Human bocavirus in Iranian children with acute respiratory infections

Detection of Human Boca Virus in Gastric Adenocarcinoma

Background: Gastric cancer is one of the most common cancers worldwide. Human bocavirus (HBoV), a recently isolated virus, has been investigated for its role in many respiratory and enteric diseases. Few studies have reported its presence in solid tumors, such as lung and colon cancers. The aim of this study was to detect the presence of the HBoV1 genome in gastric adenocarcinoma, which has not yet been evaluated. Methods: Formalin-fixed paraffin-embedded (FFPE) blocks of 189 gastric tumors and 50 blocks of non-tumor gastric tissue products from elective weight reduction operations were collected. DNA extraction and real-time polymerase chain reaction (PCR) were performed for HBoV1 detection. DNA sequencing was performed using ABI Genetic Analyzer series 3500. Results: The mean age of the patients was 60±13.33 years. Tumors were more common in males than females (2.5/1). HBoV1 PCR was positive in 34 (18%) cases of GC and 10 (20%) cases of chronic gastritis (P>0.05). There was no association between age, sex, stage, and histologic subtype of the tumor and HBoV1 positivity (P>0.05) in tumor samples. The rate of intestinal metaplasia and presence of lymphoid stroma were also not more frequent in HBoV1-positive tumors (P>0.05). Conclusion: The HBoV1 can be detected in a relatively high proportion of Iranian patients with gastric cancer (18%) with no predilection for specific subtypes and no association with the degree of lymphocytic infiltration. HBoV1 can also be observed in approximately 20% of chronic gastritis cases. Further comprehensive studies are needed to elucidate the role of HBoV1 in gastric cancer development.

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.

Human bocavirus (HBoV) in Kuwait: molecular epidemiology and clinical outcome of the virus among patients with respiratory diseases

Introduction. Globally, human bocavirus (HBoV) has been detected in respiratory samples from patients suffering from upper and lower respiratory diseases. In Kuwait, little is known about the epidemiological and clinical characterization of the virus and genetic characterization of the virus as a respiratory pathogen is unknown.Aim. This study aims to explore the molecular epidemiology and clinical features of HBoV isolates in patients with respiratory diseases.Methodology. Retrospectively, between 2018 and 2020, 5941 respiratory samples from patients with respiratory diseases were screened for respiratory viruses using multiplex real-time PCR. Samples that were positive for HBoV were then subjected to NP1 and VP1/PV2 phylogenetic analysis.Results. HBoV was detected in 1.9 % of the patients, with a peak incidence of infection among children <1 year old. Co-infection with other respiratory viruses was observed in 56.8 % of HBoV-positive patients. Fever, cough and respiratory distress were the most common clinical features of HBoV infection. Phylogenetic analysis of the Kuwaiti HBoV isolates revealed that all the isolates were of the HBoV-1 genotype, with slight sequence variations among the isolates.Conclusion. This study illustrated the predominance of the HBoV-1 genotype in patients with respiratory diseases in Kuwait with minimal genetic variability. It also highlighted the clinical features of HBoV-1 infection, verifying its role in respiratory diseases.

Human coronavirus OC43 and other respiratory viruses from acute respiratory infections of Egyptian children

Respiratory infections have a significant impact on health worldwide. Viruses are major causes of acute respiratory infections among children. Limited information regarding its prevalence in Egypt is available. This study investigated prevalence of 10 respiratory viruses; Adenovirus, influenza A, B, respiratory syncytial virus (RSV), Parainfluenza virus (PIV)type 1-4, enterovirus, and human coronavirus OC43 (HCoV-OC43) among children in Alexandria, Egypt presenting with acute lower respiratory tract infections.The study was conducted on children <14 years of age selected from ElShatby Pediatric Hospital, Alexandria University, Egypt. One hundred children presenting during winter season with influenza-like illness were eligible for the study. Oropharyngeal swabs were collected and subjected to viral RNA and DNA extraction followed by polymerase chain reaction.Viral infections were detected in 44% of cases. Adenovirus was the most common, it was found in 19% of the patients. Prevalence of PIV (3 and 4) and enterovirus was 7% each. Prevalence of RSV and HCoV-OC43 was 5% and 3% respectively. Two percentage were Influenza A positive and 1% positive for influenza B. Mixed viral infection was observed in 7%.To the best of our knowledge, this is the first report of the isolation of HCoV-OC43 from respiratory infections in Alexandria, Egypt.

Co-detection of bocavirus and bacteria in a respiratory specimen from a pregnant woman using multiplex real time PCR; a pathogenic role, or a bystander?

A pregnant woman presented by cough and dyspenia. Employing a respiratory multiplex real-time PCR, Human bocavirus (HBoV), Haemophilus influenza and Staphylococcus aureus were positive at cycle thresholds (CTs) of 21, 35 and 33.5, respectively. The patient was diagnosed for bacterial respiratory infection superimposed by bocavirus due to a relative high CT value. Patient's condition improved using bronchodilators and corticosteroid without any further antibiotic treatment. HBoV is not exclusively a bystander pathogen in some patients.

Phylogenetic analysis of human bocavirus in children with acute respiratory infections in Iran

Human bocavirus (HBoV) was first characterized in nasopharyngeal aspirates from young children with acute respiratory infections. It is prevalent among children with acute wheezing. This study was carried out in order to analyze the infection frequency and coinfection rates of HBoV with respiratory syncytial virus (RSV) and to perform phylogenetic analysis of HBoV in samples of children with acute respiratory infection in Isfahan, Iran. During the time period 2016-2017, altogether 75 respiratory samples from children hospitalized with acute respiratory infection were collected. The samples were first screened for RSV by direct immunofluorescence method and then subjected to detect HBoV DNA by PCR. Genotyping of HBoV-positive samples was conducted by direct sequencing of PCR products using NP and VP1/VP2 genes. Out of 75 respiratory samples, 20 (26.7%) and 10 (13.3%) were positive for RSV and HBoV, respectively. The coinfection rate was 40% (p = 0.048). Considering the seasonal distribution, winter has the highest extent outbreak (p = 0.036). Sequence analysis of positive samples exhibits that all of the isolated HBoV were related to genotype 1 (HBoV-1) with minimal sequence variations. Increasing frequency of HBoV suggests that the virus is related to acute respiratory infection in children. A single genetic lineage of HBoV1 seems to be the major genotype in Iran.

The Molecular Detection of Human Bocavirus (HBoV) in Colorectal Tissue with Malignant and Non-Malignant Lesions

Background: Colorectal cancer (CRC) as a worldwide human health concern is identified being a multifactorial subject that infection with specific viral particles such as oncogenic viruses is research interest. Human bocavirus (HBoV) as a recent isolated virus has been investigated in many respiratory and enteric diseases but rare studies evaluates it in tissue specimens especially in cancerous sections. The aim of this study was to detect the presence of HBoV genome and its genotyping in CRC patient’s tissue and compare the result with matched healthy control group tissue. Method: in this retrospective case-control study, CRC cases were sporadic and non-familial cancerous while control subjects had healthy or non-malignant lesions in colon tissue. A conventional-PCR performed by specific primers for HBoV VP1 gene. After sequencing of positive PCR products, raw data used for trimming and alignment by bioinformatics software CLC Main Workbench 5 and MEGA5. SPSS v.22 used for statistical calculations. Result: a total of 157 subjects were participated that 66 were diagnosed as CRC cases and 91 were non-CRC colon tissue as control group that matched by the cases. The mean age (y) ± standard deviation of each case and control groups were 59.35±14.48 and 57.21±14.66, respectively. PCR results showed there were 1.3% (2/157) HBoV positive (of each groups one was positive). Sequencing analysis showed all were HBoV-1 genotype. Conclusion: our study showed there are low rate of HBoV genome in Iranian CRC and non-CRC colon tissue. Furthermore, the predominant genotype in our studied subsets were HBoV-1 according to phylogenetic analysis.

Impact of RSV Coinfection on Human Bocavirus in Children with Acute Respiratory Infections

OBJECTIVE

The objective of this study was to assess epidemiological and clinical features of human bocavirus (HBoV) coinfection with other viruses.

METHOD

Children coinfected with HBoV between January 2012 and December 2014 were enrolled and retrospectively reviewed.

RESULT

A total of 984 patients were stratified into five groups: HBoV infection alone (n = 249), respiratory syncytial virus (RSV) infection alone (n = 649), HBoV coinfection with RSV (n = 28), with human rhinovirus (HRV) (n = 39) and with other virus (n = 19). Length of hospitalization was longer in HBoV coinfection with RSV group than HBoV (9.0 days vs. 7.0 days, p = 0.001), RSV (9.0 days vs. 8.0 days, p = 0.016) infection alone group. Pneumonia was more common in the HBoV coinfection with RSV group compared with the HBoV, RSV infection alone group, respectively (75.0% vs. 44.2%, 31.3%, p < 0.001). HBoV DNA copy numbers (383 000 copies/ml) were positively correlated with the length of hospitalization (r = 0.334, p < 0.001).

CONCLUSION

HBoV coinfection with RSV increases HBoV infection severity.

Severe outcomes associated with respiratory viruses in newborns and infants: a prospective viral surveillance study in Jordan

OBJECTIVE

To assess virus-specific hospitalisation rates, risk factors for illness severity and seasonal trends in children hospitalised with acute respiratory infections (ARI).

DESIGN

Prospective cohort study.

SETTING

A government hospital serving low-income and middle-income population in Amman, Jordan.

PARTICIPANTS

Children under 2 years of age hospitalised with fever and/or respiratory symptoms (n=3168) from 16 March 2010 to 31 March 2013. Children with chemotherapy-associated neutropenia and newborns who had never been discharged after birth were excluded from the study.

OUTCOME MEASURES

Hospitalisation rates and markers of illness severity: admission to intensive care unit (ICU), mechanical ventilation (MV), oxygen therapy, length of stay (LOS) and death.

RESULTS

Of the 3168 subjects, 2581 (82%) had at least one respiratory virus detected, with respiratory syncytial virus (RSV) being the most predominant pathogen isolated. During admission, 1013 (32%) received oxygen therapy, 284 (9%) were admitted to ICU, 111 (4%) were placed on MV and 31 (1%) children died. Oxygen therapy was higher in RSV-only subjects compared with human rhinovirus-only (42%vs29%, p<0.001), adenovirus-only (42%vs21%, p<0.001) and human parainfluenza virus-only (42%vs23%, p<0.001) subjects. The presence of an underlying medical condition was associated with oxygen therapy (adjusted OR (aOR) 1.95, 95% CI 1.49 to 2.56), ICU admission (aOR 2.51, 95% CI 1.71 to 3.68), MV (aOR 1.91, 95% CI 1.11 to 3.28) and longer LOS (aOR1.71, 95% CI 1.37 to 2.13). Similarly, younger age was associated with oxygen therapy (0.23, 95% CI 0.17 to 0.31), ICU admission (aOR 0.47, 95% CI 0.30 to 0.74), MV (0.28, 95% CI 0.15 to 0.53) and longer LOS (aOR 0.47, 95% CI 0.38 to 0.59). Pneumonia was strongly associated with longer LOS (aOR 2.07, 95% CI 1.65 to 2.60), oxygen therapy (aOR 2.94, 95% CI 2.22 to 3.89), ICU admission (aOR 3.12, 95% CI 2.16 to 4.50) and MV (aOR 3.33, 95% CI 1.85 to 6.00). Virus-specific hospitalisation rates ranged from 0.5 to 10.5 per 1000 children.

CONCLUSION

Respiratory viruses are associated with severe illness in Jordanian children hospitalised with ARI. Prevention strategies such as extended breast feeding, increased access to palivizumab and RSV vaccine development could help decrease hospitalisation rates and illness severity, particularly in young children with underlying medical conditions.

Viral aetiology of wheezing in children under five

Background & objectives:

Wheezing is a common problem in children under five with acute respiratory infections (ARIs). Viruses are known to be responsible for a considerable proportion of ARIs in children. This study was undertaken to know the viral aetiology of wheezing among the children less than five years of age, admitted to a tertiary care hospital in eastern India.

Methods:

Seventy five children, under the age of five years admitted with wheezing, were included in the study. Throat and nasal swabs were collected, and real-time multiplex polymerase chain reaction (PCR) assay was used to screen for influenza 1 and 2, respiratory syncytial virus (RSV), parainfluenza virus (PIV) 1, 2, 3 and 4, rhinovirus, human meta-pneumovirus, bocavirus (HBoV), Coronavirus, adenovirus, Enterovirus and Parechovirus.

Results:

The total viral detection rate was 28.57 per cent. Viral RNA markers were detected from children diagnosed to be having pneumonia (3 cases), bronchiolitis (9 cases), episodic wheeze (2 cases) and multitrigger wheeze (6 cases). RSV was the most common virus (35%) followed by PIV1, 2 and 3 (20%), HBoV (10%) and rhinovirus (5%). However, mixed infection was observed in 30 per cent of cases.

Interpretation & conclusions:

The study reported the presence of respiratory viral agents in 28.57 per cent of children with wheezing; RSV and PIV were most common, accounting to 55 per cent of the total cases. Mixed infection was reported in 30 per cent of cases. Seasonal variation in the occurrence of these viruses was also noted. Further studies need to be done with a large sample and longer follow up period to verify these findings.

Evidence of human coroanvirus (229E), in patients with respiratory infection, Iran, 2015: the first report

BACKGROUND AND OBJECTIVES

Human coronaviruses (HCoVs) are one of the main causes of upper respiratory tract infections in humans. While more often responsible for mild illness, they have been associated with illnesses that require hospitalization.

MATERIALS AND METHODS

270 Samples from patients hospitalized with the respiratory infection during the autumn season of 2015 were evaluated for the presence of four HCoVs (OC43, 229E, HUK1, and NL63) using an optimized SYBR green RT-PCR assay.

RESULTS

Fifteen HCoV-229E positive samples were identified (5.5 % positive). 85% of positive samples were male with the range of age between 12- 75 years old.

CONCLUSION

It is the first comprehensive study on determination of the role of human coronaviruses in respiratory infections in Iran. Our data provide a novel insight into the epidemiology of HCoVs in Iran. Further studies are needed and should include the isolation and molecular characterization of HCoVs in Iran.

Human bocavirus infections among children less than two years old in Iran during fall and winter 2012-2013

BACKGROUND AND OBJECTIVES

Human bocavirus (HBoV) is a newly discovered parvovirus. It has been detected primarily in children with acute respiratory tract infections. This study was conducted to clarify the frequency and genotype circulation pattern of HBoV in Iran.

MATERIALS AND METHODS

Conventional PCR was performed on throat swabs of patients less than two years of age with respiratory illnesses during fall and winter 2012-2013.

RESULTS

HBoV virus DNA was detected in 15 of 140 samples (10.7 %). Sequencing and phylogenetic analysis on 5 samples showed that all were HBoV1. The positive samples were negative for influenza A and B viruses while co-infection with RSV was found in 2 (13.3%).

CONCLUSION

This study adds to the body of knowledge about the role of HBoV in acute respiratory illnesses in children in Iran.

Clinical significance of different virus load of human bocavirus in patients with lower respiratory tract infection

To assess the impact of human bocavirus (HBoV) virus load on epidemiologic and clinical characteristics in children with lower respiratory tract infection (LRTI). Clinical records of a total of 654 patients with HBoV infection during January 2013 and December 2014 were retrospectively reviewed. Patients with high HBoV virus load infection had a similar age distribution with the total HBoV infection, which had a peak age group of 6–24 months. Patients with high virus load are significantly younger (P < 0.01) than those with low load. The patients who had wheeze and tachypnea/dyspnea at presentation were more strongly affiliated with the patients with high virus load (both P < 0.01). Co-infection was found significantly more frequently among patients with low virus load than those with high virus load (57.0% vs 38.9%; P < 0.01). High virus load was a significant predictor of severe LRTI (P < 0.05). HBoV infections are found in an important proportion of the hospitalized children with respiratory illnesses (8.85% in our series). A high HBoV virus load could be an etiologic agent for LRTI, which may lead to more severe lower respiratory tract symptom and severe disease.

Natural history and epidemiology of respiratory syncytial virus infection in the Middle East: Hospital surveillance for children under age two in Jordan

Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis and viral pneumonia in infants and young children worldwide. In the Middle East and Arab countries, the burden of RSV-associated hospitalizations is not well characterized. We sought to determine the burden and clinical/epidemiological characteristics of RSV hospitalization in young children in Amman, Jordan. We investigated risk factors for severity including vitamin D levels.

METHODS

We conducted viral surveillance with clinical and demographic data in children <2 years admitted with respiratory symptoms and/or fever at the Al-Bashir Government Hospital from March16, 2010 to March 31, 2013. Nasal/throat swabs were obtained and placed into lysis buffer, and frozen at -80°C until testing by real-time RT-PCR for 11 respiratory viruses. Heel stick blood or sera samples for 25-hydroxyvitamin D [25(OH)D] levels were obtained and sent to a central laboratory for mass spectrometry.

RESULTS

Of the 3168 children, >80% testing positive for one virus, with RSV the most common virus detected (44%). The RSV-associated hospitalization rate was highest in children <6 months with an annual range of 21.1-25.9 per 1000, compared to 6.0-8.0 in 6-11-month-olds and 1.6-2.5 in 12-23-month-olds. RSV-positive children compared with RSV-negative were more likely to be previously healthy without underlying medical conditions, less likely to be born prematurely, had a higher frequency of supplemental oxygen use, and had lower median vitamin D levels. Risk factors for oxygen use in RSV-positive children included underlying medical conditions, lack of breastfeeding, younger age, and higher viral load.

CONCLUSION

RSV is a major cause of illness in hospitalized Jordanian children and is associated with increased severity compared to other respiratory viruses. Children with RSV in the Middle East would benefit from future RSV vaccines and antiviral therapy.

Prevalence of human respiratory syncytial virus circulating in Iran

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infection during early childhood and is associated with a great burden on patients, parents, and society. While no treatment is yet available, results from recent phase 2 clinical trials of cell-entry inhibitors and RSV vaccines are promising. To prepare for introduction of these novel therapeutics, good understanding of its molecular epidemiology and continuous RSV surveillance data are necessary. This paper provides an overview of RSV prevalence and genotype distribution in Iran from 1996 to 2013. This meta-analysis includes 21 published studies. In total, 775 (18.7%) of 4140 respiratory specimens were positive for RSV infection. The male-female ratio of RSV-positive patients was 1.5:1. Significant peaks of RSV infection were detected during the cold season (November-March). RSV infection was mainly observed in patients <2 years of age. Phylogenetic studies showed that genotypes GA1, GA2, GA5, and BA co-circulated in Iran in 2007-2013. This review highlights the necessity of introducing standard molecular surveillance programs to inform the epidemiological, clinical, and pathological characteristics of various RSV genotypes. Improved understanding of the molecular epidemiology will be useful for development of novel RSV therapeutics.

Human bocavirus isolated from children with acute respiratory tract infections in Korea, 2010-2011

Human bocavirus (HBoV) was first recognized in respiratory samples in 2005. The clinical importance of HBoV infection remains unclear. This report describes the clinical features and molecular phylogeny of HBoV isolates in children with acute respiratory infections. Nasopharyngeal aspirates were obtained from 1,528 children with acute respiratory infections between 2010 and 2011. Respiratory samples were screened for HBoV by multiplex PCR. A phylogenetic analysis of the HBoV VP1/VP2 gene was also undertaken. HBoV was detected in 187 (12.2%) of the 1,528 patients with a peak incidence of infection observed in patients aged 12–24 months. Coinfection with other respiratory viruses was observed in 107 (57.2%) of the HBoV‐positive children. The peak of HBoV activity occurred during the month of June in both 2010 and 2011. A higher previous history of wheezing (P = 0.016), a higher frequency of chest retraction (P < 0.001) and wheezing (P = 0.022), a higher respiratory symptom score (P = 0.002), and a longer duration of hospital stay (P = 0.021) were observed in HBoV‐positive children compared with the HBoV‐negative group. Phylogenetic analysis showed all 187 HBoV‐positive isolates were identified as HBoV 1, indicating minimal sequence variations among the isolates. A single lineage of HBoV 1 was found to have circulated in children with acute respiratory infections between 2010 and 2011 and was associated with several clinical characteristics including age, seasonality, and clinical severity with retraction, wheezing, and longer hospitalization. The clinical relevance of the minimal sequence variations of HBoV remains to be determined. J. Med. Virol. 86:2011–2018, 2014. © 2014 The Authors. Journal of Medical Virology published by Wiley Periodicals, Inc.

Detection of human Bocavirus 1, 2 and 3 from patients with acute gastroenteritis

AIM

We aimed to investigate the prevalence of Human Bocavirus isolates among Iranian patients suffering from acute gastroenteritis.

BACKGROUND

Human Bocavirus is a new parvovirus that has been identified in association with gastroenteritis. Limited data are available about HBoV in Iran.

PATIENTS AND METHODS

Viral DNA was extracted from all 294 stool samples. HBoV DNA was detected in extracted samples by polymerase chain reaction (PCR) amplification of a 354 bp of noncapsid protein 1 (NP1) gene. In addition, all samples were also subjected to a nested PCR to amplify a 455 bp of nonstructural 1 (NS1) gene.

RESULTS

The main clinical symptoms among HBoV positive patients were diarrhea (77.7%), fever (62.9%), vomiting (55.5%), and anorexia (59.2%). NP1 PCR was positive in 8 samples (2.72%), NS1 was positive in 16 patients (5.44%) and 3 samples had positive results in both regions (1.02%).

CONCLUSION

Our results suggest that HBoV could be considered as one of the important etiologic agents of acute gastroenteritis cases in Iran.

Viral etiologies of lower respiratory tract infections among Egyptian children under five years of age

Background

Lower respiratory tract infections (LRTI) are responsible for a considerable number of deaths among children, particularly in developing countries. In Egypt and the Middle East region, there is a lack of data regarding the viral causes of LRTI. In this study, we aimed to identify the relative prevalence of various respiratory viruses that contribute to LRTIs in young children. Although, nucleic acid-based methods have gained importance as a sensitive tool to determine the viral infections, their use is limited because of their prohibitive cost in low-income countries. Therefore, we applied three different laboratory methods, and presented the different virus prevalence patterns detected by each method.

Methods

We collected nasopharyngeal aspirate samples, demographic data and, clinical data from 450 children under five years of age who presented with LRTI at Abou El Reesh hospital in Cairo during a one-year period. To identify the viral causes of the LRTI we used direct fluorescence assay, real-time reverse-transcriptase polymerase chain reaction (rt-RT-PCR), and shell vial culture. We tested for eight major respiratory viruses.

Results

Two hundred sixty-nine patients (59.9%) had a viral infection, among which 10.8% had a co-infection with two or more viruses. By all three methods, respiratory syncytial virus (RSV) was the most predominant, and parainfluenza virus type 2 (HPIV-2), influenza B virus (FLUBV) were the least predominant. Other viral prevalence patterns differed according to the detection method used. The distribution of various viruses among different age groups and seasonal distribution of the viruses were also determined.

Conclusions

RSV and human adenovirus were the most common respiratory viruses detected by rt-RT-PCR. Co-infections were found to be frequent among children and the vast majority of co-infections were detected by nucleic acid-based detection assays.

Human bocaviruses are not significantly associated with gastroenteritis: results of retesting archive DNA from a case control study in the UK

Gastroenteritis is a common illness causing considerable morbidity and mortality worldwide. Despite improvements in detection methods, a significant diagnostic gap still remains. Human bocavirus (HBoV)s, which are associated with respiratory infections, have also frequently been detected in stool samples in cases of gastroenteritis, and a tentative association between HBoVs, and in particular type-2 HBoVs, and gastroenteritis has previously been made. The aim of this study was to determine the role of HBoVs in gastroenteritis, using archived DNA samples from the case-control Infectious Intestinal Disease Study (IID). DNA extracted from stool samples from 2,256 cases and 2,124 controls were tested for the presence of HBoV DNA. All samples were screened in a real time PCR pan-HBoV assay, and positive samples were then tested in genotype 1 to 3-specific assays. HBoV was detected in 7.4% but no significantly different prevalence was observed between cases and controls. In the genotype-specific assays 106 of the 324 HBoV-positive samples were genotyped, with HBoV-1 predominantly found in controls whilst HBoV-2 was more frequently associated with cases of gastroenteritis (p<0.01). A significant proportion of HBoV positives could not be typed using the type specific assays, 67% of the total positives, and this was most likely due to low viral loads being present in the samples. However, the distribution of the untyped HBoV strains was no different between cases and controls. In conclusion, HBoVs, including HBoV-2 do not appear to be a significant cause of gastroenteritis in the UK population.

Human bocavirus NP1 inhibits IFN-β production by blocking association of IFN regulatory factor 3 with IFNB promoter

Human bocavirus (HBoV) mainly infects young children. Although many infected children suffer from respiratory or gastroenteric tract diseases, an association between HBoV and these diseases is not definite. Because modulation of type I IFN is crucial for viruses to establish efficient replication, in this study, we tested whether HBoV modulates type I IFN production. We observed that a nearly full-length HBoV clone significantly reduced both Sendai virus (SeV)- and poly(deoxyadenylic-thymidylic) acid-induced IFN-β production. Further study showed that NP1 blocked IFN-β activation in response to SeV, poly(deoxyadenylic-thymidylic) acid, and IFN-β pathway inducers, including retinoic acid-inducible protein I, mitochondrial antiviral signaling protein, inhibitor of κB kinase ε, and TANK-binding kinase 1. In addition, NP1 interfered with IRF-3-responsive PRD(III-I) promoter activated by SeV and a constitutively active mutant of IRF-3 (IRF-3/5D). Although NP1 suppressed the IRF-3 pathway, it did not affect IRF-3 activation processes, including phosphorylation, dimerization, and nuclear translocation. Coimmunoprecipitation assays confirmed the interaction between NP1 and IRF-3. Additional deletion mutagenesis and coimmunoprecipitation assays revealed that NP1 bound to the DNA-binding domain of IRF-3, resulting in the interruption of an association between IRF-3 and IFNB promoter. Altogether, our results indicate that HBoV NP1 blocks IFN production through a unique mechanism. To our knowledge, this is the first study to investigate the modulation of innate immunity by HBoV. Our findings suggest a potential immune-evasion mechanism used by HBoV and provide a basis for better understanding HBoV pathogenesis.

High viral load of human bocavirus correlates with duration of wheezing in children with severe lower respiratory tract infection

Background

Human bocavirus (HBoV) is a newly discovered parvovirus and increasing evidences are available to support its role as an etiologic agent in lower respiratory tract infection (LRTI). The objective of this study is to assess the impact of HBoV viral load on clinical characteristics in children who were HBoV positive and suffered severe LRTI.

Methods

Lower respiratory tract aspirates from 186 hospitalized children with severe LRTI were obtained by bronchoscopy. HBoVs were detected by real-time PCR and other 10 infectious agents were examined using PCR and/or direct fluorescent assay.

Results

Thirty-one patients (24.6%) were tested positive for HBoV in the respiratory tract aspirates. Fifteen samples had a high viral load (>10⁴ copies/mL) and the other sixteen samples had a low viral load (<10⁴ copies/mL). The duration of presented wheezing and hospitalization was longer in children with high viral load of HBoV than that in children with low viral load. The days of wheezing showed a correlation with viral load of HBoV.

Conclusion

We confirmed that HBoV was frequently detected in patients with severe LRTI. Wheezing was one of the most common symptoms presented by patients with positive HBoV. A high HBoV viral load could be an etiologic agent for LRTI, which led to more severe lower respiratory tract symptom, longer duration of wheezing and hospitalization.

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.

Detection of human bocavirus and human metapneumovirus by real-time PCR from patients with respiratory symptoms in Southern Brazil

The introduction of newer molecular methods has led to the discovery of new respiratory viruses, such as human metapneumovirus (hMPV) and human bocavirus (hBoV), in respiratory tract specimens. We have studied the occurrence of hMPV and hBoV in the Porto Alegre (PA) metropolitan area, one of the southernmost cities of Brazil, evaluating children with suspected lower respiratory tract infection from May 2007-June 2008. A real-time polymerase chain reaction method was used for amplification and detection of hMPV and hBoV and to evaluate coinfections with respiratory syncytial virus (RSV), influenza A and B, parainfluenza 1, 2 and 3, human rhinovirus and human adenovirus. Of the 455 nasopharyngeal aspirates tested, hMPV was detected in 14.5% of samples and hBoV in 13.2%. A unique causative viral agent was identified in 46.2% samples and the coinfection rate was 43.7%. For hBoV, 98.3% of all positive samples were from patients with mixed infections. Similarly, 84.8% of all hMPV-positive results were also observed in mixed infections. Both hBoV and hMPV usually appeared with RSV. In summary, this is the first confirmation that hMPV and hBoV circulate in PA; this provides evidence of frequent involvement of both viruses in children with clinical signs of acute viral respiratory tract infection, although they mainly appeared as coinfection agents.

Human bocavirus in patients with respiratory tract infection

BACKGROUND

Human bocavirus (HBoV) is a newly identified viral pathogen, and its clinical epidemiology and significance in respiratory infections have not yet been completely elucidated. We investigated the prevalence of HBoV infection and the association between viral (HBoV) load and clinical features of the infection in patients of all age-groups.

METHODS

Nasopharyngeal aspirates from patients with symptoms of respiratory infection were tested for presence of HBoV by using real-time polymerase chain reaction. HBoV-positive patients were categorized into low- and high-viral-load groups using 1.0×10(6) copies/mL as the threshold value of viral load.

RESULTS

Detection rate of HBoV was 4.8% (N=93) in a total of 1,926 samples with peak incidence of infection being observed in patients aged 6-12 months. HBoV infection was more frequently observed in young children, especially, in children aged less than 5 yr, and the HBoV load decreased with increase in age. HBoV was codetected with other respiratory viruses in 17 (18.3%) of the 93 HBoV-positive patients and 15 patients (88.2%) belonged to the low-viral-load group. Patients infected with HBoV alone showed a higher viral load than those patients in whom HBoV was codetected with other respiratory viruses (median load, 3.78×10(5) copies/mL vs. 1.94×10(4) copies/mL, P=0.014). Higher pulse rate (P=0.007) and respiratory rate (P=0.021) were observed in patients with a high-viral-load.

CONCLUSIONS

Our results suggest that HBoV may be the causative agent of respiratory infection in the high-viral-load group.

Impact of bacterial colonization on the severity, and accompanying airway inflammation, of virus-induced wheezing in children

It is reported that bacterial colonization of the airway in neonates affects the likelihood and severity of subsequent wheezing in childhood. This study aimed to explore the impact of bacterial colonization on the severity of virus-induced wheezing, and accompanying airway inflammation. Nasopharyngeal aspirates (NPAs) from 68 hospitalized children with bronchiolitis and 85 children with recurrent wheezing were obtained. Eleven common respiratory viruses were sought by PCR and/or direct fluorescence assay. Bacteria were isolated from NPAs by routine culture methods. Cell numbers and concentrations of cytokines/chemokines in the NPAs were measured, and nucleated cells were characterized. The frequency of bacterial colonization in children with recurrent wheezing was significantly higher than in children with an initial attack of bronchiolitis. Bacterial colonization accompanying virus infection had no effect on clinical manifestations, duration of hospitalization, concentrations of cytokines/chemokines (except interleukin-10 (IL-10)) or cellularity in the children with bronchiolitis; however, among the children with recurrent wheezing, those who had coexistent non-invasive bacterial colonization and virus infection presented more frequent cyanosis, longer duration of hospitalization, a higher concentration of IL-10 and a higher percentage of neutrophils in NPAs than those with virus infection but without bacterial colonization. Bacterial colonization was common in children with virus-induced wheezing, particularly in the situation of recurrent wheezing. To some extent, bacterial colonization accompanying virus infection may contribute to the severity of the wheezing because of its impact on airway inflammation.

Impact of bacterial colonization on the severity, and accompanying airway inflammation, of virus-induced wheezing in children

It is reported that bacterial colonization of the airway in neonates affects the likelihood and severity of subsequent wheezing in childhood. This study aimed to explore the impact of bacterial colonization on the severity of virus-induced wheezing, and accompanying airway inflammation. Nasopharyngeal aspirates (NPAs) from 68 hospitalized children with bronchiolitis and 85 children with recurrent wheezing were obtained. Eleven common respiratory viruses were sought by PCR and/or direct fluorescence assay. Bacteria were isolated from NPAs by routine culture methods. Cell numbers and concentrations of cytokines/chemokines in the NPAs were measured, and nucleated cells were characterized. The frequency of bacterial colonization in children with recurrent wheezing was significantly higher than in children with an initial attack of bronchiolitis. Bacterial colonization accompanying virus infection had no effect on clinical manifestations, duration of hospitalization, concentrations of cytokines/chemokines (except interleukin-10 (IL-10)) or cellularity in the children with bronchiolitis; however, among the children with recurrent wheezing, those who had coexistent non-invasive bacterial colonization and virus infection presented more frequent cyanosis, longer duration of hospitalization, a higher concentration of IL-10 and a higher percentage of neutrophils in NPAs than those with virus infection but without bacterial colonization. Bacterial colonization was common in children with virus-induced wheezing, particularly in the situation of recurrent wheezing. To some extent, bacterial colonization accompanying virus infection may contribute to the severity of the wheezing because of its impact on airway inflammation.

PCR improves diagnostic yield from lung aspiration in Malawian children with radiologically confirmed pneumonia

Background

Accurate data on childhood pneumonia aetiology are essential especially from regions where mortality is high, in order to inform case-management guidelines and the potential of prevention strategies such as bacterial conjugate vaccines. Yield from blood culture is low, but lung aspirate culture provides a higher diagnostic yield. We aimed to determine if diagnostic yield could be increased further by polymerase chain reaction (PCR) detection of bacteria (Streptococcus pneumoniae and Haemophilus influenzae b) and viruses in lung aspirate fluid.

Methods

A total of 95 children with radiological focal, lobar or segmental consolidation had lung aspirate performed and sent for bacterial culture and for PCR for detection of bacteria, viruses and Pneumocystis jirovecii. In children with a pneumococcal aetiology, pneumococcal bacterial loads were calculated in blood and lung aspirate fluid.

Results

Blood culture identified a bacterial pathogen in only 8 patients (8%). With the addition of PCR on lung aspirate samples, causative pathogens (bacterial, viral, pneumocystis) were identified singly or as co-infections in 59 children (62%). The commonest bacterial organism was S.pneumoniae (41%), followed by H. influenzae b (6%), and the commonest virus identified was adenovirus (16%), followed by human bocavirus (HBoV) (4%), either as single or co-infection.

Conclusions

In a select group of African children, lung aspirate PCR significantly improves diagnostic yield. Our study confirms a major role of S.pneumoniae and viruses in the aetiology of childhood pneumonia in Africa.

Genetic Diversity in the G Protein Gene of Human Respiratory Syncytial Virus among Iranian Children with Acute Respiratory Symptoms

OBJECTIVE

Acute respiratory infection (ARI) is the major cause of morbidity and mortality in children worldwide. Human respiratory syncytial virus (HRSV) is main viral agent of ARI in infants and young children in terms of effect and prevalence. The aim of this study was to investigate HRSV genotypes during one season in Iran.

METHODS

In this cross-sectional study, 107 throat swabs were collected from children less than 5 years of age with acute respiratory infection from October to December 2009. The respiratory samples were obtained from several provinces: Tehran, Isfahan, Hamadan, Zanjan, Kordestan, Lorestan and West Azarbayjan, and were tested for G protein gene of HRSV by RT-PCR.

FINDINGS

Of the 107 respiratory samples, 24 (22.42%) were positive for HRSV, of which 16 (66.6%) belonged to subgroup A and 8 (33.4%) to subgroup B. Phylogenetic analysis revealed that subgroup A strains fell in two genotypes GA1 and GA2, whereas subgroup B strains clustered in genotype BA.

CONCLUSION

This study revealed that multiple genotypes of HRSV cocirculated during the season 2009 in Iran. Also subgroup A strains were more prevalent than subgroup B strains, and genotype GA1 was predominant during the season.

Comparison of Th-cell immunity against human bocavirus and parvovirus B19: proliferation and cytokine responses are similar in magnitude but more closely interrelated with human bocavirus

Human parvovirus B19 (B19) has been, for decades, the only parvovirus known to be pathogenic in humans. Another pathogenic human parvovirus, human bocavirus (HBoV), was recently identified in respiratory samples from children with acute lower respiratory tract symptoms. Both B19 and HBoV are transmitted by the respiratory route. The vast majority of adults are IgG seropositive for HBoV, whereas the HBoV-specific Th-cell immunity has not much been studied. The aim of this study was to increase our knowledge on HBoV-specific Th-cell immunity by examining HBoV-specific T-cell proliferation, Interferon-gamma (IFN-γ), IL-10 and IL-13 responses in 36 asymptomatic adults. Recombinant HBoV VP2 virus-like particles (VLP) were used as antigen. HBoV-specific responses were compared with those elicited by B19 VP2 VLP. Proliferation, IFN-γ and IL-10 responses with HBoV and B19 antigens among B19-seropositive subjects were statistically similar in magnitude, but the cytokine and proliferation responses were much more closely correlated in HBoV than in B19. Therefore, at the collective level, B19-specific Th-cell immunity appears to be more divergent than the HBoV-specific one.

Human bocavirus as an important cause of respiratory tract infection in Taiwanese children

BACKGROUND

Human bocavirus (HBoV), first described in September 2005, was considered a causative agent of previously unexplained respiratory tract diseases. However, only few reports provide the evidence for an association between HBoV and respiratory tract diseases. We conducted a prospective clinical and molecular study of HBoV in Taiwan.

METHODS

We enrolled 705 children who visited our outpatient pediatric clinics in a medical center because of symptoms and signs of respiratory tract infections from November 2008 to October 2009. Throat swab was performed and HBoV polymerase chain reaction and viral culture were done simultaneously.

RESULTS

Positive viral results were confirmed in 159 (22.6%) of the 705 children. HBoV was found in 35 samples and it was supposed to be as a single virus in 32 samples because viral isolation of these 32 samples did not identify other virus. The other three patients had coinfection with another virus. One child got HBoV reinfection 6 months after the first infection. Seventy-one percentage of these HBoV infections occurred between November and March. Of the 34 children with positive HBoV, 26 (76%) patients were younger than 5 years; their common symptoms were cough, rhinorrhea, and fever; the most common diagnoses were bronchitis (34%, 12/35) and sinusitis (31%, 11/35) followed by pharyngitis (29%, 10/35) and asthma exacerbation (26%, 9/35). Three of the 34 patients needed hospitalization.

CONCLUSION

HBoV is an emerging human parvovirus that may cause respiratory tract infection in young children. Diseases associated with HBoV may range from pharyngitis, sinusitis, acute otitis media to bronchitis, asthma, and even pneumonia.

Phylogenetic analysis of human bocavirus isolated from children with acute respiratory illnesses and gastroenteritis in Iran

Human bocavirus (hBoV) was first discovered in respiratory samples from children in 2005, and has been classified in the Parvoviridae family. hBoV has also been detected in children with acute gastroenteritis. This study was performed to analyze the frequency and phylogeny of hBoV in the respiratory and stool samples of children with acute respiratory tract illnesses and gastroenteritis during the time period beginning 2006 and ending 2008, at the Virology Research Centre, Masih Daneshvari Hospital, NRITLD, Tehran, Iran. Respiratory and stool samples were screened for hBoV by nested polymerase chain reaction with primers from the NS-1 gene. Nine out of 133 respiratory samples (6.8%) and 6 out of 47 stool samples (12.8%) were positive for hBoV. Ten positive samples (7 respiratory and 3 stool samples) were subjected to phylogenetic analysis by sequencing a fragment of the VP1/VP2 gene junction. The results showed a high similarity among isolates (>or=99%). It was found that hBoV isolates can be divided into 3 genetic groups.

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.

Burden of respiratory syncytial virus in hospitalized infants and young children in Amman, Jordan

Acute respiratory infections (ARI) play a major role in hospitalizations in the Middle East, but the specific viral causes are unknown. We conducted prospective viral surveillance in children <5 y of age admitted with ARI and/or fever at 2 dissimilar hospitals in Amman, Jordan during peak respiratory syncytial virus (RSV) season. We collected prospective clinical and demographic data and obtained nose/throat swabs for testing for RSV by real-time polymerase chain reaction (RT-PCR). We obtained clinical and laboratory data for 728/743 (98%) subjects enrolled. The children's median age was 4.3 months, 58.4% were males, 87% were breastfed, 4% attended day care, 67% were exposed to smokers, 7% were admitted to the intensive care unit, and 0.7% died (n = 5). Out of 728 subjects, 467 (64%) tested positive by RT-PCR for RSV. Comparing RSV-positive with RSV-negative subjects, the RSV-positive subjects had lower median age (3.6 vs 6.4 months, p < 0.001) and fewer males (55% vs 64%, p = 0.02). RSV-positive children had higher rates of oxygen use (72% vs 42%, p < 0.001), a longer hospital stay (5 vs 4 days, p = 0.001), and higher hospital charges (US$538 vs US$431, p < 0.001) than RSV-negative children. In young hospitalized Jordanian infants, the medical and financial burden of RSV was found to be high. Effective preventive measures, such as an RSV vaccine, would have a significant beneficial impact.

Frequent and prolonged shedding of bocavirus in young children attending daycare

Background. Little is known about human bocavirus (HBoV) persistence and shedding and the association between HBoV detection and the onset and resolution of respiratory symptoms.

Methods. We performed HBoV testing on nasal swab samples from a prospective, longitudinal study of respiratory illness in 119 children who attended daycare.

Results. HBoV was detected in 70 children (59%) and in 106 (33%) of the 318 cases of illness. Another virus was detected in 76 (72%) of 106 HBoV-positive cases. Extended and intermittent shedding was observed, with consistent HBoV detection documented for up to 75 days. HBoV was detected in 20 (44%) of 45 asymptomatic enrollment samples, and HBoV prevalence and viral load did not differ significantly between children with and children without symptoms at enrollment. HBoV-positive illnesses were longer than HBoV-negative illnesses (odds ratio for duration of symptoms >7 days, 2.44; 95% confidence interval, 1.41–4.22), and illnesses with HBoV load ≥4 log10 copies/mL required a visit to a health care provider more often than did HBoV-negative illnesses (odds ratio, 1.64; 95% confidence interval, 1.02–2.64).

Conclusion. HBoV was more common in illnesses with greater severity. However, detection of HBoV was not associated with the presence of respiratory illness or with specific respiratory symptoms in this prospective study of infants and toddlers attending daycare centers.

Correlation between bocavirus infection and humoral response, and co-infection with other respiratory viruses in children with acute respiratory infection

BACKGROUND

Human bocavirus (HBoV), a recently discovered virus, is prevalent among children with respiratory tract infection throughout the world. Co-infection was frequently found in HBoV-positive patients. Thus, whether HBoV is responsible for the respiratory disease is still arguable.

OBJECTIVES

A comprehensive study was carried out to integrate clinical and virological prevalence in HBoV-positive outpatient children, and to determine genetic and serologic characteristics of HBoV in Shanghai, China.

STUDY DESIGN

Nasal/throat swabs and sera were obtained over a 2-year period from 817 children with respiratory tract infection to examine the presence of HBoV and its co-infection. The seroepidemiology of HBoV was studied by ELISA and Western blot against the capsid protein VP2-based fragment. Persistence of HBoV was also analyzed in 12 pairs of return-visit cases.

RESULTS

HBoV was identified in 96 samples (11.8%). The co-infection rate with other respiratory viruses was 51%. IgM was detected in 55.7% of HBoV RT-PCR-positive patients, and in 72.7% of those who had high viral genome load. In addition, persistent viral DNA positivity was detected in 10 of 12 HBoV-positive cases tested, an average of 14 days later, and one child was still HBoV-positive after 31 days.

CONCLUSION

HBoV was found frequently in children with respiratory tract symptoms associated with other respiratory viruses, and persisted in the respiratory tract and in serum and urine. The presence of IgM was significantly more prevalent in viremic patients and those diagnosed with high load of HBoV DNA in nasal/throat swabs.

Human bocavirus in children with respiratory tract infection in Shanghai: a retrospective study

BACKGROUND

Human bocavirus (HBoV) was first reported in 2005. The worldwide presence of HBoV in children with acute respiratory tract infection (ARTI) has been confirmed. This study aimed to understand the prevalence and clinical features of HBoV in children with ARTI in Shanghai and explore the causative implication of HBoV in ARTI.

METHODS

We retrospectively reviewed the medical records of 349 hospitalized children with ARTI between November 2006 and January 2007. From these children, 351 nasopharyngeal aspirate samples were collected; 325 of the samples were obtained from those with community-acquired ARTI and 26 from those with hospital-acquired ARTI. All samples were routinely screened for seven common respiratory viruses by immunofluorescence and further tested for HBoV by polymerase chain reaction.

RESULTS

HBoV was detected in 16 (4.6%) of the 351 samples, and it was the second most commonly detected virus after respiratory syncytial virus. Three (19%) HBoV-positive samples were dual infection with respiratory syncytial virus or parainfluenza virus type 3. Of the 325 children with community-acquired ARTI, HBoV was identified to be positive in 11 (3.4%), of whom 6 were diagnosed with pneumonia with patchy or interstitial infiltrates in the lung indicated by chest radiography, 3 with bronchitis, and 2 with bronchial asthma exacerbation with attendant lung infection. Out of the 26 children with nosocomial ARTI, 5 (19.2%) had bronchitis which was found to be HBoV positive without co-detection of other viruses. The HBoV-positive children were aged 1.7 months to 43 months and their mean age was 13.7 months. Sixteen (100%) children had cough, 11 (68.8%) had wheezing, and 10 (62.5%) had fever.

CONCLUSIONS

HBoV was circulating in Shanghai during the study period, and which was detected frequently in children with ARTI. HBoV was found to be associated with community-acquired ARTI and may play a pathogenic role in nosocomial ARTI.

Antibodies against structural and nonstructural proteins of human bocavirus in human sera

Immunofluorescence assays (IFAs) for detection of human bocavirus (HBoV) proteins (VP1, VP2, NP-1, and NS1) were developed. The VP1 IFA was the most sensitive for detection of IgG antibody and suitable for screening. IgG antibodies in convalescent-phase sera from HBoV-positive patients were detected by VP1 and VP2 IFAs. Sensitivities of NP-1 and NS1 IFAs were low.

Prevalence and clinical aspects of human bocavirus infection in children

Human bocavirus (HBoV) was recently described as a new member of the Parvoviridae. In order to investigate the suggested association of HBoV with respiratory and gastric disease in infants and young children, sera of 357 paediatric patients hospitalized with infectious and non-infectious diseases were retrospectively analyzed for the presence of HBoV DNA and virus-specific antibodies using quantitative PCR and ELISA, respectively. HBoV seroprevalence was determined to range from 25% in infants younger than 1 year of age to 93% in children aged more than 3 years. Viral loads between 1 x 10(2) and 1.2 x 10(6) geq/mL were observed in 6.7% (20/297) of sera obtained preferentially from young children suffering from infectious diseases. HBoV genomes were furthermore detected in 5% (3/60) of sera collected from individuals with non-infectious illnesses. HBoV DNA was present most frequently in patients with respiratory disease (9.6%). Whereas only 5.2% of patients with upper respiratory tract disease were viraemic, HBoV DNA was found in 14.6% and 10.0% of patients with lower respiratory tract illness and pneumonia, respectively. Acute HBoV infections were also observed in 7.5% of patients with gastroenteritis and in one child with inflammatory bowel disease. None of 77 patients hospitalized for various other infectious diseases (e.g. rash, urinary tract infection, meningitis) displayed viraemia. In 60.9% and 47.8% of DNA-positive children, HBoV-specific IgM and IgG was observed, respectively. The present prospective study provides comprehensive data on the clinical association of acute HBoV infection with respiratory illness and on the seroprevalence of virus-specific antibodies in children.

Adenovirus infections within a family cohort in Iran

BACKGROUND

Adenovirus is one of the most frequent viruses associated with acute respiratory infections (ARI). There is limited information of its transmission within the community.

METHODS

Cohorts of 50 families with > or =two children were visited weekly for 2 months to ascertain the presence ARI in Rasht, Iran. Nasopharyngeal swabs were obtained from symptomatic participants and at 3-4-day intervals to assess the duration of adenovirus shedding. Adenoviruses were identified by PCR and adenovirus positive amplicons were subjected to DNA sequencing.

RESULTS

Thirty-three (35%) of 94 ARI episodes in children and 8 (27%) of 30 episodes in adults were due to adenovirus (not significant, NS). 25/50 (50%) families had adenovirus infections. Children had more infections than adults, were more likely to develop symptoms if there was a symptomatic case within the household and episodes had a longer duration (P < 0.05). Adenoviruses were recovered for a median of 11 (interquartile range 5-26) days of follow up in children and 7 (2-20) days in adults (NS). Adenovirus-7 was the most frequent serotype (12 families), followed by adenovirus-6 (5 families), adenovirus-1 and 2 (4 families each), and adenovirus-5 (3 families). Both adenovirus-5 and 7 amplicons fell into two clusters. No mutations were observed during transmission within a family.

CONCLUSION

A substantial proportion of ARI in the community are due to adenovirus with further transmission within the family. Children > or =2 years experienced a higher proportion of infections than younger children and adults. Viral shedding was more prolonged in children and adenovirus-7 and 5 predominated with several clusters co-circulating in the same season.

Human metapneumovirus and human bocavirus in children

Several new viruses have recently been described in children, including human metapneumovirus (hMPV) and human bocavirus (HBoV). hMPV has been established as a common cause of upper and lower respiratory tract infections in children, often second only to respiratory syncytial virus as a cause of bronchiolitis in infants. Diagnostic tools have been developed for the clinician and effective treatment and prevention strategies are being investigated. HBoV was more recently identified. Although it was initially identified in the airway of children, high rates of codetection of other viral pathogens and detection of the virus in the stool have raised questions about the true role of HBoV as a cause of respiratory infections. A focus on epidemiology, pathogenesis, clinical features, and diagnostic techniques for hMPV and HBoV is presented.

Evidence of prior exposure to human bocavirus as determined by a retrospective serological study of 404 serum samples from adults in the United States

Recently, molecular screening for pathogenic agents has identified a partial genome of a novel parvovirus, called human bocavirus (HBoV). The presence of this newly described parvovirus correlated with upper and lower respiratory tract infections in children. Lower respiratory tract infections are a leading cause of hospital admission in children, and the etiological agent has not been identified in up to 39% of these cases. Using baculovirus expression vectors (BEVs) and an insect cell system, we produced virus-like particles (VLPs) of HBoV. The engineered BEVs express the HBoV capsid proteins stoichiometrically from a single open reading frame. Three capsid proteins assemble into the VLP rather than two proteins predicted from the HBoV genome sequence. The denatured capsid proteins VP1, VP2, and VP3 resolve on silver-stained sodium dodecyl sulfate-polyacrylamide gels as three bands with apparent molecular masses of 72 kDa, 68 kDa, and 62 kDa, respectively. VP2 apparently initiates at a GCT codon (alanine) 273 nucleotides downstream from the VP1 start site and 114 nucleotides upstream from the VP3 initiation site. We characterized the stable capsids using physical, biochemical, and serological techniques. We found that the density of the VLP is 1.32 g/cm(3) and is consistent with an icosahedral symmetry with approximately a 25-nm diameter. Rabbit antiserum against the capsid of HBoV, which did not cross-react with adeno-associated virus type 2, was used to develop enzyme-linked immunosorbent assays (ELISAs) for anti-HBoV antibodies in human serum. Using ELISA, we tested 404 human serum samples and established a range of antibody titers in a large U.S. adult population sample.

Molecular characterization of infectious clones of the minute virus of canines reveals unique features of bocaviruses

Minute virus of canines (MVC) is a member of the genus Bocavirus in the family Parvoviridae. We have molecularly cloned and sequenced the 5'- and 3'-terminal palindromes of MVC. The MVC genome, 5,404 nucleotides (nt) in length, shared an identity of 52.6% and 52.1% with that of human bocavirus and bovine parvovirus, respectively. It had distinct palindromic hairpins of 183 nt and 198 nt at the left-end and right-end termini of the genome, respectively. The left-end terminus was also found in two alternative orientations (flip or flop). Both termini shared extensive similarities with those of bovine parvovirus. Four full-length molecular clones constructed with different orientations of the left-end terminus proved to be infectious in Walter Reed canine cell/3873D (WRD) canine cells. Both MVC infection and transfection of the infectious clone in WRD cells revealed an identical RNA transcription profile that was similar to that of bovine parvovirus. Mutagenesis of the infectious clone demonstrated that the middle open reading frame encodes the NP1 protein. This protein, unique to the genus Bocavirus, was essential for MVC DNA replication. Moreover, the phospholipase A2 motif in the VP1 unique region was also critical for MVC infection. Thus, our studies revealed important information about the genus Bocavirus that may eventually help us to clone the human bocavirus and study its pathogenesis.

Humoral immune response against human bocavirus VP2 virus-like particles

Human bocavirus (HBoV) was recently detected in samples from children and infants with infections of the respiratory tract. Here we analyze the prevalence of IgG and IgM antibodies against HBoV virus-like VP2 particles in healthy adult blood donors and children using a newly established standardized enzyme-linked immunosorbent assay. Virus-specific IgG antibodies were frequently detected in infants with active viremia and respiratory illness (10/24, 42%) and in young children without detectable HBoV genomes in their blood (27/52, 52%). In sera obtained from healthy adults, ubiquitous VP2-specific antibodies were found in 280/299 (94%) cases. HBoV-specific IgM antibodies were detected in 10/24 (42%) of sera samples obtained from HBoV DNA-positive children, and in 6/24 (25%) the sera displayed equivocal responses. In contrast, VP2-specific IgM was not detectable in samples obtained from 52 children without detectable amounts of HBoV genomes in their blood. Only 2/299 sera samples from healthy adult blood donors were found to be IgM-positive (1%), and equivocal IgM responses were observed in 9/299 (3%) individuals. In conclusion, a high IgG seroprevalence of HBoV in the adult population was observed, whereas the presence of virus-specific IgM was associated with viremia. These data show that ELISA test systems for the detection of HBoV-specific antibodies are a valuable tool for serological diagnosis of this new emerging pathogen.

CD4+ T helper cell responses against human bocavirus viral protein 2 viruslike particles in healthy adults

Background. Human bocavirus (HBoV) was recently described as a new member of the Parvoviridae family, and its possible association with respiratory illness in infants has been discussed. To date, HBoV genomes have been detected worldwide in respiratory tract samples obtained from children with pulmonary diseases, whereas only limited data on virus-specific immunity are available, mainly because of the lack of recombinant viral antigens.

Methods. HBoV viruslike particles (VLPs) were produced in insect cells and characterized by electron microscopy and cesium chloride gradient centrifugation. HBoV viral protein 2 (VP2)-specific antibodies and CD4⁺ T helper cell responses were analyzed by enzyme-linked immunsorbent assay and enzyme-linked immunospot assay.

Results. VP2 capsid proteins of HBoV were produced in insect cells infected with a recombinant baculovirus, and the formation of icosahedral VLPs (diameter, 21–25 nm; sedimentation density, 1.33 g/cm³) was demonstrated. A significant increase in secretion of VP2-specific interferon-γ was detected in cultures of peripheral blood mononuclear cells obtained from 69 healthy adults found to be positive for HBoV-specific immunoglobulin G antibodies, compared with control stimulations. In parallel, T cell responses against identically expressed parvovirus B19 VP2 VLPs were frequently observed in the individuals studied, without there being obvious cross-reactions between HBoV and parvovirus B19.

Conclusions. Data suggest the presence of HBoV-specific immune responses in adults and strongly support a high prevalence of HBoV among humans.

Detection of respiratory viruses by molecular methods

SUMMARY

Clinical laboratories historically diagnose seven or eight respiratory virus infections using a combination of techniques including enzyme immunoassay, direct fluorescent antibody staining, cell culture, and nucleic acid amplification tests. With the discovery of six new respiratory viruses since 2000, laboratories are faced with the challenge of detecting up to 19 different viruses that cause acute respiratory disease of both the upper and lower respiratory tracts. The application of nucleic acid amplification technology, particularly multiplex PCR coupled with fluidic or fixed microarrays, provides an important new approach for the detection of multiple respiratory viruses in a single test. These multiplex amplification tests provide a sensitive and comprehensive approach for the diagnosis of respiratory tract infections in individual hospitalized patients and the identification of the etiological agent in outbreaks of respiratory tract infection in the community. This review describes the molecular methods used to detect respiratory viruses and discusses the contribution that molecular testing, especially multiplex PCR, has made to our ability to detect respiratory viruses and to increase our understanding of the roles of various viral agents in acute respiratory disease.

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.