Epidemiological and clinical features of hMPV, RSV and RVs infections in young children

Human metapneumovirus SH protein promotes JAK1 degradation to impair host IL-6 signaling

Human metapneumovirus (HMPV) is a leading cause of respiratory infections in children, older adults, and those with underlying conditions 1,2,3,4. HMPV must evade immune defenses to replicate successfully; however, the viral proteins used to accomplish this are poorly characterized. The HMPV small hydrophobic (SH) protein has been reported to inhibit signaling through type I and type II interferon (IFN) receptors in vitro, in part by preventing STAT1 phosphorylation5. HMPV infection also inhibits IL-6 signaling. However, the mechanisms by which SH inhibits signaling, and its involvement in IL-6 signaling inhibition are unknown. Here, we used transfection of SH expression plasmids and SH-deleted virus (ΔSH) to show that SH is the viral factor responsible for inhibition of IL-6 signaling during HMPV infection. Transfection of SH-expression vectors or infection with wildtype, but not ΔSH virus, blocked IL-6 mediated STAT3 activation. Further, JAK1 protein (but not RNA) was significantly reduced in cells infected with wildtype but not ΔSH virus. The SH-mediated reduction of JAK1 was partially restored by addition of proteasome inhibitors, suggesting proteasomal degradation of JAK1. Confocal microscopy indicated that infection relocalized JAK1 to viral replication factories. Co-immunoprecipitation showed that SH interacts with JAK1 and ubiquitin, further linking SH to proteasomal degradation machinery. These data indicate that SH inhibits IL-6 and IFN signaling in infected cells in part by promoting proteasomal degradation of JAK1 and that SH is necessary for IL-6 and IFN signaling inhibition in infection. These findings enhance our understanding of the immune evasion mechanisms of an important respiratory pathogen.

Epidemiology and Clinical Features of Human Metapneumovirus and Respiratory Syncytial Viral Infections in Children

BACKGROUND

Human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) are 2 common causes of acute respiratory tract infections in infants and young children. The objective of this study is to compare the demographics and outcomes of children hospitalized with HMPV and RSV infections in the United States.

METHODS

We performed a retrospective cohort analysis of children 1 month to less than 3 years old discharged during 2016 with HMPV or RSV infection using the Kids' Inpatient Database. Children with HMPV and RSV coinfection were excluded. Data were weighted for national estimates.

RESULTS

There were 6585 children with HMPV infection and 70,824 with RSV infection discharged during the study period. The mean age of children with HMPV infection was higher than that of children with RSV infection (0.73 ± 0.8 vs. 0.42 ± 0.7 years; P < 0.05). The mortality rate was significantly higher in children with the presence of any complex chronic conditions compared to those without, in both HMPV [odds ratio (OR): 32.42; CI: 9.931-105.857; P < 0.05] as well as RSV (OR: 35.81; CI: 21.12-57.97; P < 0.05) groups. The adjusted median length of stay was longer (4.64 days; CI: 4.52-4.76 days vs. 3.33 days; CI: 3.31-3.35 days; P < 0.001) and total charges were higher ($44,358; CI: $42,145-$46,570 vs. $22,839; CI: $22,512-$23,166; P < 0.001), with HMPV infection. The mortality rate was similar in HMPV infection compared to RSV infection on multivariable analysis (OR: 1.48; P > 0.05).

CONCLUSION

In hospitalized children in the United States, HMPV infection is less common than RSV infection. Complex chronic conditions are more prevalent in children hospitalized with HMPV infection. Hospitalization with HMPV is associated with longer length of stay and higher hospital charges. The adjusted mortality is similar with both infections.

Bronchiolitis Due to RSV and HMPV-Epidemiology, Clinical Course, and Prognosis: Experience of a Single Tertiary Center

Acute bronchiolitis is a leading cause of hospitalization in infants. In this retrospective study, 645 patients with acute bronchiolitis diagnosed as respiratory syncytial virus (RSV; n = 538) or human metapneumovirus (HMPV; n = 107) were compared in terms of demographic, clinical, and laboratory findings. The HMPV patients presented later in the winter, were older (20 vs 7.55 months; P < .001)), had higher levels of C-reactive protein (4.55 vs 3.03 mg/dL; P = .007), and a higher prevalence of complications (43.9% vs 32.7%; P = .03). This study highlights the similarities and differences between these 2 common respiratory viral pathogens and shows that HMPV has a slightly more severe disease course than RSV. These findings can help guide approaches to these 2 common viruses that cause bronchiolitis.

Etiologies of Acute Bronchiolitis in Children at Risk for Asthma, with Emphasis on the Human Rhinovirus Genotyping Protocol

This research aims to determine acute bronchiolitis' causative virus(es) and establish a viable protocol to classify the Human Rhinovirus (HRV) species. During 2021-2022, we included children 1-24 months of age with acute bronchiolitis at risk for asthma. The nasopharyngeal samples were taken and subjected to a quantitative polymerase chain reaction (qPCR) in a viral panel. For HRV-positive samples, a high-throughput assay was applied, directing the VP4/VP2 and VP3/VP1 regions to confirm species. BLAST searching, phylogenetic analysis, and sequence divergence took place to identify the degree to which these regions were appropriate for identifying and differentiating HRV. HRV ranked second, following RSV, as the etiology of acute bronchiolitis in children. The conclusion of the investigation of all available data in this study distributed sequences into 7 HRV-A, 1 HRV-B, and 7 HRV-C types based on the VP4/VP2 and VP3/VP1 sequences. The nucleotide divergence between the clinical samples and the corresponding reference strains was lower in the VP4/VP2 region than in the VP3/VP1 region. The results demonstrated the potential utility of the VP4/VP2 region and the VP3/VP1 region for differentiating HRV genotypes. Confirmatory outcomes were yielded, indicating how nested and semi-nested PCR can establish practical ways to facilitate HRV sequencing and genotyping.

Epidemiological and clinical characteristics of human rhinovirus caused bronchiolitis in children in Southeast China

BACKGROUND

Human rhinovirus (hRV) is a critical viral pathogen implicated in bronchiolitis in children. However, there is no study on hRV bronchiolitis in children from Southeast China. The aim of this study was to determine the incidence and clinical features of hRV bronchiolitis in Southeast China.

METHODS

The study was carried out in Children's Hospital of Soochow University on children admitted with the diagnosis of bronchiolitis from January 2013 to December 2014. hRV was tested using reverse-transcription polymerase chain reaction.

RESULTS

hRV was identified in 140 of 797 specimens (17.6%). hRV was detected with a highest rate in June and August. The hRV positive rate in patients younger than 6 months of age was significantly lower than that in other age groups (P<0.01). The most common radiological finding was hyperinflation (51.4%). Patients with hRV infection were older and more likely to have eczema than those with RSV.

CONCLUSIONS

The hRV was an important viral pathogen associated with bronchiolitis in children with an epidemic peak in summer. Most of patients were between 6 to 24 months and with a high presence of eczema.

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.

Influenza and other respiratory viruses in children: prevalence and clinical features

With the COVID-19 pandemic still ongoing, the annual season of influenza and other respiratory virus epidemics has arrived. Specimens from patients suspected of respiratory viruses infection were collected. Viral detection was performed following RNA extraction and real-time RT-PCR. During the study period, we received and tested a total of 606 specimens. Rhinovirus virus was the viral type most prevalent, detected in 186 (45.47%) specimens. The age range of patients positive for influenza A, influenza A (H1N1), and influenza B was 18 days to 13 years. With female prevalence for this viral type, cough and asthma were the main clinical manifestations presented by this viral type. Our results indicate that rhinoviruses, adenoviruses, metapneumoviruses, and influenza are among the most important agents of ARI in pediatrics. The epidemic period of respiratory infections observed in Goiânia can be useful for planning and implementing some prevention strategies.

Spontaneous Pneumomediastinum in Children with Viral Infections: Report of Three Cases Related to Rhinovirus or Respiratory Syncytial Virus Infection

Background: Spontaneous pneumomediastinum (SP) is generally a benign condition which can have various etiologies. Data on SP related to respiratory viral infections in children are rare and there are currently no official guidelines or consistent treatment recommendations for these patients. Aim: To discuss treatment options considering the recommendations for SP with different etiologies. Methods: We report three cases of SP, which were related to rhinovirus or respiratory syncytial virus (RSV) infection. Results: All three patients presented with typical symptoms of a respiratory tract infection and required oxygen supplementation during the hospital stay. All children benefited from a conservative, supportive therapy, and bed rest, and could be discharged after seven days or less without remaining symptoms. Conclusion: Surveillance and monitoring might be reasonable to detect and treat potential complications in children with SP due to viral infections, as one child developed an increasing pneumothorax, which had to be treated with a thoracic drainage.

Molecular epidemiological surveillance of viral agents of acute lower respiratory tract infections in children in Accra, Ghana

BACKGROUND

Acute lower respiratory tract infection (ALRTI) in children under 5 years is known to be predominantly caused by respiratory syncytial virus (RSV). In recent times, however, human metapneumovirus (HMPV) has also been implicated. This study sought to investigate and genotype respiratory syncytial virus and human metapneumovirus in children presenting with ALRTIs infection at the Princess Marie Louis Children's Hospital in Accra, Ghana.

METHODS

Children below 5 years who were clinically diagnosed of ALRTI and on admission at the study site were recruited between September 2015 and November 2016 for this study. Demographic data information was obtained by means of a standardized questionnaire; and relevant clinical information was obtained from medical records. Nasopharyngeal swabs were collected from 176 children recruited for the study. Ribonucleic acid was extracted from swabs and cDNA syntheses were performed by RT-PCR. RSV-positive amplicons were sequenced and analyzed for genotype assignment.

RESULTS

RSV and HMPV prevalence among the sampled subjects were 11.4 and 1.7% respectively. Of the RSV positives, 8/20 (40%) were RSV-A and 12/20 (60%) were RSV-B. The highest prevalence was observed in children less than 12 months old. Phylogenetic analysis of the second hypervariable region of the RSV G-gene revealed that all RSV group A viruses belonged to the "novel" ON1 genotype containing the 72-nucleotide duplication; and RSV group B viruses belong to the BA IX genotype.

CONCLUSION

RSV is frequently detected in children aged under 5 years admitted with ALRTI in Ghana. Continued surveillance of viral aetiological agents is warranted to elucidate the prevalence and transmission patterns of viral pathogens that cause respiratory tract infections among children. This will help inform appropriate intervention approaches.

Co-infection of SARS-CoV-2 with other viral respiratory pathogens in Yogyakarta, Indonesia: A cross-sectional study

Background

Growing evidence shows that viral co-infection is found repeatedly in patients with Coronavirus Disease–2019 (COVID-19). This is the first report of SARS-CoV-2 co-infection with viral respiratory pathogens in Indonesia.

Methods

Over a one month period of April to May 2020, SARS-CoV-2 positive nasopharyngeal swabs in our COVID-19 referral laboratory in Yogyakarta, Indonesia, were tested for viral respiratory pathogens by real-time, reverse transcription polymerase chain reaction (RT-PCR). Proportion of co-infection reported in percentage.

Results

Fifty-nine samples were positive for other viral respiratory pathogens among a total of 125 samples. Influenza A virus was detected in 32 samples, Influenza B in 16 samples, Human metapneumovirus in 1 sample, and adenovirus in 10 samples. We did not detect any co-infection with respiratory syncytial virus. Nine (7.2%) patients had co-infection with more than two viruses.

Conclusion

Viral co-infection with SARS-CoV-2 is common. These results will provide a helpful reference for diagnosis and clinical treatment of patients with COVID-19.

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Viral co-infection with SARS-CoV-2 is common.

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Co-infection by two viral respiratory pathogens is prevalent.

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Pandemic transmission control may also impact in other viral respiratory infections.

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Early identification of co-infection is necessary, given differences in treatment.

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Simple laboratory diagnosis algorithm may be applied to screen viral co-infection.

Viral etiology and epidemiology of pediatric patients hospitalized for acute respiratory tract infections in Macao: a retrospective study from 2014 to 2017

Background

Acute respiratory infections (ARIs) are among the leading causes of hospitalization in children. Understanding the local dominant viral etiologies is important to inform infection control practices and clinical management. This study aimed to investigate the viral etiology and epidemiology of respiratory infections among pediatric inpatients in Macao.

Methods

A retrospective study using electronic health records between 2014 and 2017 at Kiang Wu Hospital was performed. Nasopharyngeal swab specimens were obtained from hospitalized children aged 13 years or younger with respiratory tract diseases. xMAP multiplex assays were employed to detect respiratory agents including 10 respiratory viruses. Data were analyzed to describe the frequency and seasonality.

Results

Of the 4880 children enrolled in the study, 3767 (77.1%) were positive for at least one of the 13 viral pathogens tested, of which 2707 (55.5%) being male and 2635 (70.0%) under 2 years old. Among the positive results, there were 3091 (82.0%) single infections and 676 (18.0%) multiple infections. The predominant viruses included human rhinovirus/enterovirus (HRV/EV 27.4%), adenovirus (ADV, 15.8%), respiratory syncytial virus B (RSVB, 7.8%) and respiratory syncytial virus A (RSVA, 7.8%). The detection of viral infection was the most prevalent in autumn (960/1176, 81.6%), followed by spring (1095/1406, 77.9%), winter (768/992, 77.4%), and summer (944/1306, 72.3%), with HRV/EV and ADV being most commonly detected throughout the 4 years of study period. The detection rate of viral infection was highest among ARI patients presented with croup (123/141, 87.2%), followed by lower respiratory tract infection (1924/2356, 81.7%) and upper respiratory tract infection (1720/2383, 72.2%). FluA, FluB and ADV were positive factors for upper respiratory tract infections. On the other hand, infection with RSVA, RSVB, PIV3, PIV4, HMPV, and EV/RHV were positively associated with lower respiratory tract infections; and PIV1, PIV2, and PIV3 were positively associated with croup.

Conclusions

This is the first study in Macao to determine the viral etiology and epidemiology of pediatric patients hospitalized for ARIs. The study findings can contribute to the awareness of pathogen, appropriate preventative measure, accurate diagnosis, and proper clinical management of respiratory viral infections among children in Macao.

Comparison of clinical features of acute lower respiratory tract infections in infants with RSV/HRV infection, and incidences of subsequent wheezing or asthma in childhood

Background

To compare the clinical characteristics of acute lower respiratory tract infections (ALRTIs) caused by respiratory syncytial virus (RSV) and human rhinovirus (HRV) and to explore the relationship between the development of recurrent wheezing/asthma and RSV/ HRV infections in infancy.

Methods

Retrospective study was conducted to compare the clinical characteristics of acute lower respiratory tract infections (ALRTIs). Hospitalized patients with ALRTIs from March 2007 to December 2016 were screened. Single RSV cases (s-RSV), single HRV cases (s-HRV), and cases who had co-infection with the two viruses were enrolled. Follow-up was performed to determine whether either specific respiratory virus infection was related to subsequent development of recurrent wheezing/asthma.

Results

The s-RSV children were the youngest (P = 0.021), they experienced the most serious condition (P < 0.001) and respiratory failure (P < 0.001), they also required highest demand of oxygen therapy (P < 0.001). And in s-RSV group, the incidence of development of recurrent wheezing was significantly higher in subgroup with the family history of wheezing than that without (P < 0.001).

Conclusion

The s-RSV cases suffered from the worst severity of illness, respiratory failure and required highest demand of oxygen therapy. Recurrent wheezing was more common in s-RSV group with family history of wheezing than those without.

Epidemiology of RSV and hMPV in Belgium: a 10-year follow-up

Objectives: Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) are important respiratory pathogens. Both viral pathogens have similar clinical manifestations. The epidemiology of RSV is well known, that of hMPV is less clear. We reviewed the results of 10 consecutive years of molecular testing for RSV and hMPV in respiratory samples of Flemish patients. Methods: In the laboratory of the OLV hospital Aalst, Belgium, multiplex RT-PCR assays are used for the detection of RSV and hMPV. The lab receives invasive and noninvasive respiratory samples of patients from all over Flanders. Results: Between September 2006 and August 2016, 16,826 respiratory samples were analyzed for RSV and hMPV. Of these samples, 18% tested positive for RSV and 7.3% for hMPV. RSV consistently peaked in November/December each year within a very narrow time frame. The occurrence of hMPV was less predictable and spreaded more widely throughout the winter and spring. Both viruses were mainly found in samples from young children. RSV was most frequently detected in samples from infants <3 months, while hMPV peaked between 6 and 9 months. After the age of 1 year, RSV rapidly dropped. hMPV dropped a little later and slower. Both viruses slightly increased again at older age (>50 years). Conclusions: Despite their similarities, some of the epidemiologic characteristics of hMPV and RSV differ. The most striking difference is the annual distribution of RSV and hMPV infections.

Virologic study of acute lower respiratory tract infections in children admitted to the paediatric department of Blida University Hospital, Algeria

Acute lower respiratory tract infections (ALRTI) such as pneumonia and bronchiolitis are major causes of mortality and morbidity in children under 5 years of age. The main microbial agents responsible for ALRTI are either bacterial agents (Streptococcus pneumoniae, Haemophilus influenzae type b, Mycoplasma pneumoniae) or viruses (respiratory syncytial virus (RSV, also known as human orthopneumovirus), Myxovirus influenzae, Myxovirus parainfluenzae, adenovirus) [1]. More recently, other viruses (rhinovirus, metapneumovirus, coronavirus, bocavirus) have been implicated in ALRTI; their identification has been facilitated by new molecular biology techniques such as real-time PCR. To our knowledge, these emerging viruses have never been the subject of epidemiologic studies in our country.

Respiratory syncytial virus, human metapneumovirus, and influenza virus infection in Bangkok, 2016-2017

Children and adults residing in densely populated urban centers around the world are at risk of seasonal influenza-like illness caused by respiratory viruses such as influenza virus, human metapneumovirus (hMPV), and respiratory syncytial virus (RSV). In a large metropolitan of Thailand’s capital city Bangkok, most respiratory infections are rarely confirmed by molecular diagnostics. We therefore examined the frequency of RSV, hMPV, and influenza virus in 8,842 patients who presented influenza-like illness and sought medical care at a large hospital in Bangkok between 2016 and 2017. Using a multiplex real-time reverse-transcription polymerase chain reaction (RT-PCR), 30.5% (2,699/8,842) of nasopharyngeal (NP) swab samples tested positive for one or more of these viruses. Influenza virus comprised 17.3% (1,528/8,842), of which the majority were influenza A/H3N2. Such infection was most prevalent among adults and the elderly. RSV was identified in 11.4% (1,011/8,842) and were mostly ON1 and BA9 genotypes. Of the hMPV-positive samples (3.6%, 318/8,842), genotypes A2, B1, and B2 were detected. A small number of individuals experienced co-infections (1.8%, 155/8,842), most commonly between RSV and influenza A/H3N2. RSV and hMPV co-infections were also found, but mainly in young children. Viral respiratory tract infection peaked locally in the rainy season (June to September). These findings support the utility of rapid nucleic acid testing of RSV, hMPV, and influenza virus in patients with ILI.

[Etiological structure of influenza and other ARVI in St. Petersburg during epidemic seasons 2012-2016.]

The etiological structure of influenza and other acute respiratory viral infections including their rate of incidence in St. Petersburg and Leningrad region during 4 epidemic seasons has been studied. Seasonality of some respiratory viruses was shown and peaks of circulation of RSV, adenovirus, parainfluenza viruses, rhinovirus, bocavirus, metapneumovirus and coronavirus were marked. The interference of influenza A viruses and RSV, RSV and rhinoviruses was highlighted. A high incidence of adenovirus infection in organized communities and RSV infection in children was revealed.

Retrospective Review of Clinical and Chest X-Ray Findings in Children Admitted to a Community Hospital for Respiratory Syncytial Virus Infection

INTRODUCTION

We performed a retrospective study to evaluate demographics, clinical course, outcome, and radiological findings of children with respiratory syncytial virus (RSV) infection.

METHODS

Four hundred patients admitted between October 2013 and May 2016 were enrolled. Clinical and radiographic trends were evaluated for association with severity of RSV presentation. Severity was defined as hospitalization >2 days, pediatric intensive care unit admission, or need for mechanical ventilation.

RESULTS

Common clinical findings included fever (78.5%), coughing (97%), rhinorrhea/congestion (93%), and hypoxia (44.8%). Hypoxia was seen in 64.7% of the severe group compared with 32.0% in the nonsevere group ( P < .001). Airspace opacification was seen in 49.2% of chest X-rays of the severe group compared with 26.4% in the nonsevere group ( P < .001).

CONCLUSION

Higher incidence of hypoxia or airspace opacification on chest X-ray may be predictors of poorer outcomes for patients with RSV infection.

Comparative analysis of miRNA profile in human dendritic cells infected with respiratory syncytial virus and human metapneumovirus

OBJECTIVE

Human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) are responsible for respiratory diseases, mostly in children. Despite the clinical and epidemiological similarities between these two pneumoviruses, they elicit different immune responses. This work aims to further our understanding of the differential immune response induced by these respiratory viruses by determining the changes of small non-coding RNAs (miRNAs), which regulate gene expression and are involved in numerous cellular processes including the immune system.

RESULTS

In the present study, we analyzed the expression of miRNA transcripts of human dendritic cells infected with RSV or HMPV by high throughput sequencing using Illumina sequencing technology. Further validation of miRNA expression by quantitative polymerase chain reaction indicated that HMPV infection up-regulated the expression of 2 miRNAs (hsa-miR-182-5p and hsa-miR-4634), while RSV infection induced significant expression of 3 miRNAs (hsa-miR-4448, hsa-miR-30a-5p and hsa-miR-4634). The predominant miRNA induced by both viruses was hsa-miR-4634.

Nation-wide surveillance of human acute respiratory virus infections between 2013 and 2015 in Korea

The prevalence of eight respiratory viruses detected in patients with acute respiratory infections (ARIs) in Korea was investigated through analysis of data recorded by the Korea Influenza and Respiratory Viruses Surveillance System (KINRESS) from 2013 to 2015. Nasal aspirate and throat swabs specimens were collected from 36 915 patients with ARIs, and viral nucleic acids were detected by real‐time (reverse‐transcription) polymerase chain reaction for eight respiratory viruses, including human respiratory syncytial viruses (HRSVs), influenza viruses (IFVs), human parainfluenza viruses (HPIVs), human coronaviruses (HCoVs), human rhinovirus (HRV), human adenovirus (HAdV), human bocavirus (HBoV), and human metapneumovirus (HMPV). The overall positive rate of patient specimens was 49.4% (18 236/36 915), 5% of which carried two or more viruses simultaneously. HRV (15.6%) was the most predominantly detected virus, followed by IFVs (14.6%), HAdV (7.5%), HPIVs (5.8%), HCoVs (4.2%), HRSVs (3.6%), HBoV (1.9%), and HMPV (1.6%). Most of the ARIs were significantly correlated with clinical symptoms of fever, cough, and runny nose. Although HRV and HAdV were frequently detected throughout the year in patients, other respiratory viruses showed apparent seasonality. HRSVs and IFVs were the major causative agents of acute respiratory diseases in infants and young children. Overall, this study demonstrates a meaningful relationship between viral infection and typical manifestations of known clinical features as well as seasonality, age distribution, and co‐infection among respiratory viruses. Therefore, these data could provide useful information for public health management and to enhance patient care for primary clinicians.

Risk factors of respiratory syncytial virus infection among pediatric influenza-like illness and severe acute respiratory infections in Suzhou, China

The characteristics and risk factors of respiratory syncytial virus (RSV) infection among children has not yet been fully understood. To address the characteristics of RSV-associated illness and risk factors of RSV infection among children under 5 years of age in Suzhou, China. From April 2011 to March 2014, we conducted a prospective surveillance among children in Suzhou, China. Nasal or throat swabs were collected from outpatients with influenza-like illness (ILI) and inpatients with severe acute respiratory infections (SARI). RSV was detected by reverse-transcriptase polymerase chain reaction and direct fluorescent antibody assay for children with ILI and SARI, respectively. Multivariable logistic-regression models were constructed to explore risk factors and symptoms of RSV infection. Of 3267 ILI and 1838 SARI children enrolled in the study, 192 (5.9%) and 287 (15.6%) tested positive for RSV, respectively. Among ILI patients, children with RSV infections visited clinics more often (P = 0.005) and had longer duration of fever (P = 0.032) than those without RSV infection. All RSV-positive children had an increased risk of having cough (OR = 2.9), rhinorrhea (OR = 1.6), breathing difficulty (OR = 3.4), wheezing (OR = 3.3), and irritability (OR = 2.7). Children aged <2 years, had history of prematurity (OR = 2.0) and recent respiratory infections (OR = 1.3) were more likely to get infected by RSV. Children with SARI had higher positive rate of RSV than those with ILI. Cough, rhinorrhea, and wheezing were the most common symptoms in RSV infection. Children aged <2 years, had history of prematurity and recent respiratory infections were the potential risk factors for RSV infection.

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.

Novel human metapneumovirus with a 180-nucleotide duplication in the G gene

AIM

To describe the circulation, genetic diversity and clinical features of human metapneumovirus (HMPV) in pediatric patients that attended the Hospital Universitari Vall d'Hebron, Spain from 2014 to 2016.

MATERIALS & METHODS

Partial G gene was sequenced from laboratory-confirmed HMPV respiratory specimens for subsequent phylogenetic analysis.

RESULTS

A total of 121 different samples were HMPV laboratory-confirmed out of 6658 specimens received. The highest circulation was from February to April, with a prevalence of 3%. Different genetic groups within both genotypes were detected at variable levels. A 180-nucleotide duplication was first characterized within the G gene in nine cases, mostly related to lower respiratory-tract infection.

CONCLUSION

This study reported on the circulation of a novel HMPV with a 180-nucleotide duplication in the G gene, but no clinical changes in related cases were observed. Their prevalence increased during the last season suggesting changes in viral features.

Simultaneous detection of respiratory syncytial virus and human metapneumovirus by one-step multiplex real-time RT-PCR in patients with respiratory symptoms

BACKGROUND

Both respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) are important viral pathogens causing respiratory tract infection (RTI) in the pediatric population. However, the clinical manifestations of RSV and hMPV infections are similar. Therefore, a reliable and rapid diagnostic tool is needed for diagnostic performance.

METHODS

In order to optimize diagnosis efficiency of RTI, the aim of this study is to establish a rapid and advanced method for simultaneous detecting RSV and hMPV in nasopharyngeal aspirates specimens from patients. We designed a one-step triplex real-time RT-PCR (qRT-PCR) protocol using TaqMan probes for detecting RSV and hMPV. The plasmid clones containing RSV nucleoprotein gene and hMPV fusion gene were established as reference standards. We used virus culture supernatants from 86 known pediatric RTI patient to test the specificity and sensitivity of our assay. Then we used total 222 nasopharyngeal aspirates specimens from pediatric patients hospitalized with respiratory symptoms to evaluate our assay.

RESULTS

Our one-step triplex qRT-PCR assay showed 100% sensitivity and specificity in testing RSV and hMPV in 86 known virus culture supernatants, with excellent linearity (R² > 0.99) and reliable reproducibility (CV lower than 1.04%). This assay has a wide dynamic range 10²-10⁹copies/reaction (limit of detection; LOD = 100 copies/reaction). A total of 222 patients hospitalized with respiratory symptoms were enrolled for clinical evaluation. In these samples, our qRT-PCR assay detected 68 RSV positive and 18 hMPV positive cases. However, standard virus culture only detected 8 RSV positive cases and 0 hMPV cases. Based on this improved triplex qRT-PCR assay, we found that RSV infection was associated with severe inflammation by chest X-ray and occurrence of pneumonia which were not observed previously.

CONCLUSIONS

In summary, we have developed a highly specific and sensitive one-step triplex qRT-PCR assay to detect hMPV and RSV simultaneously. This assay offers a valuable tool for routine diagnosis.

Current developments and prospects on human metapneumovirus vaccines

INTRODUCTION

Human metapneumovirus (hMPV) has become one of the major pathogens causing acute respiratory infections (ARI) mainly affecting young children, immunocompromised patients, and the elderly. Currently there are no licensed vaccines against this virus. Areas covered: Since the discovery of hMPV in 2001, many groups have focused on developing vaccines against this pathogen. This review presents the outcomes and perspectives derived from preclinical studies performed in cell cultures and animals as well as the only candidate that has reached evaluation in a clinical trial. Limitations of the current vaccine candidates are discussed and perspectives for the development of plant-based vaccines are analyzed. Expert commentary: Several hMPV vaccine candidates are under development with the potential to progress into clinical trials. In parallel, the molecular farming field offers new opportunities to generate innovative vaccines that will offer several advantages in the fight against hMPV.

The presence of fever in adults with influenza and other viral respiratory infections

We compared the rates of fever in adult subjects with laboratory-confirmed influenza and other respiratory viruses and examined the factors that predict fever in adults. Symptom data on 158 healthcare workers (HCWs) with a laboratory-confirmed respiratory virus infection were collected using standardized data collection forms from three separate studies. Overall, the rate of fever in confirmed viral respiratory infections in adult HCWs was 23·4% (37/158). Rates varied by virus: human rhinovirus (25·3%, 19/75), influenza A virus (30%, 3/10), coronavirus (28·6%, 2/7), human metapneumovirus (28·6%, 2/7), respiratory syncytial virus (14·3%, 4/28) and parainfluenza virus (8·3%, 1/12). Smoking [relative risk (RR) 4·65, 95% confidence interval (CI) 1·33-16·25] and co-infection with two or more viruses (RR 4·19, 95% CI 1·21-14·52) were significant predictors of fever. Fever is less common in adults with confirmed viral respiratory infections, including influenza, than described in children. More than 75% of adults with a viral respiratory infection do not have fever, which is an important finding for clinical triage of adult patients with respiratory infections. The accepted definition of 'influenza-like illness' includes fever and may be insensitive for surveillance when high case-finding is required. A more sensitive case definition could be used to identify adult cases, particularly in event of an emerging viral infection.

Respiratory Viral Infections and Coinfections in Children With Cancer, Fever and Neutropenia: Clinical Outcome of Infections Caused by Different Respiratory Viruses

BACKGROUND

Respiratory viral infections in episodes of fever and neutropenia (FN) in children with cancer are not well characterized. We compared the clinical outcome of infections caused by different respiratory viruses (RVs) and by RV coinfection in this population.

METHODS

Children with cancer and FN at 3 hospitals in Chile were prospectively evaluated by clinical examination, blood cultures and detection of 17 RVs using multiplex polymerase chain reaction (nasopharyngeal samples). Clinical characterization and outcome variables were determined and compared by the type of RV detected.

RESULTS

A total of 1044 episodes of FN in 525 children were included. At least 1 RV was detected in 46%. In 350 of 1044 (34%) episodes, we detected only RVs, of which 284 (81%) were classified as a single-RV infection and 66 (19%) as a viral coinfection. Respiratory symptoms were present at admission in 65% of the episodes with any detected RV. Median age was 6 years (interquartile range, 3-10), and 51% were women. The most common RVs detected were rhinovirus, respiratory syncytial virus, parainfluenza, influenza, adenovirus and human metapneumovirus. Episodes caused by different types of RVs had no differences in the clinical outcome (days of hospitalization, days of fever, O2 requirement, admission to the intensive care unit and death) and when comparing single and viral coinfection.

CONCLUSIONS

To our knowledge, this is the largest report comparing clinical outcome in FN episodes caused by different RVs in children with cancer. A positive polymerase chain reaction for RV at admission was significantly associated with the presence of respiratory symptoms. Our data showed a favorable outcome in all episodes with RV detection, including single and viral coinfections.

Burden of respiratory syncytial virus infections in China: Systematic review and meta-analysis

BACKGROUND

Respiratory syncytial virus (RSV) is the most important cause of acute respiratory tract infection (ARTI) related morbidity and mortality worldwide. However, the disease burden due to RSV has not been systematically summarized in China.

METHOD

A systematic search was performed in the Chinese BioMedical Database (CBM), China National Knowledge Infrastructure (CNKI), Wanfang database and PubMed to identify available published RSV studies in China.

RESULTS

A total of 489 641 patients with ARTIs from 135 studies were included in the analysis. Among patients with ARTIs, RSV accounted for 18.7% (95% confidence interval CI 17.1-20.5%). The prevalence of RSV was highest in infants (26.5%, 95% CI 23.7-29.5%) and lowest in those aged ≥16 years (2.8%, 95% CI 1.3-6.1). A higher prevalence of RSV was seen in inpatients (22%, 95% CI 19.9-24.2%) than in outpatients (14%, 95% CI 9.6-19.9%). RSV type A accounted for 63.1% (95% CI 52.3-72.8%) of all RSV infections. RSV infections occurred mainly in winter and spring. The most common clinical manifestations were cough, production of sputum, wheezing and fever.

CONCLUSION

RSV is the leading cause of viral ARTIs in China, particularly in infants and young children. Our findings are valuable for guiding the selection of appropriate therapies for ARTIs and implementation of preventive measures against RSV infections. Our data further supports the development of a successful RSV vaccine as a high priority.

Pathogen profiles and molecular epidemiology of respiratory viruses in Japanese inpatients with community-acquired pneumonia

Background

The etiological profile of viruses among adult patients with community-acquired pneumonia (CAP) has not been characterized yet. The aim of this study was twofold: first, investigate the pathogen profiles and the molecular epidemiology of respiratory viruses among Japanese CAP patients; and second, explore the clinical significance of viral infections.

Methods

A cross-sectional observational study was conducted at Kyorin University Hospital. To identify respiratory pathogens, hospitalized CAP patients were enrolled, and reverse transcriptase–polymerase chain reaction technology was applied alongside conventional microbiological methods. Phylogenetic and pairwise distance analyses of 10 viruses were performed. CAP patients were divided into four etiological groups (virus alone, bacteria alone, co-detection of virus and bacteria, and not detected) and the clinical findings were compared.

Results

Seventy-six patients were enrolled. Bacteria alone were detected in 39.5% (n=30) of CAP patients. Virus alone or co-detection were found in 10.5% (n=8) and 11.8% (n=9) of cases, respectively. Streptococcus pneumoniae and human metapneumovirus were the most frequently detected bacterium and virus, respectively. Phylogenetic analyses of human metapneumovirus, human rhinovirus, and human respiratory syncytial virus showed that different subgroups and genotypes might be associated with CAP. Respiratory failure was more common when a virus was detected (both virus alone and co-detection groups; n=17, 100%, p<0.05) than when a bacteria alone was detected (n=17, 56.7%).

Conclusion

Prevalence of respiratory virus infection in CAP inpatients was 22.3%. The detected viruses display high genetic divergence and correlate with increased respiratory failure.

Respiratory Viral Detections During Symptomatic and Asymptomatic Periods in Young Andean Children

BACKGROUND

Viruses are commonly detected in children with acute respiratory illnesses (ARIs) and in asymptomatic children. Longitudinal studies of viral detections during asymptomatic periods surrounding ARI could facilitate interpretation of viral detections but are currently scant.

METHODS

We used reverse transcription polymerase chain reaction to analyze respiratory samples from young Andean children for viruses during asymptomatic periods within 8-120 days of index ARI (cough or fever). We compared viral detections over time within children and explored reverse transcription polymerase chain reaction cycle thresholds (CTs) as surrogates for viral loads.

RESULTS

At least 1 respiratory virus was detected in 367 (43%) of 859 samples collected during asymptomatic periods, with more frequent detections in periods with rhinorrhea (49%) than those without (34%, P < 0.001). Relative to index ARI with human rhinovirus (HRV), adenovirus (AdV), respiratory syncytial virus (RSV) and parainfluenza virus detected, the same viruses were also detected during 32, 22, 10 and 3% of asymptomatic periods, respectively. RSV was only detected 8-30 days after index RSV ARI, whereas HRV and AdV were detected throughout asymptomatic periods. Human metapneumovirus and influenza were rarely detected during asymptomatic periods (<3%). No significant differences were observed in the CT for HRV or AdV during asymptomatic periods relative to ARI. For RSV, CTs were significantly lower during ARI relative to the asymptomatic period (P = 0.03).

CONCLUSIONS

These findings indicate that influenza, human metapneumovirus, parainfluenza virus and RSV detections in children with an ARI usually indicate a causal relationship. When HRV or AdV is detected during ARI, the causal relationship is less certain.

What We Have Learned from the Influenza A pH1N1 2009/10 Pandemic: High Clinical Impact of Human Metapneumovirus and Respiratory Syncytial Virus in Hospitalized Pediatric Patients

The influenza pandemic in 2009/2010 shifted public awareness to respiratory tract infections caused by the influenza virus. A prospective study was conducted during the influenza pandemic from November 2009 through April 2010 to determine the causative pathogens and clinical symptoms present in all children and adolescents admitted to the University Children's Hospital, Duesseldorf, Germany, with signs and symptoms of respiratory tract infection. A total of 272 children and adolescents were admitted with symptoms of acute respiratory tract infection (ARI) or influenza-like illness. Viral pathogens were detected in 80% (218/272). However, influenza A pH1N1 infection was only detected in 11% (30/272) of children. Human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) were the predominant identified pathogens that led to the admission of young tachypneic children with pneumonia in the post pandemic phase and the requirement for more intense treatment. During the pandemic and early post-pandemic phase the clinical impact of other respiratory viruses, such as HMPV and RSV, led to a higher clinical disease burden than pH1N1. Consequently, HMPV testing should be performed as routinely as RSV testing in patients hospitalized for ARI. Even while preparing for pandemics, the awareness of other respiratory viruses must be maintained.

Virologic testing in bronchiolitis: does it change management decisions and predict outcomes?

The aim of this study was to evaluate the clinical, therapeutic, laboratory, and radiological differences between respiratory syncytial virus (RSV) and non-RSV bronchiolitis in order to assess if the prior knowledge of viral etiology changed management decisions and would be able to predict outcomes. Medical charts of children <1 year admitted to the emergency department with bronchiolitis during two RSV seasons (2010-2012) were reviewed. We analyzed 221 episodes of bronchiolitis. The percentage of exams performed (95 % confidence interval (CI) 0.74-2.52), abnormal laboratory and radiological findings (95 % CI 0.53-16.89) did not differ between groups. RSV bronchiolitis had a more severe clinical course. However, virologic testing for RSV had low specificity in identifying at-risk patients for hospitalization, longer hospital length of stay, and need of oxygen therapy and nasogastric tube (44, 40, 42, and 35 %, respectively), and while statistically significant, the positive likelihood ratios were only slightly greater than 1.

CONCLUSION

Although RSV bronchiolitis has a more severe clinical course, virologic testing does not help in management decisions, and at an individual level, as a performance test, it seems insufficient to precisely predict outcomes.

Central nervous system alterations caused by infection with the human respiratory syncytial virus

Worldwide, the human respiratory syncytial virus (hRSV) is the leading cause of infant hospitalization because of acute respiratory tract infections, including severe bronchiolitis and pneumonia. Despite intense research, to date there is neither vaccine nor treatment available to control hRSV disease burden globally. After infection, an incubation period of 3-5 days is usually followed by symptoms, such as cough and low-grade fever. However, hRSV infection can also produce a larger variety of symptoms, some of which relate to the individual's age at infection. Indeed, infants can display severe symptoms, such as dyspnea and chest wall retractions. Upon examination, crackles and wheezes are also common features that suggest infection by hRSV. Additionally, infection in infants younger than 1 year is associated with several non-specific symptoms, such as failure to thrive, periodic breathing or apnea, and feeding difficulties that usually require hospitalization. Recently, neurological symptoms have also been associated with hRSV respiratory infection and include seizures, central apnea, lethargy, feeding or swallowing difficulties, abnormalities in muscle tone, strabismus, abnormalities in the CSF, and encephalopathy. Here, we discuss recent findings linking the neurological, extrapulmonary effects of hRSV with infection and functional impairment of the CNS.

Comparison of virological profiles of respiratory syncytial virus and rhinovirus in acute lower tract respiratory infections in very young Chilean infants, according to their clinical outcome

BACKGROUND

Respiratory syncytial virus (RSV) and rhinovirus (HRV) are the main cause of acute lower respiratory tract infections (ALRTIs) in infants. Viral and host-related risk factors for severe disease have also not been clearly established.

OBJECTIVE

To assess whether certain viral features of RSV and, or HRV are associated with severe ALRTI.

STUDY DESIGN

RSV and HRV were studied in nasopharyngeal samples of infants by immunofluorescence, Luminex(®) and/or real-time RT-PCR assays. Quantitation and genotyping of RSV and HRV by PCR were done.

RESULTS

Of 124 virus positive specimens, 74 (59.7%) had RSV; 22 (17.7%) HRV and 28 (22.6%) RSV-HRV co-infection. Hospitalization was required in 57/74 RSV infants (77.0%); in 10/22 HRV cases (45.5%) (p=0.006) and in 15/28 co-infected by both viruses (53.6%) (p=0.003). Severe cases were 33/74 (44.6%) RSV infections, 2/22 HRV cases (9.1%), (p<0.002) and 6/28 (21.4%) patients co-infected by RSV-HRV (p<0.026). Three genotypes (NA1, B7, B9) of RSV circulated during the study. In 33 severe infants, NA1 was detected in 19 cases (57.6%); B7 in 13 (39.4%) and B9 in 1 (3.0%) (p<0.01; OR=10.0). RSV loads were similar between outpatients and hospitalized infants (p=0.7) and among different severities (p=0.7). NA1 loads were higher than other strains (p=0.049). Three geno-groups of HRV circulated homogeneously.

CONCLUSION

In very young infants, RSV cause more severe disease than HRV. Co-infection does not increase the severity of illness. NA1 RSV genotype was associated with major frequency of hospitalization, severe respiratory disease and higher viral load.

Human metapneumovirus viral load is an important risk factor for disease severity in young children

BACKGROUND

The role of viral load in human metapneumovirus (HMPV) disease severity has not yet been clearly determined.

OBJECTIVE

We evaluated the importance of viral load along with other factors in HMPV disease severity among children aged <3 years old.

STUDY DESIGN

HMPV-positive cases were selected from a cohort of outpatients and hospitalized children with lower respiratory tract infections. HMPV groups (A or B) and viral loads were determined in their nasopharyngeal aspirates. Disease severity was defined by assessing risk for hospitalization and by using two validated clinical severity scores.

RESULTS

Of the 118 HMPV cases detected over 4 years for which viral load could be determined, 60 belonged to genotype A and 58 to genotype B. Baseline characteristics were similar in HMPV-A and HMPV-B mono-infected patients. In multivariate analysis, HMPV hospitalization was associated with viral load ≥1000 copies/10(4)cells (OR, 3.2; 95%CI, 1.4-7.4), age <6 months (OR, 3.1; 95%CI, 1.2-8.6) and presence of ≥3 children in the household (OR, 2.7; 95%CI, 1.04-6.9). A high HMPV viral load was also associated with pulmonary rales (p=.03), use of bronchodilators (p=.02) and inhaled corticosteroids (p=.01).

CONCLUSION

HMPV viral load is associated with disease severity in young children along with young age and household crowding.

Infections and their role in childhood asthma inception

The association of early-onset wheezing with common viral and bacterial infections has raised significant interest in the role of infections in childhood asthma inception. This article serves to review these relationships among infections, host factors, and asthma inception in childhood.

A new laboratory-based surveillance system (Respiratory DataMart System) for influenza and other respiratory viruses in England: results and experience from 2009 to 2012

Binary file ES_Abstracts_Final_ECDC.txt matches

Epidemiology of human respiratory viruses in children with acute respiratory tract infections in Jinan, China

The viral etiologies of UTRIs and LTRIs in children in Jinan city were investigated between July 2009 and June 2010. Nasal and throat swabs were collected from 397 children with URTIs and bronchoalveolar lavage fluid specimens were collected from 323 children with LRTIs. RT-PCR/PCR was used to examine all samples for IFV, PIV, RSV, RV, hMPV, HBoV, CoV, ADV, RSV, and EV. Viral pathogens were detected in 47.10% of URTI samples and 66.57% samples, and the incidence of viral coinfection was 5.29% and 21.05%, respectively. IFV was the most common virus in URTIs, with a detection rate of 19.40%, followed by PIV (10.83%), RV (10.58%), and EV (6.30%). For LRTIs, PIV and RV were both detected in 27% of samples, followed by RSV (9.91%), HBoV (8.36%), IFV (5.57%), and hMPV (5.57%). RSV and HBoV were more prevalent in the youngest children of no more than six months. Meanwhile, RV, PIV, and RSV were the most frequent viruses combined with bacterial pathogens in LRTIs. In conclusion, the spectrum of respiratory virus infections in URTIs and LRTIs differed in terms of the most common pathogens, seasonal distribution, and coinfection rate.

Respiratory syncytial virus--a comprehensive review

Respiratory syncytial virus (RSV) is amongst the most important pathogenic infections of childhood and is associated with significant morbidity and mortality. Although there have been extensive studies of epidemiology, clinical manifestations, diagnostic techniques, animal models and the immunobiology of infection, there is not yet a convincing and safe vaccine available. The major histopathologic characteristics of RSV infection are acute bronchiolitis, mucosal and submucosal edema, and luminal occlusion by cellular debris of sloughed epithelial cells mixed with macrophages, strands of fibrin, and some mucin. There is a single RSV serotype with two major antigenic subgroups, A and B. Strains of both subtypes often co-circulate, but usually one subtype predominates. In temperate climates, RSV infections reflect a distinct seasonality with onset in late fall or early winter. It is believed that most children will experience at least one RSV infection by the age of 2 years. There are several key animal models of RSV. These include a model in mice and, more importantly, a bovine model; the latter reflects distinct similarity to the human disease. Importantly, the prevalence of asthma is significantly higher amongst children who are hospitalized with RSV in infancy or early childhood. However, there have been only limited investigations of candidate genes that have the potential to explain this increase in susceptibility. An atopic predisposition appears to predispose to subsequent development of asthma and it is likely that subsequent development of asthma is secondary to the pathogenic inflammatory response involving cytokines, chemokines and their cognate receptors. Numerous approaches to the development of RSV vaccines are being evaluated, as are the use of newer antiviral agents to mitigate disease. There is also significant attention being placed on the potential impact of co-infection and defining the natural history of RSV. Clearly, more research is required to define the relationships between RSV bronchiolitis, other viral induced inflammatory responses, and asthma.

Temporal characteristics of respiratory syncytial virus infection in children and its correlation with climatic factors at a public pediatric hospital in Suzhou

BACKGROUND

Respiratory syncytial virus (RSV) is the most important viral pathogen in infants and children. It is important to analyze RSV epidemic patterns and related relevant factors in order to prevent further infections and related complications.

OBJECTIVE

To explore the relationship between RSV infection rate in hospitalized children from Suzhou area and climatic factors.

STUDY DESIGN

42,664 nasopharyngeal specimens from hospitalized children with acute respiratory infections were screened for RSV antigens using direct immunofluorescence. 472 RSV positive samples were randomly selected and performed real-time PCR to identify RSV subtype. Monthly meteorological data in Suzhou area was collected (average temperature, relative humidity, precipitation, total sunshine, and average wind speed) from 2001 to 2011. The relation between RSV infections and climatic factors was evaluated using correlation and stepwise regression analyses.

RESULTS

The annual RSV infection rate in hospitalized children in Suzhou from 2001 to 2011 varied between 11.85% and 27.30%. The highest monthly infection rates occurred from November to April. The time interval from November to April was considered the infection season. Seasonal RSV infection rates from 2001 to 2010 were 40.75%, 22.72%, 39.93%, 27.37%, 42.71%, 21.28%, 38.57%, 19.86%, and 29.73%. The infection rate of any season was statistically different from the next season. There was no significant difference in RSV infection rates in the 2010-2011 and 2009-2010 epidemic seasons. Among the 472 randomly selected RSV positive samples, 412 were found to be RSV subtype A (RSV-A), while 60 subtype B (RSV-B). The monthly RSV infection rate was negatively correlated with monthly average temperature (r=-0.84), total sunshine (r=-0.47), precipitation (r=-0.31), relative humidity (r=-0.20), and average wind speed (r=-0.20), (P<0.05). Stepwise regression analysis showed monthly average temperature fit into a linear model (R(2)=0.64, P<0.01) with a regression coefficient of -1.52 (t=15.21, P<0.01).

CONCLUSIONS

RSV infection in Suzhou occurred most frequently between November and April. The number of infections peaked every other year. Abnormally high infection rate in non-epidemic season only caused by RSV-A. Ambient temperature played an important role in the development of RSV infection.

Molecular detection of human metapneumovirus and human bocavirus on oropharyngeal swabs collected from young children with acute respiratory tract infections from rural and peri-urban communities in South India

Background

Acute respiratory tract infections (ARTIs) are one of the major causes of morbidity and mortality among young children in developing countries. Information on the incidence of human metapneumovirus (hMPV) and human bocavirus (HBoV) infections in developing countries, especially among rural children, is very limited.

Objectives

This study was conducted to identify whether these viruses were associated with ARTI among children ≤5 years of age in rural and peri-urban populations in South India.

Methods

The study was cross-sectional with prospective sample collection. Oropharyngeal swabs were collected from children ≤5 years of age presenting with ARTI. None of the children in this study were known to have any immunosuppressive conditions. The two viruses, hMPV and HBoV, were identified using semi-nested polymerase chain reaction (PCR) assays and one-step PCR assays, respectively. The lower limits of detection of hMPV and HBoV were 6.69 × 10⁵ plasmid copies and 5.77 × 10³ plasmid copies, respectively, per 5 μL PCR reaction input.

Results

The frequency of hMPV infection in children was higher than that of HBoV infection. The different frequencies of hMPV in patients in various age groups with upper and lower respiratory tract infections were compared, and the variance was found to be insignificant. In the 38 children who were hMPV positive, the majority (73.7 %) were from rural communities. The overall hMPV-positive rate was higher in the rural population than in the peri-urban population, but the difference was statistically insignificant. The youngest age at which hMPV-positive status was recorded was 5 months.

Conclusion

This study demonstrated that hMPV was associated with a significant number (i.e. >10 %) of ARTIs in children in South India, whereas a relatively smaller number of HBoV infections was observed.

Molecular epidemiology of respiratory viruses in virus-induced asthma

Acute respiratory illness (ARI) due to various viruses is not only the most common cause of upper respiratory infection in humans but is also a major cause of morbidity and mortality, leading to diseases such as bronchiolitis and pneumonia. Previous studies have shown that respiratory syncytial virus (RSV), human rhinovirus (HRV), human metapneumovirus (HMPV), human parainfluenza virus (HPIV), and human enterovirus infections may be associated with virus-induced asthma. For example, it has been suggested that HRV infection is detected in the acute exacerbation of asthma and infection is prolonged. Thus it is believed that the main etiological cause of asthma is ARI viruses. Furthermore, the number of asthma patients in most industrial countries has greatly increased, resulting in a morbidity rate of around 10-15% of the population. However, the relationships between viral infections, host immune response, and host factors in the pathophysiology of asthma remain unclear. To gain a better understanding of the epidemiology of virus-induced asthma, it is important to assess both the characteristics of the viruses and the host defense mechanisms. Molecular epidemiology enables us to understand the pathogenesis of microorganisms by identifying specific pathways, molecules, and genes that influence the risk of developing a disease. However, the epidemiology of various respiratory viruses associated with virus-induced asthma is not fully understood. Therefore, in this article, we review molecular epidemiological studies of RSV, HRV, HPIV, and HMPV infection associated with virus-induced asthma.

Prevalence of human metapneumovirus in children with acute lower respiratory infection in Changsha, China

Human metapneumovirus (hMPV) causes acute respiratory infections in children. The prevalence and clinical characteristics of hMPV were determined in nasopharyngeal aspirates of children in Changsha, China. Reverse transcription-polymerase chain reaction (RT-PCR) or PCR was employed to screen for both hMPV and other common respiratory viruses in 1,165 nasopharyngeal aspirate specimens collected from children with lower respiratory tract infections from September 2007 to August 2008. All PCR products were sequenced, and demographic and clinical data were collected from all patients. Seventy-six of 1,165 (6.5%) specimens were positive for hMPV, of which 85.5% (65/76) occurred in the winter and spring seasons. The hMPV coinfection rate was 57.9% (44/76), and human bocavirus was the most common virus detected in conjunction with hMPV. Phylogenetic analysis revealed that 94.7% of the hMPV detected were of subgroup A2, 5.3% were subgroup B2, and none belonged to either the A1 or B1 subgroups. No significant differences were found in terms of the frequency of diagnosis and clinical signs between either the co- and mono-infection groups, or between patients with and without underlying diseases. It was concluded that hMPV is an important viral pathogen in pediatric patients with lower respiratory tract infections in Changsha. Only hMPV genotypes A2 and B2 were co-circulating in this locality; human bocavirus was the most common coinfecting virus, and coinfection did not affect disease severity.

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

Background/Purpose

To investigate the prevalence of common viruses and Mycoplasma pneumoniae (MP) in hospitalized infants with acute bronchiolitis and study the relationship between bronchiolitis and meteorological conditions.

Methods

A 2-year prospective study was conducted on infants with a first episode of bronchiolitis admitted to Respiratory Department of Suzhou Children's Hospital. Demographic and clinical characteristics and meteorological conditions were obtained and analyzed.

Results

Pathogens were identified in 59.6% of 998 cases analyzed. The most frequent pathogen identified was respiratory syncytial virus (28.7%), followed by human bocavirus (11.6%), MP (9.0%), human parainfluenza virus-3 (7.8%), human metapneumovirus (6.6%), influenza A (3.5%), adenovirus (1.0%), and human parainfluenza virus-1 (0.3%). The clinical scores in children with MP or human metapneumovirus single infections, based on the assessment of severity of acute bronchiolitis, were significantly lower than in children with respiratory syncytial virus single infections. Respiratory syncytial virus had the strongest inverse correlation with mean temperature, followed by influenza A and human metapneumovirus. In addition, MP and human parainfluenza virus-3 showed positive correlations with mean temperature.

Conclusion

Although respiratory syncytial virus was the most frequent pathogen in patients in whom bronchiolitis was diagnosed, other pathogens, including newly identified viruses and MP, also play important roles in infants with bronchiolitis. Different respiratory pathogens have different traits in response to certain meteorological conditions.

Severe metapneumovirus infections among immunocompetent and immunocompromised patients admitted to hospital with respiratory infection

Human metapneumovirus (hMPV) is considered an important cause of acute respiratory infections. hMPV can cause morbidity in hematopoietic stem cell transplant recipients and recent research has demonstrated that it is an important virus in patients admitted to hospital with respiratory infections and suspected of having pandemic 2009 influenza A (H1N1pdm09) virus. The purpose of this study was to investigate infections caused by hMPV in two groups of patients admitted to hospital: Immunocompromized patients with a potential risk of severe outcomes and immunocompetent patients with severe acute respiratory syndrome. A total of 288 samples were tested: 165 samples were collected from patients with suspected influenza A (H1N1) pdm09 infection during the first pandemic wave in 2009; and 123 samples were collected from patients of a hematopoietic stem cell transplantation program in 2008-2009. Amplification of the hMPV genes was performed by polymerase chain reaction. This was followed by sequencing and phylogenetic analysis. hMPV was detected in 14.2% (41/288) of all samples: 17% (28/165) of immunocompetent patients with suspected H1N1 infection and 10.6% (13/123) among hematopoietic stem cell transplant recipients. hMPV accounted for 12.1% (8/66) of immunocompetent adults patients with severe respiratory infections (median age, 55.9 years). Two hMPV subtypes were identified, A2 (26.9%; 7/26) and B2 (73.1%; 19/26) but no difference was observed between the patient groups in terms of age or immunosuppression level. This study highlights the significance of hMPV in immunocompetent adult patients with severe infections and further investigations are recommended for understanding the impact of this virus.

Nebulised deoxyribonuclease for viral bronchiolitis in children younger than 24 months

BACKGROUND

Bronchiolitis is one of the most common respiratory problems in the first year of life. The sputum of infants with bronchiolitis has increased deoxyribonucleic acid (DNA) content, leading to mucous plugging and airway obstruction. Recombinant human deoxyribonuclease (rhDNase), an enzyme that digests extracellular DNA, might aid the clearance of mucus and relieve peripheral airway obstruction.

OBJECTIVES

To determine the effect of nebulised rhDNase on the severity and duration of viral bronchiolitis in children younger than 24 months of age in the hospital setting.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) 2012, Issue 7 which includes the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to July Week 4, 2012), EMBASE (1974 to August 2012) and LILACS (1982 to August 2012).

SELECTION CRITERIA

Randomised controlled trials (RCTs) using nebulised rhDNase alone or with concomitant therapy in children younger than 24 months of age hospitalised with acute bronchiolitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed literature searches, assessed trial quality and extracted data. We obtained unpublished data from trial authors. We used Review Manager 5.1 to pool treatment effects expressed as the mean difference (MD) or standardised mean difference (SMD) with 95% confidence intervals (CI).

MAIN RESULTS

Three RCTs (333 participants) were identified, two of which were multicentre trials comprising only participants positive for respiratory syncytial virus (RSV). The other trial enrolled participants clinically diagnosed with bronchiolitis from a hospital in Italy. All studies used 2.5 mL (1 mg/mL) of nebulised rhDNase compared with placebo either as a daily or a twice daily dose. Adjunctive therapy included nebulised salbutamol, steroids, supplemental oxygen, intravenous fluids or tube feeding, nasal washing, nasal decongestants and antibiotics.Overall, nebulised rhDNase showed no benefit in clinically meaningful outcomes. Meta-analysis favoured the control group with a shorter duration of hospital stay (MD 0.50; 95% CI 0.10 to 0.90, P = 0.01) and better clinical score improvement (SMD -0.24; 95% CI -0.50 to 0.01, P = 0.06). The largest trial showed no difference in supplemental oxygen use or intensive care unit (ICU) admission.In one RCT, four out of 11 patients in the treatment group had atelectasis. Two of these patients showed distinctive clinical improvement after nebulised rhDNase.There was no significant difference in adverse events. These included temporary desaturation, temporary coughing, increased coughing, facial rash, hoarseness, dyspnoea and bad taste, reported in a total of 11 patients from both treatment groups.

AUTHORS' CONCLUSIONS

The results based on the three included studies in this review did not support the use of nebulised rhDNase in children under 24 months of age hospitalised with acute bronchiolitis. In these patients, treatment did not shorten the length of hospitalisation or improve clinical outcomes. It might have a role in severe bronchiolitis complicated by atelectasis, but further clinical studies would need to be performed.

Use of an innovative web-based laboratory surveillance platform to analyze mixed infections between human metapneumovirus (hMPV) and other respiratory viruses circulating in Alberta (AB), Canada (2009-2012)

We investigated the proportions of mono vs. mixed infections for human metapneumovirus (hMPV) as compared to adenovirus (ADV), four types of coronavirus (CRV), parainfluenza virus (PIV), RSV, and enterovirus/rhinovirus (ERV) in Alberta, Canada. Using the Data Integration for Alberta Laboratories (DIAL) platform, 26,226 respiratory specimens at ProvLab between 1 July 2009 and 30 June 2012 were selected and included in the study. Using the Respiratory Virus Panel these specimens tested positive for one or more respiratory virus and negative for influenza A and B. From our subset hMPV was the fourth most common virus (n=2,561) with 373 (15%) identified as mixed infection using DIAL. Mixed infection with hMPV was most commonly found in infants less than 6 months old and ERV was most commonly found in mixed infection with hMPV (230/373, 56%) across all age groups. The proportion of mixed-infection vs. mono-infection was highest for ADV (46%), followed by CRV 229E (32%), CRV HKU1 (31%), CRV NL63 (28%), CRV OC43 (23%), PIV (20%), RSV (17%), hMPV (15%) and ERV (13%). hMPV was significantly more likely to be identified in mono infection as compared with ADV, CRV, PIV, and RSV with the exception of ERV [p < 0.05].

Nonstructural protein-1 of respiratory syncytial virus regulates HOX gene expression through interacting with histone

Human respiratory syncytial virus (RSV), a major cause of severe respiratory diseases, constitutes an important risk factor for the development of subsequent asthma. In searching for its mechanism, the present study was designed to screen the interacting proteins of two important nonstructural (NS) proteins in human BECs. The subcellular localization and the effects of NS on HOX gene expression were also examined. The results showed that NS1 was distributed throughout the nucleus and cytoplasm, while NS2 was mainly distributed in cytoplasm of BECs. NS1 interacted specifically with host histone H2BD, inducing histone ubiquitination and subsequent HOX gene expression. In conclusion, the results of the present study indicated that RSV NS-1 induces HOX gene expression, through histone ubiquitination in a BEC cell line, which may provide a novel conception for understanding the relationship between severe RSV bronchiolitis during early life and the development of subsequent asthma.

Human Metapneumovirus: lessons learned over the first decade

It has been 10 years since human metapneumovirus (HMPV) was identified as a causative agent of respiratory illness in humans. Since then, numerous studies have contributed to a substantial body of knowledge on many aspects of HMPV. This review summarizes our current knowledge on HMPV, HMPV disease pathogenesis, and disease intervention strategies and identifies a number of areas with key questions to be addressed in the future.

RNA interference in vitro and in vivo using DsiRNA targeting the nucleocapsid N mRNA of human metapneumovirus

Human metapneumovirus causes respiratory diseases with outcomes that can be severe in children, the immunocompromised, and the elderly. Synthetic small interfering RNAs (siRNAs) that silence targeted genes can be used as therapeutic agents. Currently, there is no specific therapy for hMPV. In this study, we designed Dicer-substrate siRNAs (DsiRNAs) that target metapneumovirus sequences on the mRNAs of the N, P, and L genes. In vitro, six DsiRNAs were shown to inhibit virus replication using cell proliferation tests. Of those, the DsiRNA that targets the most conserved mRNA sequence was then resynthesized in Evader™ format with heavy 2'-O-methyl modification of the guide strand. In a murine model, the prophylactic administration of this Evader™ DsiRNA was effective at partially inhibiting viral replication of hMPV (13×10(3) vs. 29×10(3)PFU/g of lung; p<0.01), which was not the case for the control, a mismatched DsiRNA. Inhibition was achieved without inducing cytokines or off-target effects. Moreover, the specificity of the siRNA mechanism of action was demonstrated in vitro and in vivo using 5'-RACE methodology. This in vivo approach of using a DsiRNA against hMPV is an important step in the development of synthetic siRNA as a therapeutic agent for this virus.