Etiology of acute bronchiolitis and the relationship with meteorological conditions in hospitalized infants in China

Short-term association among meteorological variation, outdoor air pollution and acute bronchiolitis in children in a subtropical setting

OBJECTIVES

To examine the association among acute bronchiolitis-related hospitalisation in children, meteorological variation and outdoor air pollution.

METHODS

We obtained the daily counts of acute bronchiolitis-related admission of children≤2 years old from all public hospitals, meteorological data and outdoor air pollutants' concentrations between 1 January 2008 and 31 December 2017 in Hong Kong. We used quasi-Poisson generalised additive models together with distributed lag non-linear models to estimate the associations of interest adjusted for confounders.

RESULTS

A total of 29 688 admissions were included in the analysis. Increased adjusted relative risk (ARR) of acute bronchiolitis-related hospitalisation was associated with high temperature (ambient temperature and apparent temperature) and was marginally associated with high vapour pressure, a proxy for absolute humidity. High concentration of NO₂ was associated with elevated risk of acute bronchiolitis admission; the risk of bronchiolitis hospitalisation increased statistically significantly with cumulative NO₂ exposure over the range 66.2-119.6 µg/m³. For PM₁₀, the significant effect observed at high concentrations appears to be immediate but not long lasting. For SO₂, ARR increased as the concentration approached the 75th percentile and then decreased though the association was insignificant.

CONCLUSIONS

Acute bronchiolitis-related hospitalisation among children was associated with temperature and exposure to NO₂ and PM₁₀ at different lag times, suggesting a need to adopt sustainable clean air policies, especially to target pollutants produced by motor vehicles, to protect young children's health.

Systematic review and meta-analysis of the prevalence of common respiratory viruses in children < 2 years with bronchiolitis in the pre-COVID-19 pandemic era

INTRODUCTION

The advent of genome amplification assays has allowed description of new respiratory viruses and to reconsider the role played by certain respiratory viruses in bronchiolitis. This systematic review and meta-analysis was initiated to clarify the prevalence of respiratory viruses in children with bronchiolitis in the pre-COVID-19 pandemic era.

METHODS

We performed an electronic search through Pubmed and Global Index Medicus databases. We included observational studies reporting the detection rate of common respiratory viruses in children with bronchiolitis using molecular assays. Data was extracted and the quality of the included articles was assessed. We conducted sensitivity, subgroups, publication bias, and heterogeneity analyses using a random effect model.

RESULTS

The final meta-analysis included 51 studies. Human respiratory syncytial virus (HRSV) was largely the most commonly detected virus 59.2%; 95% CI [54.7; 63.6]). The second predominant virus was Rhinovirus (RV) 19.3%; 95% CI [16.7; 22.0]) followed by Human bocavirus (HBoV) 8.2%; 95% CI [5.7; 11.2]). Other reported viruses included Human Adenovirus (HAdV) 6.1%; 95% CI [4.4; 8.0]), Human Metapneumovirus (HMPV) 5.4%; 95% CI [4.4; 6.4]), Human Parainfluenzavirus (HPIV) 5.4%; 95% CI [3.8; 7.3]), Influenza 3.2%; 95% CI [2.2; 4.3], Human Coronavirus (HCoV) 2.9%; 95% CI [2.0; 4.0]), and Enterovirus (EV) 2.9%; 95% CI [1.6; 4.5]). HRSV was the predominant virus involved in multiple detection and most codetections were HRSV + RV 7.1%, 95% CI [4.6; 9.9]) and HRSV + HBoV 4.5%, 95% CI [2.4; 7.3]).

CONCLUSIONS

The present study has shown that HRSV is the main cause of bronchiolitis in children, we also have Rhinovirus, and Bocavirus which also play a significant role. Data on the role played by SARS-CoV-2 in children with acute bronchiolitis is needed.

REVIEW REGISTRATION

PROSPERO, CRD42018116067.

A review on disease burden and epidemiology of childhood parainfluenza virus infections in Asian countries

Human parainfluenza viruses (HPIVs) are an important cause of acute respiratory tract infections (ARTIs) in children less than 5 years, second only to human respiratory syncytial viruses (HRSVs). Generally, patients infected with HPIVs are treated in outpatient clinics, yet also contribute to ARTI-associated hospitalization in children. Although HPIV infections are well studied in developed countries, these infections remain under-investigated and not considered in the routine laboratory diagnosis of childhood ARTI in many developing countries in Asia. We performed an extensive literature search on the prevalence, epidemiology, and burden of HPIV infections in children less than 5 years in Asia using PubMed and PubMed Central search engines. Based on the literature, the prevalence of HPIV infection in Asia ranges from 1% to 66%. According to many studies, HPIV-3 is the major virus circulating among children; however, several studies failed to detect HPIV-4 due to unavailability of diagnostic tools. In Asian countries, HPIV contributes a substantial disease burden in children. The data in this review should assist researchers and public health authorities to plan preventive measures, including accelerating research on vaccines and antiviral drugs.

The prevalence of human bocavirus in <2-year-old children with acute bronchiolitis

Acute bronchiolitis is one of the most common lower respiratory tract infections in children with less than 2 years of age. Nowadays, molecular methods provide an opportunity to better understand the etiology of bronchiolitis. Several viral agents including Respiratory syncytial virus (RSV), Rhinovirus, Parainfluenza and Human bocavirus (HBoV) are responsible for acute bronchiolitis. There are growing studies on the prevalence of HBoV in patients with bronchiolitis. The present systematic review and meta-analysis were conducted to determine the pooled prevalence of HBoV in the respiratory samples of children with acute bronchiolitis. A literature search was conducted in the databases of PubMed, Scopus and Web of Science to recruit studies reporting the frequency of HBoV in <2-year-old children with acute bronchiolitis from 2005 to 2019. Only studies that used polymerase chain reaction (PCR)-based methods to detect the virus in nasopharyngeal samples were included. A total of 22 studies assessing 6751 cases were analyzed. According to the meta-analysis based on the random-effects model, the overall prevalence of HBoV in children with <2 years old was obtained 13% (95% CI: 0.09-0.17). Additionally, the rates of single (as the sole organism) and mixed (in combination with other viruses) HBoV infections were 4% and 9%, respectively. This study showed a high rate of HBoV detection in children with acute bronchiolitis. This should be considered as part of a diagnostic test panel for respiratory infections in children with bronchiolitis.

Temporal and climate characteristics of respiratory syncytial virus bronchiolitis in neonates and children in Sousse, Tunisia, during a 13-year surveillance

This study established the correlation between respiratory syncytial virus (RSV) bronchiolitis and climate factors in the area of Sousse, Tunisia, during 13 years (2003-2015), from neonates and children <= 5 years old and hospitalized in Farhat Hached University-Hospital of Sousse. The meteorological data of Sousse including temperature, rainfall, and humidity were obtained. RSV detection was carried out with the direct immunofluorescence assay. The impact of climate factors on viral circulation was statistically analyzed. From 2003 to 2015, the total rate of RSV bronchiolitis accounted for 34.5% and peaked in 2007 and 2013. RSV infection was higher in male cases and pediatric environment (p<0.001) and was detected in 47.3% of hospitalizations in intensive care units. The epidemic of this pathogen started in October and peaked in January (41.6%). When the infectivity of RSV was at its maximum, the monthly average rainfall was high (31 mm) and the monthly average temperature and the monthly average humidity were at their minimum (11 °C and 66%, respectively). RSV activity was negatively correlated with temperature (r = - 0.78, p = 0.003) and humidity (r = - 0.62, p = 0.03). Regression analysis showed that the monthly average temperature fits into a linear model (R² = 61%, p < 0.01). No correlation between RSV activity and rainfall was observed (p = 0.48). The meteorological predictions of RSV outbreaks with specific Tunisian climate parameters will help in determining the optimal timing of appropriate preventive strategies. In the area of Sousse, preventive measures should be enhanced since October especially, when the temperature is around 11 °C and humidity is above 60%.

Is multiple viral infection a predictor of severity in children with acute bronchiolitis?

Background:

Acute bronchiolitis is a common cause of pediatric emergency department admissions in children younger than 2.

Objectives:

The study aimed to compare the outcomes and the severity of bronchiolitis in young children with multiple simultaneous respiratory virus infections to those with single virus infection and no virus identified group.

Methods:

Patients with moderate and severe bronchiolitis who visited our emergency department between November 2016 and May 2017 had nasopharyngeal swab samples results tested by multiplex polymerase chain reaction were included in the study. Patients’ characteristics, clinical severity of illness, and outcome (pediatric emergency department discharge, admission to ward or pediatric intensive care unit) were compared with the detected viral agents.

Results:

A total of 241 patients were included in the study. The mean age was 7.8 ± 2.6 months and 147 (61%) were male. Respiratory syncytial virus was the most common detected viral agent in 108 (39%) cases followed by human rhinoviruses in 67 (24%). Respiratory syncytial virus was found more frequently in February and March (p = 0.002). Leukocytosis and pneumonia were more likely observed in patients with only human rhinoviruses (+) subjects (p = 0.010 and p = 0.015, respectively). Intensive care hospitalization rate (16%) was higher in patients with multiple viral agents (p = 0.004).

Conclusions:

Respiratory syncytial virus remains the most common detected viral agent in acute bronchiolitis patients. While the pathogens detected were seasonally different, there was a significant relationship between leukocytosis, bacterial pneumonia, and detected viral agents. The disease was more severe in patients with multiple viral agents.

Association between viral seasonality and meteorological factors

Numerous viruses can cause upper respiratory tract infections. They often precede serious lower respiratory tract infections. Each virus has a seasonal pattern, with peaks in activity in different seasons. We examined the effects of daily local meteorological data (temperature, relative humidity, “humidity-range” and dew point) from Edinburgh, Scotland on the seasonal variations in viral transmission. We identified the seasonality of rhinovirus, adenovirus, influenza A and B viruses, human parainfluenza viruses 1–3 (HPIV), respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) from the 52060 respiratory samples tested between 2009 and 2015 and then confirmed the same by a generalised linear model. We also investigated the relationship between meteorological factors and viral seasonality. Non-enveloped viruses were present throughout the year. Following logistic regression adenovirus, influenza viruses A, B, RSV and HMPV preferred low temperatures; RSV and influenza A virus preferred a narrow “humidity-range” and HPIV type 3 preferred the season with lower humidity. A change (i.e. increase or decrease) in specific meteorological factors is associated with an increase in activity of specific viruses at certain times of the year.

Impact of RSV Coinfection on Human Bocavirus in Children with Acute Respiratory Infections

OBJECTIVE

The objective of this study was to assess epidemiological and clinical features of human bocavirus (HBoV) coinfection with other viruses.

METHOD

Children coinfected with HBoV between January 2012 and December 2014 were enrolled and retrospectively reviewed.

RESULT

A total of 984 patients were stratified into five groups: HBoV infection alone (n = 249), respiratory syncytial virus (RSV) infection alone (n = 649), HBoV coinfection with RSV (n = 28), with human rhinovirus (HRV) (n = 39) and with other virus (n = 19). Length of hospitalization was longer in HBoV coinfection with RSV group than HBoV (9.0 days vs. 7.0 days, p = 0.001), RSV (9.0 days vs. 8.0 days, p = 0.016) infection alone group. Pneumonia was more common in the HBoV coinfection with RSV group compared with the HBoV, RSV infection alone group, respectively (75.0% vs. 44.2%, 31.3%, p < 0.001). HBoV DNA copy numbers (383 000 copies/ml) were positively correlated with the length of hospitalization (r = 0.334, p < 0.001).

CONCLUSION

HBoV coinfection with RSV increases HBoV infection severity.

Bronchiolitis in children: The Saudi initiative of bronchiolitis diagnosis, management, and prevention (SIBRO)

Bronchiolitis is the leading cause of admissions in children less than two years of age. It has been recognized as highly debated for many decades. Despite the abundance of literature and the well-recognized importance of palivizumab in the high risk groups, and despite the existence of numerous, high-quality, recent guidelines on bronchiolitis, the number of admissions continues to increase. Only supportive therapy and few therapeutic interventions are evidence based and proved to be effective. Since Respiratory Syncytial Virus (RSV) is the major cause of bronchiolitis, we will focus on this virus mostly in high risk groups like the premature babies and children with chronic lung disease and cardiac abnormalities. Further, the prevention of RSV with palivizumab in the high risk groups is effective and well known since 1998; we will discuss the updated criteria for allocating infants to this treatment, as this medication is expensive and should be utilized in the best condition. Usually, diagnosis of bronchiolitis is not challenging, however there has been historically no universally accepted and validated scoring system to assess the severity of the condition. Severe RSV, especially in high risk children, is unique because it can cause serious respiratory sequelae. Currently there is no effective curative treatment for bronchiolitis. The utility of different therapeutic interventions is worth a discussion.

Impact of meteorological factors on the emergence of bronchiolitis in North-western Greece

OBJECTIVE

To evaluate the relationship between meteorological factors in North-western Greece and the incidence of bronchiolitis.

METHODS

Meteorological data (air temperature and rainfall) for Ioannina city in North-western Greece and medical data from hospitalised patients at University Hospital of Ioannina were collected between January 2002 and December 2013. The association between meteorological factors and rate of hospitalisation due to bronchiolitis was investigated. The data processing was done using the Pearson product-moment correlation coefficient and applying the chi-square test at contingency tables of the parameters.

RESULTS

Of the 792 hospitalised cases, 670 related to infants (<1 year) and 122 concerned patients aged 1-2 years old. The disease is more common among boys (59.5%) than girls (40.5%). The disease course through the year has a double variation with a main maximum in March and a main minimum in August. The statistical study showed statistically significant correlation of bronchiolitis with: (a) the temperature parameters on an annual basis; (b) precipitation in autumn and dryness in spring; and (c) with sudden changes in diurnal temperature range on an annual basis.

CONCLUSION

A peak incidence of bronchiolitis was noticed in cold and wet seasons during the five days preceding hospitalisation.

Etiology, Seasonality, and Clinical Features of Viral Respiratory Tract Infections in Children Hospitalized With Acute Bronchiolitis: A Single-Center Study

The purpose of this study was to evaluate the viral frequency, seasonality, and clinical and demographic features of patients hospitalized with acute bronchiolitis. A cross-sectional, descriptive study was performed in 316 infants younger than 2 years of age who were hospitalized for acute viral bronchiolitis. Respiratory tract infection agents were investigated with polymerase chain reaction (PCR). A total of 316 infants were included in this study. Of the 316 infants, at least one respiratory tract pathogen was detected in 75% (237/316). Respiratory syncytial virus (RSV) was the most common virus identified in 127 infants (40.1%) followed by rhinovirus (n = 78, 24.6%). In this study, where viral agents were determined via PCR in patients who were followed-up due to the diagnosis of acute bronchiolitis, RSV was detected as the most common agent, as in other studies. In almost half of the RSV-positive patients, RSV was accompanied by a second or third agent.

Clinical and epidemiological profiles including meteorological factors of low respiratory tract infection due to human rhinovirus in hospitalized children

BACKGROUND

Lower respiratory tract infection (LRTI) is a major cause of morbidity and mortality in children. Human rhinovirus (HRV) is confirmed to be associated with pediatric lower respiratory tract infection. Seasonal and meteorological factors may play a key role in the epidemiology of HRV. The purposes of this study were to investigate the frequency, seasonal distribution, and clinical characteristics of hospitalized children with LRTI caused by HRVs. In addition, associations between incidence of HRVs and meteorological factors in a subtropical region of China were discussed.

METHODS

Hospitalized children <14 years old admitted to the Respiratory Department of the Children's Hospital, which is affiliated to Soochow University, between January 1, 2013 and December 31, 2015, were enrolled in this study. Multi-pathogens were detected in nasopharyngeal aspirate samples. Meanwhile, meteorological factors were recorded.

RESULTS

The average incidence of HRVs infection was 11.4% (707/6194) and 240 cases of which were co-infection cases with other pathogens. Children with co-infection presented more frequent fever and tachypnea compared to children infected with HRVs only (both P < 0.05). Among 707 HRV positive children, the mean age was 23.2 months (range 1 to 140 months). Among all respiratory infections, the highest incidence of HRVs cases occurred in children age 13-36 months old (15.1%, 203/1341). Of all 228 HRV cases in 2014, 85 cases (37.3%) were HRV-C positive. HRVs and HRV-C infection occurred throughout the year during the study period, although a higher incidence was observed in summer and autumn seasons. HRVs or HRV-C incidence in hospitalized children with LRTI was associated with the monthly mean temperature (both P < 0.05).

CONCLUSION

HRV was one of the most common viral pathogen detected in hospitalized children with LRTI at the Children's Hospital of Suzhou, China, and had its own seasonal distribution including HRV-C, which was partly caused by temperature.

Human metapneumovirus in patients hospitalized with acute respiratory infections: A meta-analysis

This meta-analysis aimed to estimate the prevalence of human metapneumovirus (hMPV) infections in patients hospitalized for acute respiratory infection (ARI) and to study factors associated with this prevalence. Medline and ScienceDirect databases were searched for prospective observational studies that screened hospitalized patients with ARI for hMPV by RT-PCR, with data available at December 27, 2014. The risk of bias was assessed regarding participation rate, definition of ARI, description of diagnostic technique, method of inclusion identical for all subjects, standardized and identical sampling method for all subjects, analysis performed according to the relevant subgroups, and presentation of data sources. Random-effect meta-analysis with arcsine transformation and meta-regressions was used. In the 75 articles included, the prevalence of hMPV among hospitalized ARI was 6.24% (95% CI 5.25-7.30). An effect of the duration of the inclusion period was observed (p=0.0114), with a higher prevalence of hMPV in studies conducted during periods of 7-11 months (10.56%, 95% CI 5.97-16.27) or complete years (7.55%, 95% CI 5.90-9.38) than in periods of 6 months or less (5.36%, 95% CI 4.29-6.54). A significant increase in the incidence with increasing distance from the equator was observed (p=0.0384). hMPV should be taken into account as a possible etiology in hospitalized ARI.

Epidemiological and clinical profiles of respiratory syncytial virus infection in hospitalized neonates in Suzhou, China

BACKGROUND

This study was designed to explore the epidemiological and clinical profiles of respiratory syncytial virus (RSV) infection in neonates from the Suzhou area of China, taking into consideration how climate factors influence disease.

METHODS

From 2010 to 2014, nasopharyngeal aspirates (NPA) collected from hospitalized neonates with lower respiratory tract infections (LRIs) were screened for seven common respiratory viruses including RSV by direct immunofluorescence assay. Human bocavirus, human metapneumovirus, and mycoplasma pneumoniae were detected by polymerase chain reaction.

RESULTS

Of the 1803 hospitalized neonates analyzed, 20.74 % were found to be infected with RSV. Interestingly, 30 subjects were identified as being coinfected with other viruses. The rate of RSV infection was highestduring thewinter and early spring seasons; however, infection was negatively associated with monthly mean temperature (rs = -0.821, P < 0.0001), total rainfall (rs = -0.406, P = 0.002), and sum of sunshine (rs = -0.386, P = 0.001). Monthly mean temperature was the only independent factor associated with RSV activity, as determined using multivariate regression analysis. Compared with non-RSV neonates, neonates with RSV infection presented more frequently with tachypnea,moist rales, and abnormal chest X-rays requiring supplemental oxygen and extended hospitalization postpartum. Neonatal admittance into the NICU was determined based on prematurity and coinfection with other viruses; two independent risk factors for RSV disease, as determined by multivariate logistic analysis.

CONCLUSIONS

Important as a major cause of LRIs in hospitalized neonate, we found that the subtropical climate of the Suzhou area was associated with RSV activity. The identified risk factors ofsevere disease in neonates with RSV infection should be taken into consideration when implementing disease health interventions.

Clinical and epidemiological profiles of lower respiratory tract infection in hospitalized children due to human bocavirus in a subtropical area of China

Lower respiratory tract infection is a major cause of morbidity and mortality in children. Human bocavirus (HBoV) is confirmed to have an association with pediatric lower respiratory tract infection. Seasonal and meteorological factors may play a key role in the epidemiology of HBoV. The purpose of this study was to ascertain the frequency, season, and clinical characteristics of hospitalized children with HBoV infection. In addition, an evaluation of the effects of meteorological factors on the incidence of HBoV in a subtropical area in China will be conducted. Children were <14 years in age and hospitalized for lower respiratory tract infection between January 1, 2009 and December 31, 2012 in the Respiratory Disease Department at the Children's Hospital affiliated to Soochow University. Multi‐pathogens were detected in nasopharyngeal aspirate samples. The association between HBoV activity and regional meteorological conditions was analyzed. The average incidence of HBoV infection was 6.6% (502/7,626). Of the 502 HBoV positive children, the median age was 13 months (range 1–156 months). The HBoV infection rate was highest among the 7–12 months groups (12.9%, 163/1,267). Seasonal distribution of HBoV was noted during June to November, especially during the summer season (June to August). HBoV activity was associated with temperature and humidity although the lag effect between temperature and HBoV activity observed. HBoV is one of the most common viral pathogens in children with lower respiratory tract infection. HBoV infection occurs throughout the year with a peak during the summer. Temperature and humidity may affect the incidence of HBoV. J. Med. Virol. 86:2154–2162, 2014. © 2014 Wiley Periodicals, Inc.