Infections In Exacerbations Of Asthma Research Articles

Association of specific viral infections with childhood asthma exacerbations.

IntroductionAsthma exacerbations may occur due to a variety of triggers including respiratory viruses. The aim of this study was to determine the role of particular viral infections in asthma exacerbations in children.Materials and methodsThe study was performed at Dr. Daneshvari Hospital Pediatric Emergency Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran between 2014 and 2015. A nasopharyngeal aspirate or swab was obtained from each patient during admission. All samples were maintained at 4 °C until submission to the virology laboratory and were tested for respiratory viruses by nucleic acid testing.ResultsA total of 60 patients with asthma exacerbations were recruited for this study. Of the 60 samples collected from the patients with acute asthma exacerbations, rhinovirus was detected in 12 patients (20%), respiratory syncytial virus in 5 (8%), adenovirus in 5 (8%), and influenza virus in 1 (1.6%). Respiratory pathogens were not detected in 37 (61%) samples. All the samples investigated showed single viral infection.ConclusionsTo conclude, the most common viruses detected were rhinovirus followed by respiratory syncytial virus (RSV) and adenovirus. RSV was more commonly associated with more severe attacks. Both the study design (e.g., time of sampling, age of the patients, etc.) and also the method used for viral detection influence the frequency of detection of the respiratory viruses.

Asthma exacerbations: Understanding role of viral respiratory tract infections and possible treatment strategies

Asthma is common, affecting around 500 billion people worldwide. It is a complex disease influenced by both genetic and environmental factors. Upper respiratory tract infections with viruses commonly precipitate severe and sustained asthma exacerbations (AEs). Exacerbations are responsible for the enormous amount of emotional and economic stress apart from imposing risk of hospitalization and even death. Hence, agents targeting these infections can contribute toward decreasing asthma morbidity and associated financial burden. Over the past years novel, pharmacological therapies are evolved for the treatment of asthma, but their exact role in exacerbations is still unclear. This article reviews the role of respiratory viral infections in AEs and discusses role of new therapeutic approaches to overcome it. Medline, Medscape, EMBASE, Cochrane database, Scopus and clinicaltrials.gov were searched using terms such as asthma, AE and viral respiratory infections. Journal articles published from 2000 to 2013 describing AEs were screened.

Role of viral infections in asthma exacerbations

Role of viral infections in asthma exacerbations

A role of respiratory infections in exacerbations of asthma

Nineteen patients aged 18–65 years with moderate and severe exacerbations of atopic asthma were examined for respiratory viruses, Mycoplasma pneumoniae, and Chlamydophila pneumoniae. Interferon system, IL-4 and γ-IFN serum levels were also investigated. Viral infections (RS-virus, adenovirus, influenza types A (H1N1, H3N2) and B viruses, parainfluenza types 1 and 3 viruses) were diagnosed serologically or using PCR with direct detection of viral nucleic acids in 73.6 % of the patients. Diagnostic level of Mycoplasma pneumoniae antigen was found in 78.9 % of the patients, anti-Chlamydophila pneumoniae antibodies were detected in 31.6 %. Leukocyte interferon-producing function was decreased in all the patients.

How Viral Infections Cause Exacerbation of Airway Diseases

Exacerbations of asthma and COPD are major causes of morbidity, mortality, and health-care costs. Over the last decade, studies using new molecular diagnostic techniques have established that respiratory viruses are a major cause of exacerbations of both asthma and COPD. The most prevalent viruses detected during exacerbations are the rhinoviruses. Despite the burden of disease associated with exacerbations, little is known about the mechanisms of virus-induced exacerbations of airway diseases. Exacerbations are associated with increased airway inflammation in patients with both asthma and COPD, but many questions remain unanswered regarding the key inflammatory cells and mediators involved. Identifying the key inflammatory mediators involved in exacerbations holds the promise of developing diagnostic and prognostic markers of exacerbation. In addition, such studies can identify new therapeutic targets for the development of novel drugs for the prevention and treatment of exacerbations.

The many faces of the hygiene hypothesis

About 15 years have gone by since Strachan first proposed the idea that infections and unhygienic contact might confer protection against the development of allergic illnesses. The so-called hygiene hypothesis has ever since undergone numerous more or less subtle modifications by various researchers in the fields of epidemiology, clinical science, and immunology. Three major tracts have developed exploring the role of overt viral and bacterial infections, the significance of environmental exposure to microbial compounds, and the effect of both on underlying responses of the innate and adaptive immunity. To date, a truly unifying concept has not yet emerged, but various pieces of a complex interplay between immune responses of the host, characteristics of the invading microorganism, the level and variety of the environmental exposure, and the interactions between a genetic background and a range of exposures becomes apparent. These influences are discussed as determinants for a number of complex allergic illnesses in this review, while we attempt to pay attention to the importance of different phenotypes, namely of the asthma syndrome. Even if today practical implications cannot directly be deduced from these findings, there is great potential for the development of novel preventive and therapeutic strategies in the future.

Treating the allergic patient: think globally, treat globally.

Treating the allergic patient: think globally, treat globally.

Respiratory infections and asthma

What we know What we need to know

Detection of viral, Chlamydia pneumoniae and Mycoplasma pneumoniae infections in exacerbations of asthma in children.

Background: A high frequency of virus infections has been recently pointed out in the exacerbations of asthma in children. Objectives: To confirm this, using conventional and molecular detection methods, and expanding the study to younger children.Study design: One hundred and thirty-two nasal aspirates from 75 children hospitalized for a severe attack of asthma were studied (32 infants, mean age 9.1 months; and 43 children, mean age 5.6 years). According to the virus, a viral isolation technique, immunofluorescence assays (IFA) or both were used for the detection of rhinovirus, enterovirus, respiratory syncytial (RS) virus, adenovirus, coronavirus 229E, influenza and parainfluenza virus. Polymerase chain reaction (PCR) assays were used for the detection of rhinovirus, enterovirus, RS virus, adenovirus, coronavirus 229E and OC43, Chlamydia pneumoniae and Mycoplasma pneumoniae.Results: Using IFA and viral isolation techniques, viruses were detected in 33.3% of cases, and by PCR techniques, nucleic acid sequences of virus, Chlamydia pneumoniae and Mycoplasma pneumoniae were obtained in 71.9% of cases. The combination of conventional and molecular techniques detects 81.8% of positive samples. Two organisms were identified in the same nasal sample in 20.4% of the cases. The percentage of detections was higher (85.9%) in the younger group than in the other (77%). The most frequently detected agents were rhinovirus (46.9%) and RS virus (21.2%). Using PCR rather than conventional techniques, the detection rates were increased 5.8- and 1.6-fold in rhinovirus and RS virus infections, respectively. The detection levels of the other organisms are as follows: 9.8, 5.1, 4.5, 4.5, 4.5, 3.7, and 2.2% for enterovirus, influenza virus, Chlamydia pneumoniae, adenovirus, coronavirus, parainfluenza virus, and Mycoplasma pneumoniae, respectively.Conclusion: These results confirm the previously reported high frequency of rhinovirus detection in asthmatic exacerbations in children. They also point out the frequency of RS virus detection, and emphasize the fact that PCR assays may be necessary to diagnose respiratory infections in asthma.

Current research and future needs in allergic rhinitis and asthma

Although effective therapies are available to treat asthma and allergic rhinitis, research is now focused on defining the cause of these disorders, including an in-depth analysis of the role of the inflammatory process. An enhanced understanding of the mechanism of the asthmatic inflammatory response should aid in the discovery of more-targeted therapies and preventative

The cellular and mediator basis of asthma in relation to natural history

The cellular and mediator basis of asthma in relation to natural history

Role of viral infections in exacerbations of asthma

EDITOR,--Sebastian L Johnston and colleagues1 highlight what patients with asthma have been saying for years: that asthma …

Microbial inciters of acute asthma in urban Nigerian children.

In tropical Africa the role of microbial agents of acute respiratory infections in acute exacerbations of bronchial asthma remains largely unexplored. However, empirical antibacterial therapy is frequently initiated in moderate to severe cases of acute asthma with symptoms of acute respiratory infection. A study was set up to determine how often acute respiratory infection is associated with acute asthma, to identify the associated pathogens, and to proffer appropriate therapeutic suggestions. Over a 16 month period, 86 episodes of acute asthma were studied for clinical and laboratory features of acute respiratory infection at the University College Hospital (UCH), Ibadan. Virological diagnosis was based on immunofluorescence studies of nasopharyngeal aspirates and/or serological tests using the microtitre complement fixation technique. Throat swabs and blood were cultured for bacterial agents. Of the 64 cases who presented with rhinorrhoea, 51 (79.7%) were pyrexial (T > or = 37.6 degrees C). Inflammatory changes (frequently interstitial streakiness) were identified in 10 (19.6%) of the 51 chest radiographs; only two of these had lobar shadowing. Significant bacterial isolates were made in only three (3.5%) of the throat swabs and two (2.4%) of the blood cultures from the 86 cases; none had clinical septicaemia. On the other hand, 55 viral agents were identified from 39 (53%) of the 74 subjects studied; 16 (41.0%) had dual viral identifications. Respiratory syncytial virus (RSV) accounted for 20 (36.4%) identifications, parainfluenza virus (PIV) type 3 for 15 (27.3%), and influenza type A (Flu A) for 12 (21.8%). Viral identifications were significantly higher in infants and preschool subjects (< 5 years) and in those presenting with either rhinorrhoea or pyrexia. The results of this study underscore the importance of viral upper respiratory infections in asthma exacerbations in a tropical setting. The paucity of clinical and investigative features of bacterial acute respiratory infection suggests that there is little rationale for routine antibiotic cover in children with acute exacerbations of asthma in the tropics.

The Contribution of Respiratory Viruses to Severe Exacerbations of Asthma in Adults

Viral infections are known to be associated with severe exacerbations of asthma in children. In contrast, there is limited data that viral infections evoke acute episodes of asthma that require emergency care in adults. To determine the role of viral infections in exacerbations of asthma in adults, we examined 33 patients who presented to the emergency room with 35 exacerbations of asthma between September 1990 and March 1991 for the presence of a viral infection. A nasal swab was obtained for virus isolation by culture and rapid antigen detection by fluorescent staining. In 16 patients, serum was collected at initial presentation and 3 to 4 weeks later for acute and convalescent viral antibody titers. All patients had acute episodes of asthma ascertained by medical history and physical examination. About 56% of the patients with asthma exacerbations had symptoms suggestive of viral illness. Rapid antigen detection and viral cultures for influenza A and B, parainfluenza-1, 2, 3, respiratory syncytial virus, adenovirus, and rhinovirus were negative on all patients. Likewise, in all 16 patients tested, acute and convalescent serologic studies did not show a significant rise in titer by complement fixation test. Thus, despite symptoms consistent with viral infection, viral pathogens could not be shown by current virologic techniques. This study suggests that viral infection may not be as prevalent a precipitate of asthma in adults requiring emergency room treatment as is generally thought.

Community study of role of viral infections in exacerbations of asthma in 9-11 year old children.

To study the association between upper and lower respiratory viral infections and acute exacerbations of asthma in schoolchildren in the community. Community based 13 month longitudinal study using diary card respiratory symptom and peak expiratory flow monitoring to allow early sampling for viruses. 108 Children aged 9-11 years who had reported wheeze or cough, or both, in a questionnaire. Southampton and surrounding community. Upper and lower respiratory viral infections detected by polymerase chain reaction or conventional methods, reported exacerbations of asthma, computer identified episodes of respiratory tract symptoms or peak flow reductions. Viruses were detected in 80% of reported episodes of reduced peak expiratory flow, 80% of reported episodes of wheeze, and in 85% of reported episodes of upper respiratory symptoms, cough, wheeze, and a fall in peak expiratory flow. The median duration of reported falls in peak expiratory flow was 14 days, and the median maximum fall in peak expiratory flow was 81 l/min. The most commonly identified virus type was rhinovirus. This study supports the hypothesis that upper respiratory viral infections are associated with 80-85% of asthma exacerbations in school age children.