Antonella Frassanito

Bronchiolitis: Analysis of 10 consecutive epidemic seasons

Bronchiolitis is the leading cause of hospitalization in infants under 12 months. Our aims were to analyze epidemiological characteristics of infants with bronchiolitis over 10 consecutive seasons and to evaluate whether there are any clinical differences between infants hospitalized for bronchiolitis during epidemic peak months and infants in non‐peak months. We enrolled consecutive enrolled 723 previously healthy term infants hospitalized at the Paediatric Emergency Department, “Sapienza” University of Rome over the period 2004–2014. Fourteen respiratory viruses were detected from nasopharyngeal aspirates by molecular methods. Clinical and demographic data were extracted from clinical charts. Viruses were detected in 351 infants (48.5%): RSV in 234 (32.4%), RV in 44 (6.1%), hBoV in 11 (1.5%), hMPV in 12 (1.6%), co‐infections in 39 (5.4%), and other viruses in 11 (1.5%). Analyzing the 10 epidemic seasons, we found higher incidence for bronchiolitis every 4 years with a peak during the months December–January. Infants hospitalized during peak months had lower family history for asthma (P = 0.003), more smoking mothers during pregnancy (P = 0.036), were slightly higher breastfed (0.056), had lower number of blood eosinophils (P = 0.015) and had a higher clinical severity score (P = 0.017). RSV was detected mostly during peak months, while RV was equally distributed during the seasons. We found some variations in bronchiolitis incidence during epidemics, and discriminative characteristics in infants hospitalized for bronchiolitis during peak months and in non‐peak months, that might reflect two different populations of children. Pediatr Pulmonol. 2016;51:1330–1335.

Risk Factors for Virus-induced Acute Respiratory Tract Infections in Children Younger Than 3 Years and Recurrent Wheezing at 36 Months Follow-up After Discharge

Background: We sought to know more about how 14 common respiratory viruses manifest clinically, and to identify risk factors for specific virus-induced acute respiratory tract infections (ARTIs) in children younger than 3 years old and for wheezing at 36-month follow-up. Methods: We retrospectively studied the clinical records for 273 full-term children (median age, 2.9 months; range, 0.26–39; boys, 61.2%) hospitalized for ARTIs, whose nasopharyngeal specimen tested positive for a respiratory virus and 101 children with no history of respiratory diseases (median age, 8 months; range, 0.5–36.5; boys, 58.4%). At 12, 24 and 36 months after children’s discharge, all parents were interviewed by telephone with a structured questionnaire on wheezing episodes. Results: The most frequently detected viruses were respiratory syncytial virus in bronchiolitis, human rhinovirus in pneumonia and human bocavirus in wheezing. Multivariate analysis identified, as risk factors for virus-induced ARTIs, the presence of siblings [odds ratio (OR): 3.0 (95% confidence interval [CI]: 1.8–5.2)], smoking cohabitants (OR: 2.3 (95% CI: 2–4.2)] and breastfeeding lasting less than 3 months [OR: 0.5 (95% CI: 0.3–0.9)]. The major risk factor for respiratory syncytial virus–induced ARTIs was exposure to tobacco smoke [OR: 1.8 (95% CI: 1.1–3.2)]. Risk factors for human rhinovirus–induced ARTIs were attending day-care [OR: 5.0 (95% CI: 2.3–10.6)] and high eosinophil blood counts [OR: 2.6 (95% CI: 1.2–5.7)]. The leading risk factor for recurrent wheezing was exposure to tobacco smoke [OR: 2.5 (95% CI: 1.1–15.6)]. Conclusions: Each respiratory virus leads to a specific clinical manifestation. Avoiding exposing children to tobacco smoke might restrict viral spread from sick parents and siblings to younger children, prevent severe respiratory diseases, and possibly limit sequelae.

Respiratory syncytial virus bronchiolitis, weather conditions and air pollution in an Italian urban area: An observational study

Background In this study we sought to evaluate the association between viral bronchiolitis, weather conditions, and air pollution in an urban area in Italy. Methods We included infants hospitalized for acute bronchiolitis from 2004 to 2014. All infants underwent a nasal washing for virus detection. A regional agency network collected meteorological data (mean temperature, relative humidity and wind velocity) and the following air pollutants: sulfur dioxide, nitrogen oxide, carbon monoxide, ozone, benzene and suspended particulate matter measuring less than 10 &mgr;m (PM10) and less than 2.5 &mgr;m (PM2.5) in aerodynamic diameter. We obtained mean weekly concentration data for the day of admission, from the urban background monitoring sites nearest to each childs home address. Overdispersed Poisson regression model was fitted and adjusted for seasonality of the respiratory syncytial virus (RSV) infection, to evaluate the impact of individual characteristics and environmental factors on the probability of a being positive RSV. Results Of the 723 nasal washings from the infants enrolled, 266 (68%) contained RSV, 63 (16.1%) rhinovirus, 26 (6.6%) human bocavirus, 20 (5.1%) human metapneumovirus, and 16 (2.2%) other viruses. The number of RSV‐positive infants correlated negatively with temperature (p < 0.001), and positively with relative humidity (p < 0.001). Air pollutant concentrations differed significantly during the peak RSV months and the other months. Benzene concentration was independently associated with RSV incidence (p = 0.0124). Conclusions Seasonal weather conditions and concentration of air pollutants seem to influence RSV‐related bronchiolitis epidemics in an Italian urban area. HighlightsPeak RSV activity correlates with cold temperatures and higher relative humidity.RSV‐positive cases correlates positively with BZ, NOx, SO2, PM10 and PM2.5.The most predictive pollutant for RSV cases (constant temperature and humidity)is BZ.

Protection against Pertussis in Humans Correlates to Elevated Serum Antibodies and Memory B Cells

Pertussis is a respiratory infection caused by Bordetella pertussis that may be particularly severe and even lethal in the first months of life when infants are still too young to be vaccinated. Adults and adolescents experience mild symptoms and are the source of infection for neonates. Adoptive maternal immunity does not prevent pertussis in the neonate. We compared the specific immune response of mothers of neonates diagnosed with pertussis and mothers of control children. We show that women have pre-existing pertussis-specific antibodies and memory B cells and react against the infection with a recall response increasing the levels specific serum IgG, milk IgA, and the frequency of memory B cells of all isotypes. Thus, the maternal immune system is activated in response to pertussis and effectively prevents the disease indicating that the low levels of pre-formed serum antibodies are insufficient for protection. For this reason, memory B cells play a major role in the adult defense. The results of this study suggest that new strategies for vaccine design should aim at increasing long-lived plasma cells and their antibodies.

Acute bronchiolitis: Influence of viral co-infection in infants hospitalized over 12 consecutive epidemic seasons

Bronchiolitis is the first lower respiratory tract viral infection manifesting in infants younger than 12 months of age. Our aim was to evaluate clinical and serological differences in infants with bronchiolitis from a single or from multiple viruses. Our secondary aim was to investigate differences in recurrent wheezing episodes after 12‐24‐36 months of follow‐up. We reviewed the clinical records for 486 full‐term infants hospitalized for bronchiolitis with at least one virus detected in the nasopharyngeal aspirate. In 431 (88.7%) patients one virus was detected and in 55 (11.3%) infants more than one virus was found. No differences were observed in the length of hospitalization, clinical severity score, O2 supplementation or admission to the intensive care unit. Single virus was associated with higher serum C‐reactive protein (C‐RP) than infants with multiple viruses and higher blood neutrophil counts. Respiratory syncytial virus (RSV) was the most frequently detected virus. RSV alone was associated with higher C‐RP (P = 0.007), compared to RSV coinfection. Infants with human rhinovirus (hRV) alone had higher white blood cell counts, higher blood neutrophils, and higher serum C‐RP levels than hRV co‐infection (P = 0.029, P = 0.008, P = 0.008). RSV + hRV, the most frequent co‐infection, was associated with lower neutrophil count and lower C‐RP levels (P = 0.008, P = 0.016) and less fever (P = 0.012), when comparing RSV versus hRV versus RSV + hRV. No differences were found in the frequency of recurrent wheezing between single versus multiple viruses after bronchiolitis. Our findings suggest that in infants with bronchiolitis multiple viral co‐infections can occur, without influence in the clinical severity of the disease. Infants with co‐infection seems to mount a lower inflammatory response.

Modifiable risk factors associated with bronchiolitis

Background: We sought to clarify possibly modifiable risk factors related to pollution responsible for acute bronchiolitis in hospitalized infants. Methods: For this observational study, we recruited 213 consecutive infants with bronchiolitis (cases: median age: 2 months; age range: 0.5–12 months; boys: 55.4%) and 213 children aged <3 years (controls: median age: 12 months; age range: 0.5–36 months; boys: 54.5%) with a negative medical history for lower respiratory tract diseases hospitalized at ‘Sapienza’ University Rome and IRCCS Bambino Gesù Hospital. Infants’ parents completed a standardized 53-item questionnaire seeking information on social-demographic and clinical characteristics, indoor pollution, eating habits and outdoor air pollution. Multivariate logistic regression analyses were run to assess the independent effect of risk factors, accounting for confounders and effect modifiers. Results: In the 213 hospitalized infants the questionnaire identified the following risk factors for acute bronchiolitis: breastfeeding ⩾3 months (OR: 2.1, 95% confidence interval [CI]: 1.2–3.6), presence of older siblings (OR: 2.8, 95% CI: 1.7–4.7), ⩾4 cohabitants (OR: 1.5, 95% CI: 1.1–2.1), and using seed oil for cooking (OR: 1.7, 95% CI: 1.2–2.6). Having renovated their home in the past 12 months and concurrently being exposed daily to smoking, involving more than 11 cigarettes and two or more smoking cohabitants, were more frequent factors in cases than in controls (p = 0.021 and 0.05), whereas self-estimated proximity to road and traffic was similar in the two groups. Conclusions: We identified several risk factors for acute bronchiolitis related to indoor and outdoor pollution, including inhaling cooking oil fumes. Having this information would help public health authorities draw up effective preventive measures – for example, teach mothers to avoid handling their child when they have a cold and eliminate exposure to second-hand tobacco smoke.

How Respiratory Syncytial Virus Genotypes Influence the Clinical Course in Infants Hospitalized for Bronchiolitis

Background We aimed to study respiratory syncytial virus (RSV) genotype distribution, clinical presentation, and disease severity in infants with bronchiolitis from RSV subtypes and new RSV genotypes. Methods We prospectively enrolled previously healthy term infants less than 1 year old hospitalized for bronchiolitis in an Italian university hospital over 12 epidemic seasons. In 312 nasopharyngeal washings positive for RSV, we sequenced the viral genotype and analyzed this according to patient data. Strain-specific RSV loads were quantified for 273 specimens. Results From 2005-2006 to 2011-2012, the RSV-A genotype NA1 predominated, and was replaced in 2012 by the novel ON1. All infants infected with RSV subtype B were genotype BA. Stratifying data according to genotypes NA1, ON1, and BA showed that NA1-infected infants were the youngest and had the most severe clinical course. Conversely, BA-infected infants had less severe symptoms and more frequently had eosinophilia and a family history of asthma. Infants with the ON1 genotype had a milder clinical course than those with NA1 and more risk factors for asthma, despite having the highest viral loads. Conclusion The disease course in infants hospitalized for acute RSV bronchiolitis may depend on the RSV genotype.

Analysis of the immune response in infants hospitalized with viral bronchiolitis shows different Th1/Th2 profiles associated with respiratory syncytial virus and human rhinovirus

Severe bronchiolitis is often associated with the development of wheezing and asthma during childhood but the mechanisms behind the development of respiratory disorders after bronchiolitis remain controversial (1). The respiratory syncytial virus (RSV) and the human rhinovirus (HRV) are the most important etiologies of bronchiolitis (2, 3). Compared to RSV, HRV-infected infants display peculiar clinical characteristics and a correlation of HRV-bronchiolitis with asthma has been suggested (4-7). We report here the results of a preliminary investigation aimed at the evaluation of the ongoing T-cell responses in infants with bronchiolitis of different etiology. This article is protected by copyright. All rights reserved.

Interferon lambda receptor 1 (IFNL1R) transcript is highly expressed in rhinovirus bronchiolitis and correlates with disease severity

BACKGROUND As the expression of type III IFN receptor is restricted to the mucosal surfaces, its evaluation could be crucial to characterize the role of IFNλs during bronchiolitis. OBJECTIVES This study was designed to investigate airway type III IFN receptor (IFNLR1/IL10RB) expression during respiratory syncytial virus (RSV) or human rhinovirus (HRV) bronchiolitis. STUDY DESIGN Seventy-one 1-6 month old infants hospitalized with their first episode of acute RSV or HRV bronchiolitis were selected for this study. Expression of IFNLR1, IL10RB and IFN-stimulated genes (ISGs) MxA and ISG56 in cells of nasopharyngeal washings taken within the first 48 h of admission were determined by a real-time hydrolysis probe RT-PCR assay. The ability of types I and III IFNs to induce the expression of both IFNLR1 and IL10RB in vitro was also evaluated. RESULTS Airway IFNLR1 transcript levels were significantly higher in HRV bronchiolitis infants compared to those with RSV bronchiolitis. No differences were recorded for IL10RB-mRNA between RSV or HRV infection. IFNLR1 mRNA levels increased significantly in infants infected with the C species of HRV and in those with a higher clinical score index and with an eosinophil count >3%. There were no correlations in vivo between type III IFN receptors and those of ISGs and neither IFNLR1 nor IL10RB were induced in vitro by IFNs. CONCLUSIONS These results suggest that IFNLR1 are increased in HRV-infected infants with more severe bronchiolitis and blood eosinophilia and in those infected with the HRVC species.

Difficult diagnosis of atypical kawasaki disease in an infant younger than six months: a case report

BackgroundKawasaki disease (KD) is an acute inflammatory vasculitis of unknown origin.Case presentationWe report the case of a 5-month-old child with an atypical form of KD, characterized by undulating symptoms, who developed an aneurysm of the right coronary artery and an ectasia of the left anterior descending coronary artery.ConclusionThis case report underlines the difficulties in recognizing incomplete forms of the illness in young infants, who are at higher risk of cardiac complications.