Impact of human metapneumovirus and respiratory syncytial virus co-infection in severe bronchiolitis

We have previously shown high rates of co-infection with Respiratory Syncytial Virus (RSV) and human Metapneumovirus (hMPV) in infants with severe bronchiolitis at our institution in 2000-2002, and that co-infection was associated with increased disease severity. In this study, we have attempted to identify differences in intubated infants with severe RSV infection with and without hMPV co-infection. Here we show that RSV+/hMPV+ were clinically symptomatic for longer than RSV+/hMPV- infants, but that no differences in airway total cell concentration, differential cell count or cytokine/chemokine concentrations were detectable.     

Human metapneumovirus and respiratory syncytial virus infections in older children with cystic fibrosis

BACKGROUND: Human metapneumovirus (hMPV) has been isolated from children with acute respiratory infection worldwide. Its epidemiology remains to be defined in children with cystic fibrosis (CF). We describe the epidemiology and clinical impact of hMPV in CF children and compared it to respiratory syncytial virus (RSV). METHODS: CF children ages 7-18 years were studied prospectively during the 1998 -1999 RSV season. Nasopharyngeal specimens were collected during acute respiratory illnesses and tested for respiratory viruses. Blood specimens were drawn early, mid, and end of the RSV season, and tested for serological evidence of hMPV and RSV infections. Rates of lower respiratory tract illnesses (LRTI) and hospitalizations for pulmonary exacerbations were compared during the time intervals they developed serological evidence of infection to their non-infection intervals. RESULTS: Six of 44 CF children had a virus positive respiratory illness in 56 LTRI events and 18 hospitalizations. Serological evidence of hMPV and RSV infections occurred in 16 and 20 CF children, respectively; 8 had infections with both viruses. A greater proportion of CF children had >or=1 LRTI during their infection intervals compared to their non-infection intervals (13/25 vs. 5/25; P=0.03). A trend for higher rates of LRTI was observed in the infection intervals compared to non-infection intervals (9.5 +/- 11.0 vs. 4.2 +/- 9.9 per 1,000 child-days; P=0.06), and it was significantly greater with a more conservative estimate (one event per child per interval; 7.4 +/- 7.7 vs. 2.6 +/- 5.4 per 1,000 child-days; P 相似文献   

Respiratory syncytial virus bronchiolitis in infancy is an important risk factor for asthma and allergy at age 7

We previously reported an increased risk for bronchial obstructive disease and allergic sensitization up to age 3 in 47 children hospitalized with a respiratory syncytial virus (RSV) bronchiolitis in infancy compared with 93 matched control subjects recruited during infancy. The aims of the present study were to evaluate the occurrences of bronchial obstructive disease and allergic sensitization in these children at age 7(1)/ (2). All 140 children reported for the follow-up, which included physical examination, skin prick tests, and serum IgE tests for common food and inhaled allergens. The cumulative prevalence of asthma was 30% in the RSV group and 3% in the control group (p < 0.001), and the cumulative prevalence of "any wheezing" was 68% and 34%, respectively (p < 0.001). Asthma during the year prior to follow-up was seen in 23% of the RSV children and 2% in the control subjects (p < 0.001). Allergic sensitization was found in 41% of the RSV children and 22% of the control subjects (p = 0.039). Multivariate evaluation of possible risk factors for asthma and sensitization using a stepwise logistic statistical procedure for all 140 children showed that RSV bronchiolitis had the highest independent risk ratio for asthma (OR: 12.7, 95% CI 3.4 to 47.1) and a significantly elevated independent risk ratio for allergic sensitization (OR: 2.4, 95% CI 1.1 to 5.5). In conclusion, RSV bronchiolitis in infancy severe enough to cause hospitalization was highly associatied with the development of asthma and allergic sensitization up to age 7(1)/ (2). The results support the theory that the RSV influences the mechanisms involved in the development of asthma and allergy in children.     

Absence of human metapneumovirus co-infection in cases of severe respiratory syncytial virus infection

It has been suggested that co-infection of human metapneumovirus (hMPV) in severe respiratory syncytial (RSV) virus bronchiolitis is very common. To evaluate the epidemiology of hMPV co-infection in children with severe lower respiratory tract infection caused by RSV virus. This was an observational cohort study in which hMPV and RSV viral load was measured by RT-PCR in tracheal specimens from the target population. hMPV could not be detected in any of the 30 mechanically ventilated children with RSV lower respiratory tract infection. Our study suggests that hMPV co-infection is not very common in severe RSV lower respiratory tract infection.     

Acute lower respiratory tract infections by human metapneumovirus in children in Southwest China: A 2‐year study

Human metapneumovirus (hMPV) has been reported to cause both upper and lower respiratory tract diseases in susceptible populations, particularly in children and the elderly. In this study, we describe a hospital‐based epidemiological study of hMPV in patients presenting to a children's hospital and show the demographic and clinical characteristics associated with hMPV infection in China, retrospectively. Specimens were collected over a 2‐year period from children hospitalized with acute lower respiratory tract infections (ALRTI) and analyzed for the presence of hMPV using real‐time RT‐PCR assays. The presence of hMPV was detected in 227 (25.9%) of the 878 children studied and may circulate year‐round in the area, peaking during the winter–spring season. Younger children (aged less than 6 months) had the highest positive rate. Infections by hMPV showed similar epidemiology and clinical manifestations as for respiratory syncytial virus (RSV) and were found in high co‐infections with RSV. Subgroup A2 hMPV was the most predominant genotype identified during the study period. This study indicates that hMPV is one of the major respiratory pathogens found in children in southwest China and vaccine development should be under consideration. Pediatr. Pulmonol. 2010; 45:824–831. © 2010 Wiley‐Liss, Inc.     

Eosinophil cationic protein in infants with respiratory syncytial virus bronchiolitis: predictive value for subsequent development of persistent wheezing

Infants with acute bronchiolitis during the first months of life are at increased risk of developing persistent wheezing and bronchial asthma later in life. The study of eosinophil cationic protein (ECP) suggests that eosinophil-related inflammatory mechanisms may play a role in respiratory syncytial virus (RSV) bronchiolitis. The aim of our study was to verify whether serum ECP (s-ECP) measurements are useful in predicting the development of persistent wheezing in children affected by RSV bronchiolitis during a 5 years follow-up period. Forty-eight infants were enrolled prospectively (mean age: 153.5 days). All had a clinical and radiological diagnosis of acute bronchiolitis and confirmed RSV infection. Peripheral eosinophil counts, levels of s-ECP, and serum IgE concentrations were measured during bronchiolitis. Five years later the children were re-evaluated in regard to their respiratory symptoms (standardized questionnaires) and atopic status (specific IgE levels). We observed significantly higher s-ECP levels (P < 0.001) at enrollment in subjects who developed persistent wheezing compared to subjects who did not show late wheezing. Initial s-ECP values allowed significant and correct prediction of persistent wheezing (P < 0.001). The risk to develop respiratory symptoms was 9.73 higher for infants with s-ECP levels > or = 8 microg/L than for those with s-ECP levels <8 microg/L (P < 0.0001). In conclusion, our study suggests that s-ECP levels in infants with bronchiolitis are useful in predicting the risk to develop wheezing in the subsequent 5 years.     

Allergy is an important factor in asthma exacerbation: A Pro/Con Debate

Allergy and allergens have been implicated in asthma and it has historically been assumed that deteriorating asthma is related to allergen exposure. In the current pro/con debate some leading academics and researchers in the field consider this notion in the light of recent evidence. They conclude that allergy does not directly cause exacerbations but suggest that it may contribute to acute asthma in a different fashion. Possibilities that are proposed by the authors include specific allergy phenotypes acting as risk factors for virus‐associated exacerbations or alternatively that allergy may be implicated in the blunted innate immune responses detected in asthma.     

Retrospective comparison of respiratory syncytial virus and metapneumovirus clinical presentation in hospitalized children

Respiratory syncytial virus (RSV) and Human metapneumovirus (hMPV), members of Pneumoviridae family are common causes of acute respiratory tract infections (ARTI) among children. Study material includes routine nasopharyngeal samples obtained during 8-year period for hMPV and one single season for RSV in children hospitalized for ARTI between 0 and 15 years at the Center Hospitalier Universitaire (CHU) Saint Pierre in Brussels. Positive samples for RSV or hMPV identified by viral culture, lateral flow chromatography test for RSV or direct fluorescent assay for hMPV were selected retrospectively. Characteristics of children hospitalized for RSV or hMPV infections were compared. Children hospitalized for RSV infection were significantly younger and requiring more respiratory support, longer hospital stay and transfers in Pediatric intensive Care Units than those hospitalized for hMPV infection. Pneumonia diagnostic and antibiotics therapies were more significantly associated with hMPV infections. In conclusion, despite their genetic similarities, RSV, and hMPV present epidemiological and clinical differences in pediatric infections. Our results should be confirmed prospectively.     

Effect of secondhand cigarette smoke, RSV bronchiolitis and parental asthma on urinary cysteinyl LTE4

Cysteinyl leukotrienes promote airway inflammation, bronchoconstriction and mucus hypersecretion. Cigarette smoking and respiratory syncytial virus (RSV) bronchiolitis are known to increase urinary cysteinyl leukotriene E4 (uLTE4), the end product of the cysteinyl leukotriene biosynthetic pathway. We tested the following hypotheses: (1) Secondhand smoke (SHS) exposure increases uLTE4 in well infants and in those hospitalized for RSV bronchiolitis; (2) Length of hospital stay for those with RSV bronchiolitis correlates with uLTE4; and (3) Infants with parent(s) with asthma will have higher uLTE4. Parental asthma for infants hospitalized with RSV bronchiolitis (n = 79) and Well babies (n = 31) was determined by questionnaire. Urine was analyzed for LTE4, cotinine, and creatinine. SHS exposure was determined by cotinine to creatinine ratio. Chi square, or t-tests were used to determine significant differences between two groups. A three-way analysis of variance compared the effects of SHS exposure and parental asthma on uLTE4 in Well versus RSV babies. Independent variables predicting length of hospital stay were determined by stepwise multiple regression. High SHS exposure and RSV significantly increased uLTE4. The SHS induced increase in uLTE4 was seen in infants with no parental asthma but not in those with parental asthma. Length of hospital stay positively correlated with uLTE4. We concluded that SHS exposure may increase the severity of bronchiolitis in RSV-infected infants by enhancing production of cysLTs in infants with no parental asthma.     

Bronchodilator response during acute viral bronchiolitis in infancy

Bronchodilator responsiveness was assessed by measuring specific respiratory conductance before and after inhalation of aerosolized bronchodilator in 50 infants who had acute bronchiolitis due to respiratory syncytial virus infection. Thirty per cent of the infants showed an improvement in specific conductance. Responders could not be differentiated from nonresponders by family histories of atopy, eosinophil counts, or immunoglobulin levels in blood and nasal secretions. Eighty-three per cent of the families and 54% of the mothers of the infants were smokers. Babies of smoking mothers had lower specific conductances than did those of nonsmoking mothers but showed no differences in bronchodilator response. The clinical significance of this bronchodilator-responsive sub-group has yet to be defined.     

Efficacy of nebulized epinephrine versus salbutamol in hospitalized infants with bronchiolitis

We enrolled 30 infants (median age 3 months, range 1-12 months), hospitalized for bronchiolitis in a randomized double-blind trial, to examine the efficacy and safety of nebulized epinephrine compared to salbutamol. Once admitted, patients were treated with either nebulized 0.5 mg of an 0.1% epinephrine solution (0.5 mL in 3.5 mL normal saline (NS)) or 2.5 mg nebulized salbutamol (0.5 mL in 3.5 mL NS). They were evaluated daily before and after nebulization until discharge. The outcome measures used were: baseline clinical score (based on respiratory rate, subcostal retraction, presence of wheezing, and O2 requirement), change in clinical O2 score after nebulization, duration of O2 therapy, and duration of hospitalization. A significant improvement in the clinical score was noted on the first day of hospitalization in subjects receiving epinephrine (P = 0.025); that change was not seen in those on salbutamol (P = 0.6). Nebulized epinephrine decreased the baseline clinical score faster than salbutamol (P = 0.02), though on the fourth study day there was no significant difference between the two scores. On the fourth and fifth days of study there were more patients hospitalized in the salbutamol group than in the epinephrine group (P = 0.03 vs. P = 0.025). No adverse effects were associated with nebulized therapy. We conclude that nebulized epinephrine is a more effective agent than salbutamol in the initial treatment of bronchiolitis and is equally safe.