Detection of viruses identified recently in children with acute wheezing

The etiologic role of recently identified respiratory viruses for acute wheezing in children is not yet clear. The purpose of this study was to investigate the prevalence of recently identified viruses, including human metapneumovirus (hMPV), human bocavirus (hBoV), human coronavirus NL63 (hCoV-NL63), and human coronavirus HKU1 (hCoV-HKU1) in children with acute wheezing. Viral etiology was identified in 231 children hospitalized with acute wheezing, aged from 1 month to 5 years. Viral antigens for common respiratory viruses were detected by IFA or multiplex PCR. RT-PCR was used to detect respiratory rhinoviruses, hCoV-NL63, hCoV-HKU1, and hMPV. PCR assays for hBoV DNA were performed using the primer sets for noncapsid protein (NP1) and nonstructural protein (NS1) genes. Viruses were found in 61.5% (142/231) of the study population and a single virus was detected in 45.5% (105/231) of the study population. Rhinovirus (33.3%), human respiratory syncytial virus (hRSV; 13.8%), and hBoV (13.8%) were the most frequently detected viruses. hMPV and hCoV-NL63 were detected in 7.8% and 1.3% of wheezing children, respectively. HCoV-HKU1 was not detected. In 16.0% of the study population, more than one virus was detected. In children with acute wheezing, rhinovirus, hRSV, and hBoV were most frequently detected. Further studies including healthy control subjects are needed to define the clinical significance of hBoV in acute wheezing.     

Infections and coinfections by respiratory human bocavirus during eight seasons in hospitalized children

The human bocavirus (hBoV) has been identified in respiratory infections in children in a large number of studies. Despite this, the pathogenic role of the HBoV is under discussion. The main objectives of the study were: to determine the incidence of HBoV in hospitalized children; to describe the main clinical features of the positive children; and to compare the data with those from other viral infections in the same population. A prospective study was performed between 2005 and 2013 including children up to 14‐year old with respiratory infection admitted to the Severo Ochoa Hospital (Spain). Nasopharyngeal aspirates were taken from 3,275 patients and were tested for HBoV and other 15 respiratory viruses by RT‐nested PCR. HBoV was detected in 319 patients (9.9%); 80 cases as a single pathogen, and 239 cases (75%) as coinfections with other viruses. The HBoV was the fourth most common virus detected, behind respiratory syncytial virus (39.8%), rhinovirus (30.6%), and adenovirus (15%). The most common clinical diagnosis, in cases that HBoV was detected as a single pathogen was asthma exacerbation followed by pneumonia. A seasonal distribution was shown, with higher positivity rates in December and January. Children affected by HBoV were older than children infected by other viruses. Differences in terms of clinical diagnosis were found, bronchiolitis diagnosis was lower compared with the other viruses, and HBoV was associated with diagnosis of pneumonia, with increased use of antibiotics (41.8%), and radiographic infiltrates (47%). These findings could suggest a pathogenic role of HBoV in respiratory infections in children under 14 years of age. J. Med. Virol. 88:2052–2058, 2016. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

     

Clinical and socio-economic impact of influenza and respiratory syncytial virus infection on healthy children and their households

This prospective study compared the clinical and socio-economic impact of laboratory-confirmed influenza and respiratory syncytial virus (RSV) infection on healthy children and their families. Among 1,520 otherwise healthy children aged< 15 years attending the Emergency Department for acute conditions other than trauma, influenza viruses and RSV were found in 234 (15.4%) and 116 (7.6%; p<0.0001) patients, respectively. The fact that influenza has a similar global clinical impact on the community to that of RSV infection, but represents a greater socio-economic burden, may contribute to broadening the acceptance of influenza vaccination.     

Etiology,seasonality, and clinical characterization of viral respiratory infections among hospitalized children in Beirut,Lebanon

Acute respiratory tract viral infections occur worldwide and are one of the major global burdens of diseases in children. The aim of this study was to determine the viral etiology of respiratory infections in hospitalized children, to understand the viral seasonality in a major Lebanese hospital, and to correlate disease severity and the presence of virus. Over a 1‐year period, nasal and throat swabs were collected from 236 pediatric patients, aged 16‐year old or less and hospitalized for acute respiratory illness. Samples collected were tested for the presence of 17 respiratory viruses using multiplex real‐time RT‐PCR. Pathogens were identified in 165 children (70%) and were frequently observed during fall and winter seasons. Co‐infection was found in 37% of positive samples. The most frequently detected pathogens were human Rhinovirus (hRV, 23%), Respiratory Syncytial Virus (RSV, 19%), human Bocavirus (hBov, 15%), human Metapneumovirus (hMPV, 10%), and human Adenovirus (hAdV, 10%). A total of 48% of children were diagnosed with bronchiolitis and 25% with pneumonia. While bronchiolitis was often caused by RSV single virus infection and hAdV/hBoV coinfection, pneumonia was significantly associated with hBoV and HP1V1 infections. No significant correlation was observed between a single viral etiology infection and a specific clinical symptom. This study provides relevant facts on the circulatory pattern of respiratory viruses in Lebanon and the importance of using PCR as a useful tool for virus detection. Early diagnosis at the initial time of hospitalization may reduce the spread of the viruses in pediatric units. J. Med. Virol. 88:1874–1881, 2016 . © 2016 Wiley Periodicals, Inc.

     

Co-circulation of genetically distinct human metapneumovirus and human bocavirus strains in young children with respiratory tract infections in Italy

The discovery of human Metapneumovirus (hMPV) and human Bocavirus (hBoV) identified the etiological causes of several cases of acute respiratory tract infections in children. This report describes the molecular epidemiology of hMPV and hBoV infections observed following viral surveillance of children hospitalized for acute respiratory tract infections in Milan, Italy. Pharyngeal swabs were collected from 240 children ≤3 years of age (130 males, 110 females; median age, 5.0 months; IQR, 2.0-12.5 months) and tested for respiratory viruses, including hMPV and hBoV, by molecular methods. hMPV-RNA and hBoV-DNA positive samples were characterized molecularly and a phylogenetical analysis was performed. PCR analysis identified 131/240 (54.6%) samples positive for at least one virus. The frequency of hMPV and hBoV infections was similar (8.3% and 12.1%, respectively). Both infections were associated with lower respiratory tract infections: hMPV was present as a single infectious agent in 7.2% of children with bronchiolitis, hBoV was associated with 18.5% of pediatric pneumonias and identified frequently as a single etiological agent. Genetically distinct hMPV and hBoV strains were identified in children examined with respiratory tract infections. Phylogenetic analysis showed an increased prevalence of hMPV genotype A (A2b sublineage) compared to genotype B (80% vs. 20%, respectively) and of the hBoV genotype St2 compared to genotype St1 (71.4% vs. 28.6%, respectively). Interestingly, a shift in hMPV infections resulting from A2 strains has been observed in recent years. In addition, the occurrence of recombination events between two hBoV strains with a breakpoint located in the VP1/VP2 region was identified.     

Bacterial coinfections in children with viral wheezing

Bacterial coinfections occur in respiratory viral infections, but the attack rates and the clinical profile are not clear. The aim of this study was to determine bacterial coinfections in children hospitalized for acute expiratory wheezing with defined viral etiology. A total of 220 children aged 3 months to 16 years were investigated. The viral etiology of wheezing was confirmed by viral culture, antigen detection, serologic investigation, and/or PCR. Specific antibodies to common respiratory bacteria were measured from acute and convalescent serum samples. All children were examined clinically for acute otitis media, and subgroups of children were examined radiologically for sinusitis and pneumonia. Rhinovirus (32%), respiratory syncytial virus (31%), and enteroviruses (31%) were the most common causative viruses. Serologic evidence of bacterial coinfection was found in 18% of the children. Streptococcus pneumoniae (8%) and Mycoplasma pneumoniae (5%) were the most common causative bacteria. Acute otitis media was diagnosed in 44% of the children. Chest radiographs showed alveolar infiltrates in 10%, and paranasal radiographs and clinical signs showed sinusitis in 17% of the older children studied. Leukocyte counts and serum C-reactive protein levels were low in a great majority of patients. Viral lower respiratory tract infection in children is often associated with bacterial-type upper respiratory tract infections. However, coexisting bacterial lower respiratory tract infections that induce systemic inflammatory response are seldom detected.     

Rhinovirus frequently detected in elderly adults attending an emergency department

The general aim was to investigate the burden of respiratory virus illness in a hospital emergency department, during two different epidemic seasons. Consecutive patients attending an emergency department during two study periods (February/March 2009 and 2010) were enrolled using broad inclusion criteria (fever/preceding fever and one of a set of ICD-9 codes suggestive of respiratory illness); nasopharyngeal washes were tested for the most common respiratory viruses using PCR-based methods. Influenza A virus was detected in 24% of samples collected in February/March 2009, whereas no samples tested positive for influenza during February/March 2010 (pandemic H1N1 Influenza A having circulated earlier in October-December 2009). Rhinovirus (HRV) was detected in 16% and 8% of patients recruited over the two study periods, respectively. Other respiratory viruses were detected rarely. Patient data were then analyzed with specific PCR results, comparing the HRV-positive group with virus-positive and no virus-detected groups. Individuals over 65 years old with HRV presented with signs, symptoms and underlying conditions and were admitted to hospital as often as the other enrolled patients, mainly for dyspnoea and chronic obstructive pulmonary disease acute exacerbation. Conversely, younger individuals with HRV, although presenting with respiratory signs and symptoms, were generally diagnosed with non-respiratory conditions. HRV was detected frequently in elderly patients attending the emergency department for respiratory distress without distinguishing clinical features. Molecular diagnosis of lower respiratory tract infections and surveillance of infectious diseases should include tests for HRV, as this virus is associated frequently with hospitalization of the elderly.     

Human bocavirus in Italian patients with respiratory diseases.

BACKGROUND: hBoV, a recently discovered parvovirus, can be present in the respiratory tract of patients with acute respiratory diseases (ARD), but its etiologic involvement in the underlying diseases is still uncertain. OBJECTIVE: To determine in a retrospective study, the prevalence of hBoV, compared with common respiratory viruses (RV), in respiratory specimens from patients with ARD. STUDY DESIGN: A total of 335 specimens obtained over 7 years were examined. Two hundred were nasal swabs from infants hospitalized for ARD, 84 were nasal swabs or bronchoalveolar lavages from adults with pneumonia, bronchopneumonia or asthma, and 51 were nasal swabs from healthy children. RESULTS: The overall rate of hBoV detection in specimens from infants with ARD, which was 4.5%, varied slightly from year to year, except for the period 2000-2002, when no specimen was positive. Unlike other RV, no seasonal variation in hBoV incidence was noted. Infants with hBoV infection suffered either from bronchiolitis or from bronchopneumonia and 5 out of 9 cases yielded no co-infecting viral pathogen. Only one sample from an adult was hBoV positive. None of the nasal swabs from healthy subjects tested hBoV-positive. CONCLUSIONS: The findings indicate that hBoV can cause ARD in infants.     

Human metapneumovirus in hospitalized children in Amman,Jordan

Human metapneumovirus (HMPV) has recently been identified as an important cause of acute respiratory infections (ARI) in children worldwide. However, there is little systematic data on its frequency and importance as a cause of ARI in the Middle East. We conducted a viral surveillance study in children <5 years of age admitted with respiratory symptoms and/or fever at two major tertiary care hospitals in Amman, Jordan from 1/18‐3/29/07. Nose and throat swabs were collected and tested for HMPV and other respiratory viruses by real‐time RT‐PCR. A total of 743 subjects were enrolled. Forty‐four (6%) subjects were positive for HMPV, 467 (64%) were positive for RSV and 13 (1.3%) had co‐infection with both HMPV and RSV. The frequency of HMPV in January, February, and March was 4.1%, 3.0%, and 11.9% respectively. Clinical features associated with HMPV infection were similar to those of other respiratory viruses, except children with HMPV were more likely to present with fever than children not infected with HMPV. Children with HMPV and RSV co‐infection were administered supplemental oxygen and were admitted to the ICU more frequently than children infected with HMPV alone or RSV alone, though these differences did not reach statistical significance. We conclude that HMPV is an important cause of acute respiratory infections in children in Amman, Jordan. Longer surveillance studies are needed to better understand the seasonal epidemiology of HMPV and to assess if co‐infection with HMPV and RSV leads to more severe illness. J. Med. Virol. 82:1012–1016, 2010. © 2010 Wiley‐Liss, Inc.     

Contribution of common and recently described respiratory viruses to annual hospitalizations in children in South Africa

The contribution of viruses to lower respiratory tract disease in sub-Saharan Africa where human immunodeficiency virus may exacerbate respiratory infections is not well defined. No data exist on some of these viruses for Southern Africa. Comprehensive molecular screening may define the role of these viruses as single and co-infections in a population with a high HIV-AIDS burden. To address this, children less than 5 years of age with respiratory infections from 3 public sector hospitals, Pretoria South Africa were screened for 14 respiratory viruses, by PCR over 2 years. Healthy control children from the same region were included. Rhinovirus was identified in 33% of patients, RSV (30.1%), PIV-3 (7.8%), hBoV (6.1%), adenovirus (5.7%), hMPV (4.8%), influenza A (3.4%), coronavirus NL63 (2.1%), and OC43 (1.8%). PIV-1, PIV-2, CoV-229E, -HKU1, and influenza B occurred in <1.5% of patients. Most cases with adenovirus, influenza A, hMPV, hBoV, coronaviruses, and WU virus occurred as co-infections while RSV, PIV-3, and rhinovirus were identified most frequently as the only respiratory pathogen. Rhinovirus but not RSV or PIV-3 was also frequently identified in healthy controls. A higher HIV sero-prevalence was noticed in patients with co-infections although co-infections were not associated with more severe disease. RSV, hPMV, PIV-3, and influenza viruses had defined seasons while rhinovirus, adenovirus, and coronavirus infections occurred year round in this temporal region of sub-Saharan Africa.     

Viruses in community-acquired pneumonia in children aged less than 3 years old: High rate of viral coinfection

The occurrence of viral coinfections in childhood pneumonia has received little attention, probably because suitable detection methods have been lacking. Between November 2004 and October 2006, the presence of 14 respiratory viruses in children aged less than 3 years old with community-acquired pneumonia were investigated using molecular or immunochromatographic techniques and/or viral culture. A total of 315 children (338 episodes) were included, and hospitalization was required in 178 episodes. At least one virus was detected in 66.9% of the episodes and simultaneous detection of two or more viruses was frequent (27% of the episodes with viral detection). The most frequently detected virus was respiratory syncytial virus (n = 67: 33 subgroup A, 33 subgroup B, 1 not typed), followed by human bocavirus (n = 48), rhinovirus (n = 46), human metapneumovirus (n = 39: 13 genotype A2, 8 B1, 5 B2, 1 A1, 12 not genotyped) and parainfluenza viruses (n = 38: 1 type 1, 3 type 2, 22 type 3, 11 type 4 and 1 not typed). The 14 viruses investigated were found in viral coinfections, which were more frequent in children aged less than 12 months. Except for adenovirus, the incidence of which was low, the percentage of viral coinfection ranged between 28.2% and 68.8%. Children with viral coinfection more frequently required hospital admission than those with single viral infection. It is concluded that viral coinfections are frequent in children aged less than 3 years old with community-acquired pneumonia and can be a poor prognostic factor.     

Virological and clinical characterization of respiratory infections in children attending an emergency department during the first autumn-winter circulation of pandemic A (HINI) 2009 influenza virus

To characterize respiratory virus infections during the first autumn-winter season of pandemic A (H1N1) 2009 influenza virus (A/H1N1/2009) circulation, a prospective study in children attending a paediatric emergency department at the Sapienza University hospital, Rome, was conducted from November 2009 to March 2010. By means of both nasal washings and pharyngeal swabs, enrolled children were checked for 14 respiratory viruses. The majority of acute respiratory infections resulted from viral pathogens (135/231, 58%). Overall, the most common was respiratory syncytial virus (RSV), in 64% of positive samples; A/H1N1/2009 was the only influenza virus found in 16% and rhinovirus (RV) in 15%. Virus-positive children did not differ significantly from virus-negative children in signs and symptoms at presentation; of the virus groups, RSV-infected children were younger and more frequently admitted to intensive-care units than those infected with A/H1N1/2009 and RV. Of the hospitalized children, stratified by age, both infants and children aged >1 year with RSV were most severely affected, whereas A/H1N1/2009 infections were the mildest overall, although with related pulmonary involvement in older children. Children with RV infections, detected in two flares partially overlapping with the A/H1N1/2009 and RSV peaks, presented with bronchiolitis, wheezing and pneumonia. Leukocytosis occurred more frequently in RV-infected and A/H1N1/2009-infected children, and numbers of blood eosinophils were significantly elevated in RV-infected infants. Given the fact that clinical and epidemiological criteria are not sufficient to identify viral respiratory infections, a timely virological diagnosis could allow different infections to be managed separately.     

Th1 and Th2 cytokine levels in nasopharyngeal aspirates from children with human bocavirus bronchiolitis.

BACKGROUND: Human bocavirus (hBoV) is regarded as one of the possible etiologic agents in lower respiratory tract infection and bronchial asthma exacerbation in children despite frequent co-detection with other respiratory viruses. The immunologic response in children with hBoV infection is still not clear. OBJECTIVES: To investigate the profiles of T helper-1 (Th1)/T helper-2 (Th2) cytokines in children with hBoV-associated bronchiolitis. STUDY DESIGN: This study utilized of 59 nasopharyngeal aspirates from 59 infants aged 24 months or younger, including 29 from children with hBoV-related bronchiolitis and 30 with respiratory syncytial virus (RSV)-related bronchiolitis. Eighteen infants hospitalized for elective surgeries were included as controls. Nasopharyngeal aspirates were tested simultaneously for cytokines interleukin (IL)-2, IL-4, IL-5, IL-10, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha using the Cytometric Bead Array. RESULTS: Significantly higher concentrations of IFN-gamma (p=0.0001), IL-2 (0.006), and IL-4 (p=0.0002) were observed in hBoV positive specimens than in controls. The concentration of IL-10 (p=0.04) and TNF-alpha (p=0.006) in the RSV-positive group was significantly higher than in the hBoV-positive group, while there was no difference in other cytokines concentration between the two groups. CONCLUSIONS: These results showed that both of Th1 and Th2 cytokines were increased in children with hBoV-related bronchiolitis compared to normal controls, but Th2-polarized responses were not observed.     

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

BACKGROUND: Human metapneumovirus (hMPV) has recently been isolated from children with acute respiratory tract infections (RTIs). The epidemiological and clinical characteristics of hMPV infection need further investigation. OBJECTIVES: The purpose of this study was to compare the clinical features of hMPV, respiratory syncytial virus (RSV) and rhinoviruses (RV) infections in children less than 3 years of age presenting to an emergency department with acute respiratory illness. STUDY DESIGN: From December 2002 to April 2004, all children under age three (n=931) admitted for acute respiratory illness to Dijon Hospital, France, were investigated for respiratory viruses in nasal washes. RESULTS: hMPV was detected in 6% of children (in 10.1% (n=38) the first winter and in 3.3% (n=17) the second winter); RSV was detected in 28.5% of the children, while rhinoviruses were found in 18.3%. Five hMPV-infected children had evidence of dual infection, two with RSV and three others with RV. The median age of the patients with hMPV infection was 6 months, and the main clinical symptoms were rhinorrhea (74.5%) and cough (67%). A lower tract disease occurred in 66% of hMPV-positive patients. Gene sequencing of hMPV isolates revealed co-circulation of the two major groups of hMPV during the study period; no difference in pathogenicity was found. There was no difference in the prevalence of bronchiolitis where hMPV, RSV or rhinoviruses were present. Asthma was found more often in hospitalized children with hMPV and rhinoviruses than among those with RSV (p<0.001). CONCLUSIONS: These results provide further evidence of the importance of hMPV as a pathogen associated with respiratory tract infection in children.     

Simultaneous detection of human bocavirus and adenovirus by multiplex real-time PCR in a Belgian paediatric population

Since the discovery of human bocavirus (hBoV), the virus has been detected worldwide in respiratory tract samples from young children by various polymerase chain reaction (PCR) assays and real-time PCRs (Q-PCR). Until now, no data have been reported on the presence of hBoV in Belgium and the detection of hBoV in a multiplex Q-PCR setting has not been described. The aim of this study was to develop a fast and reliable multiplex Q-PCR for the simultaneous detection of hBoV DNA and adenovirus (AdV) DNA. During the winter of 2004–2005, 445 nasopharyngeal aspirates (NPAs) were analysed from 404 Belgian children up to 5 years old with acute respiratory tract infections (ARTIs). (Co)infections with hBoV, AdV, respiratory syncytial virus (RSV), human metapneumovirus (hMPV) and influenza A virus were investigated. A viral agent was detected in 61% (n = 272/445) of the NPAs. Multiplex Q-PCR found a prevalence of 11% (n = 51/445) hBoV and 13% (n = 58/445) AdV. Coinfections were more frequently found with AdV (62%; n = 36/58) than with hBoV (49%; n = 25/51). Follow-up samples were available from 22 patients with ARTIs. In three patients, hBoV DNA persisted for one month. Multiplex Q-PCR may help in closing the diagnostic gap by addressing a broader range of potential respiratory pathogens.     

Comparison of multiplex PCR assays and conventional techniques for the diagnostic of respiratory virus infections in children admitted to hospital with an acute respiratory illness

The performances of four multiplex PCR (m-PCR) were compared to direct immunofluorescence assay (DFA) and HuH7 cell culture for the detection of viruses in 263 children admitted to hospital with an acute respiratory illness. One hundred fifty (57.6%) nasal aspirates were found DFA-positive; 188 (72.3%) were found positive by both DFA and HuH7 cell culture, and 242 (92%) were PCR-positive. The m-PCR detected 124 viruses which were not found by conventional methods: 68 rhinovirus, 17 human metapneumovirus, 15 respiratory syncytial virus (RSV), 8 parainfluenza virus (PIV), 5 coronavirus 229E, 3 OC43 and 3 NL63, 4 enterovirus, 2 influenza virus B and C virus. The m-PCR were more sensitive, had the advantages of a shorter delay in specific diagnosis, and a lower cost than DFA and culture. Using these m-PCR, the prevalence of each virus was compared between in-patient and out-patient groups of children attending the emergency unit of the hospital. Nasal aspirates from 411 (91.5%) children were found positive by the PCRs. RSV, rhinovirus, and influenza virus were the most frequent viruses detected in this population, representing 43.6%, 31.8%, and 8.8% of the virus found, respectively, followed by human metapneumovirus (4.4%), coronavirus (3.4%), parainfluenza virus (3.2%), adenovirus (2.3%), and enterovirus (2.1%). RSVs were detected more significantly in the in-patient group than in the out-patient group, and influenza viruses were detected more frequently in the out-patient group than in the in-patient group. Moreover, the use of m-PCR pointed out the frequency of rhinovirus and mixed viral detections in these patients. In conclusion, according to the requirements of speed and low cost of the methods, and to achieve the highest rate of detection of respiratory viruses, the combined use of DFA and m-PCR is today likely to be the best way to improve diagnosis of respiratory illnesses in children.     

Role of Cytomegalovirus Infection in the Incidence of Viral Acute Respiratory Infections in Children Attending Day-Care Centers

 In a prospective study carried out in Lyon, France, the association between the excretion of cytomegalovirus (CMV) and the increasing frequency and severity of viral respiratory infections in children attending day-care centers was evaluated. Urine samples were collected in November 1992 (S1) and 4 months later in February 1993 (S4). A total of 246 children aged 6–12 months attending 29 day-care centers from 1 November to 28 February were screened for the excretion of CMV in urine. The diagnosis of viral acute respiratory infection was performed in the case of outbreaks only. Forty-eight (19.5%) children were both S1 and S4 positive for CMV, 30 (12.4%) became CMV positive (S1–/S4+), 4 (1.6%) became negative (S1+/S4–) and 164 (66.7%) remained negative. The percentage of children becoming CMV positive was significantly (P<0.001) higher in day-care centers where more than 40 children were enrolled. Nine outbreaks due to respiratory syncytial virus, rhinovirus and enterovirus were recorded in 8 of 29 (27.6%) day-care centers. Viral acute respiratory infections were significantly (P<0.05) more frequently recorded in day-care centers in which CMV and respiratory viruses cocirculated and were significantly (P<0.001) more frequently reported in CMV-infected children. These findings suggest that viral acute respiratory infections are significantly more likely to occur in CMV-infected children.