Human Bocavirus infection, Canada

Phospholipase A2-like activity of human bocavirus VP1 unique region

Human bocavirus (HBoV) is a new parvovirus first discovered in 2005, which is associated with acute respiratory infection. Analysis of sequence homology has revealed that a putative phospholipase A2 (PLA2) motif exists in the VP1 unique region of HBoV. However, little is known about whether the VP1 unique region of HBoV has PLA2 enzymatic activity and how these critical residues contribute to its PLA2 activity. To address these issues, the VP1 unique region protein and four of its mutants, were expressed in Eschericha coli. The purified VP1 unique protein (VP1U) showed a typical Ca2+-dependent secreted PLA2-like (sPLA2) activity, which was inhibited by sPLA2-specific inhibitors in a time-dependent manner. Mutation of one of the amino acids (21Pro, 41His, 42Asp or 63Asp) in VP1U almost eliminated the sPLA2 activity of HBoV VP1U. These data indicate that VP1U of HBoV has sPLA2-like enzymatic activity, and these residues are crucial for its sPLA2-like activity. Potentially, VP1U may be a target for the development of anti-viral drugs for HBoV.

Infections respiratoires virales émergentes

Viral respiratory infections are very frequent diseases with variable degrees of severity. During the past few years, new respiratory viruses have been discovered by means of molecular biology techniques. In fact, these so far unidentified viruses have been present in humans for a long time but remained unidentified. These viruses are mainly represented by the human metapneumovirus (HMPV), the coronaviruses HCoV-NL63, HCoV-NH and HCoVHKU1, the human bocavirus (HBoV), and the newly described human polyomaviruses WU and KI. Beside these newly identified viruses, new respiratory viruses have emerged in humans within the last years. These viruses have been introduced from animal reservoirs and they generally present a high degree of pathogenicity with high level of mortality in humans. These emerging respiratory viruses are represented by the henipaviruses (Hendra and Nipah viruses), the New World hantaviruses associated with the Hantavirus Pulmonary Syndrome, the coronavirus responsible for the Severe Acute Respiratory Syndrome (SARS-CoV), and the avian influenza virus H5N1. This latter constitutes a major threat, with the risk of a murderous pandemic offering some parallels with the 1918-1919 Spanish flu which caused 20-50 millions deaths worldwide.

Human bocavirus infection in children with gastroenteritis, Brazil

Human bocavirus (HBoV) was detected in 14 (2%) of 705 fecal specimens from Brazilian children with gastroenteritis. Coinfection with rotavirus, adenovirus, or norovirus was found in 3 (21.4%) HBoV-positive specimens. None of the HBoV-positive patients had respiratory symptoms.

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

We investigated coinfection of human bocavirus (HBoV) and other respiratory viruses in hospitalized children by real-time PCR. A high rate (69.2%) of adenovirus infection was found among children infected with HBoV. Such high rates of HboV-adenovirus coinfection have not been previously reported, underscoring the need to investigate the contribution of HBoV in patient clinical presentations.

Human bocavirus infection in hospitalized children during winter

Human bocavirus (HBoV) has recently been described as a common agent of acute upper and lower respiratory tract infections in children. We screened by polymerase chain reaction for HBoV nucleic acid nasopharyngeal aspirates from hospitalized children with negative culture and immunofluorescence assay for respiratory syncytial virus, influenza viruses, adenovirus, and parainfluenza viruses. HBoV was detected in 32 children (5.5%) and was the second virus identified in nasopharyngeal aspirates after respiratory syncytial virus. Most of the children had severe disease.

High incidence of human bocavirus infection in children in Spain

BACKGROUND

The newly identified human bocavirus (HBoV), a member of the Parvoviridae family, has been associated to low respiratory tract infections in young children.

OBJECTIVES

To present the epidemiological profile and the main clinical characteristics showed by children infected with this virus in Spain.

STUDY DESIGN

We have studied the incidence of HBoV and other 15 respiratory viruses in 917 nasopharyngeal aspirates taken from 730 infants and children under age of 14 with acute lower respiratory tract infection from September-04 to August-06.

RESULTS

HBoV was detected in 123 samples (13.4%) showing a seasonal distribution with November and December as the peak months. Out of the 558 samples which rendered a positive result for at least one of the virus tested, HBoV (22%) ranked fourth behind respiratory syncytial virus (181, 32%), adenoviruses (155, 28%) and rhinoviruses (136, 24%). Co-infections with HBoV and other respiratory viruses were detected in 74 out of 123 HBoV-positive specimens (60%). In addition, HBoV was also found in stool and, for the first time, in urine samples.

CONCLUSIONS

Results obtained provide further evidence that HBoV is involved in acute lower respiratory tract infections. HBoV-associated disease should not be limited to the respiratory tract.

Prospective study of Human Bocavirus (HBoV) infection in a pediatric university hospital in Germany 2005/2006

Background

Human Bocavirus (HBoV), a new species of the genus parvovirus newly detected in 2005, seems to be a worldwide distributed pathogen among children with respiratory tract infection (prevalence 2%–18%). Recently published retrospective studies and one prospective birth cohort study suggest that HBoV-primary infection occurs in infants.

Methods

Prospective single center study over one winter season (November 2005–May 2006) with hospitalized children without age restriction using PCR-based diagnostic methods.

Results

HBoV DNA was detected in 11 (2.8%) of 389 nasopharyngeal aspirates from symptomatic hospitalized children (median age 9.0 months; range: 3–17 months). RSV, HMPV, HCoV, and Influenza B were detected in 13.9% (n = 54), 5.1% (n = 20), 2.6% (n = 10), and 1.8% (n = 7), respectively. There was no influenza A DNA detected in any of the specimens. The clinical diagnoses were acute wheezing (bronchitis) in four patients, radiologically confirmed pneumonia in six patients (55%) and croup syndrome in one patient. In five to six patients with pneumonia, HBoV was the only pathogen detected. While no patient had to be mechanically ventilated, 73% needed oxygen supplementation. In four (36.4%) patients at least one other viral pathogen was found (plus RSV n = 3; 27.3%; Norovirus n = 1; 9.1%).

Conclusion

HBoV causes severe respiratory tract infections in infants and young children. Its role as a copathogen and many other open questions has to be defined in further prospective studies.

Detection of human bocavirus in children with Kawasaki disease

Human bocavirus (HboV) is an emerging virus that has been implicated as a cause of acute upper and lower respiratory tract infection in children. As no serological assay is available, PCR was used to screen nasopharyngeal, serum or stool samples from 16 patients with Kawasaki disease for HBoV nucleic acid. HBoV was identified by PCR in five (31.2%) patients, suggesting that this emerging virus may also play a pathogenic role in some cases of Kawasaki disease.

[Human bocavirus infections in Spanish 0-14 year-old: clinical and epidemiological characteristics of an emerging respiratory virus]

INTRODUCTION

In 2005 a new respiratory virus, called human bocavirus (HBoV), was cloned from respiratory samples from Swedish infants and children with lower respiratory tract infections.

OBJECTIVES

To determine whether HBoV has circulated in Spain, estimate the frequency of HBoV infections in patients hospitalized for respiratory infection and describe the clinical and epidemiological characteristics of these patients.

PATIENTS AND METHODS

We performed a descriptive prospective study of confirmed HBoV infections in patients aged < 14 years old, hospitalized for respiratory infections between October 2004 and June 2005. Virologic diagnosis was based on multiple RT-PCR for respiratory syncytial virus (RSV) A and B, influenza A,B, and C, parainfluenza 1-4, adenovirus and rhinovirus; PCR was used for human metapneumovirus (hMPV) and PCR in nasopharyngeal aspirates was used for HBoV. The clinical and epidemiological characteristics of patients were analyzed.

RESULTS

Fifty-two cases of HBoV infection were detected, representing 17.1% (95% CI: 13% a 21%) of patients hospitalized for respiratory infections. HBoV was the third most frequent viral agent after RSV (30%) and rhinovirus (25%). In 39 patients (71.1%) coinfection with another respiratory virus was detected. Fifty percent of the patients were aged less than 13.6 months and 75% were aged less than 2 years. The most frequent diagnoses were recurrent wheezing (55.8%), bronchiolitis (21.2%) and pneumonia (15.4%). Clinical sepsis with petechial exanthema was found in two patients. Fever > 38 degrees C was found in 72.1% and radiological infiltrate in 44%. Hypoxia was present in 55.8 % of the patients. HBoV was isolated in distinct episodes in two patients. Coinfections were similar to simple infections except that hypoxia was more frequent in the former (p = 0.038).

CONCLUSIONS

HBoV is one of the most frequent viruses in severe respiratory infections in patients aged less than 14 years old. Only RSV and rhinovirus are more frequent. Coinfections are highly frequent. Most patients are infants with recurrent wheezing and bronchiolitis.

Clinical and molecular epidemiology of human bocavirus in respiratory and fecal samples from children in Hong Kong

Background. Human bocavirus (HBoV) is a recently discovered parvovirus associated with respiratory tract infections in children. We conducted the first systematic prospective clinical and molecular study using nasopharyngeal aspirates (NPAs) and fecal samples.

Methods. NPAs negative for influenza virus, parainfluenza virus, respiratory syncytial virus, adenovirus, and coronavirus and fecal samples from patients with acute gastroenteritis were included. On the basis of results from a pilot study using 400 NPAs from all age groups, a prospective 12-month study was conducted to detect HBoV in 1200 NPAs and 1435 fecal samples from patients <18 years old by polymerase chain reaction. The complete genome sequences of HBoVs from 12 NPAs and 12 fecal samples were determined.

Results. Of the 400 NPAs collected in the pilot study, 20 (5.0%) were found to contain HBoV, all from children <5 years old. In the subsequent prospective study of pediatric patients, HBoV was detected in 83 (6.9%) of 1200 NPAs. Upper and lower respiratory tract infections were equally common. HBoV was detected in 30 (2.1%) of 1435 fecal samples. Fever and watery diarrhea were the most common symptoms. The seasonality of HBoV in NPAs and fecal samples was similar. Codetection with other pathogens occurred in 33% and 56% of NPAs and fecal samples, respectively, from patients with HBoV infection. Genomes of HBoVs from NPAs and fecal samples displayed minimal sequence variations.

Conclusions. HBoV was detected in fecal specimens in children with acute gastroenteritis. A single lineage of HBoV was associated with both respiratory tract and enteric infections.

The transcription profile of the bocavirus bovine parvovirus is unlike those of previously characterized parvoviruses

The Bocavirus bovine parvovirus generated a single pre-mRNA from a promoter at its left-hand end; however, the pattern of its alternative polyadenylation and splicing was different from that of other parvoviruses. A large left-hand-end open reading frame (ORF) encoded a nonstructural protein of approximately 95 kDa. An abundant, spliced, internally polyadenylated transcript encoded the viral NP1 protein from an ORF in the center of the genome. Transcripts encoding the capsid proteins were polyadenylated in the right-hand terminal palindrome. This is the first published transcription map of a member of the Bocavirus genus of the Parvovirinae.

Seroepidemiology of human bocavirus in Hokkaido prefecture, Japan

A new human virus, provisionally named human bocavirus (HBoV), was discovered by Swedish researchers in 2005. A new immunofluorescence assay using Trichoplusia ni insect cells infected with a recombinant baculovirus expressing the VP1 protein of HBoV was developed, and the levels of immunoglobulin G antibody to the VP1 protein of HBoV in serum samples were measured. The overall seroprevalence rate of antibodies against the VP1 protein of HBoV in a Japanese population aged from 0 months to 41 years was 71.1% (145 of 204). The seropositive rate was lowest in the age group of 6 to 8 months and gradually increased with age. All of the children had been exposed to HBoV by the age of 6 years. A rise in titers of antibody against the VP1 protein of HBoV during the convalescent phase was observed for four patients with lower respiratory tract infections, and HBoV DNA was detected in nasopharyngeal swab and serum samples from all four patients. These results suggest that HBoV is a ubiquitous virus acquired early in life and that HBoV might play a role in the course of lower respiratory tract infections.

Frequent detection of the parvoviruses, PARV4 and PARV5, in plasma from blood donors and symptomatic individuals

BACKGROUND

Plasma pools used in the manufacture of blood- and plasma-derived medicinal products are frequently contaminated with parvovirus B19. The presence of the novel human parvovirus PARV4 and a related variant PARV5 in manufacturing plasma pools was recently demonstrated. Another recently identified parvovirus, human bocavirus (HBoV), has been identified in respiratory samples from children with lower respiratory tract disease.

STUDY DESIGN AND METHODS

Recent and archived manufacturing plasma pools, as well as plasma from healthy blood donors (individual donations; pools of 16 donations) and febrile patients, were examined for the presence of PARV4 and PARV5 with conventional and TaqMan polymerase chain reaction assays. In addition, highly sensitive assays were used to examine the presence of HBoV DNA in manufacturing pools.

RESULTS

Of 351 recent manufacturing plasma pool samples, 14 (4%) tested positive for the presence of PARV4 and PARV5. This frequency was elevated in the archived pools. Viral loads ranged from less than 100 up to 4 million copies per mL plasma, with some pools containing a mixture of both viruses. In individual plasma samples from healthy blood donors and febrile patients, the frequencies of detection were 2 and 6 percent, respectively. No HBoV sequences were identified in manufacturing plasma pools (n = 167).

CONCLUSION

PARV4 and PARV5 are readily detected in manufacturing plasma pools, test pools (constructed from 16 donations), and individual donations derived from healthy blood donors. The prevalence of these viruses was increased in plasma samples from febrile patients. Despite the use of highly sensitive assays for HBoV, it was not possible to identify manufacturing plasma pools containing HBoV sequences.

Electron microscopy observation of human bocavirus (HBoV) in nasopharyngeal samples from HBoV-infected children

The newly identified human bocavirus is frequently detected by molecular techniques in respiratory samples from children with respiratory tract infections, but virions have not been observed so far. We report the electron microscopy observation of viral particles in nasopharyngeal aspirates previously found to be positive for human bocavirus DNA. The virions presented the expected structural characteristics of a Parvoviridae family member.

Human bocavirus, a respiratory and enteric virus

In Spain, human bocavirus (HBoV) was detected in 48 (9.1%) of 527 children with gastroenteritis at similar frequency as for children with respiratory illness (40/520, 7.7%). Fecal excretion adds new concern about the transmission of HBoV. To our knowledge, this report is the first to document HBoV in human feces.

Human bocavirus in Iranian children with acute respiratory infections

Human bocavirus (HBoV), a virus discovered in Sweden in 2005, has been associated with acute respiratory infections in young children and subsequent reports suggest that HBoV may have a worldwide distribution. This report describes the frequency and clinical presentation of HBoV in 261 Iranian children<5 years old with acute respiratory infections attending two regional hospitals in Rasht, Iran in the winter of 2003-2004. Polymerase chain reaction (PCR) and reverse transcription PCR (RT-PCR) were used for the detection of HBoV and other respiratory pathogens from nasopharyngeal specimens. HBoV was detected in 21 (8%) children. Fifteen (12%) of these children were identified among 122 children admitted to hospital and 6 (4%) from 139 outpatients (P < 0.05). Most children with HBoV were less than 2 years (17/21, 81%) and 7 (33%) were less than 1 year old. Although HBoV was identified in all ages it affected slightly older children than the respiratory syncytial virus (RSV). The frequency of the virus varied from 1 (3%) in 40 patients in November to 7 (12%) of 61 in February, suggesting a seasonal pattern during the autumn and early winter. Seven children had co-infections with RSV, adenovirus or influenza A. The relatively high frequency of HBoV suggests that the virus may contribute substantially to acute respiratory infections in children.

High-throughput, sensitive, and accurate multiplex PCR-microsphere flow cytometry system for large-scale comprehensive detection of respiratory viruses

Human respiratory viruses are a diverse group of pathogens composed of hundreds of virus strains, and this presents a major challenge for diagnostic laboratories. To efficiently detect numerous viruses in a large epidemiologic study, we developed a fast, multitarget, sensitive, and specific assay named the Respiratory MultiCode-PLx Assay (RMA). The RMA utilizes improved multiplex PCR chemistry (EraGen MultiCode-PLx technology) coupled with high-throughput microsphere flow cytometry (Luminex). Eighteen sets of virus-specific multiplex PCR primers were developed based on the conserved sequences of all available respiratory-virus sequences for eight distinct groups: human rhinovirus (HRV), respiratory syncytial virus (RSV), parainfluenza virus (PIV), influenza virus (InfV), metapneumovirus, adenovirus (Ad), coronavirus, and enterovirus. Each primer set detected 20 cDNA copies of the intended target per sample and had no reaction with 60,000 copies of human genomic DNA. The accuracy and sensitivity of the RMA for detecting respiratory viruses in human samples were tested with two sets of clinical specimens. First, 101 nasal-wash specimens that were positive for HRV, RSV, InfV, PIV, or Ad by traditional techniques were reanalyzed by RMA, and all target viruses were detected with an overall sensitivity of 94% and specificity of 99%. Second, 103 nasal-wash samples from 5-year-old children with asthma and respiratory symptoms were analyzed; RMA detected viruses in 74 specimens (71.8%) compared to only 24 (23.3%) by traditional culture and immunofluorescent-staining techniques. These results show that RMA is an accurate, sensitive, and practical test for respiratory-virus infections.

Complete coding sequences and phylogenetic analysis of Human Bocavirus (HBoV)

Human Bocavirus (HBoV) is a novel virus which can cause respiratory tract disease in infants or children. Recently, the prevalence of this virus has been studied worldwide. In this study, 18 of 252 (7.14%) nasopharyngeal suctions from infants or children between 1 month and 9 years of age with respiratory tract illness were HBoV-positive by PCR. Three positive samples were selected for sequencing the entire coding sequences using a new conserved set of primers. The results showed that the most conserved regions of HBoV are the NS1 and NP1 genes, whereas VP1 and VP2 showed frequent variations. However, the complete coding sequences showed that the variations did not depend on the origin of virus found. The complete coding sequences determined in this study can resolve the problem of an HBoV detection method, which can be advantageously implemented in laboratory detection.

Real-time PCR for diagnosis of human bocavirus infections and phylogenetic analysis

The human bocavirus (hBoV) was first described in 2005 in respiratory tract samples. The clinical relevance of hBoV is still unclear. The aim of our study was to establish a real-time PCR assay for the detection and quantification of hBoV DNA, to apply the real-time assay for the analysis of stool and serum samples for the presence of hBoV DNA, and to perform a phylogenetic analysis of the hBoV positive samples. A total of 834 nasopharyngeal aspirates (NPA), 10 serum samples, and 31 stool samples of children with acute respiratory diseases were retrospectively tested. For phylogenetic analysis, 968 bp of the VP2 gene were sequenced from 69 hBoV-positive NPA samples. The qualitative results of the real-time hBoV PCR were in good agreement with a conventional hBoV PCR. We found that 12% of the NPA were positive for hBoV DNA. The median viral load in the NPA was 4.9 x 10(3) copies/ml (range, 2.7 x 10 degrees to 1.5 x 10(11) copies/ml). There was no difference of the hBoV load in NPA between children with or without known coinfection, but the load was significantly higher in children with bronchitis than in children with the diagnosis of febrile seizures. hBoV DNA was found in 1 of 10 serum samples and in 14 of 31 stool samples. hBoV sequence identity was >99% in the VP2 region. In conclusion, hBoV DNA can be found in NPA samples at very high titers. In addition to being found in the respiratory tract, hBoV was found in stool samples. The clinical relevance of these findings remains to be determined.

Human bocavirus infection, People's Republic of China

A newly identified parvovirus, human bocavirus (HBoV), was found in 21 (8.3%) of 252 nasopharyngeal aspirates from hospitalized children with lower respiratory tract infection in Hunan Province, People’s Republic of China. Viral loads were 10⁴ to 10¹⁰ copies/mL. Phylogenetic analysis of the VP1 gene showed a single genetic lineage of HBoV worldwide.

Human bocavirus infection, People's Republic of China

A newly identified parvovirus, human bocavirus (HBoV), was found in 21 (8.3%) of 252 nasopharyngeal aspirates from hospitalized children with lower respiratory tract infection in Hunan Province, People's Republic of China. Viral loads were 10(4) to 10(10) copies/mL. Phylogenetic analysis of the VP1 gene showed a single genetic lineage of HBoV worldwide.

Comparison of tissue distribution, persistence, and molecular epidemiology of parvovirus B19 and novel human parvoviruses PARV4 and human bocavirus

Background. PARV4 and human bocavirus (HBoV) are newly discovered human parvoviruses with poorly understood epidemiologies and disease associations. We investigated the frequencies of persistence, tissue distribution, and influence of immunosuppression on replication of these viruses.

Methods. At autopsy, bone marrow, lymphoid tissue, and brain tissue from human immunodeficiency virus (HIV)—infected individuals with acquired immunodeficiency syndrome (AIDS) and those without AIDS and from HIV-uninfected individuals were screened for parvovirus B19, PARV4, and HBoV DNA by means of quantitative polymerase chain reaction analyses.

Results. B19 DNA was detected both in HIV-infected study subjects (13 of 24) and in HIV-uninfected study subjects (8 of 8), whereas PARV4 DNA was detected only in HIV-infected study subjects (17 of 24). HBoV DNA was not detected in any study subjects. The degree of immunosuppression with HIV infection did not influence B19 or PARV4 viral loads. B19 or PARV4 plasma viremia was not detected in any study subjects (n = 76; viral load <25 DNA copies/mL). A significantly older age distribution was found for study subjects infected with B19 genotype 2, compared with those infected with B19 genotype 1. Two genotypes of PARV4 were detected; study subjects carrying prototype PARV4 (genotype 1) were younger (all born after 1958) than those infected with genotype 2 (PARV5; study subjects born between 1949 and 1956).

Conclusions. Tight immune control of replication of B19 and PARV4 was retained despite profound immunosuppression. Recent genotype replacement of PARV4, combined with absent sequence diversity among genotype 1 sequences, suggests a recent, epidemic spread in the United Kingdom, potentially through transmission routes shared by HIV.

Detection of bocavirus DNA in nasopharyngeal aspirates of a child with bronchiolitis

We describe a case of bronchiolitis associated with the newly detected human bocavirus (hBoV) in a child with a suspected Noonan syndrome. This is the first report of a bronchiolitis probably linked to hBoV that required intensive care while being accompanied by a congenital heart disease and a history of several episodes of severe respiratory symptoms.

Viral metagenomics

Characterisation of new viruses is often hindered by difficulties in amplifying them in cell culture, limited antigenic/serological cross-reactivity or the lack of nucleic acid hybridisation to known viral sequences. Numerous molecular methods have been used to genetically characterise new viruses without prior in vitro replication or the use of virus-specific reagents. In the recent metagenomic studies viral particles from uncultured environmental and clinical samples have been purified and their nucleic acids randomly amplified prior to subcloning and sequencing. Already known and novel viruses were then identified by comparing their translated sequence to those of viral proteins in public sequence databases. Metagenomic approaches to viral characterisation have been applied to seawater, near shore sediments, faeces, serum, plasma and respiratory secretions and have broadened the range of known viral diversity. Selection of samples with high viral loads, purification of viral particles, removal of cellular nucleic acids, efficient sequence-independent amplification of viral RNA and DNA, recognisable sequence similarities to known viral sequences and deep sampling of the nucleic acid populations through large scale sequencing can all improve the yield of new viruses. This review lists some of the animal viruses recently identified using sequence-independent methods, current laboratory and bioinformatics methods, together with their limitations and potential improvements. Viral metagenomic approaches provide novel opportunities to generate an unbiased characterisation of the viral populations in various organisms and environments.

Human bocavirus: a new respiratory pathogen?

A new virus was recently discovered by molecular techniques in respiratory samples collected from young children with respiratory disease. This virus is a new member of the Parvoviridae family and has been classified in the Bocavirus genus. This virus, named human bocavirus, is genetically related to the bovine parvovirus and the canine minute virus, which both belong to the Bocavirus genus. Recent studies conducted in different countries have shown that this virus is found in 3–18% of children with respiratory disease worldwide, and a seasonal distribution with a peak in winter and spring is suspected. Genetic analysis has indicated that this virus has low genetic variability. The clinical signs observed in patients infected with human bocavirus are not different from those caused by other respiratory viruses. Given the frequent association of human bocavirus with other respiratory pathogens, the exact role played by this virus in human diseases still remains unclear, and further studies including control subjects are needed to ascertain the pathogenic potential of this virus.

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 bocavirus: a novel parvovirus epidemiologically associated with pneumonia requiring hospitalization in Thailand

Background. We detected human bocavirus (HBoV) infection in 4.5% of hospitalized patients with pneumonia in rural Thailand. However, the role of HBoV as a pathogen is unclear.

Methods. We compared HBoV infection in patients with pneumonia with that in asymptomatic control patients enrolled between 1 September 2004 and 31 August 2005 in the same hospitals in Thailand.We examined outpatients with influenza-like illness for HBoV infection and tested for 13 additional respiratory viruses. Epidemiologic and clinical characteristics of HBoV infection are described.

Results. HBoV infection was detected in 20 (3.9%) of 512 outpatients and 3 (1%) of 280 control patients. Coinfection with other viruses was detected in 83% of patients with pneumonia and in 90% of outpatients. Compared with control patients, HBoV infection was significantly associated with pneumonia requiring hospitalization (adjusted odds ratio, 3.56 [95% confidence interval, 1.06–11.91]; P = .04). Eighty-three percent of HBoV infections were detected in patients with pneumonia who were <5 years old. More patients with pneumonia associated with HBoV—respiratory syncytial virus (RSV) or human parainfluenza virus (HPIV) coinfections had wheezing than patients with RSV and HPIV infections alone (9 [53%] of 17 vs. 32 [23%] of 138]; P = .01).

Conclusions. HBoV infection was epidemiologically associated with pneumonia among young children in rural Thailand, but infection and illness may be dependent on coinfection with other viruses.

Human bocavirus and acute wheezing in children

Background. Human bocavirus is a newly discovered parvovirus. It has been detected primarily in children with acute lower respiratory tract infection, but its occurrence, clinical profile, and role as a causative agent of respiratory tract disease are not clear.

Methods. We investigated the presence of human bocavirus by quantitative polymerase chain reaction of nasopharyngeal aspirate specimens and selected serum samples obtained from 259 children (median age, 1.6 years) who had been hospitalized for acute expiratory wheezing. The samples were analyzed for 16 respiratory viruses by polymerase chain reaction, virus culture, antigen detection, and serological assays.

Results. At least 1 potential etiologic agent was detected in 95% of children, and >1 agent was detected in 34% of children. Human bocavirus was detected in 49 children (19%). A large proportion of the cases were mixed infections with other viruses, but human bocavirus was the only virus detected in 12 children (5%). High viral loads of human bocavirus were noted mainly in the absence of other viral agents, suggesting a causative role for acute wheezing. In addition, infections that had uncertain clinical relevance and low viral loads were prevalent. Human bocavirus DNA was frequently detected in serum specimens obtained from patients with acute wheezing, suggesting systemic infection.

Conclusions. Human bocavirus is prevalent among children with acute wheezing and can cause systemic infection. Results suggest a model for bocavirus infection in which high viral loads are potentially associated with respiratory symptoms and low viral loads indicate asymptomatic shedding. Therefore, quantitative polymerase chain reaction analysis may be important for additional studies of human bocavirus.

Isolation of human bocavirus from Swiss infants with respiratory infections

Human bocavirus (HBoV) is a novel agent associated with respiratory symptoms in adults and children. We studied prospectively the first acute respiratory infection in a birth cohort of healthy neonates in Switzerland. HBoV was identified in 5 (4.5%) of 112 infants as young as 3 months of age. In 4 of the 5 infants, HBoV was associated with other respiratory viruses. We conclude that HBoV circulates in the community and is acquired early in life.

Quantification of human bocavirus in lower respiratory tract infections in China

A quantitative PCR method was established to quantify human bocavirus (HBoV) genomic copies in clinical specimens from children with lower respiratory tract infections (LRTI) in China. A total of 257 respiratory tract specimens were tested, and 7 (2.7%) of these (all sputum samples) were positive, with genomic copies that ranged from 8.0 × 10³ to 8.0 × 10⁹ in the samples. The main clinical symptom of patients who were positive for HBoV DNA was a pneumonia-like syndrome represented by high fever and cough. Our results suggest that HBoV may be an important etiological agent of LRTI in children in China.

Detection of human bocavirus in Canadian children in a 1-year study

Human bocavirus was detected by PCR in 65 (5.1%) of 1,265 respiratory specimens collected in 2002 and 2003 from the Stollery Children's Hospital from children <17 years of age. The spectrum of illness included upper respiratory infection, croup, bronchiolitis, and pneumonia with a prominence of cough and fever.

Le bocavirus humain (HboV) un nouveau pathogene respiratoire?

Un nouveau virus a été très récemment identifié par biologie moléculaire dans des prélèvements respiratoires chez de jeunes enfants. Ce virus est un nouveau représentant de la famille des Parvoviridae et a été classé dans le genre Bocavirus aux côtés du parvovirus bovin (BPV) et du virus minute canin (MCV). Quelques études ont depuis été conduites sur ce virus qui est désormais appelé le bocavirus humain (HboV). Les premières conclusions sur l'épidémiologie de ce nouveau virus révèlent une prévalence assez importante, comprise entre 3 à 10 % des infections respiratoires de l'enfant, une association fréquente avec d'autres virus respiratoires, une répartition mondiale et l'absence de réelle distribution saisonnière. Un seul type viral semble circuler dans la population cible qui apparaît être essentiellement les jeunes enfants. Les données cliniques disponibles ne permettent pas la mise en évidence de spécificité par rapport aux autres viroses respiratoires. A ce jour, les liens de causalité entre la présence de ce nouveau virus découvert par génie moléculaire et une pathologie respiratoire sont loin d'être établis. Le rôle exact du HBoV en pathologie humaine reste donc à confirmer.

Real-time PCR assays for detection of bocavirus in human specimens

The recently discovered human bocavirus (HBoV) is the first member of the family Parvoviridae, genus Bocavirus, to be potentially associated with human disease. Several studies have identified HBoV in respiratory specimens from children with acute respiratory disease, but the full spectrum of clinical disease and the epidemiology of HBoV infection remain unclear. The availability of rapid and reliable molecular diagnostics would therefore aid future studies of this novel virus. To address this, we developed two sensitive and specific real-time TaqMan PCR assays that target the HBoV NS1 and NP-1 genes. Both assays could reproducibly detect 10 copies of a recombinant DNA plasmid containing a partial region of the HBoV genome, with a dynamic range of 8 log units (10(1) to 10(8) copies). Eight blinded clinical specimen extracts positive for HBoV by an independent PCR assay were positive by both real-time assays. Among 1,178 NP swabs collected from hospitalized pneumonia patients in Sa Kaeo Province, Thailand, 53 (4.5%) were reproducibly positive for HBoV by one or both targets. Our data confirm the possible association of HBoV infection with pneumonia and demonstrate the utility of these real-time PCR assays for HBoV detection.

Epidemiological profile and clinical associations of human bocavirus and other human parvoviruses

BackgroundHuman bocavirus (HBoV) and PARV4 are newly discovered human parvoviruses. HBoV, which was first detected in respiratory samples, has a potential role in the development of human respiratory disease. The present study compared the frequencies, epidemiological profiles, and clinical backgrounds of HBoV and PARV4 infections with those of other respiratory virus infections, by evaluating diagnostic samples referred to the Specialist Virology Laboratory (SVL) at the Royal Infirmary of Edinburgh (Edinburgh, United Kingdom)

MethodsAnonymized samples and study subject information were obtained from the respiratory sample archive of the SVL. Samples were screened for HBoV, PARV4, B19, respiratory syncytial virus (RSV), adenoviruses, influenza viruses, and parainfluenza viruses by use of nested polymerase chain reaction

ResultsHBoV infection was detected in 47 (8.2%) of 574 study subjects,&amp;ranking third in prevalence behind RSV infection (15.7%) and adenovirus infection (10.3%). Peak incidences of HBoV were noted among infants and young children (age, 6–24 months) during the midwinter months (December and January) and were specifically associated with lower respiratory tract infections. HBoV infections were frequently accompanied by other respiratory viruses (frequency, 43%), and they were more prevalent among individuals infected with other respiratory viruses (17%), frequently adenovirus or RSV. All respiratory samples were negative for PARV4

ConclusionsIn the present study, HBoV was a frequently detected, potential respiratory pathogen, with a prevalence and an epidemiological profile comparable to those of RSV. Identification of HBoV infections may be clinically important in the future

Frequent detection of bocavirus DNA in German children with respiratory tract infections

Background

In a substantial proportion of respiratory tract diseases of suspected infectious origin, the etiology is unknown. Some of these cases may be caused by the recently described human bocavirus (hBoV). The aim of this study was to investigate the frequency and the potential clinical relevance of hBoV in pediatric patients.

Methods

We tested 835 nasopharyngeal aspirates (NPA) obtained between 2002 and 2005 from pediatric in-patients with acute respiratory tract diseases at the University of Würzburg, Germany, for the presence of hBoV DNA. The specificity of positive PCR reactions was confirmed by sequencing.

Results

HBoV DNA was found in 87 (10.3 %) of the NPAs. The median age of the infants and children with hBoV infection was 1.8 years (mean age 2.0 years; range 18 days – 8 years). Infections with hBoV were found year-round, though most occurred in the winter months. Coinfections were found in 34 (39.1 %) of the hBoV positive samples. RSV, influenza A, and adenoviruses were most frequently detected as coinfecting agents. Sequence determination of the PCR products in the NP-1 region revealed high identity (99 %) between the nucleotide sequences obtained in different years and in comparison to the Swedish viruses ST1 and ST2. An association of hBoV with a distinct respiratory tract manifestation was not apparent.

Conclusion

HBoV is frequently found in NPAs of hospitalized infants and children with acute respiratory tract diseases. Proving the clinical relevance of hBoV is challenging, because application of some of Koch's revised postulates is not possible. Because of the high rate of coinfections with hBoV and other respiratory tract pathogens, an association between hBoV and respiratory tract diseases remains unproven.