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PubMed1972

Immunofluorescence for routine diagnosis of respiratory syncytial virus infection.

A comparison of immunofluorescent tests for the diagnosis of respiratory syncytial (RS) virus infections was carried out on 42 hospitalized cases of respiratory infection in childhood. Respiratory syncytial virus was detected in 22 (52%) cases, the most sensitive method of detection being by indirect immunofluorescence of Bristol HeLa tissue cultures inoculated with nasopharyngeal aspirates. The highest detection rate was in bronchiolitis cases (92%). Detection of antibody rises in paired sera, eight days apart, confirmed RS virus infection in 13 of 16 cases, the most sensitive test being detection of a specific rise in IgG antibody by indirect immunofluorescence. A serodiagnosis was made in all 10 non-bronchiolitis cases. Recommendations are made for the application ofimmunofluorescence to routine diagnosis of RS virus infection.

Bronchiolitis, Viral↗
PubMed1981

Acute fatal pneumonia in calves due to respiratory syncytial virus.

An acute pneumonia developed in 28 calves which had been housed together from one to two weeks of age. The clinical signs included pyrexia, tachypnoea, respiratory distress and coughing. Some of the calves died. The pneumonia was characterised by an alveolitis with multinucleated syncytia, alveolar epithelial hyperplasia and bronchiolitis. Interstitial emphysema was also present. Fifteen of 19 calves examined serologically had rising neutralising antibody titres to respiratory syncytial virus; in nine calves the rise was fourfold or greater. Respiratory syncytial virus was not isolated from the calves. There was no evidence of parainfluenza type 3 virus involvement. The adult cows being sucked by the calves remained clinically normal throughout the incident. Six calves examined six weeks after the outbreak started had a chronic cuffing pneumonia characterised by lymphocytic bronchiolitis; some of the calves also had bronchiolitis obliterans. Mycoplasma dispar was found in two of them.

Acute Disease↗
PubMed1985

Spontaneous bovine respiratory syncytial virus infections in calves: arterial blood gas, pH and bicarbonate values.

Arterial blood gas values of 12 calves in the acute stage of a bovine respiratory syncytial virus infection were compared with corresponding values of 11 healthy calves. The patients appeared to be severely hypoxic. Mean (+/- sd) arterial oxygen tension (PaO2) values of patients and healthy calves were 7.7 +/- 1.9 and 14.2 +/- 1.5 kPa, respectively. Hypercapnia was present in only three of the diseased calves. These findings are in close agreement with findings in young children with respiratory syncytial virus infections. It is argued that the pathophysiological mechanism involved probably is a ventilation-perfusion abnormality.

Animals↗
PubMed1986

Clenbuterol hydrochloride in calves with a natural bovine respiratory syncytial virus infection.

The effect of clenbuterol hydrochloride on the course of disease in calves with a natural bovine respiratory syncytial virus infection was examined. Six calves (three to nine months of age) originating from four herds with respiratory tract disease and serological evidence of a bovine respiratory syncytial virus infection were used in this study. The calves were injected intravenously with clenbuterol hydrochloride. The effect of clenbuterol on the course of disease was measured using the PO2 in blood taken from an indwelling canula inserted in the caudal auricular artery and by clinical signs. Clenbuterol did not improve clinical signs. After clenbuterol administration arterial PO2 values decreased significantly in five out of six patients. Six to eight hours after medication the mean arterial PO2 values were higher than initial values. The moderate positive effect of clenbuterol after six to eight hours may be caused by enhancing ciliary activity and by the secretolytic activity of clenbuterol.

Airway Resistance↗
PubMed1988

Epidemiological study of bovine respiratory syncytial virus infections in calves: influence of maternal antibodies on the outcome of disease.

A prospective epidemiological survey on bovine respiratory syncytial virus (BRSV) infections in calves was carried out on 21 dairy farms during one BRSV epidemic season. Special attention was paid to the role of maternal antibodies. On 15 farms the spread of the virus was demonstrated during the investigation period and on eight farms this was accompanied by an outbreak of acute respiratory disease. Disease seldom occurred in calves younger than two weeks old and the most severe disease was observed in calves from one to three months old. Although maternal antibodies did not effectively prevent the disease, both the incidence and severity of disease were inversely related to the level of specific maternal antibodies. Two serodiagnostic techniques were compared. In calves older than three months from herds with disease outbreaks associated with bovine respiratory syncytial virus the diagnosis was established in 80 per cent of the animals by an increase in IgG titre against BRSV and in 77 per cent by the detection of BRSV specific IgM. In comparison, only 10 per cent of the calves younger than three months were positive by IgG serodiagnosis, and 51 per cent by IgM serodiagnosis. On farms where the spread of the virus was accompanied by an outbreak of clinical disease more calves were present, a higher proportion of the calves was younger than three months, and calves of all ages were more often housed together.

Animals↗
PubMed1992

Radiographic and radionuclide lung perfusion imaging in healthy calves and calves naturally infected with bovine respiratory syncytial virus.

Nine calves between three and 18 weeks old with serologically confirmed natural bovine respiratory syncytial virus infection were examined clinically, radiographically and by radionuclide lung perfusion imaging. The results were compared with those from seven healthy calves. The diseased calves were euthanased and examined pathologically, virologically and bacteriologically. The clinical signs indicated that the disease was in an acute stage. Radiography of the diseased animals revealed cysts, corresponding morphologically with bullous emphysema, and infiltrations roughly corresponding in distribution with atelectatic and, or, pneumonic areas. Radionuclide lung perfusion imaging revealed no perfusion shifts between the left and right lungs and a normal perfusion pattern in five of the nine diseased calves. The abnormalities in the perfusion patterns of three calves were probably caused by anatomical disorders such as cysts and pleural adhesions, but no cause of the abnormality could be found in one calf. These findings suggest that in calves infected with bovine respiratory syncytial virus, the normal perfusion pattern is maintained until anatomical disorders occur. The pathological examination and radiography revealed that the cranioventral lung fields were particularly poorly ventilated. This finding and the normal perfusion pattern indicate that these parts of the lungs are probably the sites where shuntings and perfusion-ventilation mismatchings occur.

Animals↗
PubMed1990

Immunoglobulin E responses and lung pathology resulting from aerosol exposure of calves to respiratory syncytial virus and Micropolyspora faeni.

Bovine respiratory syncytial virus (BRSV) infection of calves has been associated with a type-I hypersensitivity syndrome not unlike respiratory syncytial virus-associated pulmonary symptomatology in humans. To study the mechanism of pulmonary pathology in calves and define the relationship with both viral-specific IgE response and IgE titers to concurrent aerosol of Micropolyspora faeni (Mf) we subjected groups of calves to inhalation of Mf during acute BRSV infection. The calves were divided into 4 groups: exposed to virus only (group 1); exposed to aerosolized Mf over a 24-day period and then challenged with Mf during BRSV infection (group 2); similarly exposed to aerosolized Mf and then challenged with Mf without BRSV infection (group 3) and exposed to aerosolized Mf, infected with virus but not challenged with Mf (group 4). All calves were followed for appearance of IgE-specific responses to both BRSV and Mf, clinical disease expression, and pulmonary pathology including viral and allergen localization by immunohistology. Our data indicate an association of BRSV-specific IgE with increased development of lung pathology and clinical disease expression and an enhancing effect of aerosolized Mf on induction of virus-specific IgE. The presence of BRSV-specific IgE was solely in calves with the most significant macroscopic and microscopic pneumonic lesions.

Actinomycetales Infections↗
PubMed1995

Sequelae of respiratory syncytial virus infections. A role for intervention studies.

The association between respiratory syncytial virus (RSV) infections in infancy and respiratory abnormalities later in life has been attributed both to a direct effect of the infection itself and to an inherent susceptibility. Observational studies do not allow a rigorous test of these hypotheses. Respiratory syncytial virus infection is universal in the first years of life and no uninfected control group exists. Randomized, controlled trials using new prophylactic agents such as vaccines or specific therapeutic agents will provide a powerful test of the relationship between RSV infection and long-term respiratory sequelae.

Adult↗
PubMed1983

Cell-mediated cytotoxic responses in lungs of cotton rats infected with respiratory syncytial virus.

Pneumonia induced in cotton rats (Sigmodon hispidus) after inoculation of respiratory syncytial virus (RSV) was accompanied by the appearance of leukocytes in infected lungs. The number of these leukocytes increased until Day 5 after inoculation when sixfold more leukocytes were recovered from infected lungs using transpleural lavage than were recovered from lungs of uninfected control animals. Although macrophages and lymphocytes constituted approximately 65 and 25%, respectively, of the cells observed in lavage suspensions from both infected and uninfected lungs, only leukocytes in suspensions from infected animals appeared to be activated, as judged by cellular morphologic examination, cytochemical staining, and bactericidal activity. Leukocytes from lungs and adjacent lymph nodes of infected cotton rats, but not similar cells from uninfected animals, caused significant chromium release when they were added to primary cotton rat embryo and Hep-2 tissue culture cells infected with RSV in cytotoxicity assays. Cytotoxic activity peaked 5 days after inoculation, was neither virus-specific nor H-2 restricted, and was associated with both adherent and nonadherent fractions of lung cells. There was a close temporal relationship between the appearance of cytotoxic activity in the lung and termination of virus replication in this organ, suggesting a role for cytotoxic effector cells in recovery from respiratory syncytial virus infection of cotton rats.

Animals↗
PubMedDate not supplied

Efficacy of ribavirin aerosol treatment for respiratory syncytial virus bronchiolitis in infants.

The therapeutic efficacy of ribavirin, an anti-viral agent with a broad spectrum of activity, was studied in 14 infants with bronchiolitis which, in seven cases, was caused by a respiratory syncytial virus infection. The drug was administered for 5-6 days using an aerosol in periods of either 4 or 6 h with an interval of either 4 or 2 h between administrations. The body temperature of patients with fever returned to normal by day 3 of therapy. A significant decrease in the respiratory rate occurred by day 2 when there was also a marked improvement in the subjective and objective symptomatology. The most significant clinical improvements occurred in infants presenting a respiratory syncytial virus antigen in nasal wash specimens. This suggests therapeutic selectivity by ribavirin for (or a more pronounced sensibility of) this virus.

Aerosols↗
PubMed1986

Mycoplasma bovis infection in gnotobiotic calves and combined infection with respiratory syncytial virus.

Mycoplasma bovis was inoculated alone or in combination with respiratory syncytial virus into the respiratory tracts of 12 gnotobiotic calves. Clinical signs ranged from transient pyrexia to protracted fever accompanied by severe lower respiratory signs and in one case, arthritis. Pulmonary lesions included foci of coagulative necrosis surrounded by mononuclear cells and suppurative bronchiolitis with varying degrees of lympho-reticular hyperplasia. No enhancement of lesions occurred in the combined infections of M. bovis and respiratory syncytial virus. M. bovis was identified by immunoperoxidase labelling in lesions of necrosis, especially at interfaces between the lesion and mononuclear cells and in bronchiolar exudates. Organisms were also located in necrotic lesions of joint capsules, in tonsillar crypts, and in liver.

Animals↗
PubMed1989

A blocking ELISA for the detection of specific antibodies to bovine respiratory syncytial virus.

A blocking enzyme-linked immunosorbent assay (ELISA) has been adapted to detect specific antibodies in bovine sera to respiratory syncytial virus using a horseradish peroxidase-labeled monoclonal antibody to the fusion protein of the virus. This assay plus an indirect blocking ELISA and indirect ELISA were used to detect antibodies to the bovine respiratory syncytial virus (BRSV) in 159 field-origin bovine sera. Results of these assays were compared with serum antibody titers measured by the serum neutralization (SN) test. Over a 56-day period, the mean neutralization titers and the mean delta absorbance values for the blocking ELISA, on the same sera, showed similar declines. However, the calculated correlation coefficients between mean SN titer and mean absorbance value for the blocking ELISA of the individual sera ranged from -0.2 to -0.5 depending on the source of sera. Similar values were obtained whether using crude or purified viral antigen in the assays. Corresponding calculated correlation coefficients were generally higher for the indirect blocking ELISA or indirect ELISA than for the blocking ELISA. The blocking ELISA was between 70 and 64% as sensitive as the serum neutralization test with a specificity of 100 or 90% using the crude and purified viral antigen, respectively. The indirect blocking ELISA and indirect ELISA had similar calculated sensitivities and specificities. The blocking ELISA was faster to run than either of the other ELISA's or the neutralization test. Further, nonspecific background absorbance was obviated because the blocking ELISA detects antibodies to 1 specific viral protein, the fusion protein. These studies suggest that the blocking ELISA should be useful as a serological test for BRSV antibodies.

Animals↗
PubMed1999

Effects of respiratory syncytial virus persistence on airway responsiveness and inflammation in guinea-pigs.

Recurrent wheezing and asthma often develop after acute respiratory syncytial virus (RSV) bronchiolitis, but the mechanisms of these sequelae are poorly understood. Using a guinea-pig model of human RSV lung infection, the effects of long-term viral persistence on three hallmarks of asthma: nonspecific airway responsiveness, airway inflammation and airway remodelling were examined. Guinea-pigs were studied 100 days after intranasal instillation of either human RSV or uninfected vehicle, using: 1) acetylcholine challenge to test for airway hyperresponsiveness (AHR); 2) lung histology to quantify the numbers of airway eosinophils and metachromatic cells (mast cells/basophils); 3) airway morphometry of the areas of the airway subepithelial connective tissue, smooth muscle and adventitia, to test for airway remodelling; and 4) immunohistochemistry to identify lung cells containing RSV antigens. The RSV-inoculated group had significantly elevated AHR and airway eosinophils compared to uninfected control animals (p<0.05). There were no significant differences between the two groups in terms of numbers of airway metachromatic cells, or the areas of subepithelial connective tissue, smooth muscle or adventitia. Viral proteins were identified by immunohistochemistry within several types of lung cells. In conclusion, long-term persistence of respiratory syncytial virus in the guinea-pig lung is associated with airway hyperresponsiveness and airway eosinophilia, and these changes may be pertinent to the pathogenesis of postbronchiolitis wheezing and asthma in children.

Animals↗
PubMed1988

The release of leukotrienes in the respiratory tract during infection with respiratory syncytial virus: role in obstructive airway disease.

Samples of nasopharyngeal secretions from a group of 73 infants with bronchiolitis or upper respiratory illness alone during infection with respiratory syncytial virus were analyzed for leukotriene C4 (LTC4) content using a reverse-phase high-pressure liquid chromatography assay with confirmation by radioimmunoassay. Titers of respiratory syncytial virus (RSV)-specific IgE in nasopharyngeal secretion (NPS) specimens were determined using an enzyme-linked immunosorbent assay. The highest concentrations of LTC4 were found in the first 3 to 8 days after the onset of illness, and LTC4 was detectable in progressively lower concentrations in samples obtained up to 28 days after the onset of illness. LTC4 was detected in samples of NPS obtained in the acute phase of illness from 67% of infants with bronchiolitis due to RSV and in 33% of samples of NPS obtained during the same interval from infants with upper respiratory illness alone (p less than 0.025). Concentrations of LTC4 in children with bronchiolitis were 5-fold higher (1271 pg/ml) than the mean concentration of LTC4 in children with upper respiratory illness (224 pg/ml, p less than 0.02). LTC4 was detected in 83% of the children developing an RSV-IgE response and in 24% of subjects not developing an RSV-IgE response (p less than 0.001). Quantities of LTC4 measured in NPS were directly correlated with the magnitude of the RSV-IgE response in secretions (r = 0.33, p less than 0.02). These studies lend support to previous investigations suggesting that severe bronchiolitis due to RSV results from IgE-mediated hypersensitivity reactions to viral antigens, with release of chemical mediators of airway obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1998

Prevention of respiratory syncytial virus infections: indications for the use of palivizumab and update on the use of RSV-IGIV. American Academy of Pediatrics Committee on Infectious Diseases and Committee of Fetus and Newborn.

The Food and Drug Administration recently approved the use of palivizumab (pal-vizh-mäb), an intramuscularly administered monoclonal antibody preparation. Recommendations for its use are based on a large, randomized study demonstrating a 55% reduction in the risk of hospitalization attributable to respiratory syncytial virus (RSV) infections in high-risk pediatric patients. Infants and children with chronic lung disease (CLD), formerly designated bronchopulmonary dysplasia, as well as prematurely born infants without CLD experienced a reduced number of hospitalizations while receiving palivizumab compared with a placebo. Both palivizumab and respiratory syncytial virus immune globulin intravenous (RSV-IGIV) are available for protecting high-risk children against serious complications from RSV infections. Palivizumab is preferred for most high-risk children because of ease of administration (intramuscular), lack of interference with measles-mumps-rubella vaccine and varicella vaccine, and lack of complications associated with intravenous administration of human immune globulin products. RSV-IGIV, however, provides additional protection against other respiratory viral illnesses and may be preferred for selected high-risk children including those receiving replacement intravenous immune globulin because of underlying immune deficiency or human immuno-deficiency virus infection. For premature infants about to be discharged from hospitals during the RSV season, physicians could consider administering RSV-IGIV for the first month of prophylaxis. Most of the guidelines from the American Academy of Pediatrics for the selection of infants and children to receive RSV-prophylaxis remain unchanged. Palivizumab has been shown to provide benefit for infants who were 32 to 35 weeks of gestation at birth. RSV-IGIV is contraindicated and palivizumab is not recommended for children with cyanotic congenital heart disease. The number of patients with adverse events judged to be related to palivizumab was similar to that of the placebo group (11% vs 10%, respectively); discontinuation of injections for adverse events related to palivizumab was rare.

Antibodies, Monoclonal↗
PubMed1999

Predicting deterioration in previously healthy infants hospitalized with respiratory syncytial virus infection.

OBJECTIVE: To estimate the incidence of clinical deterioration leading to intensive care unit transfer in previously healthy infants with respiratory syncytial virus (RSV) infection hospitalized on a general pediatric unit and, to assess the hypothesis that history, physical examination, oximetry, and chest radiographic findings at time of presentation can accurately identify these infants. STUDY DESIGN: A virology database was used to identify and determine the disposition of all children </=1 year of age admitted to the Children's Hospital at Strong (CHaS) with RSV infection during the 1985 to 1994 respiratory seasons. Index patients were all previously healthy, full-term infants admitted initially to the general inpatient services at CHaS or Rochester General Hospital, a second University of Rochester teaching hospital, whose clinical deterioration led to transfer to the pediatric intensive care unit (PICU). These infants were matched retrospectively (for year and date of infection, sex, chronologic age, and race) with two hospitalized controls who did not require PICU transfer. Chest radiographic findings, respiratory rate (RR), O(2) saturation, and presence of wheezing at time of presentation to the emergency department (ED) were compared. RESULTS: During the study years, 542 previously healthy, full-term infants were admitted to the general pediatric unit at CHaS with proven RSV infection. Ten (1.8%; 95% confidence interval, 0.9%, 3.4%) were transferred subsequently to the PICU, primarily for close monitoring of progressive respiratory distress. Data for these patients and 7 patients transferred from Rochester General Hospital to the PICU at the CHaS were compared with those for control patients. The mean RR in the ED (63 vs 50), and O(2) saturation in the ED (88% vs 93%) were modestly abnormal in cases compared with controls. Wheezing on examination at time of presentation and chest radiographic findings did not differ between the two groups. A RR >80 and an O(2) saturation <85% at time of presentation each had a specificity >97% for predicting subsequent deterioration. Each parameter, however, had a sensitivity </=30%. CONCLUSION: Clinical deterioration requiring PICU admission is an uncommon occurrence in previously healthy infants admitted to a general pediatric inpatient unit with RSV infection. Extreme tachypnea and hypoxemia were both associated with subsequent deterioration; however, only a small proportion of patients who clinically deteriorated presented in this way. The clinical usefulness of these parameters, therefore, is limited. respiratory syncytial virus, deterioration, healthy infants, prediction.

Case-Control Studies↗
PubMed2003

Characterization of bovine respiratory syncytial virus isolated in Brazil.

This paper presents the first isolation of bovine respiratory syncytial virus in Brazil and its physicochemical, morphological and molecular characterization. The virus was isolated from 33 samples of nasotracheal secretions, successively inoculated into a Madin-Darby bovine kidney cell culture, which was characterized by physicochemical tests and morphological observation by electron microscopy. The Brazilian sample is an RNA pleomorphic, enveloped, thermolabile and non-hemagglutinating spicular virus. Reverse transcription, followed by nested polymerase chain reaction (nRT-PCR) assay was carried out using oligonucleotides B1, B2A, B3 and B4 for the fusion proteins (F) and B5A, B6A, B7A and B8 for the attachment protein (G). The nRT-PCR-F amplified a fragment of 481 bp corresponding to part of the gene that codes for protein F, whereas nRT-PCR-G amplified a fragment of 371 bp, in agreement with part of the G gene. The virus isolated from Brazilian samples in this study corresponded to the bovine respiratory syncytial virus, and RT-PCR proved to be useful for the diagnosis of bovine clinical samples.

Animals↗
PubMed1999

[Detection of respiratory syncytial virus using immunohistochemistry. Report of 53 cases of sudden infant death].

We analyzed 53 cases of sudden infant death to detect immunohistochemical expression of respiratory syncytial virus on pulmonary sections. The virus was identified in 7 cases. The immunohistochemical staining was intracytoplasmic and mainly observed in bronchioles. Among these 7 cases, 6 showed severe pulmonary lesions which were assumed to be accountable for decrease. The inflammatory lesions related to respiratory syncytial virus were diffuse, located with the same intensity to either bronchi, bronchioles, alveoles and upper respiratory tract. The immunohistochemical staining was markedly heterogeneous, requiring numerous pulmonary samples.

Female↗