Viral coinfection in childhood respiratory tract infections

Prevalence of Influenza Viruses A and B, Adenovirus, Respiratory Syncytial Virus, and Human Metapneumonia Viruses among Children with Acute Respiratory Tract Infection

Background

Acute respiratory tract infection (ARTI) is a significant cause of morbidity and mortality among children worldwide. The majority of acute respiratory infections in children are caused by viruses, with respiratory syncytial virus (RSV) being the most frequently encountered. Other important viral pathogens include human metapneumovirus, human coronaviruses, adenovirus, and influenza. These infections can lead to complications such as bronchitis and pneumonia. So, this study aimed to evaluate the prevalence of influenza viruses A and B, adenovirus, respiratory syncytial virus (RSV), and human metapneumovirus (HMPV) in children with ARTI.

Methods

The molecular diagnostic of polymerase chain reaction approach was used to detect influenza (A and B), metapneumovirus, respiratory syncytial virus (RSV), and adenovirus in respiratory samples of children with acute respiratory infection hospitalization in a teaching hospital of the Shiraz University of Medical Sciences in January 2016-March 2017.

Results

Of the 340 patients examined, 208 (61.20%) were male and the median age was 3.13 ± 2.38 years. Respiratory viruses were found in 179 (52.64%) patients. The male-to-female ratio was 1.63 : 1 in patients who were viral positive. Detection rates for influenza A, adenovirus, influenza B, RSV, and HMPV were 28.23%, 24.70%, 8.52%, 3.23%, and 2.64%, respectively, and coinfections were detected in 24.02%. The most common combination of two-virus coinfections was IFVA/AdV, followed by IFVB/AdV, AdV, IFVB/IFVA, RSV/IFVA, HMPV/AdV, RSV/AdV, and HMPV/IFVA.

Conclusion

The high prevalence of respiratory viruses in children hospitalized with ARTI suggests that viral infection may play a role in disease pathogenesis. This should be confirmed through the conduct of case-control studies and may inform the role of vaccination to prevent respiratory viral infections.

Viral Coinfections

In nature, viral coinfection is as widespread as viral infection alone. Viral coinfections often cause altered viral pathogenicity, disrupted host defense, and mixed-up clinical symptoms, all of which result in more difficult diagnosis and treatment of a disease. There are three major virus-virus interactions in coinfection cases: viral interference, viral synergy, and viral noninterference. We analyzed virus-virus interactions in both aspects of viruses and hosts and elucidated their possible mechanisms. Finally, we summarized the protocol of viral coinfection studies and key points in the process of virus separation and purification.

Viral etiology of acute respiratory infections during 2014–16 in Riyadh, Saudi Arabia

Aim: Viral etiology of respiratory infections is not well understood in Saudi Arabia. This study was conceptualized to understand viral etiology in children with acute respiratory tract infections (ARTI) from Riyadh. Patients and methods: Respiratory viruses were detected by real-time PCR in nasopharyngeal aspirates or swab from 580 children aged ≤5 years. Results: Respiratory viruses were detected in 64% of the samples with 6% mixed viral infections. Respiratory syncytial virus, adenovirus, influenza, parainfluenza and human metapneumovirus infections accounted for 42, 20, 16, 12 and 10%, respectively. Maximum prevalence (37%) was among the lowest age group followed by 30% among the 7- to 12-month age group. Conclusion: The prevalence and determinants of viral etiology are in line with the previous report from the region. No major shift in the viral etiologies was observed in the 2-year study period.

Is viral coinfection a risk factor for severe lower respiratory tract infection? A retrospective observational study

OBJECTIVE

To determine whether viral coinfection is a risk for severe lower respiratory tract infection (LRTI).

WORKING HYPOTHESIS

Children with viral coinfection had a higher risk for admission to the intensive care unit (ICU) than those with a single virus infection.

STUDY DESIGN

Retrospective, observational study for 10 years.

PATIENT-SUBJECT SELECTION

Children between 1 and 60 months of age hospitalized with LRTI.

The Differences in Viral Etiologies between Children with and without Severe Disability Admitted to the Pediatric Intensive Care Unit with Acute Respiratory Illness

Objectives The objectives of this study were to evaluate the differences in the viral etiologies and variability in the clinical course between children with and without severe disability (SD) admitted to the pediatric intensive care unit (PICU) with acute respiratory illness (ARI).

Methods The medical records of patients admitted to our PICU between June 2017 and July 2019 were retrospectively reviewed for viral etiology and clinical course.

Results Forty-eight of 136 patients included in the study had SD. The rates of requiring positive pressure ventilation (43.5% vs. 20.5%) or inotropic support (39.9% vs. 15.9%), and the median length of stay (11 [10] vs. 5 [8]) were significantly higher in children with SD (p < 0.01, each). Influenza infection was significantly higher in children with SD (20.8% vs. 2.3%; p < 0.01) whereas respiratory syncytial virus (RSV) infection was more common in children without SD (47.7% vs. 4.2%; p < 0.01). There was no statistically significant difference in terms of other viruses between study groups.

Conclusion In this present study, influenza was an important pathogen for children with SD, while RSV was the main cause of ARI-associated PICU admission in children without SD. By focusing on increasing the rate of immunization against influenza in children with SD and their caregivers the burden of influenza-associated PICU admissions could be decreased.

Respiratory syncytial virus infection: why does disease severity vary among individuals?

Introduction: Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory tract infections in infancy. While many infants are infected with RSV, the nature and severity of the disease vary among individuals. RSV causes bronchiolitis, pneumonia, and asthma exacerbation. However, most children infected with RSV have only mild upper airways disease and may be asymptomatic.Areas covered: Despite efforts to elucidate mechanisms for the various clinical responses to RSV infection, they remain largely unknown, suggesting that susceptibility and disease are influenced by multiple intrinsic and extrinsic factors. This article reviews the available literature on the field of RSV disease severity and discusses important factors associated to susceptibility and different disease outcome.Expert opinion: The severity of RSV-induced illness is a phenomenon that depends on a variety of graded mechanisms of interaction between the host, virus, and environment. This may lead to differences in the intensity of immune response in the lung and different courses of the disease. By characterizing, classifying, and grading the affecting factors in high-risk patients versus those who do not fall ill by RSV, we may find therapies or point to disease-limiting medications.

Evolutionary analysis of the ON1 genotype of subtype a respiratory syncytial virus in Riyadh during 2008-16

Respiratory syncytial virus is a leading cause of acute respiratory tract infection (ARI) in children worldwide. Limited information is available on molecular epidemiology of respiratory syncytial virus (RSV) from Saudi Arabia. An attempt was made to identify and characterize RSV strains in nasopharyngeal aspirates collected from hospitalized symptomatic ARI pediatric patients with <5 years of age from Riyadh, Saudi Arabia during 2016. All the samples (n = 100) were tested for RSV by real time PCR. The RSV strains were characterized by sequencing of the second hypervariable region of G protein gene. The study sequences along with the previously reported strains from Saudi Arabia were assessed for mutational, glycosylation, phylogenetic, selection pressure and entropy analyses. Fifty percent of the nasopharyngeal aspirates were positive for RSV. The RSVA (72%) predominated as compared to RSVB (24%) during the study. The study RSVA strains (n = 29) clustered into NA1 and ON1 genotypes whereas all the RSVB sequences (n = 5) were in BA genotype by phylogenetic analysis. Interestingly, 97% of RSVA sequences (n =28) clustered into ON1 genotype with 72 bp duplication in the G protein gene. Numerous mutations, variable N-/O-glycosylation sites and purifying selections were observed in the ON1 genotype. Positive selection with high entropy value was observed for three codons in ON1 (247, 262 and 274 amino acids) indicating higher probability of variations at these positions. Our study shows the progressive emergence and predominance of the ON1 genotype in Riyadh, Saudi Arabia during 2008-16. ON1 genotype almost replaced the previously circulating RSVA strains in this region during this period. Contribution of host genetic and immune factors towards disease severity of the ON1 genotype needs to be investigated in future studies. RSV surveillance in future elaborate investigations are needed in this region to understand its disease burden, evolutionary trajectory and circulation dynamics warranting steps towards vaccine development.

Clinical characteristics of the lower respiratory tract infection caused by a single infection or coinfection of the human parainfluenza virus in children

BACKGROUND

Human parainfluenza virus (HPIV), usually combined with other pathogens, causes lower respiratory tract infection (LRTI) in children. However, clinical characteristics of HPIV coinfection with other pathogens were unclear. This study aimed to investigate the viral and atypical bacterial etiology of LRTI in children and compare the clinical characteristics of HPIV single infection with those of coinfection.

METHODS

This study included 1335 patients, aged between 1 to 71 months, diagnosed with LRTI in Yuying Children's Hospital, Zhejiang, China, from December 2013 to June 2015. Nasopharyngeal secretions were collected, and respiratory pathogens were detected using Multiplex polymerase chain reaction. The clinical data of patients were collected and analyzed.

RESULTS

At least 1 pathogen was detected in 1181/1335 (88.5%) patients. The pathogens identified most frequently were respiratory syncytial virus, human rhinovirus, HPIV, adenovirus, and human metapneumovirus. The coinfection rate was 24.8%. HPIV coinfection with other viruses was more associated with running nose, shortness of breath, and oxygen support compared with HPIV single infection. Moreover, HPIV coinfection with atypical bacteria was more related to running nose, moist rales, and longer hospital duration compared with HPIV single infection, and also to longer hospital duration compared with coinfection with other viruses.

CONCLUSIONS

This study demonstrated that viral infections were highly associated with LRTI and the rate of coinfection was high. HPIV single infection was milder than coinfection with other viruses. Moreover, HPIV coinfection with atypical bacteria was more serious than HPIV single infection and coinfection with other viruses.

Viral detection profile in children with severe acute respiratory infection

Objectives

The role of viral co-detection in children with severe acute respiratory infection is not clear. We described the viral detection profile and its association with clinical characteristics in children admitted to the Pediatric Intensive Care Unit (PICU) during the 2009 influenza A(H1N1) pandemic.

Method

Longitudinal observational retrospective study, with patients aged 0–18 years, admitted to 11 PICUs in Rio de Janeiro, with suspected H1N1 infection, from June to November, 2009. The results of respiratory samples which were sent to the Laboratory of Fiocruz/RJ and clinical data extracted from specific forms were analyzed.

Results

Of 71 samples, 38% tested positive for H1N1 virus. Of the 63 samples tested for other viruses, 58 were positive: influenza H1N1 (43.1% of positive samples), rhinovirus/enterovirus (41.4%), respiratory syncytial vírus (12.1%), human metapneumovirus (12.1%), adenovirus (6.9%), and bocavirus (3.5%). Viral codetection occured in 22.4% of the cases. H1N1-positive patients were of a higher median age, had higher frequency of fever, cough and tachypnea, and decreased leukometry when compared to H1N1-negative patients. There was no difference in relation to severity outcomes (number of organic dysfunctions, use of mechanical ventilation or amines, hospital/PICU length of stay or death). Comparing the groups with mono-detection and co-dection of any virus, no difference was found regarding the association with any clinical variable.

Conclusions

Other viruses can be implicated in SARI in children. The role of viral codetection has not yet been completely elucidated.

Mixed viral infections of the respiratory tract; an epidemiological study during consecutive winter seasons

The current study aimed to describe the molecular epidemiology of mixed respiratory viral infections during consecutive winter seasons in a tertiary care hospital. Patients with symptoms of respiratory tract infection were evaluated during the 2009‐2011 and 2013‐15 winter seasons. A clinical microarray technique was used for viral detection. Clinical and epidemiological data were correlated with mixed viral detection and the need for hospitalization. In 332 out of 604 (54.4%) evaluated patients (17.6% children) a respiratory virus was identified. Mixed viral infections were diagnosed in 68/332 (20.5%) patients with virus detection (66.2% mixed Influenza‐RSV infections). Mixed viral infections were more commonly detected in children (OR 3.7; 95%CI 1.9‐5.6, P < 0.01) and patients with comorbidities. In logistic regression analyses, mixed viral infections were associated with younger age (mean age 30.4 years vs. 41.8 years, P ≤ 0.001) and increased rates of fever (OR: 2.7; 95%CI 1.04‐7.2, P < 0.05) but no adverse outcomes or increased rates of hospitalization. High rates of mixed viral infections were noted during all winter seasons (especially Influenza and RSV) and were more common in younger patients. The clinical significance of mixed respiratory viral infection needs further elucidation.

Molecular and clinical characterization of human respiratory syncytial virus in South Korea between 2009 and 2014

Respiratory syncytial virus (RSV) can cause serious respiratory infections, second only to influenza virus. In order to know RSV's genetic changes we examined 4028 respiratory specimens from local hospital outpatients in Gyeonggi Province, South Korea over six consecutive years by real-time one-step RT-PCR; 183 patients were positive for RSV infection. To investigate the specific distribution of RSV genotypes, we performed partial sequencing of the glycoprotein gene. Of the 131 RSV-A specimens sequenced, 61 (43·3%) belonged to the ON1 genotype, 66 (46·8%) were NA1 genotype, 3 (2·1%) were GA5 genotype, and 1 (0·7%) belonged to the GA1 genotype. Of the 31 RSV-B specimens sequenced, 29 were BA9 genotype (87·9%) and 2 were BA10 genotype (6·1%). The most common clinical symptoms were fever, cough, nasal discharge, and phlegm; multiple logistic regression analysis showed that RSV-positive infection on pediatric patients was strongly associated with cough (OR = 2·8, 95% CI 1·6-5·1) and wheezing (OR = 2·8, 95% CI 1·7-4·4). The ON1 genotype was significantly associated with phlegm (OR = 11·8, 95% CI 3·8-46·7), while the NA1 genotype was associated with the pediatric patients' gender (males, OR = 2·4, 95% CI 1·1-5·4) and presence of chills (OR = 5·1, 95% CI 1·1-27·2). RSV subgroup B was showed association with nasal obstruction (OR = 4·6, 95% CI 1·2-20·0). The majority of respiratory virus coinfections with RSV were human rhinovirus (47·2%). This study contributes to our understanding of the molecular epidemiological characteristics of RSV, which promotes the potential for improving RSV vaccines.

Respiratory RNA Viruses

Acute upper and lower respiratory infections are a major public health problem and a leading cause of morbidity and mortality worldwide. At greatest risk are young children, the elderly, the chronically ill, and those with suppressed or compromised immune systems. Viruses are the predominant cause of respiratory tract illnesses and include RNA viruses such as respiratory syncytial virus, influenza virus, parainfluenza virus, metapneumovirus, rhinovirus, and coronavirus. Laboratory testing is required for a reliable diagnosis of viral respiratory infections, as a clinical diagnosis can be difficult since signs and symptoms are often overlapping and not specific for any one virus. Recent advances in technology have resulted in the development of newer diagnostic assays that offer great promise for rapid and accurate detection of respiratory viral infections. This chapter emphasizes the fundamental characteristics and clinical importance of the various RNA viruses that cause upper and lower respiratory tract diseases in the immunocompromised host. It highlights the laboratory methods that can be used to make a rapid and definitive diagnosis for the greatest impact on the care and management of ill patients, and the prevention and control of hospital-acquired infections and community outbreaks.

Prevalence of non-influenza respiratory viruses in acute respiratory infection cases in Mexico

Background

Acute respiratory infections are the leading cause of morbidity and mortality worldwide. Although a viral aetiological agent is estimated to be involved in up to 80% of cases, the majority of these agents have never been specifically identified. Since 2009, diagnostic and surveillance efforts for influenza virus have been applied worldwide. However, insufficient epidemiological information is available for the many other respiratory viruses that can cause Acute respiratory infections.

Methods

This study evaluated the presence of 14 non-influenza respiratory viruses in 872 pharyngeal exudate samples using RT-qPCR. All samples met the operational definition of a probable case of an influenza-like illness or severe acute respiratory infection and had a previous negative result for influenza by RT-qPCR.

Results

The presence of at least one non-influenza virus was observed in 312 samples (35.8%). The most frequent viruses were rhinovirus (RV; 33.0%), human respiratory syncytial virus (HRSV; 30.8%) and human metapneumovirus (HMPV; 10.6%). A total of 56 cases of co-infection (17.9%) caused by 2, 3, or 4 viruses were identified. Approximately 62.5% of all positive cases were in children under 9 years of age.

Conclusion

In this study, we identified 13 non-influenza respiratory viruses that could occur in any season of the year. This study provides evidence for the prevalence and seasonality of a wide range of respiratory viruses that circulate in Mexico and constitute a risk for the population. Additionally, our data suggest that including these tests more widely in the diagnostic algorithm for influenza may reduce the use of unnecessary antibiotics, reduce the hospitalisation time, and enrich national epidemiological data with respect to the infections caused by these viruses.

Comparison of NxTAG Respiratory Pathogen Panel and Anyplex II RV16 Tests for Multiplex Detection of Respiratory Pathogens in Hospitalized Children

Multiplex molecular techniques can detect a diversity of respiratory viruses and bacteria that cause childhood acute respiratory infection rapidly and conveniently. However, currently available techniques show high variation in performance. We sought to compare the diagnostic accuracy of the novel multiplex NxTAG respiratory pathogen panel (RPP) RUO test versus a routine multiplex Anyplex II RV16 assay in respiratory specimens collected from children <18 years of age hospitalized with nonspecific symptoms of acute lower respiratory infection. Parallel testing was performed on nasopharyngeal aspirates prospectively collected at referral Children's Hospital Sant Joan de Déu (Barcelona, Spain) between June and November 2015. Agreement values between the two tests and kappa coefficients were assessed. Bidirectional sequencing was performed for the resolution of discordant results. A total of 319 samples were analyzed by both techniques. A total of 268 (84.0%) of them yielded concordant results. Positive percent agreement values ranged from 83.3 to 100%, while the negative percent agreement was more than 99% for all targets except for enterovirus/rhinovirus (EV/RV; 94.4%). Kappa coefficients ranged from 0.83 to 1.00. Discrepancy analysis confirmed 66.0% of NxTAG RPP RUO results. A total of 260 viruses were detected, with EV/RV (n = 105, 40.4%) being the most prevalent target. Viral coinfections were found in 44 (14.2%) samples. In addition, NxTAG RPP RUO detected single bacterial and mixed viral-bacterial infections in seven samples. NxTAG RPP RUO showed high positive and negative agreement with Anyplex II RV16 for main viruses that cause acute respiratory infections in children, coupled with an additional capability to detect some respiratory bacteria.

Co-Circulation of 72bp Duplication Group A and 60bp Duplication Group B Respiratory Syncytial Virus (RSV) Strains in Riyadh, Saudi Arabia during 2014

Respiratory syncytial virus (RSV) is an important viral pathogen of acute respiratory tract infection (ARI). Limited data are available on molecular epidemiology of RSV from Saudi Arabia. A total of 130 nasopharyngeal aspirates were collected from children less than 5 years of age with ARI symptoms attending the Emergency Department at King Khalid University Hospital and King Fahad Medical City, Riyadh, Saudi Arabia between October and December, 2014. RSV was identified in the 26% of the hospitalized children by reverse transcriptase PCR. Group A RSV (77%) predominated during the study as compared to group B RSV (23%). The phylogenetic analysis of 28 study strains clustered group A RSV in NA1 and ON1 genotypes and group B viruses in BA (BA9) genotype. Interestingly, 26% of the positive samples clustered in genotypes with duplication in the G protein gene (ON1 for group A and BA for group B). Both the genotypes showed enhanced O-linked glycosylation in the duplicated region, with 10 and 2 additional sites in ON1 and BA respectively. Selection pressure analysis revealed purifying selection in both the ON1 and BA genotypes. One codon each in the ON1 (position 274) and BA genotypes (position 219) were positively selected and had high entropy values indicating variations at these amino acid positions. This is the first report describing the presence of ON1 genotype and the first report on co-circulation of two different genotypes of RSV with duplication in the G protein gene from Saudi Arabia. The clinical implications of the simultaneous occurrence of genotypes with duplication in G protein gene in a given population especially in the concurrent infections should be investigated in future. Further, the ongoing surveillance of RSV in this region will reveal the evolutionary trajectory of these two genotypes with duplication in G protein gene from largest country in the Middle East.

Respiratory viral coinfection and disease severity in children: A systematic review and meta-analysis

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Respiratory viral coinfections are common in children.

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Overall pediatric respiratory viral coinfections have no impact on severity.

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Prognostic role of specific viral interactions remains unclear.

Background

With advent of molecular diagnostic technologies, studies have reported detection of two or more respiratory viruses in about 30% of children with respiratory infections. However, prognostic role of coinfection remains unclear.

Objective

Evaluate relation between respiratory viral confection and illness severity in children.

Study design

MEDLINE (through PUBMED), EMBASE, EBSCO, LILACS databases were searched up to March 2015 by two independent reviewers. Studies assessing severity of viral coinfection in patients aged less than 18 years were included. Standardized forms were used for data extraction of population, study design, clinical syndromes, virus combinations compared and severity outcomes. Risk of bias and quality of evidence were assessed through EPHPP and GRADE. Subgroup analysis was performed according to age and viral combinations.

Results

Of 5218 records screened, 43 were included in analysis. Viral coinfection did not influence risks of all outcomes assessed: length of stay (mean difference in days in coinfection, −0.10 [95% confidence interval: −0.51 to 0.31]), length of supplemental oxygen (−0.42 [−1.05 to 0.20]), need of hospitalization (odds ratio of coinfection, 0.96 [95% confidence interval: 0.61–1.51]), supplemental oxygen (0.94 [0.66 to 1.34]), need of intensive care (0.99 [0.64 to 1.54]), mechanical ventilation (0.81 [0.33 to 2.01]) and death (2.22 [0.83 to 5.95]). Sub-analyses according to age and viral combinations have not shown influence of these factors in outcomes.

Conclusions

Respiratory viral coinfection did not increase severity in all outcomes assessed. Further studies are necessary to confirm this finding, especially regarding role of specific viral interactions.

A novel primer set for improved direct gene sequencing of human bocavirus genotype-1 from clinical samples

Human bocavirus genotype (HBoV-1) is a parvovirus associated with respiratory tract infections in children with different degrees of severity. The current study intended to improve the direct gene sequencing of the HBoV-1 using a newly developed primer set. Screening the presence of human bocavirus infection among in-patients children suffering from lower respiratory tract infections was another aim of the current study. Nasopharyngeal swab samples from in-patients children suffering from lower respiratory tract infections were examined. The real-time polymerase chain reaction was used for the initial screening as a highly sensitive method to detect the HBoV. Genotyping of real-time positive samples was attempted by direct sequencing of PCR amplicons using NP, VP1/2 and the newly developed VP/NC primers. HBoV-1 was present in 56.8% of the examined children. The newly developed primer set successfully amplified all real-time PCR positive samples, however, the other primer pairs did not reliably detect real-time PCR positive samples. The gene sequences of the detected HBoV-1 showed conserved sequences to each other with a low rate of discrepancies. The high rate of infection and the similarity between the detected strains strongly suggest nosocomial infections.

Human respiratory syncytial virus in children with lower respiratory tract infections or influenza-like illness and its co-infection characteristics with viruses and atypical bacteria in Hangzhou, China

BACKGROUND

Human respiratory syncytial virus (RSV) is the most important viral pathogen in children. However, its epidemic patterns and co-infection characteristics are not fully understood.

OBJECTIVES

We attempted to determine the level of genetic variation of RSV, and describe the prevalence and co-infection characteristics of RSV in Hangzhou during two epidemic seasons.

STUDY DESIGN

Single respiratory samples from 1820 pediatric patients were screened for RSV and genotyped by RT-PCR and sequencing. In all RSV positive specimens, we screened for viruses and atypical bacteria. Demographic and clinical information was recorded and analyzed.

RESULTS

A total of 34.5% and 3.8% of samples from acute lower respiratory tract infections (ALRI) and influenza-like illness (ILI) were positive for RSV, respectively. Phylogenetic analysis revealed that 61.1% of the selected 167 RSV strains were NA1, 31.1% were BA, 3.6% were ON1, 2.4% were CB1, and 1.8% were NA3. A new genotype, BA11 was identified, which comprised 98.1% of BA strains in this study, while the rest were BA10. A total of 36.4% and 9.1% of RSV-positive children with ALRI and ILI respectively were found to be co-infected. Rhinovirus was the most common additional respiratory virus, followed by human metapneumovirus. Except for fever, no significant differences in other clinical presentation between the RSV mono-infection and co-infection groups were observed.

CONCLUSIONS

The circulating RSV strains had high genetic variability with RSV-B showing a more local pattern. In ALRI cases, co-infection of RSV with other viruses or atypical bacteria has no significant effect on the clinical presentation except fever.