High rate of human bocavirus and adenovirus coinfection in hospitalized Israeli children

A STUDY OF THE NOVEL WU AND KI POLYOMAVIRUSES, BOCAVIRUS ADENOVIRUS IN CHILDREN WITH UPPER RESPIRATORY TRACT INFECTIONS

OBJECTIVE

The aim: To find out the frequency of WU and KI polyomaviruses, and Human Boca and Adenoviruses infections among children with different types of acute upper respiratory tract infections and to compare the frequency of these viruses among immune-competent and immune compromised patients.

PATIENTS AND METHODS

Materials and methods: A case-control study conducted in children aged 3-18 years with acute upper respiratory tract infections. The samples were taken from: Group 1: 100 immuno competent children with acute upper respiratory tract infections. Group 2: 100 immuno compromised children (Leukemic, cancer, Nephrotic syndrome, chronic renal failure and children with renal transplant) with acute upper respiratory tract infections. Group 3: 100 apparently healthy children without respiratory infections as control group. Nasal swap samples were collected from children and then viral DNA extracted from these samples. Then detection of WU, KI polyomaviruses HBoV and HAdv was done by using real time PCR.

RESULTS

Results: All of 300 samples were negative for WU and KI polyomaviruses. However, human Bocavirus was detected in the three groups (immunocompromised, immunocompetent and control group) and the positivity rates were 61.61%, 37.37% and 18.18%, respectively. While human adenovirus was found only in 2% of immunocompromised patients and 1.1% of immunocompetent patients also there were cases positive for both HBoV and HAdv in 5.5% of immunocompromised patients, and 8.8% of immunocompetent patients.

CONCLUSION

Conclusions: High frequency of HBoV especially in immunocompromised patients while low number of positive cases for HAdv by using nasal swab samples, WU and KI polyomaviruses could not be detected in samples.

Prevalence and Clinical Characterization of Bocavirus Infection in a Specialized Children's Hospital in Saudi Arabia

Aim

The aim of this study was to assess the prevalence and clinical characterization of bocavirus infection in patients admitted with respiratory symptoms to a specialized children’s hospital in Riyadh, Saudi Arabia.

Methods

This is a retrospective cross-sectional study that included children aged 0-14 years and was conducted over a two-year period (2017-2019). All data were gathered from an electronic information recording system, which included patients’ demographics, comorbidities, clinical presentation, complication, and duration of hospitalization.

Results

Among all patients (11,709) admitted to King Abdullah Specialized Children’s Hospital with predominant respiratory symptoms during the study period, 193 (1.6%) patients had bocavirus infections. Most of the patients were diagnosed in winter months. Cough was the primary presenting symptom (91.7%) followed by fever (83.4%). Gastrointestinal symptoms were also common (anorexia in 62% and vomiting in 39%). In 80% (n=154/193) of cases, bocavirus co-existed with other viruses, namely, human rhinovirus (45.8%), human adenovirus (31.2%), and respiratory syncytial virus type A (17.5%). Moreover, those who required oxygen supply stayed longer in the hospital (p<0.001) and were more likely to receive multiple medications such as bronchodilators (p<0.001), corticosteroids (p<0.001), and nebulized racemic epinephrine (p>0.05). Children infected with bocavirus and co-existing viruses were less likely to require oxygen supply (p<0.050).

Conclusion

Bocavirus infection is more common during winter months and predominantly affects respiratory and gastrointestinal systems in children. More studies are needed to evaluate the global impact of this recently recognized infection.

Epidemiology of Human Bocavirus in the Middle East and North Africa: Systematic Review

The emergence of the COVID-19 pandemic highlighted the importance of studying newly emerging viruses that cause respiratory illnesses. Human bocavirus (HBoV) is one of the relatively newly discovered viruses that has been detected worldwide and causes respiratory and gastrointestinal infections, mainly in pediatric patients. However, little is known about the pathogenicity and evolution of HBoV. This systematic review was initiated to clarify the prevalence and circulating genotypes of HBoV in both respiratory and stool samples from patients of all age groups in the Middle East and North Africa (MENA) from 2005 to February 2021. We performed an electronic search through Science Direct, Scopus, PubMed, Mendeley and Cochrane Library databases. We included all studies reporting the detection rate of HBoV in the MENA region. Data were extracted, and the quality of the included articles was assessed. We included articles containing data on HBoV only or with other respiratory or gastrointestinal viral infections. Review articles, case studies, and animal and environmental studies were excluded. The final number of articles included in this study was 65 articles. The results showed that the HBoV prevalence in children was the lowest in Iran (0%) and the highest in Egypt (56.8%). In adults, the lowest and the highest prevalence were reported in Iran, with values of 0% and 6.6%, respectively. Regarding the respiratory cases, our findings revealed no significant difference between HBoV prevalence among the tested categories (p-value = 0.998). The present study has shown that HBoV is common in children and adults in the MENA region. This systematic review highlights the need for more data on the role of coinfection of HBoV and other viruses, for instance, SARS-CoV-2 in children with acute bronchiolitis.

A method to identify respiratory virus infections in clinical samples using next-generation sequencing

Respiratory virus infections are very common. Such infections impose an enormous economic burden and occasionally lead to death. Furthermore, every few decades, respiratory virus pandemics emerge, putting the entire world population at risk. Thus, there is an urgent need to quickly and precisely identify the infecting agent in a clinical setting. However, in many patients with influenza-like symptoms (ILS) the identity of the underlying pathogen remains unknown. In addition, it takes time and effort to individually identify the virus responsible for the ILS. Here, we present a new next-generation sequencing (NGS)-based method that enables rapid and robust identification of pathogens in a pool of clinical samples without the need for specific primers. The method is aimed at rapidly uncovering a potentially common pathogen affecting many samples with an unidentified source of disease.

Epidemiology of human adenovirus infection in children hospitalized with lower respiratory tract infections in Hunan, China

To investigate the current genotypes of circulating human adenovirus (HAdV) strains, we molecularly genotyped HAdV in the nasopharyngeal aspirates (NPAs) of patients with acute lower respiratory tract infections (ALRTIs) and attempted to determine their associations with clinical symptoms. A total of 4751 NPA samples were collected from 4751 patients admitted to Hunan Provincial People's Hospital from September 2007 to March 2014, of which 447 (9.4%) samples were HAdV positive. Fourteen different HAdV types were identified; HAdV types 1 to 7 (HAdV 1‐7) were identified in 95.7% of the 447 NPA samples with HAdV‐7 and HAdV‐3 being the most prevalent. In addition, 93.3% (417 of 447) of patients were younger than 5 years. The incidence of HAdV infection peaked in summer. Different HAdV types showed a predilection for different age groups and different seasonal distribution patterns. Coinfection of HAdVs and other respiratory viruses was detected in 63.3% (283 of 447) of the HAdV‐positive samples. The most common clinical diagnosis was pneumonia and the most common symptoms were fever and cough. In comparison with children infected with HAdV‐3 alone, those infected with HAdV‐7 alone had an increased frequency of severe pneumonia involvement (11.6% vs 32.4%; P = 0.031), higher intensive care unit admission rates (7.0% vs 26.5%; P = 0.019), and a longer length of hospital stay (P = 0.03). Mixed infections in younger children were associated with a longer hospital stay (P = 0.023). Our results demonstrate the recent changes in the trends of circulating HAdV genotypes associated with ALRTIs in Hunan China.

Molecular characterization of human adenovirus associated with acute respiratory infections in Cameroon from 2011 to 2014

Background

Human adenoviruses (HAdVs) cause a wide range of diseases worldwide, including respiratory infections. Studies on HAdV molecular epidemiology are limited in Cameroon. The purpose of this study is to document the different types HAdV circulating in Cameroon in children with acute respiratory infections.

Methods

Nasopharyngeal swabs were collected from 811 children under 15 years from 2011 to 2014. The HAdV detection was assessed by semi-quantitative generic PCR r-gene®. The HAdV-positive samples were typed by amplification and sequencing of partial hexon gene and a real-time PCR. Demographic data were collected and analyzed. The infection and hospitalization risk factors were assessed thought the Chi-square test.

Results

A total of 137/220 HAdV-positive samples were amplified successfully. Six species of HAdV (Mastadenovirus A to F) were detected with B (108/220) and C (47/220) being the predominant strains. Hospitalization and age were significantly associated to HAdV-B and HAdV-C respectively. Phylogenetic analysis of HAdV-B3 virus (18) and B7 (5) shows a conserved and a significant temporal stability in relation to the reference sequence (99.1 to 100% of similarity).

Conclusion

This study reported HAdV species and types detected in children with acute respiratory infections in Cameroon between September 2011 and July 2014. These results support further evaluation of the spatio-temporal circulation pattern of HAdV species and types in Cameroon.

The Role of the Human Bocavirus (HBoV) in Respiratory Infections

The human bocavirus is one of the most common respiratory viruses and occurs in all age groups. Because Koch’s postulates have been fulfilled unintendedly, it is currently accepted that the virus is a real pathogen associated with upper and lower respiratory tract infections causing clinical symptoms ranging from a mild common cold to life-threatening respiratory diseases. In order to exclude a viremia, serological analysis should be included during laboratory diagnostics, as acute and chronic infections cannot be differentiated by detection of viral nucleic acids in respiratory specimen alone due to prolonged viral shedding. Besides its ability to persist, the virus appears to trigger chronic lung disease and increases clinical symptoms by causing fibrotic lung diseases. Due to the lack of an animal model, clinical trials remain the major method for studying the long-term effects of HBoV infections.

Phylogenic analysis of human bocavirus detected in children with acute respiratory infection in Yaounde, Cameroon

Objective

Human Bocavirus (HBoV) was first identified in 2005 and has been shown to be a common cause of respiratory infections and gastroenteritis in children. In a recent study, we found that 10.7% of children with acute respiratory infections (ARI) were infected by HBoV. Genetic characterization of this virus remains unknown in Central Africa, particularly in Cameroon Leeding us to evaluate the molecular characteristics of HBoV strains in Cameroonian children with ARI.

Results

Phylogenetic analysis of partial HBoV VP1/2 sequences showed a low level of nucleotide variation and the circulation of HBoV genotype 1 (HBoV-1) only. Three clades were obtained, two clustering with each of the reference strains ST1 and ST2, and a third group consisting of only Cameroon strains. By comparing with the Swedish reference sequences, ST1 and ST2, Cameroon sequences showed nucleotide and amino acid similarities of respectively 97.36–100% and 98.35–100%. These results could help improve strategies for monitoring and control of respiratory infections in Cameroon.

Respiratory infections of the human bocavirus

The human bocavirus is one of the most common respiratory viruses and occurs in all age groups. It is associated with upper and lower respiratory tract infections, and causes clinical symptoms from the mild common cold to life threatening respiratory diseases. Besides its ability to persist the virus appears to trigger chronic lung disease and increase the clinical symptoms, while being a putative trigger for fibrotic lung diseases.

Laboratory diagnostics should include serological diagnostics in order to rule out a viremia because due to prolonged viral shedding acute and chronic infections cannot be differentiated on the detection of viral nucleic acids in respiratory specimen alone.

Although Koch’s postulates cannot be formally fulfilled due to the lack of an animal model and the chance for clinical trials with volunteers are limited due to the long term effects of HBoV infections, there is no doubt that the virus is a serious pathogen and requires attention.

The aim of the chapter is to present an overview of our current knowledge on respiratory infections with the human bocavirus, and to provide basic and essential information on clinical features, molecular diagnostics, and epidemiologic challenges arising with this pathogen.

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.

Comorbidity and high viral load linked to clinical presentation of respiratory human bocavirus infection

Human bocavirus (HBoV) is a new parvovirus associated with acute respiratory tract infection (ARTI). In order to evaluate HBoV significance as an agent of acute respiratory disease, we screened 1,135 respiratory samples from children and adults with and without symptoms during two complete calendar years. HBoV1 prevalence in patients with ARTI was 6.33 % in 2011 and 11.64 % in 2012, including neonatal and adult patients. HBoV1 was also detected in 3.77 % of asymptomatic individuals. The co-detection rate was 78.1 %. Among children, 87 % were clinically diagnosed with lower respiratory infection (no significant differences between patients with and without coinfection), and 31 % exhibited comorbidities. Pediatric patients with comorbidities were significantly older than patients without comorbidities. Patients with ARTI had either high or low viral load, while controls had only low viral load, but there were no clinical differences between patients with high or low viral load. In conclusion, we present evidence of the pathogenic potential of HBoV1 in young children with ARTI. Since patients with HBoV1-single infection are not significantly different from those with coinfection with respect to clinical features, the virus can be as pathogenic by itself as other respiratory agents are. Furthermore, an association between high HBoV1 load and disease could not be demonstrated in this study, but all asymptomatic individuals had low viral loads. Also, children with comorbidities are susceptible to HBoV1 infection at older ages than previously healthy children. Thus, the clinical presentation of infection may occur depending on both viral load and the particular interaction between the HBoV1 and the host.

Apnea induced by respiratory syncytial virus infection is not associated with viral invasion of the central nervous system

We aimed to study whether direct central nervous system invasion is responsible for the neurologic manifestations seen in hospitalized infants with respiratory syncytial virus (RSV) infection. Cerebrospinal fluid from infants with RSV infection was tested for the detection of the following respiratory RNA viruses: RSV, influenza A and B, pandemic influenza H1N1, Parainfluenza-3, human metapneumovirus, adenovirus, parechovirus and enterovirus. All children tested negative for the presence of viral material in the cerebrospinal fluid. Our results support the notion that the mechanism of RSV-induced neurologic manifestations, including apnea, is not direct central nervous system invasion.

High prevalence of human bocavirus 1 in infants with lower acute respiratory tract disease in Argentina, 2007-2009

Human bocavirus (HBoV) is a parvovirus whose association with respiratory disease is currently under investigation.

OBJECTIVE

To determine HBoV prevalence in children with lower acute respiratory infection.

METHODS

We investigated HBoV in 433 nasopharyngeal aspirates collected in 2007-2009 from children 0 to 5 years old hospitalized with bronchiolitis or pneumonia in Córdoba, Argentina.

RESULTS

The general prevalence of HBoV was 21.5% and the positive cases (HBoV+) were more frequent during winter and spring. The mean age of HBoV+ patients was 6.9 months, with 87.1% of the detections corresponding to infants less than 1 year old (among which the prevalence of HBoV was 26.3% in patients < 3 months of age, 22.1% in 3 to 6 months, 25.3% in 6 to 9 months, and 18.8% in 9 to 12 months). The sequence analysis of the NP1 coding region of 15 isolates showed that all isolates from Cordoba were HBoV1 which exhibited a homology of nearly 100% both among themselves and with the originally discovered virus from 2005.

CONCLUSION

Overall, our results indicate that HBoV is a significant pathogen that contributes to acute respiratory infection both on its own and during coinfection with other viruses.

Human bocavirus-the first 5 years

Four species of human bocavirus (HBoV) have been recently discovered and classified in the Bocavirus genus (family Parvoviridae, subfamily Parvovirinae). Although detected both in respiratory and stool samples worldwide, HBoV1 is predominantly a respiratory pathogen, whereas HBoV2, HBoV3, and HBoV4 have been found mainly in stool. A variety of signs and symptoms have been described in patients with HBoV infection including rhinitis, pharyngitis, cough, dyspnea, wheezing, pneumonia, acute otitis media, fever, nausea, vomiting, and diarrhea. Many of these potential manifestations have not been systematically explored, and they have been questioned because of high HBoV co-infection rates in symptomatic subjects and high HBoV detection rates in asymptomatic subjects. However, evidence is mounting to show that HBoV1 is an important cause of lower respiratory tract illness. The best currently available diagnostic approaches are quantitative PCR and serology. This concise review summarizes the current clinical knowledge on HBoV species.

Respiratory syncytial virus and human rhinoviruses are the major causes of severe lower respiratory tract infections in Kuwait

Respiratory infections are very common in Kuwait, yet little is known about the cause of severe lower respiratory tract infections. This study was designed to investigate the viral cause of lower respiratory tract infections using sensitive molecular methods. PCR was applied to investigate 10 respiratory viruses in respiratory samples from 1,014 patients aged between 3 days to 76 years with acute lower respiratory tract infections. Of the 1,014 patients with lower respiratory tract infections, 288 (28.4%) had a viral infection. One hundred fifty‐five (53.8%) presented with bronchiolitis, 100 (43.7%) with pneumonia, and 33 (11.5%) with croup. One hundred six (36.8%) and 99 (34.4%) patients had evidence of respiratory syncytial virus and human rhinoviruses infections, respectively. Adenoviruses were detected in 44 (15.2%) patients, while influenza A virus in 21 (7.3%) patients. The majority of respiratory syncytial virus infections (84%) were among patients aged <1 year. Similarly, of the 99 patients infected by human rhinoviruses, 50 (50.5%) were also among this age group. In contrast, most of influenza A virus infections, 12 of 21 (57.1%), were among patients aged over 16 years. Parainfluenza virus‐2 and human coronaviruses were not detected in any of the patients' samples. Over the 3‐year period, most of the hospitalized patients were seen during the autumn and winter months from October through March. These data show that respiratory syncytial virus and human rhinoviruses may be the major causes of lower respiratory tract infections in children admitted to hospital in Kuwait. J. Med. Virol. 82:1462–1467, 2010. © 2010 Wiley‐Liss, Inc.

Widespread infection with homologues of human parvoviruses B19, PARV4, and human bocavirus of chimpanzees and gorillas in the wild

Infections with human parvoviruses B19 and recently discovered human bocaviruses (HBoVs) are widespread, while PARV4 infections are transmitted parenterally and prevalent specifically in injecting drug users and hemophiliacs. To investigate the exposure and circulation of parvoviruses related to B19 virus, PARV4, and HBoV in nonhuman primates, plasma samples collected from 73 Cameroonian wild-caught chimpanzees and gorillas and 91 Old World monkey (OWM) species were screened for antibodies to recombinant B19 virus, PARV4, and HBoV VP2 antigens by enzyme-linked immunosorbent assay (ELISA). Moderate to high frequencies of seroreactivity to PARV4 (63% and 18% in chimpanzees and gorillas, respectively), HBoV (73% and 36%), and B19 virus (8% and 27%) were recorded for apes, while OWMs were uniformly negative (for PARV4 and B19 virus) or infrequently reactive (3% for HBoV). For genetic characterization, plasma samples and 54 fecal samples from chimpanzees and gorillas collected from Cameroonian forest floors were screened by PCR with primers conserved within Erythrovirus, Bocavirus, and PARV4 genera. Two plasma samples (chimpanzee and baboon) were positive for PARV4, while four fecal samples were positive for HBoV-like viruses. The chimpanzee PARV4 variant showed 18% and 15% nucleotide sequence divergence in NS and VP1/2, respectively, from human variants (9% and 7% amino acid, respectively), while the baboon variant was substantially more divergent, mirroring host phylogeny. Ape HBoV variants showed complex sequence relationships with human viruses, comprising separate divergent homologues of HBoV1 and the recombinant HBoV3 species in chimpanzees and a novel recombinant species in gorillas. This study provides the first evidence for widespread circulation of parvoviruses in primates and enables future investigations of their epidemiology, host specificity, and (co)evolutionary histories.

Human bocavirus infection in young children with acute respiratory tract infection in Lanzhou, China

Human bocavirus (HBoV) is a recognized human parvovirus associated with acute respiratory tract infection. However, HBoV has yet to be established as a causative agent of respiratory disease. In this study, the epidemiological and virological characteristics of HBoV infection were studied in children with acute respiratory tract infection in China. In total, 406 children younger than 14 years of age with acute respiratory tract infection were included in this prospective 1-year study. HBoV was detected in 29 (7.1%) of the 406 children. No clear seasonal fluctuation was observed in infection rates of HBoV. Of the 29 children infected with HBoV, 16 (55.2%) were coinfected with other respiratory viruses, most commonly respiratory syncytial virus (RSV). Viral coinfection with HBoV did not affect the severity of the respiratory disease (P = 0.291). The number of HBoV genome copies ranged from 5.80 x 10(2) to 9.72 x 10(8) copies/ml in nasopharyngeal aspirates among HBoV-positive specimens by real-time PCR, and neither coinfection nor the severity of disease correlated with the viral load (P = 0.148, P = 0.354, respectively). The most common clinical features were cough and acute upper respiratory infection, and acute bronchopneumonia. Additionally, the NP-1 gene of HBoV showed minimal sequence variation. These data suggest that HBoV is frequent in young children with acute respiratory tract infection in Lanzhou, China, and RSV is the most common coinfecting virus. There was no apparent association between the viral load of HBoV and coinfection or disease severity. The NP-1 gene was highly conserved in HBoV.

The role of viruses in the etiology and pathogenesis of common cold

Numerous viruses are able to cause respiratory tract infections. With the availability of new molecular techniques, the number of pathogens detected in specimens from the human respiratory tract has increased. Some of these viral infections have the potential to lead to severe systemic disease. Other viruses are limited to playing a role in the pathogenesis of the common cold syndrome. This chapter focuses on the viral pathogens that are linked to common cold. It is not the intention to comprehensively review all the viruses that are able to cause respiratory tract infections—this would go beyond the scope of this book. The list of viruses that are briefly reviewed here includes rhinoviruses, respiratory syncytial virus, parainfluenza virus, adenovirus, metapneumovirus and coronavirus. Bocavirus is discussed as one example of a newly identified pathogen with a less established role in the etiology and pathogenesis of common cold. Influenza virus does not cause what is defined as common cold. However, influenza viruses are associated with respiratory disease and the clinical picture of mild influenza and common cold frequently overlaps. Therefore, influenza virus has been included in this chapter. It is important to note that a number of viruses are frequently co-detected with other viruses in humans with respiratory diseases. Therefore, the viral etiology and the role of viruses in the pathogenesis of common cold is complex, and numberous questions remain to be answered.

Human bocavirus and rhino-enteroviruses in childhood otitis media with effusion

Background

Viral respiratory infections play an important role in the pathogenesis of otitis media with effusion (OME) in children. The most common human rhinoviruses (HRVs) have been detected in middle ear effusions (MEE), but there is only limited data available about the closely related human enteroviruses (HEVs). The newly discovered human bocavirus (HBoV) has not, however, been identified in MEE of OME children.

Objectives

The aim of our study was to determine the presence of HBoV and HRV/HEV and the rate of coinfection in a set of MEE samples collected from OME children.

Study design

Seventy-five MEE samples from 54 children with no acute respiratory symptoms were studied with reverse transcription polymerase chain reaction (RT-PCR) for detection of HRV/HEV and quantitative PCR for detection of HBoV.

Results

Twenty-six (35%) of 75 MEE samples were positive for viral nucleic acid, 22 (29%) for HEV, 10 (13%) for HRV and 2 (3%) for HBoV. There was no statistically significant difference between mucoid and serous effusions in the rate of virus detection. Forty-three percent of bilateral cases showed a contra-lateral difference in viral finding.

Conclusions

Our results suggest that these common respiratory viruses can be associated with OME in children. Whether these viruses are causative etiologic factors of MEE persistence or merely remnants of previous infections is not known.

Simultaneous detection of respiratory viruses in children with acute respiratory infection using two different multiplex reverse transcription-PCR assays

A 4-tube multiplex RT-PCR (mRT-PCR), which showed higher sensitivity over conventional methods, was previously developed for the diagnosis of 14 viral pathogens of the respiratory tract. Herein the mRT-PCR was compared to the commercial Luminex mPCR-microsphere flow cytometry assay (Resplex II) which allows the detection of 12 different viruses. Eleven different viruses were identified in 91 nasopharyngeal swabs of children with acute respiratory infection, influenza A (IAV) and B, respiratory syncytial virus (RSV), human rhinovirus (hRhV), human echovirus, parainfluenza viruses (PIV) 1, 2, 3 and 4, human metapneumovirus (hMPV), and human coronavirus NL63. The results of the two techniques showed 53 and 40 positive patients by the Resplex II assay and mRT-PCR, respectively, with a concordance in 35 positive and 33 negative patients (74.7%). Individual RT-PCR tests were performed to control viruses not simultaneously detected by the two multiplex assays. The major virus misdiagnosed by mRT-PCR was IAV whereas the major viruses misdiagnosed by Resplex II were PIV1, 3 and 4. The mRT-PCR remains a simple, rapid, and specific assay for the specific detection of respiratory viruses, and can be easily implemented with standards in clinical laboratories at a low cost.

Human bocavirus in an immunocompromised child presenting with severe diarrhea

Human bocavirus (HBoV) is frequently detected in young children with respiratory symptoms. However, the prevalence and pathogenicity of HBoV in immunocompromised patients are largely unknown. This report describes a case of life-threatening hypovolemic shock due to diarrhea associated with disseminated HBoV infection in an immunocompromised child.

The incidence of human bocavirus infection among children admitted to hospital in Singapore

Human bocavirus (HBoV) is a parvovirus, belonging to the genus Bocavirus. The virus was identified recently in Sweden, and has now been detected in several different countries. Although it is associated with lower respiratory tract infections in pediatric patients, the incidence of HBoV infection in a developed country in South East Asia, has not been examined. The objective of this study was to determine the importance of HBoV as a cause of lower respiratory tract infections among children admitted to hospital in Singapore. Five hundred nasopharyngeal swabs were collected from anonymized pediatric patients admitted to the Kandang Kerbau Women's and Children's Hospital for acute respiratory infections. The specimens were tested for the presence of HBoV using polymerase chain reactions. HBoV was detected in 8.0% of the patients tested, and a majority of these HBoV patients exhibited lower respiratory tract infections. A significant level of coinfection with respiratory syncytial viruses and rhinoviruses was also observed in these HBoV patients. The data suggest that HBoV is an important cause of lower respiratory tract infections among children admitted to hospital in Singapore, and is the first study examining the incidence of HBoV infection in a developed country in South East Asia. J. Med. Virol. 81:82–89, 2009. © 2008 Wiley‐Liss, Inc.

Identification of respiratory viruses in asymptomatic subjects: asymptomatic respiratory viral infections

The medical literature of the past 4 decades was searched regarding respiratory virus detection by polymerase chain reaction and conventional methods (culture, antigen detection, serology) in asymptomatic subjects in an attempt to determine the prevalence and clinical significance of such viruses in normal persons.

Clinical and epidemiological aspects of human bocavirus infection

Human bocavirus was recently described as a novel member of the Parvoviridae to infect humans. Based on accumulating clinical and epidemiological data the virus is currently being associated with respiratory infections in young children and infants and is furthermore discussed as causative agent of gastrointestinal illness.

Human bocavirus--a novel parvovirus to infect humans

For almost three decades parvovirus B19 has been described as the only member of the Parvoviridae to infect and cause illness in humans. This statement was correct until 2005 when a group of Swedish scientists identified a previously uncharacterized virus in pools of human nasopharyngeal aspirates obtained from individuals suffering from diseases of the respiratory tract. Comprehensive sequence and phylogenetic analysis allowed the identification of the new virus as a member of the Parvoviridae. Based on its close relation to the minute virus of canines and the bovine parvovirus, it was named human bocavirus (HBoV). Since the identification of HBoV, viral genomes have been frequently detected worldwide in nasopharyngeal swabs, serum and fecal samples almost exclusively derived from young children with various symptoms of the respiratory or the gastrointestinal tract. The detection of HBoV genomes tends to be associated with elevated rates of coinfections with further respiratory viruses, e.g. respiratory syncytial virus or metapneumovirus. First studies on virus-specific immune responses have described the presence of ubiquitous humoral and cellular immune reactions against HBoV in adults and adolescents, indicating a high seroprevalence of this new virus in humans.

Comparison between pernasal flocked swabs and nasopharyngeal aspirates for detection of common respiratory viruses in samples from children

In this prospective study we compared the use of pernasal flocked swab samples with the use of nasopharyngeal aspirate (NPA) samples for the detection of respiratory viruses from 455 children less than 5 years of age. Overall, the sensitivity and the specificity of the pernasal flocked swab samples were 98.5% and 100%, respectively. The excellent sensitivity of the flocked swab samples in combination with the rapid means by which they may be collected makes them an alternative to NPA samples, whose collection is more invasive.