Human bocavirus in Saudi Arabia: Molecular epidemiology and Co-infections among children with acute respiratory tract infections during 2014-2016

Respiratory tract infections due to a variety of viruses continue to threaten the human population worldwide, particularly in developing countries. Among the responsible viruses, Human Bocavirus (HBoV), a novel discovered virus, causes respiratory tract and gastroenteritis disorders in young children. In Saudi Arabia, data regarding virus molecular epidemiology and evolution and its implication in respiratory tract infection are scarce. In the current study, genetic diversity and circulation pattern of HBoV-1 among hospitalized children due to acute respiratory tract infection (ARTI) during two consecutive years were charted. We found that 3.44% (2014/2015) and 11.25% (2015/2016) of children hospitalized due to ARTI were infected by HBoV-1. We have shown that HBoV was detected year-round without a marked seasonal peak. HBoV-1 also was co-detected with one or multiple other respiratory viruses. The multisequence analysis showed high sequence identity (∼99%) (few point mutation sites) between strains of each genotype and high sequence variation (∼79%) between HBoV-1 and the other 3 genotypes. Phylogenetic analysis showed the clustering of the study's isolates in the HBoV-1 subclade. Our data reveal that genetically conserved HBoV-1 was circulating among admitted children during the course of the study. Further epidemiological and molecular characterization of multiple HBoV-1 strains for different years and from all regions of Saudi Arabia are required to understand and monitor the virus evolution.

Molecular characterization of human bocavirus in municipal wastewaters using amplicon target sequencing

Human bocavirus (HBoV) is an emerging health concern worldwide, associated with range of clinical manifestations, including gastroenteritis and respiratory infections. Therefore, it is crucial to comprehend and minimize their prevalence in different systems. In this study, we conducted regular sampling throughout the year in two different sizes and work processes of wastewater treatment plants (WWTPs) in Tianjin, China. Our objective was to investigate the occurrence, prevalence, and endurance of HBoV in wastewater, while also evaluating the efficacy of amplicon target sequencing in directly detecting HBoV in wastewater. At two WWTPs, HBoV2 (45.51 %-45.67 %) and HBoV3 (38.30 %-40.25 %) were the most common genotypes identified, and the mean concentration range of HBoV was 2.54-7.40 log10 equivalent copies/l as determined by multiplex real-time quantitative PCR assay. A positive rate of HBoV was found in 96.6 % (29/30) samples of A-WWTP, and 96.6 % (26/27) samples of B-WWTP. The phylogenetic analysis indicated that the nucleotide similarity between the HBoV DNA sequences to the reference HBoV sequences published globally ranged from 90.14 %-100 %. A significant variation in the read abundance of HBoV2 and HBoV3 in two wastewater treatment plants (p < 0.05) was detected, specifically in the Winter and Summer seasons. The findings revealed a strong correlation between the genotypes detected in wastewater and the clinical data across various regions in China. In addition, it is worth mentioning that HBoV4 was exclusively detected in wastewater and not found in the clinical samples from patients. This study highlights the high prevalence of human bocavirus in municipal wastewater. This finding illustrates that amplicon target sequencing can amplify a wide variety of viruses, enabling the identification of newly discovered viruses.

The role of human bocavirus as an agent of community-acquired pneumonia in children under 5 years of age in Fortaleza, Ceará (Northeast Brazil)

The human bocavirus (HBoV) is an agent of upper and lower respiratory infections, affecting mainly children under 5 years of age. Community-acquired pneumonia (CAP) is an important public health problem in developing countries, representing one of the main causes of hospitalizations and deaths in children. The aim of this study was to describe the prevalence of HBoV and the clinical and epidemiological characteristics in children diagnosed with CAP. For this purpose, nasopharyngeal aspirates were collected from 545 children aged 0 to 60 months diagnosed with CAP between January 2013 and December 2014 in a reference pediatric hospital in Fortaleza, Ceará, Brazil. The samples were subjected to PCR for detection of HBoV and parainfluenza 4 (PIV4) and indirect immunofluorescence for detection of respiratory syncytial virus (RSV), adenovirus (AdV), influenza A and B (FLU A and FLU B), and parainfluenza 1, 2, and 3 (PIV1, PIV2, PIV3). Clinically, most CAP were non-complicated (487/545; 89.3%); however, 10.7% (58/545) of children were treated in the ICU/resuscitation sector. Among the total samples analyzed, 359 (65.8%) were positive for at least one virus surveyed and 105 (19.2%) samples had two or more viruses. HBoV was detected in 87 samples (15.9%), being the second most prevalent virus. RSV, AdV, FLU A, FLU B, and PIV 1-3 were detected in 150 (27.5%), 45 (8.2%), 30 (5.5%), 3 (0.5%), and 131 (24%) samples, respectively. The age average was 12.1 months in children infected with HBoV, and the most frequent symptoms were dyspnea and cough. In addition, 90.6% of HboV-positive children received antibiotics as empirical treatment. HBoV did not show any circulation pattern; however, it seemed to be more frequent in the first half of the year, totaling 68.9% of the cases. HBoV is a frequent agent of pneumonia in the child population studied.

Molecular characterization of human bocavirus in recycled water and sewage sludge in Thailand

The study aimed to assess the presence and molecular characterization of human bocavirus (HBoV) in recycled water and sewage sludge samples in Thailand. One hundred and two recycled water and eighty-six sewage sludge samples collected from a wastewater treatment plant were tested for the presence of HBoV using nested PCR with broad-range primer pairs targeting the capsid proteins VP1 and VP2. HBoV DNA was detected in recycled water of 9/102 (8.8%) samples and sewage sludge of 27/86 (31.4%) samples. Based on DNA sequencing and phylogenetic analysis, the HBoV DNA sequences had 98.8-100.0% nucleotide identity to the sequences from HBoV reported globally. Thirty-five HBoV-positive samples were identified to genotypes as the predominant HBoV2; 26 followed by HBoV3; 8 and the rare HBoV4; 1 sample. Concerning recycled water, HBoV2 was detected in 3 (2.9%) and HBoV3 was detected in 5 (4.9%) of all samples. The sewage sludge samples were characterized as HBoV2 in 23 (26.7%), HBoV3 in 3 (3.5%) and HBoV4 in 1 (1.2%) of all samples. The frequency of HBoV detected in recycled water and sewage sludge samples significantly differed in sample type (p-value = 0.007). The findings of three HBoV genotypes in recycled water and sewage sludge emphasized the circulation of the virus in the environment and the potential source of transmission to the community.

Epidemiologic and clinical characteristics of human bocavirus infection in infants and young children suffering with community acquired pneumonia in Ningxia, China

Background

Pneumonia has a high incidence rate and is a major cause of mortality in children, mostly community-acquired pneumonia (CAP). Human bocavirus (HBoV), since it first identified in 2005, has been repeatedly associated with respiratory tract infections. Nevertheless, the role and related information of HBoV as a pathogen of CAP has not been fulfilled. Here our study is to assess the epidemiological and clinical features in HBoV-positive children with CAP.

Methods

A total of 878 secretions of lower respiratory samples were obtained, multiplex PCR was used to detect HBoV and other respiratory viruses.

Results

Of all cases, HBoV was detected in 10.0%, with a peak incidence of infection among children < 2 year old, and predominantly noted in autumn and winter. Only 8 patients were HBoV single infection. Co-infection with other respiratory viruses was observed in 86.4%. Moreover, co-infection with bacteria occurred in 27.3% and with Mycoplasma pneumoniae (MP) in 33.0% of HBoV-positive patients. Among all HBoV-positive samples co-infected with bacteria, 87.5% are gram negative bacteria. Compared with HBoV-negative group, age (P = 0.048), wheezing (P = 0.015), tachypnea (P = 0.016), lactate dehydrogenase (P = 0.026) and severe pneumonia (P = 0.023) were statistically significant in HBoV-positive patients. Furthermore, HBoV-positive patients less than 1 year old were more likely to have co-infection with bacteria (P = 0.007).

Conclusions

HBoV can be detected alone in respiratory samples of children with CAP, maybe it is one of the causes of CAP in infants. The high incidence of severe pneumonia was found in HBoV-positive patients compared with HBoV-negative cases may indicate a relationship between severe pneumonia and HBoV.

Human bocavirus-1 screening in infants with acute lower respiratory tract infection

Background

Recent studies have reported associations between, human bocavirus (HBoV), and respiratory tract diseases in children. However, there is limited information on the epidemiology of HBoV in infants. This prospective study investigated the prevalence and clinical characteristics of HBoV infection in infants with acute lower respiratory tract infection (ALRTI) in eastern China.

Methods

Nasopharyngeal aspirates and throat swab samples were collected from infants with ALRTI and age-matched healthy infants between January 2016 and December 2019. HBoV was identified by polymerase chain reaction. Laboratory data and clinical characteristics were analyzed.

Results

Of 2510 infants, 145 tested positive for HBoV. The highest prevalence of HBoV was detected during the winter. Co-infection was frequently observed during this period of high viral transmission. There were no HBoV-positive infants in the control group. Clinical signs and symptoms included cough, wheezing, fever, nasal discharge, vomiting, diarrhea, hypoxemia, and tachypnea. Co-infections included: Streptococcus pneumoniae, Staphylococcus aureus, Mycoplasma pneumoniae, Chlamydophila pneumoniae, respiratory syncytial virus, and adenovirus.

Conclusions

HBoV was frequently detected in infants with ALRTI in China. The prevalence of HBoV was highest in winter. Co-infection was common, especially in infants requiring intensive care unit admission. Comprehensive clinical evaluation may facilitate optimal treatment.

A systematic review and meta-analysis

Human bocaviruses (HBoVs) are recently described as human emergent viruses, especially in young children. In this study, we undertook a systematic review and meta-analysis to estimate their prevalence in Europe. PubMed, Web of Science and Scopus databases were systematically screened for clinical studies, up to October 2020. Study eligibility criteria were primary full-text articles from clinical studies, conducted using valid screening test methods and published in peer-reviewed journals, in English or Spanish and from European countries. The overall pooled prevalence, prevalence by country as well as the prevalence of HBoV as a single or co-pathogen were estimated using a random-effects model. Sub-group and meta-regression analyses explored potential sources of heterogeneity in the data. A total of 35 studies involving 32,656 subjects from 16 European countries met the inclusion criteria. Heterogeneity (I²  = 97.0%, p < .01) was seen among studies; HBoV prevalence varied from 2.0 to 45.69% with a pooled estimate of 9.57% (95%CI 7.66-11.91%). The HBoV prevalence both as a single infection (3.99%; 95%CI 2.99-5.31%) or as co-infection with other viruses (5.06%; 95%CI 3.88-6.58%) was also analysed. On a geographic level, prevalence by country did not show statistical differences, ranging from 3.24% (Greece) to 21.05% (Denmark). An odds ratio analysis was also included in order to evaluate the relevance of the variable 'age' as a risk factor of HBoV infection in children <5 years old. The OR value of 1.77 (95%CI 1.13-2.77; p < .01) indicated that being <5 years old is a risk factor for HBoV infection. This study showed that HBoV has a moderate prevalence among European countries.

Investigation of human bocavirus in pediatric patients with respiratory tract infection

INTRODUCTION

Human bocavirus (HBoV) is a linear single-stranded DNA virus belonging to the Parvoviridae family. This study aimed to investigate the incidence of HBoV and co-infections in pediatric patients with symptoms of viral respiratory tract infection.

METHODOLOGY

This study included 2,310 patients between the ages of 0-18 in whom HBoV and other respiratory tract viral pathogens were analyzed in nasopharyngeal swab specimens.

RESULTS

In the pediatric age group, HBoV was found in 4.5% (105/2310) of the patients and higher in children between the ages of 1 and 5. Mixed infection was detected in 43.8% (46/105) of HBoV positive patients (p = 0.10). Mono and mixed infection rates were higher in outpatients than in inpatients (p < 0.05). Respiratory syncytial virus was significantly higher than the other respiratory viral pathogens (p < 0.001).

CONCLUSIONS

This study is important as it is one of the rare studies performed on the incidence of HBoV in the Marmara region. In pediatric age group, the incidence of HBoV was found 4.5%. The incidence rate of HBoV in this study was similar to those in studies around the world, but close to low rates. The incidence of HBoV was found higher especially among children between the ages of 1-5 in this study. In addition to the incidence of HBoV, accompanying co-infections in the pediatric age group were also investigated in this study. Since concurrence of RSV, HRV and hMPV with HBoV was the most common it must be considered that there may be more than one agents in patients with symptoms of respiratory tract infection.

Human Bocavirus Infection in Adults: Clinical Features and Radiological Findings

OBJECTIVE

Human bocavirus (HBoV) is a newly identified pathogen that can cause upper and lower respiratory infections usually in children; however, its clinical characteristics and significance in respiratory infections in adults have not been well known. Our objective was to evaluate the clinical features of respiratory HBoV infection and to describe the CT findings of HBoV pneumonia in adults.

MATERIALS AND METHODS

A total of 185 adult patients diagnosed with HBoV infection at a tertiary referral center between January 2010 and December 2017 were retrospectively evaluated with respect to the clinical characteristics of HBoV infection and its risk factors for pneumonia. Chest CT findings for 34 patients with HBoV pneumonia without co-infection were analyzed and compared between immunocompetent (n = 18) and immunocompromised (n = 16) patients.

RESULTS

HBoV infections were predominantly noted between February and June. Among the 185 patients with HBoV infection, 119 (64.3%) had community-acquired infections and 110 (59.5%) had pneumonia. In multivariable analysis, older age (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.00-1.04; p = 0.045) and nosocomial infection (OR, 2.07; 95% CI, 1.05-4.10; p = 0.037) were associated with HBoV pneumonia. The main CT findings were bilateral consolidation (70.6%) and/or ground-glass opacities (64.7%); centrilobular nodules (14.7%) were found less frequently. The pattern of CT findings were not significantly different between immunocompetent and immunocompromised patients (all, p > 0.05).

CONCLUSION

HBoV infection can be a potential respiratory tract infection in adults. The most frequent CT findings of HBoV pneumonia were bilateral consolidation and/or ground-glass opacities.

The First Detection of Human Bocavirus Species 2 and 3 in Raw Sewage and Mussels in South Africa

Human bocavirus (HBoV) has a global distribution and is associated with respiratory and enteric infections, particularly in the paediatric population. In this study, raw sewage and mussel samples were analysed for the presence of HBoV using nested PCR with primers targeting the VP1/VP2 junction. Amplification and sequencing of the 382 bp region followed by phylogenetic analysis indicated the presence of HBoV 2 in mussel samples and HBoV 3 in sewage samples. This is the first report describing the presence of enteric-associated HBoV in environmental samples from South Africa and in mussel samples from the African continent. The results signify the need for further studies examining the potential risk of foodborne transmission of HBoV and highlight the importance of continued screening to determine the prevalence and epidemiology of HBoV in South Africa.

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.

Human bocavirus in children hospitalized for acute respiratory tract infection in Rome

BACKGROUND

The role of human bocavirus (HBoV) as a respiratory pathogen has not been fulfilled yet. We aimed to describe clinical and serological characteristics of children with HBoV hospitalized for acute respiratory tract infection and to evaluate whether differences occur between HBoV alone and in co-infection.

METHODS

We retrospectively reviewed data from 60 children (median age of 6.2 months, range 0.6-70.9) hospitalized for acute respiratory symptoms, with HBoV detected from a respiratory sample, using a reverse transcriptase-PCR for 14 respiratory viruses (including respiratory syncytial virus (RSV), influenza virus A and B, human coronavirus OC43, 229E, NL-63 and HUK1, adenovirus, rhinovirus, parainfluenza virus1-3, and human metapneumovirus).

RESULTS

HBoV was detected alone in 29 (48.3%) patients, while in co-infection with other viruses in 31 patients (51.7%), with a peak between December and January. Among the 60 patients, 34 were bronchiolitis, 19 wheezing, 3 pneumonia, 2 upper respiratory tract infection, and 2 whooping cough. Seven children (11.6%) required admission to the paediatric intensive care unit (PICU) for respiratory failure. No differences was observed in age, family history for atopy and/or asthma, clinical presentations, chest X-ray, or laboratory findings in children with HBoV alone vs. multiple viral detection. RSV was the most frequently co-detected virus (61.3%). When compared with HBoV detection alone, the co-detection of RSV and HBoV was associated with male sex (P = 0.013), younger age (P = 0.01), and lower blood neutrophil count (P = 0.032).

CONCLUSIONS

HBoV can be detected alone and in co-infection respiratory samples of children with an acute respiratory tract infection. A cause-effect relationship between HBoV and respiratory infection is not clear, so further studies are needed to clarify this point.

The Role of Emerging and Neglected Viruses in the Etiology of Hepatitis

PURPOSE OF REVIEW

In this review, we present the overview of emerging and neglected viruses associated with liver involvement.

RECENT FINDINGS

Hepatitis E virus (HEV) emerged in the last two decades, causing hepatitis in many parts of the world. Moreover, liver involvement was also described in some emerging arboviral infections. Many reports showed dengue-associated liver injury; however, chikungunya, West Nile, tick-borne encephalitis, and Zika virus are rarely associated with clinically manifest liver disease. In addition, some neglected highly prevalent viruses such as adenoviruses and parvovirus B19 are capable of causing hepatitis in specific population groups. Anelloviruses (torque teno virus/torque teno mini virus/torque teno midi virus, SEN virus), human bocavirus, pegiviruses, and lymphocytic choriomeningitis virus have shown a little potential for causing hepatitis, but their role in the etiology of liver disease remains to be determined. In addition to the well-known hepatotropic viruses, many emerging and neglected viruses have been associated with liver diseases. The number of emerging zoonotic viruses has been increasingly recognized. While zoonotic potential of HEV is well documented, the recent identification of new hepatitis-related animal viruses such as HEV strains from rabbits and camels, non-primate hepaciviruses in domestic dogs and horses, as well as equine and porcine pegivirus highlights the possible zoonotic transmission in the context of "One Health." However, zoonotic potential and hepatotropism of animal hepatitis viruses remain to be determined.

Human bocavirus infections and co-infections with respiratory syncytial virus and Rotavirus in children with acute respiratory or gastrointestinal disease

The objective of this study was to determine the frequency and seasonal distributions of HBoV detections among Iranian children presenting with acute respiratory or gastrointestinal symptoms and to compare infections among children with concomitant respiratory syncytial virus (RSV) and rotavirus (RV) infections. A cross-sectional study at Mofid Children's Hospital in Tehran, Iran, enrolled children < 3 years old presenting with either acute respiratory or gastrointestinal symptoms during the period of 2017-2018. Respiratory or stool specimens collected from each group were initially tested by RT-PCR assays for RSV and RV, respectively, and all specimens were tested for HBoV by PCR assay. Clinical and demographic data were collected and statistically compared. Five hundred respiratory and stool specimens each were tested and 67 (13.4%) and 72 (14.4%) were PCR positive for HBoV, respectively. Of 128 (25.6%) respiratory specimens positive for RSV, 65% were also positive for HBoV (p = 0.019); of 169 (33.8%) stool specimens positive for RV, 62.5% were also positive for HBoV (p = 0.023). Peak circulation of all viruses was during late winter and early spring months (Jan-Mar) in gastrointestinal infections and during winter (Feb-Jan) in respiratory infections. HBoV is commonly detected among Iranian children presenting with acute respiratory or gastrointestinal symptoms and is often present as co-infections with RSV and RV, respectively.

Nosocomial infection by human bocavirus and human rhinovirus among paediatric patients with respiratory risks

BACKGROUND

Nosocomial infections by respiratory viruses undetected by rapid tests are not often diagnosed. For paediatric patients with background diseases, nosocomial infection could be fatal.

AIM

To determine the relationship between developing symptoms by respiratory viruses undetectable by rapid tests and respiratory risks and to improve the management of infection control.

METHODS

Two episodes of nosocomial infection by human bocavirus (HBoV) and human rhinovirus (HRV) were retrospectively investigated in a tertiary hospital paediatric ward in Japan. Viruses were identified by polymerase chain reaction to determine infection control management. When viruses of the same species were detected from different patients, the virus homology was investigated. The relationship between respiratory risks and developing symptoms was statistically investigated.

FINDINGS

Three and four patients with respiratory risks in the HBoV and HRV outbreaks, respectively, developed respiratory symptoms. The nucleotide sequences of two patients in the HBoV outbreak and all four patients in the HRV outbreak were phylogenetically close. In both outbreaks, the patients with respiratory risks developed significantly more symptoms than those without any risk (P = 0.035 and 0.018, respectively). After the patients with respiratory infection were separated from those with respiratory risks, no additional nosocomial infection occurred.

CONCLUSION

Patients with respiratory risks easily develop respiratory symptoms and acquire severe symptoms of nosocomial infection by those viruses. In a paediatric ward, we should adopt not only standard precautions but also isolation management of the patients with respiratory symptoms, even if they have negative results in rapid tests.

[Correlation between human bocavirus 2 infection in children and acute diarrhea in Beijing]

Objective: To investigate the relationship between human bocavirus 2 (HBoV2) infection and acute diarrhea in children younger than 5 years of age in a case-control study. Methods: This was a prospective case-control study. During May 2016 to December 2016, fecal specimens were collected from children ≤5 years of age with acute diarrhea who visited the Affiliated Children's Hospital of Capital Institute of Pediatrics (case group), or from children ≤5 years of age without diarrhea from Longtan Community Medical Service Center, Beijing (control group). The case group (n=240) and the control group (n=240) were divided into 8 age subgroups: ≤1 month old, >1-3 months old, >3-6 months old, >6-12 months old,>1-2 years old,>2-3 years old,>3-4 years old and >4-5 years old, and there were 30 cases in each age subgroup. The specimens were tested for 7 types of diarrhea-associated viruses, especially for HBoV2 by real-time PCR method. The HBoV2 viral load was predicted according to the cycle threshold (Ct). Finally, t-test was used to compare the differences between groups. Results: In the case group (n=240), the positive rate of norovirus was 16.7% (40 cases); rotavirus, 10.8% (26 cases); HBoV2, 7.5% (18 cases); adenovirus, 7.1% (17 cases); astrovirus, 6.3% (15 cases); parachovirus, 3.8% (9 cases); and Aich virus, 0.4% (1 case). The positive rates of HBoV2 in case group (7.5%, 18 cases) and control group (5.0%, 12 cases) showed no significant difference (χ(2)=1.280, P=0.258), as well as in different age groups (all P>0.05) . However, the mean viral load of the HBoV2 in the case group (1×10(9)copies/L with cycle threshold (Ct) 25.8) was higher than that of control group (1×10(5)copies/L with Ct 33.8), showing a significant difference (t=0.597, P=0.000). Conclusions: Norovirus and rotavirus are still the important viral pathogens in children with acute diarrhea. A higher load of HBoV2 may indicate a higher risk of acute diarrhea in children ≤5 years of age in Beijing.

Human Bocavirus: Detection, Quantification and Molecular Characterization in Sewage and Surface Waters in Uruguay

Human bocavirus (HBoV) infections are related to respiratory and gastroenteric diseases. The aim of this study was to investigate the presence of HBoV in both sewage and surface waters in Uruguay. Sixty-eight sewage samples from the cities of Salto, Paysandú, Bella Unión, Fray Bentos, Treinta y Tres and Melo and 36 surface water samples from the cities of Salto, Florida and Santa Lucía were studied. HBoV was screened by multiplex qPCR for the detection of the four subtypes, followed by monoplex qPCRs for the independent quantification of each subtype. A qualitative PCR followed by DNA sequencing and phylogenetic analysis was carried out for molecular characterization of HBoV strains. HBoV was present in a high frequency (69%) in sewage and only one positive sample (3%) was found in surface water. Concerning sewage samples, HBoV1 was detected in 11 (23%) out of the 47 positives samples, with a mean concentration of 8.2 × 10⁴ genomic copies/Liter (gc/L), HBoV3 was detected in 35 (74%) of the positive samples with a mean concentration of 4.1 × 10⁶ gc/L and subtypes 2 and/or 4 were detected in 39 (83%) of the positive samples with a mean concentration of 7.8 × 10⁶ gc/L. After the phylogenetic analysis performed by a Bayesian approach, the four HBoV subtypes were confirmed. This is the first study determining a high frequency of HBoV and the presence of the four HBoV subtypes in aquatic matrices in Latin America, mainly in sewage. Although HBoV was scarcely detected in surface water, a waterborne transmission is likely to occur if people enter in contact with polluted surface waters for recreational activities such as fishing or swimming since an elevated frequency of HBoV was detected in raw sewage which is usually directly discharged into surface waters.

Human bocavirus in hospitalized children under 5 years with acute respiratory infection, São Paulo, Brazil, 2010

The aims of this study were to investigate the human bocavirus (HBoV) frequency and genotypes in hospitalized children <5 years presenting acute respiratory infections (ARI) within the São Paulo metropolitan area. Nasopharyngeal samples from 300 patients, previously screened for common respiratory viruses, were tested by qPCR for the NSP1 and NP-1 genes. The VP1/2 gene in positive samples was then amplified by PCR and sequenced. A total of 49 positive HBoV cases (16.3%; mean Ct value of 34.41) were detected with the mean age being 18.1 months (range 1 month to 5 years) and the median age being 1 year of age. Children aged between 0 and 12 months had higher detection rates of HBoV (69.4%; 34/49; mean Ct = 34.45) than children from other age groups (30.6%; 15/49; mean Ct = 34.34). No significant differences were observed between HBoV Ct levels and clinical illness. The occurrence was more frequently associated with fall (38.8%; 19/49) and spring (36.7%; 18/49). All 12 sequenced isolates were identified as HBoV-1, displaying minor genetic variation compared to the Swedish reference strains ST1 and ST2 (99.1–99.7% nt). The sole identification of HBoV-1 supports the hypothesis that this particular genotype is strongly related to ARI, and contributes to the role of this virus in the aetiology of respiratory diseases.

Three-dimensional Culture of Human Airway Epithelium in Matrigel for Evaluation of Human Rhinovirus C and Bocavirus Infections

OBJECTIVE

Newly identified human rhinovirus C (HRV-C) and human bocavirus (HBoV) cannot propagate in vitro in traditional cell culture models; thus obtaining knowledge about these viruses and developing related vaccines are difficult. Therefore, it is necessary to develop a novel platform for the propagation of these types of viruses.

METHODS

A platform for culturing human airway epithelia in a three-dimensional (3D) pattern using Matrigel as scaffold was developed. The features of 3D culture were identified by immunochemical staining and transmission electron microscopy. Nucleic acid levels of HRV-C and HBoV in 3D cells at designated time points were quantitated by real-time polymerase chain reaction (PCR). Levels of cytokines, whose secretion was induced by the viruses, were measured by ELISA.

RESULTS

Properties of bronchial-like tissues, such as the expression of biomarkers CK5, ZO-1, and PCK, and the development of cilium-like protuberances indicative of the human respiration tract, were observed in 3D-cultured human airway epithelial (HAE) cultures, but not in monolayer-cultured cells. Nucleic acid levels of HRV-C and HBoV and levels of virus-induced cytokines were also measured using the 3D culture system.

CONCLUSION

Our data provide a preliminary indication that the 3D culture model of primary epithelia using a Matrigel scaffold in vitro can be used to propagate HRV-C and HBoV.

In silico prediction of potential vaccine candidates on capsid protein of human bocavirus 1

Human bocavirus 1 (HBoV1) is a newly identified parvovirus that causes serious respiratory infection among children across the globe. Aim of the present study was to predict immunogenic residues located on the VP2 protein of HBoV1 towards development of epitope based vaccines. Several computational tools were employed to predict epitopes (bothT and B cell restricted) with stringent regulation for the improvement of confidence. After meticulous analysis, the peptide "TTPWTYFNFNQY" was identified as potential candidate for development of preventive vaccine. Of note, the epitope "TTPWTYFNFNQY" was found to be recognized by fifteen different alleles belonging to seven HLA supertypes (A1, A3, A24, A26, B7, B58 and B62). Further, mutational variability analysis pointed that most of the amino acids were well conserved. Docking scores obtained from ClusPro and Autodock Vina for selected epitopes displayed energetically favorable and stable interaction of peptide-HLA-I complexes. The core peptide "LLYQMPFFL" was found to recognize by wide range of HLA class II allele recognition thereby qualified as candidate for therapeutic vaccine. Five distinct linear peptides (withT cell epitope superimposition) belonging to B cells were identified in the VP2 protein. Further attention on the enlisted epitopes may shed light on the path for development of diagnostic, therapeutic and preventive tools against HBoV1 infection. Additionally, the predicted epitopes may help us to address the original antigenic sin phenomena observed during consecutive HBoV2-4 infection.

Human Bocavirus Capsid Messenger RNA Detection in Children With Pneumonia

Background

The role of human bocavirus (HBoV) in respiratory illness is uncertain. HBoV genomic DNA is frequently detected in both ill and healthy children. We hypothesized that spliced viral capsid messenger RNA (mRNA) produced during active replication might be a better marker for acute infection.

Methods

As part of the Etiology of Pneumonia in the Community (EPIC) study, children aged <18 years who were hospitalized with community-acquired pneumonia (CAP) and children asymptomatic at the time of elective outpatient surgery (controls) were enrolled. Nasopharyngeal/oropharyngeal specimens were tested for HBoV mRNA and genomic DNA by quantitative polymerase chain reaction.

Results

HBoV DNA was detected in 10.4% of 1295 patients with CAP and 7.5% of 721 controls (odds ratio [OR], 1.4 [95% confidence interval {CI}, 1.0–2.0]); HBoV mRNA was detected in 2.1% and 0.4%, respectively (OR, 5.1 [95% CI, 1.6–26]). When adjusted for age, enrollment month, and detection of other respiratory viruses, HBoV mRNA detection (adjusted OR, 7.6 [95% CI, 1.5–38.4]) but not DNA (adjusted OR, 1.2 [95% CI, .6–2.4]) was associated with CAP. Among children with no other pathogens detected, HBoV mRNA (OR, 9.6 [95% CI, 1.9–82]) was strongly associated with CAP.

Conclusions

Detection of HBoV mRNA but not DNA was associated with CAP, supporting a pathogenic role for HBoV in CAP. HBoV mRNA could be a useful target for diagnostic testing.

Relative Abundance of Human Bocaviruses in Urban Sewage in Greater Cairo, Egypt

Human bocavirus (HBoV) is predominantly found in the respiratory tract infections and in the stool of patients with gastroenteritis symptoms. However, data on the prevalence of HBoV genotypes in environmental samples are limited. Here we addressed the prevalence of HBoV in sewage collected from three different wastewater treatment plants in Egypt. HBoV-1, HBoV-2, and HBoV-3 were detected, whereas none of the samples were positive for HBoV-4. The median concentration of HBoV in influent samples was 8.5 × 10³ GC/l for HBoV-1, 3.0 × 10⁴ GC/l for HBoV-2, and 2.5 × 10⁴ GC/l for HBoV-3. The concentration was reduced but not completely removed in the effluent samples. The median concentration in the outlet samples was 2.9 × 10³ GC/l for HBoV-1, 4.1 × 10³ GC/l for HBoV-2, and 2.1 × 10³ GC/l for HBoV-3. Moreover, no seasonality pattern of HBoVs was found. The high incidence of HBoV in sewage samples provided an evidence of its circulation in the local population. Although the role of HBoV in respiratory or gastro-intestinal infections still remains to be fully elucidated, the risk of infection via contaminated water should be taken into consideration.

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

Objective

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

Results

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

Investigation of viral infection in idiopathic pulmonary fibrosis among Iranian patients in Tehran

AIM OF THE STUDY

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease, which can be lethal with chronic complications. Viral infections may be associated with IPF and other fibrotic lung diseases. In the present study, we investigate for the first time in Iran the related viral etiology of IPF in order to detect three respiratory viruses; human adenovirus, enterovirus and bocavirus.

MATERIALS AND METHODS

In this cross-sectional study which was supported by Iran University of Medical Sciences, Tehran, Iran. The diagnostic criteria for IPF were based on internationally accepted clinical and imaging criteria in accordance with the 2011 IPF guidelines. 30 nasopharyngeal (NP) swabs or broncho-alveolar lavage (BAL) samples were obtained from the lung of IPF patients that were diagnosed by a sophisticated practitioner from April 2015 to February 2016. Real-time (RT) polymerase chain reaction (PCR) method was performed to detect the three viruses. Fluorescence dye of a labeled probe recorded the results in order to create positive and negative controls. SPSS version 20 software was used to calculate basic descriptive and frequency features.

RESULTS

Of 30 specimens, 13 (43.4%) were male and 17 (56.6%) were female with the total mean age ± standard deviation 68.2 ± 12.0. RT-PCR assay results illustrated there was no infection of human adenovirus, enterovirus, and bocavirus detected in these samples. Significant results between IPF incidence and variables were not significant (p > 0.05).

CONCLUSION

The causes of IPF in Iranian patients need more research although, based on the results of this study, there was no association between human adenovirus, enterovirus, bocavirus, and IPF.

Human bocavirus: Current knowledge and future challenges

Human bocavirus (HBoV) is a parvovirus isolated about a decade ago and found worldwide in both respiratory samples, mainly from early life and children of 6-24 mo of age with acute respiratory infection, and in stool samples, from patients with gastroenteritis. Since then, other viruses related to the first HBoV isolate (HBoV1), namely HBoV2, HBoV3 and HBoV4, have been detected principally in human faeces. HBoVs are small non-enveloped single-stranded DNA viruses of about 5300 nucleotides, consisting of three open reading frames encoding the first two the non-structural protein 1 (NS1) and nuclear phosphoprotein (NP1) and the third the viral capsid proteins 1 and 2 (VP1 and VP2). HBoV pathogenicity remains to be fully clarified mainly due to the lack of animal models for the difficulties in replicating the virus in in vitro cell cultures, and the fact that HBoV infection is frequently accompanied by at least another viral and/or bacterial respiratory and/or gastroenteric pathogen infection. Current diagnostic methods to support HBoV detection include polymerase chain reaction, real-time PCR, enzyme-linked immunosorbent assay and enzyme immunoassay using recombinant VP2 or virus-like particle capsid proteins, although sequence-independent amplification techniques combined with next-generation sequencing platforms promise rapid and simultaneous detection of the pathogens in the future. This review presents the current knowledge on HBoV genotypes with emphasis on taxonomy, phylogenetic relationship and genomic analysis, biology, epidemiology, pathogenesis and diagnostic methods. The emerging discussion on HBoVs as true pathogen or innocent bystander is also emphasized.

Recurrent wheezing and asthma after bocavirus bronchiolitis

BACKGROUND

Human bocavirus (HBoV) was recently discovered and identified as an important cause of respiratory infection in young children. However, the relationship between HBoV-bronchiolitis and the development of recurrent wheezing has not yet been established.

OBJECTIVE

We designed this study in order to describe the mid-term outcome, regarding the development of recurrent wheezing and asthma of HBoV-bronchiolitis patients and to compare it with RSV-bronchiolitis infants.

METHODS

We studied 80 children (10 with HBoV and 70 with RSV infection), currently aged ≥4 years and previously hospitalised during the seasons 2004-2009 due to acute bronchiolitis. Epidemiological and clinical data were collected through structured clinical interviews at the follow-up visit. Spirometry and skin prick tests to common food and inhaled allergens were performed.

RESULTS

All HBoV-patients developed recurrent wheezing and half of them had asthma at age 5-7 years. Almost 30% required hospital admission for recurrent wheezing. Asthma (odds ratio (OR)=1.28) and current asthma (OR=2.18) were significantly more frequent in children with HBoV-bronchiolitis than in RSV-bronchiolitis. FEV1 values were 99.2±4.8 in HBoV-group vs. 103±11 in RSV-group, p: 0.09. No differences were found with respect to allergic rhinitis, atopic dermatitis, food allergy, proportion of positive prick tests, and family history of atopy or asthma.

CONCLUSIONS

Severe HBoV-bronchiolitis in infancy was strongly associated with asthma at 5-7 years.

Genetic characterization of human bocavirus among children with severe acute respiratory infection in China

OBJECTIVES

To investigate the genetic character of Human bocavirus (HBoV) among children with severe acute respiratory infection (SARI) in China.

METHODS

We screened 993 respiratory samples for HBoV by PCR among hospitalized children with SARI between September 2007 and March 2014. Four of HBoV1 samples were selected for complete genomes analysis by next-generation sequencing.

RESULTS

The results show that 200 (20.1%) out of 993 samples were HBoV-positive, most of these HBoV belong to HBoV1 subtype (n = 197), HBoV2 (n = 1) and HBoV3 (n = 2) were also detected. Fifty (5.04%) of 993 SARI patient were detected as HBoV-positive only. Four HBoV1 genomes in this study were conserved and showed no significant difference among the nucleotide diversity from different regions. Analyses of evolutionary rates showed that NS1 exhibited the highest degree of conservation while the VP1 gene exhibited the fastest rate of evolution at 4.20 × 10(-4) substitutions/site/year. The nucleotide deletions and substitutions occurred in NP1 and VP1 represented novel molecular signatures enabling subtype differentiation between HBoVs.

CONCLUSIONS

We described some new characteristics in the epidemiology of HBoV among children with SARI, these data will significantly expand the current knowledge of HBoV epidemic and genomic characterization among children with SARI.

Pediatric Asthma and Viral Infection

Respiratory viral infections, particularly respiratory syncytial virus (RSV) and rhinovirus, are the most importance risk factors for the onset of wheezing in infants and small children. Bronchiolitis is the most common acute respiratory infection in children under 1year of age, and the most common cause of hospitalization in this age group. RSV accounts for approximately 70% of all these cases, followed by rhinovirus, adenovirus, metapneumovirus and bocavirus. The association between bronchiolitis caused by RSV and the development of recurrent wheezing and/or asthma was first described more than 40years ago, but it is still unclear whether bronchiolitis causes chronic respiratory symptoms, or if it is a marker for children with a genetic predisposition for developing asthma in the medium or long term. In any case, sufficient evidence is available to corroborate the existence of this association, which is particularly strong when the causative agent of bronchiolitis is rhinovirus. The pathogenic role of respiratory viruses as triggers for exacerbations in asthmatic patients has not been fully characterized. However, it is clear that respiratory viruses, and in particular rhinovirus, are the most common causes of exacerbation in children, and some type of respiratory virus has been identified in over 90% of children hospitalized for an episode of wheezing. Changes in the immune response to viral infections in genetically predisposed individuals are very likely to be the main factors involved in the association between viral infection and asthma.

Detection and monitoring of human bocavirus 1 infection by a new rapid antigen test

Clinically relevant diagnosis of human bocavirus 1 (HBoV1) is challenging, as the virus is frequently detected in asymptomatic patients, and cofindings with other respiratory viruses are common. The clinical value of current diagnostic methods, such as PCR, is therefore low, and alternative diagnostic strategies are needed. We describe for the first time the use of an antigen detection assay for the rapid identification of HBoV1 in a paediatric patient with respiratory tract infection symptoms. We estimate the duration of active HBoV1 infection to be 6 days.

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.

[Bocavirus in infants under 5 years with acute respiratory infection. Chaco Province, Argentina, 2014]

Acute respiratory infection (ARI) is the most frequent pathology along human life, being the most common cause of morbidity and mortality in children under 5 years. The aim of this study was to determine the frequency of bocavirus (BoV) in infants under 5 years with symptoms of ARI from north Argentina (Chaco province). The study was performed on nasopharyngeal aspirates from 488 patients, in the period of January-December 2014. The samples were tested by real time PCR and 36 positive BoV cases (7.4%) were detected. The period with the highest detection rate was June-September with 28 cases (77.8%), of which 26 (72.2%) were infants between 6-18 moths of life. In half of BoV positive cases this virus was detected as single infection of the upper respiratory tract, and in the remaining 50%, as concomitant infection with other microorganisms. To our knowledge, this would be the first study on molecular epidemiology of BoV in northern Argentina. We emphasize the importance of investigating these new viruses capable of generating acute respiratory disease and also to disseminate awareness on their circulation within the community.

Is the role of rhinoviruses as causative agents of pediatric community-acquired pneumonia over-estimated?

The role that rhinoviruses, enteroviruses, parainfluenza viruses, coronaviruses and human bocavirus play in pediatric pneumonia is insufficiently studied. We used polymerase chain reaction (PCR) to study 9 virus groups, including 16 different viruses or viral strains, in 56 ambulatory children with radiologically confirmed community-acquired pneumonia (CAP). The same tests were carried out on 474 apparently healthy control children of the same age and sex. The mean age of children with CAP was 6.5 years (SD 4.2). Respiratory syncytial virus (RSV) was found in 19.6 % of 56 cases and in 2.1 % of 474 controls. Adenoviruses were present in 12.5 % of cases (0.2 % controls) and metapneumovirus and influenza A virus each in 10.7 % of cases (0.2 % controls). Interestingly, rhinoviruses were less common in cases (10.7 %) than in controls (22.4 %): odds ratio 0.36 (95%CI) 0.15-0.87) in conditional logistic regression including 56 cases and 280 controls matched for age, sex and sampling month. The prevalence of parainfluenza viruses, enteroviruses, coronaviruses and human bocavirus were similar in both groups.

CONCLUSION

We conclude that the role of rhinoviruses as an etiology of pediatric CAP has been over-estimated, mainly due to the non-controlled designs of previous studies. What is Known: • In non-controlled studies, rhinovirus detection has been common, next to respiratory syncytial virus, in children with viral community-acquired pneumonia (CAP). • Enteroviruses, coronaviruses and the human bocavirus have been found less frequently. What is New: • In this controlled study, rhinoviruses were detected more often in healthy controls than in children with CAP, and enteroviruses, coronaviruses and human bocavirus were detected equally often in cases and controls. • We conclude that previous studies have over-estimated the role of rhinoviruses in the etiology of CAP in children.

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

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

Human bocavirus infection as a cause of severe acute respiratory tract infection in children

In 2005 human bocavirus (HBoV) was discovered in respiratory tract samples of children. The role of HBoV as the single causative agent for respiratory tract infections remains unclear. Detection of HBoV in children with respiratory disease is frequently in combination with other viruses or bacteria. We set up an algorithm to study whether HBoV alone can cause severe acute respiratory tract infection (SARI) in children. The algorithm was developed to exclude cases with no other likely cause than HBoV for the need for admission to the paediatric intensive care unit (PICU) with SARI. We searched for other viruses by next-generation sequencing (NGS) in these cases and studied their HBoV viral loads. To benchmark our algorithm, the same was applied to respiratory syncytial virus (RSV)-positive patients. From our total group of 990 patients who tested positive for a respiratory virus by means of RT-PCR, HBoV and RSV were detected in 178 and 366 children admitted to our hospital. Forty-nine HBoV-positive patients and 72 RSV-positive patients were admitted to the PICU. We found seven single HBoV-infected cases with SARI admitted to PICU (7/49, 14%). They had no other detectable virus by NGS. They had much higher HBoV loads than other patients positive for HBoV. We identified 14 RSV-infected SARI patients with a single RSV infection (14/72, 19%). We conclude that our study provides strong support that HBoV can cause SARI in children in the absence of viral and bacterial co-infections.

Detection of human bocavirus in children with acute respiratory tract infections in Lanzhou and Nanjing, China

OBJECTIVE

The aim of this study was to explore the prevalent characteristics of HBoV1 and its co-infection.

METHODS

PCR was used to detect HBoV1-DNA (HBoV1) and other viruses. A multivariate logistic regression model was used to explore possibility of co-detected for related viruses.

RESULTS

The positivity rates in Nanjing and Lanzhou were 9.38% (74/789) and 11.62% (161/1386), respectively (P>0.05). The HBoV1 positive group was younger than negative group (P<0.05). Seasonal differences were noted, with a higher frequency of infection in December and July. HBoV1-positive children [72.34% (169/235)] were co-infected with other respiratory viruses. Multifactorial analysis showed no correlations between HBoV1 and the clinical classification, region, gender, age, or treatment as an outpatient or in a hospital. Correlations were identified between HBoV1 infections with ADV (OR=1.53, 95% CI 1.03-2.28), RSV (OR=0.71, 95% CI 0.52-0.98), and IFVA (OR=1.77, 95% CI 1.00-3.13).

CONCLUSION

Presence of HBoV1 in nasopharyngeal aspirates did not correlate with region or gender, although the prevalence of HBoV1 was higher in younger children. There were no correlations between HBoV1 and other variables, except for the season and ADV, RSV, or IFVA infections.

A study of the human bocavirus replicative genome structures

The complete genomes of two human bocavirus 4 (HBoV4) isolates recovered in 2011 in Novosibirsk, Russia have been determined. A set of primers was designed based on the determined and previously published HBoV sequences; this primer pair was able to detect all possible HBoV replicative intermediates. This primer set was used to assay all HBoV genotypes and detected only those structures that correspond to an episomal form of this viral genome. Also, for the first time, head-to-tail nucleotide sequences have been determined for HBoV4. Secondary structures of the terminal noncoding regions (NCRs) of episomal forms have been computed for all HBoV genotypes, as well as for the canine bocavirus. Conserved secondary structures in episomal NCRs, which are likely to play an important part in the replication of bocaviruses, were found. NCR heterogeneity in the genomes of individual HBoV isolates has been shown for the first time.

Recombination in the evolution of human bocavirus

Whole genome sequencing of Novosibirsk human bocavirus (HBoV) isolates has detected an isolate that emerged via recombination between HBoV3 and HBoV4 genotypes. The recombination site is located between regions with abnormally low and abnormally high GC contents in the genome. This site is a bocavirus recombination hotspot and coincides with one of two parvovirus recombination hotspots. The Novosibirsk recombinant isolate, which is similar to a previously studied isolate from Thailand, utilizes the strategy of borrowing ORF3, which encodes structural proteins, of a rare genotype HBoV4. The role of recombination in HBoV evolution is discussed.

Emerging respiratory viruses other than influenza

Non-influenza respiratory virus infections are common worldwide and contribute to morbidity and mortality in all age groups. The recently identified Middle East respiratory syndrome coronavirus has been associated with rapidly progressive pneumonia and high mortality rate. Adenovirus 14 has been increasingly recognized in severe acute respiratory illness in both military and civilian individuals. Rhinovirus C and human bocavirus type 1 have been commonly detected in infants and young children with respiratory tract infection and studies have shown a positive correlation between respiratory illness and high viral loads, mono-infection, viremia, and/or serologically-confirmed primary infection.

A novel integrated strategy for detection of human bocavirus based on a heminested PCR assay combined with boiling lysis method of samples in human specimens

Human bocavirus (HBoV) has been shown to be associated with acute respiratory tract infection in children. The aim of the work was to develop a novel integrated strategy for human bocavirus detection: heminested PCR assay combined with boiling lysis method of samples. The detection limit of the heminested PCR assay was 1.2 copies of a recombinant DNA plasmid, and no cross-reaction with other respiratory viruses or bacteria was observed. By using the integrated strategy, a total of 202 secretions of the lower respiratory tract of children with acute respiratory diseases were collected and tested. The samples were treated and lysed in boiling lysis buffer rather than extracting viral DNA from secretions, then these sample lysates could be templates and tested by heminested PCR assay, and the amplification of HBoV DNA was detected by using agarose gel electrophoresis. The results showed that, only 7 samples were found to be positive by conventional single-round PCR; importantly, the other new 41 samples were positive by heminested PCR assay. Additionally, the genomic viral DNA was extracted from all positive and some negative specimens, amplified, and sequenced. The results were perfectly consistent with those of the integrated strategy. Taken together, these results suggest that the novel integrated strategy (heminested PCR assay combined with boiling lysis method of samples) is a convenient, sensitive, cost-effective and reliable detective method for HBoV detection and will have broad application prospects in clinical diagnosis.

Detection of spliced mRNA from human bocavirus 1 in clinical samples from children with respiratory tract infections

Human bocavirus 1 (HBoV1) is a parvovirus associated with respiratory tract infections (RTIs) in children, but a causal relation has not yet been confirmed. To develop a qualitative reverse transcription PCR to detect spliced mRNA from HBoV1 and to determine whether HBoV1 mRNA correlated better with RTIs than did HBoV1 DNA, we used samples from HBoV1 DNA–positive children, with and without RTIs, to evaluate the test. A real-time reverse transcription PCR, targeting 2 alternatively spliced mRNAs, was developed. HBoV1 mRNA was detected in nasopharyngeal aspirates from 33 (25%) of 133 children with RTIs but in none of 28 controls (p<0.001). The analytical sensitivity and specificity of the test were good. Our data support the hypothesis that HBoV1 may cause RTIs, and we propose that HBoV1 mRNA could be used with benefit, instead of HBoV1 DNA, as a diagnostic target.

Human bocavirus 1 infects commercially available primary human airway epithelium cultures productively. J Virol Methods. 2014;195:112-119. [PMID: 24134939 PMCID: PMC3855471 DOI: 10.1016/j.jviromet.2013.10.012]

Human bocavirus 1 (HBoV1), a human parvovirus, belongs to the genus Bocavirus of the Parvoviridae family. It causes wheezing in young children with acute respiratory tract infections. HBoV1 has been shown to infect polarized human airway epithelium (HAE) made in house, and induces airway epithelial damage. In this study, two commercially available HAE cultures, EpiAirway and MucilAir HAE, were examined for HBoV1 infection. Both HAE cultures support fully productive HBoV1 infection. Infected EpiAirway and MucilAir HAE cultures showed loss of cilia, disruption of the tight junction barrier, and a significant decrease in transepithelial electrical resistance. Notably, HBoV1 persistent infection was demonstrated by maintaining HBoV1-infected EpiAirway HAE for as long as 50 days. After 2 days post-infection, progeny virus was produced consistently daily at a level of over 2×10(8) viral genome copies per culture (0.6 cm(2)). This study is the first to use commercial sources of HAE cultures for HBoV1 infection. The availability of these cultures will enable a wide range of laboratories to study HBoV1 infection.

[New and rare pneumotropic viruses]

While acute viral respiratory tract infections are one of the major reasons for the loss of productivity among the general population in industrialized nations, they are one of the top killers among infants worldwide, in particular in low-income countries. With the advances in molecular diagnostics and the introduction of high-throughput screening techniques a variety of novel, so far unknown viruses have been discovered from respiratory secretions. However, the clinical significance is often difficult to determine. This review article provides an introduction to those novel viruses which have been described since the beginning of the millennium and discusses the clinical relevance in the light of current scientific evidence. The viruses covered by the present review are human metapneumovirus, human bocavirus, human coronaviruses OC43, 229E, NL63, HKU1, SARS and MERS, human polyomaviruses KI, MC and WU and human parechoviruses.

Viral etiology of bronchiolitis among pediatric inpatients in northern Taiwan with emphasis on newly identified respiratory viruses

Purpose

Viral etiology of bronchiolitis in children in Taiwan has been fragmentary. We conducted a prospective study to figure out the viral epidemiology of bronchiolitis in Taiwan.

Materials and methods

From January 2009 to March 2011, a total of 113 children with bronchiolitis, aged <2 years, hospitalized in Chang Gung Children’s Hospital were randomly selected for viral etiology investigation. Nasopharyngeal aspirates were obtained from each case and sent for viral detection by tissue culture, antigen test, and polymerase chain reaction.

Results

A total of 120 viruses were detected from 113 children. Positive viral etiology was identified in 86 (76%) children. Mixed viral pathogens were found in 28 cases (25%). Respiratory syncytial virus (RSV) was the most common pathogen and was identified in 43.4% of the cases. Human bocavirus (hBoV) was the second most common identified virus (in 19.5%), followed by human metapneumovirus (hMPV), rhinovirus, influenza viruses, and coronavirus OC43. In terms of clinical characteristics, no significant difference was found among the children with bronchiolitis either caused by different single or mixed viral infection.

Conclusion

RSV was the most common etiologic agent for children with bronchiolitis in Taiwan. Newly identified viruses, including hMPV and hBoV, were also among the common causative agents. Clinical characteristics were not significantly different among the children with bronchiolitis caused by different viruses.

Association of Human bocavirus with Respiratory Infections in Outpatients and in Patients Attended at a Reference Hospital

The role of Human bocavirus (HBoV) in human infectious disease is unclear due to the frequent detection of this virus in association with other respiratory viruses with a recognized pathogenic role in acute respiratory infection. We have analyzed the impact of HBoV in outpatients and in patients requiring hospitalisation or emergency attention for acute respiratory infections. Respiratory viruses were investigated by real-time PCR, direct antigen detection and/or viral culture by shell-vial assay. Nasopharyngeal aspirates, BAL and/or sputum samples from patients attended at a reference hospital, and nasal/throat swabs from outpatients were used. Respiratory viruses were detected in 660 samples (47%). HBoV detection rate was 12.6%, only preceded by respiratory syncytial virus (25%). Co-detections were observed in 12.9% of samples, and HBoV was present in 81% of them. Similar detection rates of HBoV were obtained in individuals with positive and negative results for other respiratory viruses (12.5% and 12.7%, respectively). The crossing point value was taken as a measure of HBoV viral load. Higher HBoV loads were observed in children, and in patients from the hospital. HBoV viral load was not associated with symptoms of upper respiratory tract infection or lower respiratory tract disease. Although HBoV is frequently detected in respiratory specimens, there is a poor association between HBoV-positive specimens and clinical parameters. A clinical impact of HBoV in respiratory infection probably occurs in few cases.

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.