Human rhinovirus group C in hospitalized children, Singapore

Etiology of febrile respiratory infections in the general adult population in Singapore, 2007-2013

Pathogens that cause upper respiratory infections are numerous and specific preventive and therapeutic strategies are scarce. In order to ascertain the etiological agents resulting in upper respiratory tract infections (URTI) in adults in Singapore, nasal swab samples were collected from 2057 patients presenting with fever at primary healthcare clinics in Singapore from December 2007 to February 2013. Samples were tested using the Luminex NxTAG Respiratory Pathogen Panel that includes 22 respiratory pathogen targets. Patient-reported symptoms and vital signs were recorded and full blood and differential counts taken. Pathogens were detected in the following order of frequency: influenza viruses, rhino-/enteroviruses, coronaviruses, parainfluenza viruses, pneumoviruses, adenovirus, bocavirus and C. pneumoniae. Fifteen virus species were detected as part of coinfections, in which rhinoviruses were the most commonly observed pathogen. Our results suggest that influenza viruses are the main etiological agents, but multiple other respiratory viruses contribute to the total burden of URTI in adults in Singapore.

Diversity of respiratory viruses detected among hospitalized children with acute lower respiratory tract infections at Hospital Serdang, Malaysia

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Discovery of new viruses have created a renewed interest in the epidemiology of respiratory viruses.

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Respiratory viruses are the major cause of acute lower respiratory tract infections (ALRTIs) in children.

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Assessment of the morbidity of specific etiological agents of ALRTIs is important to determine agent-specific interventions.

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Sensitive and rapid diagnosis of respiratory infections in hospitalized children is cost-effective.

Background

The role of respiratory viruses as the major cause of acute lower respiratory tract infections (ALRTIs) in children is becoming increasingly evident due to the use of sensitive molecular detection methods. The aim of this study was to use conventional and molecular detection methods to assess the epidemiology of respiratory viral infections in children less than five years of age that were hospitalized with ALRTIs.

Methods

The cross-sectional study was designed to investigate the occurrence of respiratory viruses including respiratory syncytisl virus (RSV), human metapneumovirus (HMPV), influenza virus A and B (IFV-A and B), parainfluenzavirus 1, 2, 3 and 4 (PIV 1, 2, 3 and 4), human rhinoviruses (HRV), human enterovirus (HEV), human coronaviruses (HCoV) 229E and OC43, human bocavirus (HBoV) and human adenovirus (HAdV) in hospitalized children with ALRTIs, at Hospital Serdang, Malaysia, from June 16 to December 21, 2009. The study was also designed in part to assess the performance of the conventional methods against molecular methods.

Results

Viral pathogens were detected in 158 (95.8%) of the patients. Single virus infections were detected in 114 (67.9%) patients; 46 (27.9%) were co-infected with different viruses including double-virus infections in 37 (22.4%) and triple-virus infections in 9 (5.5%) cases. Approximately 70% of samples were found to be positive using conventional methods compared with 96% using molecular methods. A wide range of respiratory viruses were detected in the study. There was a high prevalence of RSV (50.3%) infections, particularly group B viruses. Other etiological agents including HAdV, HMPV, IFV-A, PIV 1–3, HBoV, HCoV-OC43 and HEV were detected in 14.5, 9.6, 9.1, 4.8, 3.6, 2.4 and 1.8 percent of the samples, respectively.

Conclusion

Our results demonstrated the increased sensitivity of molecular detection methods compared with conventional methods for the diagnosis of ARTIs in hospitalized children. This is the first report of HMPV infections in Malaysia.

High correlation between human rhinovirus type C and children with asthma exacerbations in Taiwan

BACKGROUND/PURPOSES

Human rhinovirus type C (HRV-C) has been associated with asthma exacerbation (AE) in children in several countries. However, in Taiwan the association between HRV, especially HRV-C, and AE in children has yet to be elucidated. We sought to investigate the prevalence of respiratory viruses in children with acute lower respiratory tract infection (ALRTI) in Taiwan and the association between different types of HRV and AE in children.

METHODS

This prospective study was conducted from 2011 to 2013, and enrolled children with ALRTI, including an asthma exacerbation group (AE; n = 28) and a Non-asthma group (n = 66). Viruses were detected by culture, reverse transcription-polymerase chain reaction, and molecular sequencing of nasopharyngeal swabs.

RESULTS

The prevalence of identified respiratory viruses was 78.6% in the AE group and 65.2% in the Non-asthma group. The prevalence rates of HRV and HRV-C were significantly higher in the AE group than in the Non-asthma group (67.9% vs. 33.3% in HRV, p = 0.002; and 50% vs. 15.2% in HRV-C, p < 0.001). Among the children with HRV, the prevalence of HRV-C (68.4%) was higher than that of the other types of HRV (31.6%, including HRV-A 26.3%, and HRV-B 5.3%) in the AE group but not in the Non-asthma group (40.9% vs. 59.1%).

CONCLUSIONS

HRV is the most predominant viral infection responsible for pediatric AE in Taiwan, and HRV-C is responsible for more of these exacerbations than HRV-A or HRV-B.

Review on Clinical and Molecular Epidemiology of Human Rhinovirus-Associated Lower Respiratory Tract Infections in African and Southeast Asian Children

BACKGROUND

The detection of human rhinoviruses (HRV) is highly prevalent in children with pneumonia, bronchiolitis, acute asthma and croup; however, there is also evidence that HRV is common in asymptomatic individuals. The majority of studies on the role of different HRV serotypes during acute respiratory tract infections episodes have limited sample size to fully characterize the epidemiology of HRV infection, including those from low-middle income countries, where the burden of childhood respiratory disease is greatest.

METHODS

We systematically reviewed HRV clinical and molecular epidemiology in low- and middle-income countries in Africa and Southeast Asia before November 2015.

RESULTS

We identified 31 studies, which included data from 13 African and 6 Southeast Asian countries, emphasizing the gaps in knowledge surrounding HRV infections. HRV was one of the most prevalent respiratory viruses detected during childhood respiratory disease (13%-59%); however, many studies could not determine the attributable role of HRV in the pathogenesis of acute respiratory infections due to high prevalence of detection among asymptomatic individuals (6%-50%). A meta-analysis showed no significant difference in the prevalence of HRV identification between children of different age groups; or between children with severe disease compared with asymptomatic children.

CONCLUSIONS

These data highlight the need for large-scale surveillance projects to determine the attributable etiologic role of HRV in respiratory disease.

[An epidemiological study on human rhinovirus C in hospitalized children with respiratory tract infections]

OBJECTIVE

To investigate the detection rates, epidemical characteristics, and clinical features of human rhinovirus C (HRV-C) in hospitalized children with respiratory tract infections (RTIs) in Suzhou, China.

METHODS

A total of 1 702 hospitalized children with RTIs from January to December, 2014 were enrolled, and 1 702 nasopharyngeal aspirate samples were collected from all children. RT-PCR was used to measure HRV mRNA, and quantitative real-time PCR combined with high-resolution melting curve was used to measure HRV-C.

RESULTS

Of all children, 244 (14.34%) were detected to have HRV infection, among whom 69 (69/244, 28.3%) had HRV-C infection. The rate of mixed infection of HRV-C with other viruses and bacteria was 61% (42/69). HRV-C was detected in each month of the year, and the detection rate of HRV-C in autumn was significantly higher than that in spring, summer, and winter (P<0.05). The children aged 2-5 years had a significantly higher detection rate of HRV-C than those in the other age groups (P<0.05). Compared with HRV-A/B infection, HRV-C infection led to significantly higher proportions of patients with lobar pneumonia and acute exacerbation of asthma (P<0.05), as well as patients with increased neutrophil count and CRP level (P<0.05). There were no significant differences in sex distribution or other clinical manifestations (P>0.05).

CONCLUSIONS

HRV-C infection accounts for about 1/3 of HRV infection, with a high incidence rate in autumn. The rate of mixed infection of HRV-C with other viruses and bacteria is high, and children aged 2-5 years have the highest detection rate of HRV-C. Children with HRV-C infection have similar clinical manifestations as those with HRV-A/B infection.

[An epidemiological study on human rhinovirus C in hospitalized children with respiratory tract infections]

OBJECTIVE

To investigate the detection rates, epidemical characteristics, and clinical features of human rhinovirus C (HRV-C) in hospitalized children with respiratory tract infections (RTIs) in Suzhou, China.

METHODS

A total of 1 702 hospitalized children with RTIs from January to December, 2014 were enrolled, and 1 702 nasopharyngeal aspirate samples were collected from all children. RT-PCR was used to measure HRV mRNA, and quantitative real-time PCR combined with high-resolution melting curve was used to measure HRV-C.

RESULTS

Of all children, 244 (14.34%) were detected to have HRV infection, among whom 69 (69/244, 28.3%) had HRV-C infection. The rate of mixed infection of HRV-C with other viruses and bacteria was 61% (42/69). HRV-C was detected in each month of the year, and the detection rate of HRV-C in autumn was significantly higher than that in spring, summer, and winter (P<0.05). The children aged 2-5 years had a significantly higher detection rate of HRV-C than those in the other age groups (P<0.05). Compared with HRV-A/B infection, HRV-C infection led to significantly higher proportions of patients with lobar pneumonia and acute exacerbation of asthma (P<0.05), as well as patients with increased neutrophil count and CRP level (P<0.05). There were no significant differences in sex distribution or other clinical manifestations (P>0.05).

CONCLUSIONS

HRV-C infection accounts for about 1/3 of HRV infection, with a high incidence rate in autumn. The rate of mixed infection of HRV-C with other viruses and bacteria is high, and children aged 2-5 years have the highest detection rate of HRV-C. Children with HRV-C infection have similar clinical manifestations as those with HRV-A/B infection.

Infection and coinfection of human rhinovirus C in stem cell transplant recipients

In 54 adult stem cell transplant recipients, the presence and persistence of human rhinoviruses (including the novel lineage C) were evaluated by molecular detection and phylogenetic analysis, independently from respiratory symptoms. In the same group of patients, the presence of other coinfecting respiratory pathogens, including the novel enterovirus 109, was also evaluated.

Epidemiology and seasonality of respiratory viral infections in hospitalized children in Kuala Lumpur, Malaysia: a retrospective study of 27 years

Background

Viral respiratory tract infections (RTI) are relatively understudied in Southeast Asian tropical countries. In temperate countries, seasonal activity of respiratory viruses has been reported, particularly in association with temperature, while inconsistent correlation of respiratory viral activity with humidity and rain is found in tropical countries. A retrospective study was performed from 1982-2008 to investigate the viral etiology of children (≤ 5 years old) admitted with RTI in a tertiary hospital in Kuala Lumpur, Malaysia.

Methods

A total of 10269 respiratory samples from all children ≤ 5 years old received at the hospital's diagnostic virology laboratory between 1982-2008 were included in the study. Immunofluorescence staining (for respiratory syncytial virus (RSV), influenza A and B, parainfluenza types 1-3, and adenovirus) and virus isolation were performed. The yearly hospitalization rates and annual patterns of laboratory-confirmed viral RTIs were determined. Univariate ANOVA was used to analyse the demographic parameters of cases. Multiple regression and Spearman's rank correlation were used to analyse the correlation between RSV cases and meteorological parameters.

Results

A total of 2708 cases were laboratory-confirmed using immunofluorescence assays and viral cultures, with the most commonly detected being RSV (1913, 70.6%), parainfluenza viruses (357, 13.2%), influenza viruses (297, 11.0%), and adenovirus (141, 5.2%). Children infected with RSV were significantly younger, and children infected with influenza viruses were significantly older. The four main viruses caused disease throughout the year, with a seasonal peak observed for RSV in September-December. Monthly RSV cases were directly correlated with rain days, and inversely correlated with relative humidity and temperature.

Conclusion

Viral RTIs, particularly due to RSV, are commonly detected in respiratory samples from hospitalized children in Kuala Lumpur, Malaysia. As in temperate countries, RSV infection in tropical Malaysia also caused seasonal yearly epidemics, and this has implications for prophylaxis and vaccination programmes.

Clinical spectrum of human rhinovirus infections in hospitalized Hong Kong children

BACKGROUND

Human rhinovirus (HRV) is classified into A, B, and C genogroups. HRVs cause mild upper respiratory infections, but HRV-C was recently found to be a major cause of asthma exacerbation in whites. This study elucidated disease spectrum of HRV infections among Hong Kong children hospitalized with respiratory illnesses.

METHODS

This retrospective study recruited 128 children with asthma exacerbations and 192 inpatient controls without allergy and hospitalized for respiratory illnesses within the same week. Their clinical information was retrieved from case records. HRVs in nasopharyngeal aspirates were detected by molecular assays using primers targeting consensus VP4/VP2 coding regions, and their genogroups identified by sequencing.

RESULTS

The mean (standard deviation) age of cases and controls was 5.6 (3.6) years and 5.4 (3.8) years, respectively (P = 0.601). HRV was detected in 107 (84.9%) cases and 63 (33.0%) controls (P < 0.0001), and HRV-C in 69.8% and 18.8% of these groups, respectively (P < 0.0001). Detection of HRV-A and -B was similar between these groups (P > 0.15). More subjects with HRV-C needed oxygen supplementation (11.1% vs. 2.6%; P = 0.043). Among controls, HRV infection was associated with acute bronchiolitis (P < 0.001) and bronchitis (P = 0.04), which paralleled those of HRV-C. HRV-A was associated with acute bronchiolitis (P = 0.005). Phylogenetic analysis revealed a diverse group of HRV serotypes (21 for HRV-A, 2 for HRV-B, and 32 for HRV-C).

CONCLUSIONS

HRV-C is associated with asthma exacerbation, whereas the presence of all HRVs, or either HRV-A or HRV-C alone, is associated with wheezing respiratory infections in nonasthmatic children. HRV is an important respiratory virus responsible for childhood wheezing illnesses.

Host and viral factors associated with severity of human rhinovirus-associated infant respiratory tract illness

BACKGROUND

Risk factors for severe human rhinovirus (HRV)-associated infant illness are unknown.

OBJECTIVES

We sought to examine the role of HRV infection in infant respiratory tract illness and assess viral and host risk factors for HRV-associated disease severity.

METHODS

We used a prospective cohort of term, previously healthy infants enrolled during an inpatient or outpatient visit for acute upper or lower respiratory tract illness during the fall-spring months of 2004-2008. Illness severity was determined by using an ordinal bronchiolitis severity score, with higher scores indicating more severe disease. HRV was identified by means of real-time RT-PCR. The VP4/VP2 region from HRV-positive specimens was sequenced to determine species.

RESULTS

Of 630 infants with bronchiolitis or upper respiratory tract illnesses (URIs), 162 (26%) had HRV infection; HRV infection was associated with 18% of cases of bronchiolitis and 47% of cases of URI. Among infants with HRV infection, 104 (64%) had HRV infection alone. Host factors associated with more severe HRV-associated illness included a maternal and family history of atopy (median score of 3.5 [interquartile range [IQR], 1.0-7.8] vs 2.0 [IQR, 1.0-5.2] and 3.5 [IQR, 1.0-7.5] vs 2.0 [IQR, 0-4.0]). In adjusted analyses maternal history of atopy conferred an increase in the risk for more severe HRV-associated bronchiolitis (odds ratio, 2.39; 95% CI, 1.14-4.99; P = .02). In a similar model maternal asthma was also associated with greater HRV-associated bronchiolitis severity (odds ratio, 2.49, 95% CI, 1.10-5.67; P = .03). Among patients with HRV infection, 35% had HRVA, 6% had HRVB, and 30% had HRVC.

CONCLUSION

HRV infection was a frequent cause of bronchiolitis and URIs among previously healthy term infants requiring hospitalization or unscheduled outpatient visits. Substantial viral genetic diversity was seen among the patients with HRV infection, and predominant groups varied by season and year. Host factors, including maternal atopy, were associated with more severe infant HRV-associated illness.

New human rhinovirus species and their significance in asthma exacerbation and airway remodeling

Asthma is the most common chronic disease of childhood, affecting 10% to 15% of all children. Several different stimuli including allergens, tobacco smoke, certain drugs, and viral or bacterial infections are known to exacerbate asthma symptoms. Among these triggers, viruses are frequent inducers of asthma exacerbations, with human rhinoviruses being the most common in children and adults. This article describes the different species of this virus and their roles as major triggers of asthma exacerbations.

The role of rhinovirus infections in the development of early childhood asthma

PURPOSE OF REVIEW

To discuss the role of human rhinoviruses (HRVs) in early childhood wheezing illnesses and how HRVs contribute to the development of childhood asthma.

RECENT FINDINGS

Advanced molecular diagnostics have identified HRVs as pathogens frequently causing wheezing illnesses in infants and young children. Wheezing during HRV infection in early life identifies children at particularly high-risk of asthma development. Plausible mechanisms by which HRV could cause airway damage, promote airway remodeling, and lead to asthma development have recently been identified.

SUMMARY

HRV is a significant source of morbidity in infants and young children. The present review identifies mechanisms by which HRV lower respiratory tract infection, particularly in a susceptible host, could promote the development of childhood asthma. Further studies are needed to elucidate the mechanisms underlying the link between HRV wheezing in early childhood and subsequent asthma development, with the critical goal of identifying novel therapeutic and prevention strategies for both early childhood wheezing and asthma.

Allergy is an important factor in asthma exacerbation: a pro/con debate

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

Newly identified human rhinoviruses: molecular methods heat up the cold viruses

Human rhinovirus (HRV) infections cause at least 70% of virus‐related wheezing exacerbations and cold and flu‐like illnesses. They are associated with otitis media, sinusitis and pneumonia. Annually, the economic impact of HRV infections costs billions in healthcare and lost productivity. Since 1987, 100 officially recognised HRV serotypes reside in two genetically distinct species; HRV A and HRV B, within the genus Enterovirus, family Picornaviridae. Sequencing of their ∼7kb genomes was finalised in 2009. Since 1999, many globally circulating, molecularly‐defined ‘strains’, perhaps equivalent to novel serotypes, have been discovered but remain uncharacterised. Many of these currently unculturable strains have been assigned to a proposed new species, HRV C although confusion exists over the membership of the species. There has not been sufficient sampling to ensure the identification of all strains and no consensus criteria exist to define whether clinical HRV detections are best described as a distinct strain or a closely related variant of a previously identified strain (or serotype). We cannot yet robustly identify patterns in the circulation of newly identified HRVs (niHRVs) or the full range of associated illnesses and more data are required. Many questions arise from this new found diversity: what drives the development of so many distinct viruses compared to other species of RNA viruses? What role does recombination play in generating this diversity? Are there species‐ or strain‐specific circulation patterns and clinical outcomes? Are divergent strains sensitive to existing capsid‐binding antivirals? This update reviews the findings that trigger these and other questions arising during the current cycle of intense rhinovirus discovery. Copyright © 2010 John Wiley & Sons, Ltd.

Human rhinoviruses in Chinese adults with acute respiratory tract infection

Objective

To evaluate the roles of human rhinoviruses (HRVs) in acute respiratory tract infections (ARTIs) in Chinese adults and determine the association between species of HRV and clinical presentations.

Methods

RT-PCR methods were used to detect HRVs in throat and nasal swabs collected from 6104 adult patients with ARTIs from December 2005 to April 2008 in Beijing, China.

Results

HRV strains were detected in 271 ARTIs cases, 65% of which tested positive for HRV-A, 25% for HRV-B, and 10% for HRV-C. Aside from fever, pharyngeal congestion and headache were the most common clinical symptoms observed in the HRVs infected patients. HRV-A infected patients had a higher percentage of upper respiratory symptoms than patients infected by the two other HRV species. Systemic symptoms such as chilliness and myalgia were more frequent in people infected by HRV-B. The three HRV species exhibited unique infection timing when analyzed monthly.

Conclusion

HRV-C can be detected in adult patients with acute upper respiratory tract infections, but is not the predominant species in this population.