rate over a study period of 1 year

CONCLUSION

Influenza A and two less-attended viruses, coronavirus OC43 and rhinovirus, were the common etiologic agents in patients hospitalized with AECOPD in Hong Kong. These should be considered in developing diagnostic and intervening strategies pertaining to AECOPD.

The Biology of a Chronic Obstructive Pulmonary Disease Exacerbation

Much of the morbidity and mortality in chronic obstructive pulmonary disease relates to symptomatic deteriorations in respiratory health termed exacerbations. Exacerbations also are associated with changes in lung function and both airway and systemic inflammation. The most common causes of exacerbation are micro-organisms: respiratory viruses such as rhinovirus, and various bacterial species. This article reviews and discusses current understanding of the biology of exacerbations, considering the definition, epidemiology, etiology, and the nature and evolution of the changes in symptoms, lung function, and inflammation that characterize these important events.

COPD exacerbations: defining their cause and prevention

Exacerbations of chronic obstructive pulmonary disease (COPD) are episodes of worsening of symptoms, leading to substantial morbidity and mortality. COPD exacerbations are associated with increased airway and systemic inflammation and physiological changes, especially the development of hyperinflation. They are triggered mainly by respiratory viruses and bacteria, which infect the lower airway and increase airway inflammation. Some patients are particularly susceptible to exacerbations, and show worse health status and faster disease progression than those who have infrequent exacerbations. Several pharmacological interventions are effective for the reduction of exacerbation frequency and severity in COPD such as inhaled steroids, long-acting bronchodilators, and their combinations. Non-pharmacological therapies such as pulmonary rehabilitation, self-management, and home ventilatory support are becoming increasingly important, but still need to be studied in controlled trials. The future of exacerbation prevention is in assessment of optimum combinations of pharmacological and non-pharmacological therapies that will result in improvement of health status, and reduction of hospital admission and mortality associated with COPD.

Cooperative effects of rhinovirus and TNF-{alpha} on airway epithelial cell chemokine expression

Rhinovirus (RV) infections trigger exacerbations of airways disease, but underlying mechanisms remain unknown. We hypothesized that RV and cytokines present in inflamed airways combine to induce augmented airway epithelial cell chemokine expression, promoting further inflammation. To test this hypothesis in a cellular system, we examined the combined effects of RV39 and TNF-alpha, a cytokine increased in asthma and chronic obstructive pulmonary disease, on airway epithelial cell proinflammatory gene expression. Costimulation of 16HBE14o- human bronchial epithelial cells and primary mucociliary-differentiated tracheal epithelial cells with RV and TNF-alpha induced synergistic increases in IL-8 and epithelial neutrophil attractant-78 production. Similar synergism was observed for IL-8 promoter activity, demonstrating that the effect is transcriptionally mediated. Whereas increases in ICAM-1 expression and viral load were noted 16-24 h after costimulation, cooperative effects between RV39 and TNF-alpha were evident 4 h after stimulation and maintained despite incubation with blocking antibody to ICAM-1 given 2 h postinfection or UV irradiation of virus, implying that effects were not solely due to changes in ICAM-1 expression. Furthermore, RV39 infection induced phosphorylation of ERK and transactivation of the IL-8 promoter AP-1 site, which functions as a basal level enhancer, leading to enhanced TNF-alpha responses. We conclude that RV infection and TNF-alpha stimulation induce cooperative increases in epithelial cell chemokine expression, providing a cellular mechanism for RV-induced exacerbations of airways disease.

Impact of a winter respiratory virus season on patients with COPD and association with influenza vaccination

BACKGROUND

We assessed the effects of an influenza season on patients with COPD. Data from 2,215 veterans in a multicenter, randomized, double-blind influenza vaccine efficacy study were analyzed for changes in spirometric and functional status, comparing patients with laboratory-documented influenza (LDI)-caused illness, non-LDI-caused respiratory illness, or no illness, and for association with influenza vaccination.

METHODS

Patients received either IM trivalent inactivated influenza virus vaccine (TIV) plus intranasal trivalent, live attenuated, cold-adapted influenza virus vaccine (TC) or TIV plus intranasal placebo (TP). We performed spirometry, measured the chronic lung disease severity index (CLDSI) score to assess functional status and well-being, and tested for influenza virus infection.

RESULTS

Worsening in FEV(1), percentage of predicted FEV(1), and CLDSI score (p < 0.001) was associated with acute respiratory illness in 585 illnesses including 94 LDI-caused illnesses. LDI-caused illness was more likely to be associated with worsening in FEV(1) and CLDSI score acutely than non-LDI-caused illness (p < 0.01). Logistic regression showed acute respiratory illness (odds ratio [OR], 1.78; 95% confidence limit [CL], 1.40 to 2.26) to be associated with worsening in CLDSI score, and receipt of TC (OR, 1.39; 95% CL, 1.10 to 1.74) and no illness (OR, 0.70; 95% CL, 0.53 to 0.91 for acute respiratory illness) to be associated with better CLDSI score at the end of the study. Hospitalization was more frequent in patients with acute respiratory illness (p < 0.0001).

CONCLUSIONS

Acute respiratory illness was associated with increased health-care utilization and obstruction to airflow, and worse functional status and well-being. At the end of the study, receipt of TC was associated with improvement and acute respiratory illness was associated with worsening in functional status and well-being.

Comment évaluer, orienter et suivre un patient ayant une pneumonie aiguë communautaire ? Une exacerbation de bronchopneumopathie chronique obstructive ?

L'objectif de cette revue est de présenter une analyse bibliographique de la littérature de ces cinq dernières années concernant les pneumonies aiguës communautaires (PAC) et les exacerbations aiguës de bronchopneumopathies chroniques obstructives (EABPCO). La PAC et l'EABPCO sont des pathologies fréquentes grevées d'une mortalité et/ou morbidité encore élevée de nos jours. La connaissance des facteurs de risque d'évolution compliquée et l'identification des signes de gravité souvent liés au risque de mortalité permettent d'orienter le patient pour un traitement ambulatoire, en hospitalisation conventionnelle ou en secteur de réanimation ; des règles prédictives ont été établies dans ce sens. La littérature concernant les critères de sortie d'hospitalisation et le suivi des patients est plus pauvre.

Rhinovirus replication in human macrophages induces NF-kappaB-dependent tumor necrosis factor alpha production

Rhinoviruses (RV) are the major cause of acute exacerbations of asthma and chronic obstructive pulmonary disease (COPD). Rhinoviruses have been shown to activate macrophages, but rhinovirus replication in macrophages has not been reported. Tumor necrosis factor alpha (TNF-alpha) is implicated in the pathogenesis of acute exacerbations, but its cellular source and mechanisms of induction by virus infection are unclear. We hypothesized that rhinovirus replication in human macrophages causes activation and nuclear translocation of NF-kappaB, leading to TNF-alpha production. Using macrophages derived from the human monocytic cell line THP-1 and from primary human monocytes, we demonstrated that rhinovirus replication was productive in THP-1 macrophages, leading to release of infectious virus into supernatants, but was limited in monocyte-derived macrophages, likely due to type I interferon production, which was robust in monocyte-derived but deficient in THP-1-derived macrophages. Similar to bronchial epithelial cells, only small numbers of cells supported complete virus replication. We demonstrated RV-induced activation of NF-kappaB and colocalization of p65/NF-kappaB nuclear translocation with virus replication in both macrophage types. The infection induced TNF-alpha release in a time- and dose-dependent, RV serotype- and receptor-independent manner and was largely (THP-1 derived) or completely (monocyte derived) dependent upon virus replication. Finally, we established the requirement for NF-kappaB but not p38 mitogen-activated protein kinase in induction of TNF-alpha. These data suggest RV infection of macrophages may be an important source of proinflammatory cytokines implicated in the pathogenesis of exacerbations of asthma and COPD. They also confirm inhibition of NF-kappaB as a promising target for development of new therapeutic intervention strategies.

H. influenzae potentiates airway epithelial cell responses to rhinovirus by increasing ICAM-1 and TLR3 expression

Rhinovirus (RV) is an important trigger of chronic obstructive pulmonary disease (COPD) exacerbations. In addition, respiratory viruses are more likely to be isolated in patients with a history of frequent exacerbations, suggesting that these patients are more susceptible to viral infection. To examine potential mechanisms for cooperative effects between bacterial and viral infection in COPD, we studied the responses of cultured human airway epithelial cells to nontypeable Hemophilus influenzae and RV. In both 16HBE14o- and primary mucociliary-differentiated cells, preincubation with H. influenzae enhanced RV serotype 39-induced protein expression of interleukin (IL)-8, epithelial-derived neutrophil attractant-78, and growth-related oncogene-alpha. H. influenzae infection also increased the binding of RV39 to cultured cells, as well as expression of intercellular adhesion molecule (ICAM)-1 and Toll-like receptor (TLR)-3, receptors for RV and dsRNA, respectively. Neutralizing antibody against tumor necrosis factor-alpha inhibited IL-8 expression induced by H. influenzae and RV39. Finally, siRNA against TLR3 attenuated RV-induced IL-8 expression. We conclude that H. influenzae infection increases airway epithelial cell ICAM-1 and TLR3 expression, leading to enhanced binding of RV and a potentiation of RV-induced chemokine release. These data provide a cellular mechanism by which H. influenzae infection may increase the susceptibility of COPD patients to RV-induced exacerbations.

[Definition of low respiratory tract infections]

Lower respiratory tract infection is easily suggested on clinical signs (cough and sputum) associated with fever. To discriminate between pneumonia and acute bronchitis is crucial because of the mortality associated with pneumonia and of its specific management. Chest X-ray is a key exam for the diagnosis and should be performed on the basis of validated clinical signs that are however of weak diagnostic value. Clinical as well as radiological signs cannot be reliably used to identify the causative germ. Sputum examination, the search for pneumococcal and legionella urinary antigens are of good diagnostic value. An associated COPD may lead to an acute respiratory failure. Acute exacerbation of chronic bronchitis results from various causes but infection is involved in about 50% of the cases, mostly viral and most often due to a rhinovirus. Viral infection can be associated to bacterial infection and the most frequently isolated germs are Streptococcus pneumoniae, Haemophilus influenzae, and B. catarrhalis. Severity assessment relies on the value of basal FEV1 that is often non available. Therefore Afssaps suggests using a dyspnea index to assess exacerbation severity.

Virus infection in exacerbations of chronic obstructive pulmonary disease requiring ventilation

Objectives

We aimed to characterise and quantify the incidence of common infectious agents in acute exacerbations of chronic obstructive pulmonary disease (COPD) requiring ventilation, with a focus on respiratory viruses.

Design

An epidemiological study conducted over 3 years.

Setting

A 12-bed intensive care unit (ICU).

Participants

ICU patients over 45 years of age with a primary diagnosis of COPD exacerbation requiring non-invasive ventilation (NIV) or ventilation via endotracheal tube (ETT).

Materials and methods

Nasopharyngeal aspirates (NPA) and posterior pharyngeal swabs (PS) were tested for viruses with immunofluorescence assay (IFA), virus culture (VC) and polymerase chain reaction (PCR). Paired virus and atypical pneumonia serology assays were taken. Blood, sputum and endotracheal aspirates were cultured for bacteria.

Results

107 episodes in 105 patients were recorded. Twenty-three (21%) died within 28 days. A probable infectious aetiology was found in 69 patient episodes (64%). A virus was identified in 46 cases (43%), being the sole organism in 35 cases (33%) and part of a mixed infection in 11 cases (10%). A probable bacterial aetiology was found in 25 cases (23%). There was no statistically significant difference in clinical characteristics or outcomes between the group with virus infections and that without.

Conclusion

Forty-six (43%) of the patients with COPD exacerbation requiring mechanical ventilation had a probable viral pathogen. Prodromal, clinical and outcome parameters did not distinguish virus from non-virus illness. PCR was the most sensitive whilst virus culture was the least of virus assays.

Electronic supplementary material

The electronic reference of this article is http://dx.doi.org/10.1007/s00134-006-0202-x. The online full-text version of this article includes electronic supplementary material. This material is available to authorised users and can be accessed by means of the ESM button beneath the abstract or in the structured full-text article. To cite or link to this article you can use the above reference.

Should patients with acute exacerbation of chronic bronchitis be treated with antibiotics? Advantages of the use of fluoroquinolones

The pathological changes in chronic bronchitis (CB) produce airflow obstruction, reduce the effectiveness of the mucocilliary drainage system and lead to bacterial colonisation of bronchial secretion. The presence of bacteria induces an inflammatory response mediated by leukocytes. There is a direct relationship between the degree of impairment of the mucocilliary drainage system, the density of bacteria in mucus and the number of leukocytes in the sputum. Purulent sputum is a good marker of a high bacterial load. Eventually, if the number of leukocytes is high, their normal activity could decrease the effectiveness of the drainage system, increase the bronchial obstruction and probably damage the lung parenchyma. Whenever the density of bacteria in the bronchial lumen is >or=10(6) CFU/mL, there is a high probability that the degree of inflammatory response will lead to a vicious cycle which in turn tends to sustain the process. This situation can arise during the clinical course of any acute exacerbation of CB, independently of its aetiology, provided the episode is sufficiently severe and/or prolonged. Fluoroquinolones of the third and fourth generation are bactericidal against most microorganisms usually related to acute exacerbations of CB. Their diffusion to bronchial mucus is adequate. When used in short (5-day) treatment they reduce the bacterial load in a higher proportion than is achieved by beta-lactam or macrolide antibiotics given orally. Although the clinical cure rate is similar to that obtained with other antibiotics, the time between exacerbations could be increased.

COPD exacerbations . 2: aetiology

Exacerbations of COPD are thought to be caused by complex interactions between the host, bacteria, viruses, and environmental pollution. These factors increase the inflammatory burden in the lower airways, overwhelming the protective anti-inflammatory defences leading to tissue damage. Frequent exacerbations are associated with increased morbidity and mortality, a faster decline in lung function, and poorer health status, so prevention or optimal treatment of exacerbations is a global priority. In order to evolve new treatment strategies there has been great interest in the aetiology and pathophysiology of exacerbations, but progress has been hindered by the heterogeneous nature of these episodes, vague definitions of an exacerbation, and poor stratification of known confounding factors when interpreting results. We review how an exacerbation should be defined, its inflammatory basis, and the importance of exacerbations on disease progression. Important aetiologies, with their potential underlying mechanisms, are discussed and the significance of each aetiology is considered.

COPD exacerbations .1: Epidemiology

The epidemiology of exacerbations of chronic obstructive pulmonary disease (COPD) is reviewed with particular reference to the definition, frequency, time course, natural history and seasonality, and their relationship with decline in lung function, disease severity and mortality. The importance of distinguishing between recurrent and relapsed exacerbations is discussed.

Effect of interactions between lower airway bacterial and rhinoviral infection in exacerbations of COPD

STUDY OBJECTIVES

The inflammatory responses and associated clinical severity of COPD exacerbations are greatly variable, and the determinants of these factors are poorly understood. We examined the hypothesis that bacteria and viruses may modulate this heterogeneity and that interactions between bacterial and viral infection may affect changes in airway bacterial load and the clinical features and inflammatory responses of exacerbations in patients with COPD.

DESIGN

Prospective cohort study.

SETTING

Outpatient Department, London Chest Hospital, London, UK.

PATIENTS

Thirty-nine patients with COPD.

MEASUREMENTS

We prospectively studied 56 COPD exacerbations, obtaining clinical data and paired sputum and serum samples at baseline and exacerbation. Qualitative and quantitative microbiology, polymerase chain reaction detection for rhinovirus, and estimation of cytokine levels by enzyme-linked immunosorbent assay were performed.

RESULTS

A total of 69.6% of exacerbations were associated with a bacterial pathogen, most commonly Haemophilus influenzae. Rhinovirus was identified in 19.6% of exacerbations. The rise in bacterial load at exacerbation correlated with the rise in sputum interleukin (IL)-8 (r = 0.37, p = 0.022) and fall in FEV1 (r = 0.35, p = 0.048). Exacerbations with both rhinovirus and H. influenzae had higher bacterial loads (10(8.56) cfu/mL vs 10(8.05)cfu/mL, p = 0.018) and serum IL-6 (13.75 pg/mL vs 6.29 pg/mL, p = 0.028) than exacerbations without both pathogens. In exacerbations with both cold symptoms (a marker of putative viral infection) and a bacterial pathogen, the FEV1 fall was greater (20.3% vs 3.6%, p = 0.026) and symptom count was higher (p = 0.019) than those with a bacterial pathogen alone.

CONCLUSIONS

The clinical severity and inflammatory responses in COPD exacerbations are modulated by the nature of the infecting organism: bacterial and viral pathogens interact to cause additional rises in inflammatory markers and greater exacerbation severity.

Airway mucus: From production to secretion

Mucus hypersecretion is a phenotype associated with multiple obstructive lung diseases. However, in spite of its nefarious reputation under pathologic conditions, there are significant benefits to having low levels of mucus present in the airways at baseline, such as the ability to trap and eliminate inhaled particles and to prevent desiccation of airway surfaces. Mucins are high-molecular-weight glycoproteins that are the chief components that render viscoelastic and gel-forming properties to mucus. Recent advances in animal models and in vitro systems have provided a wealth of information regarding the identification of the mucin genes that are expressed in the lungs, the signal transduction pathways that regulate the expression of these mucins, and the secretory pathways that mediate their release into the airways. In addition, the clinical and pathologic literature has corroborated many of the basic laboratory findings. As a result, mucin overproduction and hypersecretion are moving away from being markers of disease and toward being testable as functional components of lung disease processes.

Chronic cough due to chronic bronchitis: ACCP evidence-based clinical practice guidelines

BACKGROUND

Chronic bronchitis is a disease of the bronchi that is manifested by cough and sputum expectoration occurring on most days for at least 3 months of the year and for at least 2 consecutive years when other respiratory or cardiac causes for the chronic productive cough are excluded. The disease is caused by an interaction between noxious inhaled agents (eg, cigarette smoke, industrial pollutants, and other environmental pollutants) and host factors (eg, genetic and respiratory infections) that results in chronic inflammation in the walls and lumen of the airways. As the disease advances, progressive airflow limitation occurs, usually in association with pathologic changes of emphysema. This condition is called COPD. When a stable patient experiences a sudden clinical deterioration with increased sputum volume, sputum purulence, and/or worsening of shortness of breath, this is referred to as an acute exacerbation of chronic bronchitis as long as conditions other than acute tracheobronchitis are ruled out. The purpose of this review is to present the evidence for the diagnosis and treatment of cough due to chronic bronchitis, and to make recommendations that will be useful for clinical practice.

METHODS

Recommendations for this section of the review were obtained from data using a National Library of Medicine (PubMed) search dating back to 1950, performed in August 2004, of the literature published in the English language. The search was limited to human studies, using the search terms "cough," "chronic bronchitis," and "COPD."

RESULTS

The most effective way to reduce or eliminate cough in patients with chronic bronchitis and persistent exposure to respiratory irritants, such as personal tobacco use, passive smoke exposure, and workplace hazards is avoidance. Therapy with a short-acting inhaled beta-agonist, inhaled ipratropium bromide, and oral theophylline, and a combined regimen of inhaled long-acting beta-agonist and an inhaled corticosteroid may improve cough in patients with chronic bronchitis, but there is no proven benefit for the use of prophylactic antibiotics, oral corticosteroids, expectorants, postural drainage, or chest physiotherapy. For the treatment of an acute exacerbation of chronic bronchitis, there is evidence that inhaled bronchodilators, oral antibiotics, and oral corticosteroids (or in severe cases IV corticosteroids) are useful, but their effects on cough have not been systematically evaluated. Therapy with expectorants, postural drainage, chest physiotherapy, and theophylline is not recommended. Central cough suppressants such as codeine and dextromethorphan are recommended for short-term symptomatic relief of coughing.

CONCLUSIONS

Chronic bronchitis due to cigarette smoking or other exposures to inhaled noxious agents is one of the most common causes of chronic cough in the general population. The most effective way to eliminate cough is the avoidance of all respiratory irritants. When cough persists despite the removal of these inciting agents, there are effective agents to reduce or eliminate cough.

Characterization of Toll-like receptors in primary lung epithelial cells: strong impact of the TLR3 ligand poly(I:C) on the regulation of Toll-like receptors, adaptor proteins and inflammatory response

Background

Bacterial and viral exacerbations play a crucial role in a variety of lung diseases including COPD or asthma. Since the lung epithelium is a major source of various inflammatory mediators that affect the immune response, we analyzed the inflammatory reaction of primary lung epithelial cells to different microbial molecules that are recognized by Toll-like receptors (TLR).

Methods

The effects of TLR ligands on primary small airway epithelial cells were analyzed in detail with respect to cytokine, chemokine and matrix metalloproteinase secretion. In addition, the regulation of the expression of TLRs and their adaptor proteins in small airway epithelial cells was investigated.

Results

Our data demonstrate that poly(I:C), a synthetic analog of viral dsRNA, mediated the strongest proinflammatory effects among the tested ligands, including an increased secretion of IL-6, IL-8, TNF-α, GM-CSF, GRO-α, TARC, MCP-1, MIP-3α, RANTES, IFN-β, IP-10 and ITAC as well as an increased release of MMP-1, MMP-8, MMP-9, MMP-10 and MMP-13. Furthermore, our data show that poly(I:C) as well as type-1 and type-2 cytokines have a pronounced effect on the expression of TLRs and molecules involved in TLR signaling in small airway epithelial cells. Poly(I:C) induced an elevated expression of TLR1, TLR2 and TLR3 and increased the gene expression of the general TLR adaptor MyD88 and IRAK-2. Simultaneously, poly(I:C) decreased the expression of TLR5, TLR6 and TOLLIP.

Conclusion

Poly(I:C), an analog of viral dsRNA and a TLR3 ligand, triggers a strong inflammatory response in small airway epithelial cells that is likely to contribute to viral exacerbations of pulmonary diseases like asthma or COPD. The pronounced effects of poly(I:C) on the expression of Toll-like receptors and molecules involved in TLR signaling is assumed to influence the immune response of the lung epithelium to viral and bacterial infections. Likewise, the regulation of TLR expression by type-1 and type-2 cytokines is important considering the impact of exogenous and endogenous TLR ligands on Th1 or Th2 driven pulmonary inflammations like COPD or asthma, respectively.

Respiratory viral infections in patients with chronic, obstructive pulmonary disease

Objectives

The purpose of the present study was to apply reverse transcription-PCR (RT-PCR) assays to clinical specimens collected from patients with acute respiratory illness and chronic obstructive pulmonary disease (COPD).

Methods

One hundred and ninety-four samples from two different study cohorts were analysed using RT-PCR assays for picornaviruses, coronaviruses 229E and OC43, influenza A and B viruses, respiratory syncytial virus, parainfluenza types 1–3 viruses, and human metapneumovirus and a PCR assay for adenoviruses. The results were added to results obtained previously using cell culture and serologic methods.

Results

RT-PCR assays identified an additional 35 respiratory virus-associated illnesses not identified previously by cell culture or serology (n=46). Picornaviruses and coronaviruses were the most common viral infections identified only by RT-PCR. Overall, 41.8% of the acute respiratory illnesses evaluated were associated with a respiratory virus infection, with picornaviruses, coronaviruses and influenza viruses being the most common infections recognized. No human metapneumovirus infections were identified by RT-PCR assay.

Conclusions

Respiratory viral infections are commonly associated with acute respiratory illness in COPD patients, and the use of RT-PCR assays significantly increases the ability to diagnose these infections.

What is the contribution of respiratory viruses and lung proteases to airway remodelling in asthma and chronic obstructive pulmonary disease?

It is well known that the lungs of asthmatics show airway wall remodelling and that asthma exacerbations are linked to respiratory infections. There is some evidence that respiratory infections in early childhood may increase the risk of developing asthma later in life. Chronic obstructive pulmonary disease (COPD), by definition, involves structural changes to the airways. However, very little is known about what role virus infections play in the development of this remodelling. This review considers the role of matrix metalloproteases and neutrophil elastase in remodelling, and whether the induction of proteases and other mediators during respiratory virus infections may contribute to the development of airway remodelling.

Adverse effects of amantadine and oseltamivir used during respiratory outbreaks in a center for developmentally disabled adults

BACKGROUND AND OBJECTIVES

Antiviral prophylaxis is recommended for the control of institutional influenza A outbreaks. In long-term-care institutions other than nursing homes, neither the seriousness of influenza nor the risks and benefits of antiviral prophylaxis is clearly understood. We studied the severity of illness due to influenza among adults residing in a center for the developmentally disabled and assessed adverse reactions to amantadine and oseltamivir prophylaxis.

METHODS

Data were collected from the charts of consenting residents. Complications of upper respiratory tract illness were recorded. Potential adverse events were documented during amantadine and oseltamivir therapy, and during a baseline period with neither medication.

RESULTS

The median age of the 287 participants was 46.4 years. Only 15 (5%) were older than 65 years, and 69 (24%) had chronic underlying medical illness placing them at high risk for influenza. Of the 122 residents with an upper respiratory tract infection, 16 (13%) developed pneumonia, 12 (9.8%) were hospitalized, and 5 (4%) died. Twenty-eight (25%) of 112 residents had an adverse neurologic event while receiving amantadine prophylaxis, compared with 3 (2.7%) receiving no antiviral medication and 5 (4.5%) receiving oseltamivir (P < .001). Sixteen percent of the residents discontinued amantadine due to adverse events; in contrast, adverse events were identified in 2.9% of the residents prescribed oseltamivir, and none discontinued therapy.

CONCLUSIONS

Viral respiratory tract infections are associated with a high risk of complications in this population. The rate of adverse neurologic events associated with amantadine was significantly higher than that associated with oseltamivir.

Chronic obstructive pulmonary disease: the clinical management of an acute exacerbation

Exacerbations of chronic obstructive pulmonary disease impose a considerable burden of morbidity, mortality, and health care cost. Management guidelines outlining best practice, based largely on consensus expert opinion, were produced by a number of organisations during the last decade. Current interest in the field is high. This has resulted in the publication of many further studies which have extended our understanding of the pathology involved and provided, for the first time, an evidence base for many of the therapeutic options. In this review we aim to bring the non-specialist reader up to date with current management principles and the evidence underlying such interventions.

Pharmacologic therapy for acute exacerbations of chronic obstructive pulmonary disease: a review

This article reviews available data on the drug therapy armamentarium for the acute exacerbation of chronic obstructive pulmonary disease (COPD). Summaries of studies and therapeutic issues for bronchodilators, antibiotic therapy, corticosteroid use, and a few miscellaneous agents are presented. Many controversies exist in the criteria defining the acute exacerbation, in defining appropriate outcome parameters for assessment, and, consequently, in developing specific consistent recommendations for drug therapy. Five published guidelines assist the clinician in therapeutic drug management of the acute exacerbation of COPD, and each differs in its recommendations for drug therapy prescription. The article includes synopses for drug therapy recommendations from the guidelines.

Obstructive lung disease among the urban homeless

STUDY OBJECTIVES

Homelessness is a growing problem in the United States that may significantly impair physical health. The homeless have a high prevalence of cigarette smoking, poor nutrition, and adverse environmental exposures, which could contribute to obstructive lung disease (OLD). Despite this risk, the prevalence of OLD among the homeless remains unknown. We aimed to systematically assess the prevalence of OLD among the urban homeless.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a cross-sectional study of the prevalence of OLD among homeless individuals in San Francisco. By random sampling, we recruited 68 adults living in one homeless shelter to participate in a structured interview survey and spirometry assessment. We used a multifaceted approach to assess OLD, including respiratory symptoms, self-reported physician diagnosis of asthma, chronic bronchitis, emphysema, or COPD, and spirometry (defined as FEV1 < 80% predicted and FEV1/FVC ratio < 0.70).

RESULTS

Sixty-eight adults completed the survey, and 67 adults completed the spirometry. Homeless adults were likely to be homeless < 1 year and homeless for the first time. There was a high prevalence of cigarette smoking (75% ever smokers, 68% current smokers). The prevalence of symptoms suggestive of OLD was high, including cough (29%), wheezing (40%), chronic bronchitis symptoms (21%), and dyspnea on exertion (29%). A substantial proportion of homeless subjects indicated a prior diagnosis of asthma (24%), chronic bronchitis (19%), and COPD (4%). Based on spirometry, the prevalence of OLD was 15% (95% confidence interval, 8 to 26%), which was more than double the expected prevalence in the general US population.

CONCLUSIONS

As OLD is a leading cause of death in the United States, it is important to identify it early for treatment. Homeless individuals have a higher-than-expected prevalence of OLD. Public health interventions should target the homeless population for prevention and treatment of OLD.

Rhinovirus and the lower respiratory tract

Human rhinoviruses (HRVs) are well‐recognised causes of common colds and associated upper respiratory tract complications such as sinusitis and otitis media. This article reviews information linking HRV infection to illness in the lower respiratory tract. HRVs are capable of efficient replication in vitro at temperatures present in the tracheobronchial tree and have been shown to cause productive infection, elaboration of cytokines and chemokines, and up‐regulation of cell surface markers in human bronchial epithelial cells. In situ hybridisation studies have proven that HRV infection occurs in the tracheobronchial tree following experimental infection. Clinical studies report that HRV infection is the second most frequently recognised agent associated with pneumonia and bronchiolitis in infants and young children and commonly causes exacerbations of pre‐existing airways disease in those with asthma, chronic obstructive pulmonary disease or cystic fibrosis. HRV infection is associated with one‐third to one‐half of asthma exacerbations depending on age and is linked to asthma hospitalisations in both adults and children. Limited information implicates HRV infection as a cause of severe lower respiratory tract illness in older adults and in highly immunocompromised hosts, particularly bone marrow transplant recipients. More information is needed about the pathogenesis of HRV infection with regard to lower respiratory tract complications in these diverse patient groups. Given the large unmet medical need associated with HRV infections, safe and effective antiviral agents are needed for both prevention and treatment of these infections. Copyright © 2004 John Wiley & Sons, Ltd.

Acute bronchitis: state of the art diagnosis and therapy

In managing acute bronchitis, pneumonia or an exacerbation of underlying chronic bronchitis should be excluded. Simple bronchitis is best treated symptomatically while an exacerbation of chronic bronchitis can be treated with antibiotics. Broad spectrum antibiotics are appropriate in selected patients.

Host defense function of the airway epithelium in health and disease: clinical background

Respiratory infection is extremely common and a major cause of morbidity and mortality worldwide. The airway epithelium has an important role in host defense against infection and this is illustrated in this review by considering infection by respiratory viruses. In patients with asthma or chronic obstructive pulmonary disease, respiratory viruses are a common trigger of exacerbations. Rhinoviruses (RV) are the most common virus type detected. Knowledge of the immunopathogenesis of such RV-induced exacerbations remains limited, but information is available from in vitro and from in vivo studies, especially of experimental infection in human volunteers. RV infects and replicates within epithelial cells (EC) of the lower respiratory tract. EC are an important component of the innate-immune response to RV infection. The interaction between virus and the intracellular signaling pathways of the host cell results in activation of potentially antiviral mechanisms, including type 1 interferons and nitric oxide, and in the production of cytokines and chemokines [interleukin (IL)-1 beta, IL-6, IL-8, IL-11, IL-16, tumor necrosis factor alpha, granulocyte macrophage-colony stimulating factor, growth-regulated oncogene-alpha, epithelial neutrophil-activating protein-78, regulated on activation, normal T expressed and secreted, eotaxin 1/2, macrophage-inflammatory protein-1 alpha], which influence the subsequent induced innate- and specific-immune response. Although this is beneficial in facilitating clearance of virus from the respiratory tract, the generation of proinflammatory mediators and the recruitment of inflammatory cells result in a degree of immunopathology and may amplify pre-existing airway inflammation. Further research will be necessary to determine whether modification of EC responses to respiratory virus infection will be of therapeutic benefit.

Acute cough in the elderly: aetiology, diagnosis and therapy

Although the frequency of physician consultations and the sale of over-the-counter remedies establish the high prevalence of acute cough in the elderly, epidemiological studies have tended to be imprecise. However, respiratory tract infections in nose, larynx and/or bronchi, either viral or bacterial or both, are by far the commonest cause of acute cough. These are especially frequent and hazardous in the elderly, and community living and institutionalisation may aggravate this problem. A variety of viruses and bacteria have been incriminated, with rhinovirus, influenza and respiratory syncytial viruses, and Streptococcus pneumoniae, Haemophilus influenza and Bordetella pertussis being especially important. Viral infections can readily lead to community-acquired pneumonia. Successful diagnosis should point to successful treatment, and in this respect clinical examination and patient history are paramount, supplemented by chest X-ray, viral and bacterial culture and serological testing. Depending on the results of these tests, specific antibacterial therapy may be called for, although there is dispute as to the merits of antibacterial therapy in cases of uncertain diagnosis. Prevention and prophylaxis for influenza and S. pneumoniae infections are now commendably routine in the elderly, especially those in communities. Treatment, as well as the use of antibacterials, may also be directed against the inflammatory and infective processes in the airways. Non-specific antitussive therapy is common and usually highly desirable to prevent the adverse effects of repeated coughing. There have been few advances in antitussive therapy in recent years, opioids and dextromethorphan being the most commonly used agents; they act centrally on the brainstem, but also have a large placebo effect. However they work, they are much appreciated by patients and their partners. Moreover, striking advances in our understanding of the peripheral sensory and central nervous pathways of the cough reflex in recent years should soon lead to a new and more specific choice of agents to inhibit cough.

Winter respiratory viruses and health care use: a population-based study in the northwest United States

To quantify health care use among adults during influenza and respiratory syncytial virus (RSV) seasons, we identified a cohort of veterans aged >or=18 years who used Department of Veterans Affairs (VA) facilities in Oregon and Washington states as their source of health care. During 1998-2000, veterans accrued 237,159 person-years of follow-up. Using VA data sources, we measured acute cardiopulmonary hospitalizations and primary care and urgent care visits. Differences between rates of study events when influenza and/or RSV were circulating and event rates when neither virus was circulating were used to calculate winter virus-attributable morbidity. Inpatient and outpatient event rates were consistently higher during winter virus season, compared with non-winter virus season. Annual rates of cardiopulmonary hospitalizations attributable to influenza or RSV infection ranged from 0.8 (95% confidence interval [CI], 0.1-1.5) per 1000 low-risk individuals aged 18-49 years, to 10.6 (95% CI, 7.5-13.6) per 1000 high-risk individuals aged >or=65 years. Each year, circulation of influenza and RSV coincide with predictable increases in medical care use.

Efficacy and safety of oral pleconaril for treatment of colds due to picornaviruses in adults: results of 2 double-blind, randomized, placebo-controlled trials

The novel capsid-binding antiviral pleconaril inhibits in vitro replication of most rhinoviruses and enteroviruses. Oral pleconaril treatment was studied in 2 parallel randomized, double-blind, placebo-controlled trials. Among 1363 picornavirus-infected participants (65%) in the studies combined, the median time to alleviation of illness was 1 day shorter for pleconaril recipients than for placebo recipients (P<.001). Cold symptom scores and frequency of picornavirus cultured from nasal mucus specimens were lower among pleconaril recipients by day 2 of treatment. No treatment effects were seen in those without picornavirus infection. Pleconaril was associated with a higher incidence of nausea (6% vs. 4%) and diarrhea (9% vs. 7%) and with small increases in mean serum cholesterol levels and platelet counts, compared with baseline measurements. A subsequent 6-week prophylaxis study found that pleconaril induces cytochrome P-450 3A enzymes, which metabolize a variety of drugs, including ethinyl estradiol. Early pleconaril treatment was well tolerated and significantly reduced the duration and severity of colds due to picornaviruses in adults.

Infectious exacerbations of chronic obstructive pulmonary disease associated with respiratory viruses and non-typeable Haemophilus influenzae

Infectious exacerbations of chronic obstructive pulmonary disease (COPD) have been reported to occur with both viral and bacterial pathogens. In this study, 35 exacerbations associated with the isolation of non-typeable Haemophilus influenzae from sputum were identified as part of a prospective longitudinal study. Samples from these patients were subjected to immunoassays to identify a new immune response to the homologous isolate of non-typeable H. influenzae to more accurately assess a bacterial etiology. These patients also were studied carefully for evidence of viral infection using viral culture, serology and polymerase chain reaction-based assays. Sixteen of 35 exacerbations (45.7%) were associated with evidence of acute viral infection and 11 of the 35 exacerbations (31.4%) were associated with the development of new serum IgG to homologous non-typeable H. influenzae. Overall, evidence of infection with a respiratory virus or non-typeable H. influenzae was seen in 24 of 35 exacerbations (68.6%). No association between viral infection and immune response to non-typeable H. influenzae was observed, although a trend toward an immune response to non-typeable H. influenzae and absence of viral infection was seen. The results show that exacerbations in adults with COPD were associated with infection caused by virus alone, non-typeable H. influenzae alone, or virus and non-typeable H. influenzae simultaneously.

Diagnosis and treatment of rhinovirus respiratory infections

Acute upper viral respiratory infection (VRI) is the number one cause of illness for which patients seek medical care in the United States. Rhinoviruses, members of the family Picornaviridae, are the causative pathogens in more than half of VRIs, and they are associated with acute exacerbations of respiratory disease, including asthma, sinusitis, otitis media, and COPD. Owing to the lack of commercial availability of rapid and cost-effective laboratory tests to confirm the presence of VRI, the diagnosis is most commonly made empirically, based on patient history and physical examination. Currently, no antiviral agents that are active against picornaviruses are available for clinical use. Antimicrobial agents, frequently prescribed for VRIs, are not active against viruses, and their inappropriate and widespread use has contributed to an increase in antimicrobial resistance among bacteria commonly involved in respiratory tract infections. Several newer antiviral agents are being evaluated for treatment of VRIs. Although a variety of mechanisms and agents have been tested, few have shown significant clinical benefit in human trials. The most advanced antiviral agent in clinical trials is pleconaril, a novel viral capsid-binding inhibitor with potent and highly specific in vitro activity against the majority of serotypes of rhinoviruses and enteroviruses. Clinical trials of pleconaril for the treatment of VRIs have been conducted, and the role of pleconaril in patients with chronic lung disease is being evaluated.

Viral respiratory infections in elderly patients and patients with chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) and elderly individuals are prone to the development of significant lower respiratory tract symptoms from colds caused by viral respiratory pathogens. Longitudinal surveillance studies conducted to assess the impact of viral respiratory tract pathogens on morbidity and mortality in each of these at-risk populations demonstrate that there is a substantial burden of disease from viral respiratory infection (VRI), including rhinovirus infections, with respect to utilization of health-care resources. Despite a similar rate of occurrence of VRI among subjects with COPD and the control group, a cohort with moderate to severe COPD had a 2-fold increase in medical resource utilization, including clinician visits, emergency center visits, and hospitalizations. In surveillance studies of respiratory viruses in the elderly, regular seasonal infections with rhinoviruses cause substantial morbidity, which has been largely underappreciated and underreported.

Viral infections in obstructive airway diseases

The most common syndromes associated with obstructive lung disease are asthma and chronic obstructive pulmonary disease (COPD). Evidence for a viral etiology of asthmatic exacerbations is well known, but evidence for a role for viruses in COPD exacerbation is just emerging. Viruses may cause chronic infection in both diseases. This paper reviews some studies on the effects of respiratory viruses on asthma and COPD published in 2002 and discusses their relevance to current thinking in pulmonary medicine.

Evidence-based approach to acute exacerbations of COPD

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States, and it accounts for approximately 500,000 hospitalizations for exacerbations each year. New definitions of acute COPD exacerbation have been suggested, but the one used by Anthonisen et al. is still widely accepted. It requires the presence of one or more of the following findings: increase in sputum purulence, increase in sputum volume, and worsening of dyspnea. Patients with COPD typically present with acute decompensation of their disease one to three times a year, and 3% to 16% of these will require hospital admission. Hospital mortality of these admissions ranges from 3% to 10% in severe COPD patients, and it is much higher for patients requiring ICU admission. The etiology of the exacerbations is mainly infectious (up to 80%). Other conditions such as heart failure, pulmonary embolism, nonpulmonary infections, and pneumothorax can mimic an acute exacerbation or possibly act as "triggers." Baseline chest radiography and arterial blood gas analysis during an exacerbation are recommended. Oxygen administration through a venturi mask seems to be appropriate and safe, and the oxygen saturation should be kept just above 90%. Either a short acting beta 2-agonist or an anticholinergic is the preferred bronchodilator agent. The choice between the two depends largely on potential undesirable side effects and the patient's coexistent conditions. Adding a second bronchodilator to the first one does not seem to offer much benefit. The evidence suggests similar benefit of MDIs when compared with nebulized treatment for bronchodilator delivery. If MDIs are to be used, spacer devices are recommended. Steroids do improve several outcomes during an acute COPD exacerbation, and a 10- to 14-day course seems appropriate. Antibiotic use has been shown to be beneficial, especially for patients with severe exacerbation. Changes in bacteria strains have been documented during exacerbations, and newer generations of antibiotics might offer a better response rate. There is no role for mucolytic agents or chest physiotherapy in the acute exacerbation setting. Noninvasive positive pressure ventilation might benefit a group of patients with rapid decline in respiratory function and gas exchange. It has the potential to decrease the need for intubation and invasive mechanical ventilation and possibly decrease in-hospital mortality.

CD8+ T lymphocytes in viral hyperreactivity and M2 muscarinic receptor dysfunction

In the airways, inhibitory M2 muscarinic receptors (M2Rs) on parasympathetic nerves limit acetylcholine release. Viral infection causes M2R dysfunction, which increases acetylcholine release and leads to airway hyperreactivity. In these studies we tested the role of CD8+ T cells in parainfluenza virus-induced hyperreactivity and M2R dysfunction in normal guinea pigs and in guinea pigs previously sensitized to ovalbumin. Depleting CD8+ T cells prevented virus-induced M2R dysfunction and hyperreactivity in sensitized animals, but not in nonsensitized animals. Sensitization increased the number of eosinophils in close relation to the airway nerves where, when activated, they release major basic protein, which binds to and blocks the M2Rs. Regardless of sensitization, viral infection decreased the number of visible tissue eosinophils, likely reflecting eosinophil degranulation via cytolysis. Depleting CD8+ T cells prevented this virus-induced eosinophil degranulation. In addition, an antiviral effect of sensitization, which we previously showed to be eosinophil mediated, was again seen. This was prevented by depletion of CD8+ Tcells. Thus, CD8+ T cells play a role in airway hyperreactivity and M2R dysfunction of sensitized virus-infected guinea pigs by mediating eosinophil degranulation near airway nerves. In contrast, CD8+ T cells are not necessary for virus-induced hyperreactivity and M2R dysfunction in nonsensitized guinea pigs.

Recognizing influenza in older patients with chronic obstructive pulmonary disease who have received influenza vaccine

A substudy analysis was conducted to determine the clinical characteristics associated with symptomatic, laboratory-documented influenza (LDI) among 2215 veterans with chronic obstructive pulmonary disease who participated in Department of Veterans Affairs Cooperative Study 448 and who received trivalent inactivated influenza virus vaccine with or without intranasal live-attenuated, cold-adapted influenza vaccine. Of 585 evaluable first occurrences of acute respiratory illnesses, 94 (16%) were LDI. Respiratory symptoms of cough, sputum production, and dyspnea occurred in >90% of patients with LDI; 68% had documented or subjective fever, and 81% had myalgias. Stepwise logistic regression identified only fever and myalgia as being statistically associated with LDI. During the influenza outbreak period, the positive predictive value of fever and myalgia was 41%. Clinical criteria were poor predictors of LDI in these older, vaccinated patients with chronic lung disease. Additional studies are warranted to define optimal methods for the diagnosis of influenza among older persons with chronic obstructive pulmonary disease.

The common cold

Despite great advances in medicine, the common cold continues to be a great burden on society in terms of human suffering and economic losses. Of the several viruses that cause the disease, the role of rhinoviruses is most prominent. About a quarter of all colds are still without proven cause, and the recent discovery of human metapneumovirus suggests that other viruses could remain undiscovered. Research into the inflammatory mechanisms of the common cold has elucidated the complexity of the virus-host relation. Increasing evidence is also available for the central role of viruses in predisposing to complications. New antivirals for the treatment of colds are being developed, but optimum use of these agents would require rapid detection of the specific virus causing the infection. Although vaccines against many respiratory viruses could also become available, the ultimate prevention of the common cold seems to remain a distant aim.

Respiratory viruses in exacerbations of chronic obstructive pulmonary disease requiring hospitalisation: a case-control study

BACKGROUND

Acute exacerbations of chronic obstructive pulmonary disease (AE-COPD) are a common cause of hospital admission. Many exacerbations are believed to be due to upper and/or lower respiratory tract viral infections, but the incidence of these infections in patients with COPD is still undetermined.

METHODS

Respiratory syncytial virus (RSV), influenza A and B, parainfluenza 3, and picornaviruses were detected by nested reverse transcription polymerase chain reaction (RT-PCR) in upper (nasal lavage) and lower respiratory tract specimens (induced sputum). In a 2:1 case-control set up, 85 hospitalised patients with AE-COPD and 42 patients with stable COPD admitted for other medical reasons were studied.

RESULTS

Respiratory viruses were found more often in sputum and nasal lavage of patients with AE-COPD (48/85, 56%) than in patients with stable COPD (8/42, 19%, p<0.01). The most common viruses were picornaviruses (21/59, 36%), influenza A (15/59, 25%), and RSV (13/59, 22%). When specimens were analysed separately, this difference was seen in induced sputum (exacerbation 40/85 (47%) v stable 4/42 (10%), p<0.01) but was not significant in nasal lavage (exacerbation 26/85 (31%) v stable 7/42 (17%), p=0.14). In patients with AE-COPD, fever was more frequent in those in whom viruses were detected (12/48, 25%) than in those in whom viruses were not detected (2/37, 5%, p=0.03).

CONCLUSION

Viral respiratory pathogens are found more often in respiratory specimens of hospitalised patients with AE-COPD than in control patients. Induced sputum detects respiratory viruses more frequently than nasal lavage in these patients. These data indicate that nasal lavage probably has no additional diagnostic value to induced sputum in cross-sectional studies on hospitalised patients with AE-COPD and that the role of viral infection in these patients is still underestimated.

Chronic obstructive pulmonary disease . 6: The aetiology of exacerbations of chronic obstructive pulmonary disease

Exacerbations of COPD are thought to be caused by interactions between host factors, bacteria, viruses, and changes in air quality to produce increased inflammation in the lower airway. The evidence for this and the potential mechanisms by which they result in the characteristic symptoms of exacerbations is reviewed. A better understanding of the causes and processes is needed for the appropriate use of existing treatments and the development of new ones. Future studies need to define populations clearly, stratify for known confounding factors, and should aim to identify clinical correlates so that clinical practice can be modified appropriately.

Hygienic hand antiseptics: should they not have activity and label claims against viruses?

Enteric and respiratory viruses are among the most frequent causes of human infections, and hands play an important role in the spread of these and many other viral diseases. Regular and proper hand hygiene by caregivers and food handlers in particular is essential to decontaminate hands and potentially interrupt such spread. What would be considered a proper decontamination of hands? Handwashing with regular soap and water is often considered sufficient, but what of hygienic handwash and handrub antiseptic products? Are they more effective? The evidence suggests that some clearly are. Activity against bacteria may not reflect the ability of hygienic hand antiseptics to deal with viruses, especially those that are nonenveloped. In spite of the acknowledged importance of hands as vehicles for viruses, there is a lack of suitable regulatory mechanism for handwash or handrub products to make claims of efficacy against viruses. This is in contrast with the ability of general-purpose disinfectants to make antiviral claims, although transmission of viruses from surfaces other than those of reusable medical devices may play only a minor role in virus transmission. This review discusses the (1). recent information on the relative importance of viruses as human pathogens, particularly those causing enteric and respiratory infections; (2). the survival of relevant viruses on human hands in comparison with common gram-negative and gram-positive bacteria; (3). the potential of hands to transfer or receive such contamination on casual contact; (4). role of hands in the spread of viruses; (5). the potential of hygienic measures to eliminate viruses from contaminated hands; (6). relative merits of available protocols to assess the activity of hygienic hand antiseptics against viruses; and (7). factors considered crucial in any tests to assess the activity of hygienic hand antiseptics against viruses. In addition, this review proposes surrogate viruses in such testing and discusses issues for additional consideration by researchers, manufacturers, end-users, and regulators.

Exacerbations: etiology and pathophysiologic mechanisms

Some patients with COPD are prone to frequent exacerbations, which are an important determinant of health status. Such patients have elevated airway cytokine levels, suggesting the presence of increased inflammation that may increase their susceptibility to exacerbation. The inflammatory response during a COPD exacerbation is variable, but increases in interleukin-6 levels during the exacerbation are related to the presence of a common cold. Rhinovirus infection is the most important etiologic factor in COPD exacerbations and is an important target for preventive therapy. The reduction of COPD exacerbations will have an important impact on the considerable morbidity and mortality associated with COPD.

Respiratory viral infections in adults

Respiratory viral infections in adults cause significant morbidity and mortality, especially in high-risk patients. The impact of influenza virus, rhinoviruses, and respiratory syncytial virus in immunocompromised cancer patients and in asthma and chronic bronchitis patients has been documented in recent publications. Cytomegalovirus pneumonia continues to be a major cause of morbidity and mortality in transplant recipients. Newer rapid diagnostic tests and the use of polymerase chain reaction technology have provided better understanding of the causes and epidemiology of acute respiratory illness in adults. The approved neuraminidase inhibitors for influenza viruses and the nonapproved capsid inhibitors of rhinoviruses may be useful in treating high-risk individuals. The inactivated influenza vaccine has been shown to benefit healthy adults and to be safe in asthmatic adults and children.