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PubMed1988

Clinical signs following experimental lungworm infection and natural bovine respiratory syncytial virus infection in calves.

Similar clinical signs have been reported in calves infected either by Dictyocaulus viviparus or bovine respiratory syncytial virus. Three experiments were carried out to establish the clinical picture and the course of the disease in animals with these infections. The clinical signs of calves infected with lungworm included coughing, nasal discharge, tachypnoea, abdominal breathing and pyrexia, and auscultation of their lungs revealed increased bronchial sounds. Similar signs were also observed after infection with bovine respiratory syncytial virus, but the signs were more acute and resolved more rapidly than in animals infected with lungworm larvae. Calves infected with lungworm had more serious clinical signs after infection with bovine respiratory syncytial virus than calves, which were not infected with lungworm.

Animals↗
PubMed1994

Effect of bovine respiratory syncytial virus infection on hypersensitivity to inhaled Micropolyspora faeni.

Respiratory syncytial virus causes mild-to-severe respiratory disease in human infants and young children; a closely related bovine respiratory syncytial virus causes a similar disease pattern in calves. Increased disease severity in atopic children suggests that allergic reactivity may enhance the severity of RSV-induced disease. To examine the association between bovine respiratory syncytial virus (BRSV) infection and allergic reactivity two groups of calves were exposed to aerosolized Micropolyspora faeni (Mf) during an experimental BRSV infection. One group exposed to Mf concurrent with BRSV was challenge-exposed to Mf while infected a second time with BRSV, while the other similarly sensitized and infected group was mock challenged. A control group was exposed only to Mf aerosol and another control group was infected with virus but not exposed to Mf aerosol. Parameters examined included: clinical signs, Mf-specific IgG and IgE, BRSV-specific antibody and IgE, leukotrienes C4 and B4 prostaglandins E2, F2 alpha and D2, and lung pathology. While the initial BRSV infection failed to enhance sensitization to inhaled Mf, a second BRSV infection exacerbated clinical signs resulting from Mf aerosol. Consideration of eicosanoid and antibody profiles together with clinical signs suggests that mechanisms of both type I and type III hypersensitivity were operative during Mf challenge of sensitized calves.

Administration, Inhalation↗
PubMed1978

Pathogenesis of respiratory syncytial virus infection in ferret and fetal human tracheas in organ culture.

The pathogenesis of human respiratory syncytial virus infection was studied in ferret and fetal human tracheas in organ culture. Although the patterns of virus growth were similar in these species, the sites and morphologic consequences of virus replication differed markedly. In human trachea, synthesis of respiratory syncytial virus occurred in a population of ciliated epithelial cells, whereas other cells in the epithelial layer were spared. Virus replication was associated with cell injury characterized by ballooning degeneration and syncytium formation. In ferret trachea, virus growth occurred in fibroblasts of the lamina propria and serosa. Ciliated epithelial cells did not contain viral antigen and remained histologically normal. These observations are relevant to understanding the pathogenesis of human disease and the evaluation of animal models of respiratory syncytial virus bronchiolitis.

Animals↗
PubMed2004

Pro- and anti-inflammatory responses in respiratory syncytial virus bronchiolitis.

Respiratory syncytial virus (RSV) bronchiolitis is an important cause of severe respiratory disease in infants. This study aimed to characterise changes in pulmonary pro- and anti-inflammatory responses in infants with RSV bronchiolitis over the course of the illness. On the day of intubation (Day 1) and the day of extubation (Day X), nonbronchoscopic bronchoalveolar lavage was performed on term and preterm infants ventilated for RSV bronchiolitis and on control infants on Day 1. Tumour necrosis factor (TNF)-alpha, soluble TNF receptor (sTNFR) and interleukin (IL)-6 messenger ribonucleic acid (mRNA) and protein were measured. Twenty-four infants, born at term and 23 infants born preterm with RSV bronchiolitis and 10 controls were recruited. TNF-alpha and IL-6 mRNA and protein in infants with bronchiolitis were greater than the control group on Day 1. In preterm infants, who were ventilated for longer than term infants, TNF-alpha and IL-6 proteins decreased between Day 1 and Day X. Concentrations of sTNFRs differed between groups on Day 1, but levels did not change between Day 1 and Day X. Large amounts of tumour necrosis factor-alpha and interleukin-6 in the respiratory syncytial virus-infected lung suggest important roles for these cytokines in the pathogenesis of respiratory syncytial virus bronchiolitis. The decrease in tumour necrosis factor-alpha and interleukin-6 protein in preterm infants may reflect the prolonged clinical course seen in these infants.

Bronchiolitis, Viral↗
PubMed2003

Evaluation of a quantitative real-time PCR for the detection of respiratory syncytial virus in pulmonary diseases.

Respiratory syncytial virus (RSV) is known to cause acute lower respiratory tract infections (ARI) in young children and is involved in exacerbation of chronic obstructive pulmonary disease (COPD) in adults. The role of RSV in stable COPD and the viral load in different respiratory diseases has not been investigated to date. The present authors established and evaluated a quantitative TaqMan real-time polymerase chain reaction assay specific for RSV subgroup A. Absolute quantification for the determination of viral load input was achieved using a control plasmid. The assay allowed for a quantification over a >6-log range and a detection limit of <10 RSV copies per reaction mixture. The assay was 30 times more sensitive than conventional nested polymerase chain reaction assays. Interassay SD was 1.3 and coefficient of variation 4.7% on average. Clinical specimens from infants with ARI (n=62) and elderly adults with COPD (n=125) were compared for viral loads. A total of 47% RSV-positive samples were found in the ARI study group and 28% in the COPD study group. The viral load of both study groups was found to differ significantly. In the ARI study group the viral load was increased almost 2000-fold, suggesting acute infection in this group and former or latent infection in the COPD group. Respiratory syncytial virus-A specific TaqMan real-time polymerase chain reaction assay is a sensitive and rapid method for the determination of viral load in clinical samples. It enables differential statements concerning the involvement of respiratory syncytial virus in acute lower respiratory tract infections and chronic obstructive pulmonary disease to be achieved.

Acute Disease↗
PubMed2004

High-resolution CT findings of respiratory syncytial virus pneumonia after bone marrow transplantation.

OBJECTIVE: The aim of this study was to describe the high-resolution CT findings of respiratory syncytial virus pneumonia in 20 patients who had undergone allogeneic bone marrow transplantation. MATERIALS AND METHODS: The study included 20 consecutive patients who developed respiratory syncytial virus pneumonia after bone marrow transplantation and who had high-resolution CT of the chest performed within 24 hr after the onset of symptoms. The CT scans were reviewed by two chest radiologists who assessed the pattern and distribution of findings. RESULTS: Bone marrow transplantation was performed on 12 male and eight female patients ranging from 3 to 48 years old (mean age, 25 years) for treatment of various forms of leukemia (n = 12), severe aplastic anemia (n = 6), Fanconi's syndrome (n = 1), and paroxysmal nocturnal hemoglobinuria (n = 1). Sixteen patients (80%) had abnormal CT findings. The predominant patterns of abnormality on high-resolution CT scans were small centrilobular nodules (10/20, 50%), air-space consolidation (7/20, 35%), ground-glass opacities (6/20, 30%), and bronchial wall thickening (6/20, 30%). The abnormalities were distributed in the central and peripheral areas of the lungs in nine cases, only in the periphery in five cases, and only in the central regions in two cases. The abnormalities were bilateral and asymmetric in distribution in 13 patients, bilateral and symmetric in two patients, and unilateral in one patient. CONCLUSION: The most common high-resolution CT findings in patients with respiratory syncytial virus pneumonia after bone marrow transplantation consist of small centrilobular nodules and multifocal areas of consolidation and ground-glass opacities in a bilateral asymmetric distribution.

Adolescent↗
PubMed1990

Demonstration of respiratory syncytial virus in an autopsy series.

Respiratory syncytial virus (RSV) antigen was demonstrated in formalin-fixed, paraffin-embedded autopsy tissue using an immunoperoxidase technique. Eighteen autopsy cases were selected on the basis of one of the following criteria: a positive culture for RSV, antemortem or postmortem; positive ELISA test for RSV, antemortem or postmortem; or postmortem histology suggestive of paramyxovirus infection. Controls included three cases from which parainfluenza or influenza virus had been cultured and a case in which the clinical diagnosis of measles was firmly established. Sections of formalin-fixed, paraffin-embedded tissue were stained with a rabbit anti-RSV antibody (Dako) using an immunoperoxidase technique. Staining was achieved in 12 cases. This included 6 of 7 cases selected because of positive cultures or ELISA tests for RSV. The other 6 cases in which RSV was identified by the described technique lacked culture or ELISA confirmation. Granular and globular staining was seen in the cytoplasm of respiratory epithelial cells and syncytial giant cells. None of the control cases stained for RSV. The histology of RSV lungs was consistent with changes described in the literature for RSV infection, although pneumonic consolidation and syncytial giant cells were more prominent in this series.

Antigens, Viral↗
PubMed1989

The envelope proteins from purified respiratory syncytial virus protect mice from intranasal virus challenge.

A lyophilized subunit vaccine prepared from purified respiratory syncytial virus, which contained the envelope glycoproteins F and G and the nonglycosylated matrix protein VPM, was tested in SJL mice for its ability to protect the lungs of mice from intranasal viral challenge. Initially, the mice were injected subcutaneously with one, two, or three doses of 5 or 25 micrograms of vaccine in 50% complete Freund's adjuvant or with complete Freund's adjuvant or phosphate-buffered saline only. Although none of the mice produced neutralizing serum antibody, three doses of 25 micrograms elicited antibodies to F, G, and VPM. Despite the absence of detectable neutralizing antibodies, the lungs of 93% of the vaccinated mice were protected from intranasal viral challenge. Because the initial protocol did not elicit neutralizing antibodies and a few single-dose animals were not protected, a second vaccine trial was carried out. For these studies the priming dose was increased to 50 micrograms, which was followed, in half the vaccine recipients, by a second dose of 25 micrograms. Mice given the priming dose of vaccine produced antibody to G and showed no neutralizing activity, whereas the mice given two doses of vaccine produced antibodies to G, F, and VPM and also displayed neutralizing activity for respiratory syncytial virus. The lungs of 100% of the vaccine recipients in this trial were protected from intranasal challenge. Although the vaccine elicited antibody to VPM, this response did not correlate with protection. In addition, examination of the sera from unimmunized mice recovering from respiratory syncytial virus infection revealed a serum antibody profile similar to that noted for humans, lacking antibody to VPM. Thus, the data show that a combined glycoprotein subunit vaccine affords complete protection to viral challenge and offers an approach to develop a multivalent subunit vaccine.

Administration, Intranasal↗
PubMed1988

Respiratory syncytial virus infection in immunocompromised adults.

Respiratory syncytial virus disease was documented in 11 immunocompromised adults, aged 21 to 50. Underlying conditions included bone marrow transplant (6 patients), renal transplant (3 patients), renal and pancreas transplants (1 patient), and T-cell lymphoma (1 patient). Diagnosis of infection was based on specimens from bronchoalveolar lavage, sputum, throat, sinus aspirate, and lung biopsy. The virus was detected simultaneously by antibody in either an immunofluorescence or enzyme-linked immunosorbent assay in 3 of 4 patients whose culture results were positive for respiratory syncytial virus. The virus was an unexpected finding, despite widespread infection in the community. Clinical symptoms included low-grade fever, nonproductive cough, rhinorrhea or nasal congestion, and radiographic evidence of interstitial infiltrates and sinusitis. Aerosolized ribavirin therapy was used in the 6 recipients of bone marrow transplants, 3 of whom required assisted ventilation but died. Death caused by virus infection was documented in 4 of 11 patients. Respiratory syncytial virus disease must be considered in the differential diagnosis of fever and pulmonary infiltrates in immunocompromised adults.

Adult↗
PubMed1978

Respiratory syncytial virus infection in adults: clinical, virologic, and serial pulmonary function studies.

We prospectively studied 10 previously healthy adults who developed an acute respiratory illness while working in an infants' ward during a community outbreak of respiratory syncytial virus infection. In addition to clinical and viral evaluation, total respiratory resistance before and after carbachol aerosol inhalation was measured. All 10 subjects had respiratory syncytial virus infection documented by viral isolation, and all developed pronounced cough, nasal congestion, and fever. Eight subjects missed work for an average of 6 days. In all 10 patients, the total respiratory resistance was significantly elevated through 8 weeks. Altered airway reactivity, characterized by exaggerated responses of pulmonary resistance to carbachol challenge, was also observed through the first 8 weeks of evaluation. In this group, respiratory syncytial virus produced a protracted illness associated with appreciable morbidity. The pathophysiologic mechanism of this illness in part appeared to arise from altered airway reactivity.

Acute Disease↗
PubMed1999

Management strategies for respiratory syncytial virus infections in infants.

Management of respiratory syncytial virus lower respiratory tract infection in infants is predominantly supportive and symptomatic. Outpatient management requires close attention to feeding, oral hydration, and monitoring of fever, behavior, and respiratory effort. In the small proportion of patients who need hospitalization, clinicians are concerned primarily with oxygenation and the possibility of oxygen desaturation. Appropriate interventions depend on the level of oxygenation as indicated by pulse oximetry or arterial blood gases. Hydration and symptomatic treatment with alpha- or ss(2 )-adrenergic agonist bronchodilators may lessen the work of breathing. The role of these agents remains controversial, however, and anticholinergic bronchodilators are considered ineffective. Current antiviral therapy is limited to aerosolized ribavirin. Immunotherapy with respiratory syncytial virus immune globulin or a monoclonal antibody has not been rewarding in terms of clinical outcome, although the antiviral effect of these agents has been impressive. There is concern about long-term pulmonary sequelae after respiratory syncytial virus lower respiratory tract infection early in life. Several recent studies, including new data reported here, suggest that ribavirin may have a beneficial effect on some of these sequelae, whereas other studies have failed to demonstrate any benefit. Future studies may help resolve this question.

Antibodies, Monoclonal↗
PubMed1999

[Systematic surveillance of influenza, syncytial respiratory, parainfluenza and adenovirus in children with acute respiratory infections].

BACKGROUND: The efficacy of influenza vaccination programs depends on the antigenic similitude between vaccine and the influenza virus circulating in the community. Therefore the surveillance of clinical activity and antigenic features of influenza virus is of utmost importance. AIM: To perform a systematic surveillance of clinical activity and antigenic characteristics of influenza virus. MATERIAL AND METHODS: Since 1996 and during the cold months (May to September), 20 samples of upper respiratory secretions per week, were obtained from children with acute respiratory infections consulting to the emergency room of a public hospital. Using indirect immunofluorescence and cellular cultures, the presence of influenza, syncytial respiratory, parainfluenza and adenovirus was assessed. The weekly number of consultations in the emergency room and the number of hospital discharges due to acute respiratory infections, were registered. RESULTS: Influenza and syncytial respiratory were the predominant virus detected since 1996. In 1996 and 1998, the weekly detection of influenza virus followed a single seasonal curve. The maximal weekly positively results reached 85 and 80% of the obtained samples, respectively. During 1997, two curves of influenza virus activity were observed, but none reached more than 50% of weekly positive samples. The demand for outpatient care evolved in parallel to the weekly detection of influenza virus. The hospital discharges due to acute respiratory infections paralleled the syncytial respiratory virus detection rates. CONCLUSIONS: This surveillance model is effective for the detection of influenza and other virus responsible for acute respiratory infections and their relationship with the demand for health care during the cold months.

Acute Disease↗
PubMed2003

Systematic review of the biology and medical management of respiratory syncytial virus infection.

Respiratory syncytial virus, the leading cause of serious upper and lower respiratory tract infection in infants and children, accounts for 125,000 hospitalizations and 450 deaths annually in the United States. It also may predispose to development of asthma later in life. Annual epidemics occur from November to April, and virtually all infants are infected by age 2. Immunity is not durable; hence, reinfection occurs throughout life, although subsequent infections are nearly always mild. Certain populations (eg, premature infants, infants with chronic lung disease, and immunocompromised individuals) are at risk for severe morbidity and have higher risk of mortality. Infection is spread to the nose and eyes by large droplets and direct contact with secretions, and fomites may remain infectious for up to 12 hours. Nosocomial infection is common. The virus infects airway ciliated epithelial cells, spreading by the formation of syncytia. Cellular debris and inflammation cause airway obstruction, hyperinflation, localized atelectasis, wheezing, and impaired gas exchange. Both humoral and cellular immune response are critical to ending the acute infection, but wheezing and reactive airways may persist for as long as 5-10 years after acute infection. No cure exists for respiratory syncytial virus infection, but commonly employed palliative treatments include oxygen, inhaled beta(2) agonists, racemic epinephrine, dornase alfa, systemic and inhaled corticosteroids, inhaled ribavirin, and nasopharyngeal suctioning. Infants suffering severe lower airways disease may require mechanical ventilation. Prophylactic measures include rigorous infection control and administration of polyclonal (RSV-IGIV [respiratory syncytial virus - immunoglobulin intravenous]) and monoclonal (palivizumab) antibodies. The cost of the prophylactic antibody treatment is high; it is cost-effective for only the highest risk patients. Development of a vaccine remains far in the future. Application of evidence-based clinical practice guidelines is making both out-patient and in-patient therapy as effective and economical as possible.

Disease Management↗
PubMed2003

[Respiratory syncytial infections in the elderly. Seven cases and review of the literature].

We report 7 cases of respiratory syncytial virus (RSV) infections among elderly patients hospitalized for acute lower tract infection during the winter months. The median age was 95 years (range: 79-106 years). 6 patients were living in nursing homes. All patients had chronic cardiopulmonary conditions. Clinical symptoms included upper respiratory tract symptoms for 3 of them and lower respiratory tract symptoms for all of them. Three patients developed a severe infection with acute respiratory failure. The chest X ray showed an interstitial infiltrate in 3 cases, a consolidation in one case. All patients received oxygen, respiratory physical therapy, nebulized B-agonists and antibiotics. Corticosteroids were used for 4 patients. Progress was favorable for all patients and none died. Diagnosis was obtained in a few hours by direct antigen detection by enzyme immunoassays (EIA) in sputum. Respiratory syncytial virus infection is a common cause of respiratory tract infection in the elderly, during the winter months. Clinical manifestations are similar to influenza infections. Detection of RSV antigens from sputum specimens may be a useful and rapid diagnostic method and merits further evaluation in the elderly. Early diagnosis of respiratory syncytial virus infection should be encouraged to allow the implementation of effective infection control procedures and avoid inadequate therapies.

Aged↗
PubMed1992

Studies on the epidemiology of child infections. 3. Parainfluenza viruses (types 1-4) and respiratory syncytial virus infections.

A seroepidemiological study on the rate of neutralizing antibodies for parainfluenza viruses (types 1-4) and for the respiratory syncytial virus in 2,514 infants and children between 0 and 15 years, residing in Bari and its hinterland was carried out. Positive results were very high for both the individual parainfluenza serotypes (81.7% for type 3, 78.0% for type 1, 76.6% for type 4, 71.9% for type 2) and for respiratory syncytial virus (88.5%). The pattern of infections due to respiratory syncytial virus differed from that of the parainfluenza viruses not only for the higher serologic positive rate, but also for the larger number of elevated titre responses in each age group.

Adolescent↗
PubMed1992

Respiratory syncytial virus and ribavirin: quo vadis?

Respiratory syncytial virus is the major respiratory pathogen in infants and young children. Every year, this unique and ubiquitous virus accounts for substantial morbidity and occasional mortality in this age group. Until recently, therapy for respiratory syncytial virus infections was limited to supportive measures such as hydration, supplemental oxygen, and assisted ventilation. Therefore, the licensure of ribavirin in 1986 for treatment of respiratory syncytial virus infections raised hopes for specific and effective therapy. However, the use of ribavirin has been the subject of continuing controversy and debate. Despite at least eight controlled clinical trials involving collectively over 170 patients treated with ribavirin since 1983, no clear consensus has developed regarding which patients should be treated with ribavirin. Major issues are weaknesses in the design and methodology of studies that claim treatment efficacy, the clinical significance of the demonstrated treatment effects, potential teratogenicity to health care workers exposed to aerosolized ribavirin, and cost-effectiveness of the intervention. This review will explore each of these areas of controversy and consider the unanswered questions to which future research must be directed.

Animals↗
PubMed1992

[Severe respiratory syncytial virus pneumonia following bone marrow autograft. 3 cases].

Three patients developed severe respiratory syncytial virus pneumonia after bone marrow autograft for acute leukaemia. Clinically, the disease presents as interstitial or bilateral alveolo-interstitial pneumonia with hypoxaemia. Signs of ENT infection (otitis media, sinusitis) are present in 30 percent of the cases. In all 3 patients, the syncytial virus was isolated by direct immunofluorescence in bronchoalveolar lavage fluid. In 2 patients the infection began soon after the autograft, in deeply aplastic subjects, and required intubation and assisted ventilation. These 2 patients died despite inhalation of aerosolized ribavirin combined, in one of them, with ribavirin injections. In the third patient the infection began some time after the autograft and responded well to ribavirin in aerosols. In these three cases the viral infection occurred in an epidemic and nosocomial context. The respiratory syncytial virus is usually transmitted by the hands. Owing to the severity of this infection with lung involvement in immunodepressed patients, specific prophylactic measures should be taken side by side with the conventional measures.

Administration, Inhalation↗
PubMed1991

Ribavirin therapy of adult respiratory syncytial virus pneumonitis.

Respiratory syncytial virus is a common respiratory tract pathogen in infants. Pulmonary infection in adult and elderly populations can occur with severe and even fatal pneumonitis having been reported in several recent outbreaks. We present a previously healthy adult patient who developed respiratory syncytial virus pneumonia severe enough to require mechanical ventilation. Antiviral therapy with aerosolized ribavirin was successfully undertaken and the patient recovered completely. Respiratory syncytial virus infection should be considered in the differential diagnosis of atypical adult pneumonias. Aerosolized ribavirin therapy may be beneficial in treatment.

Aerosols↗