A novel bocavirus associated with acute gastroenteritis in Australian children. PLoS Pathog. 2009;5:e1000391. [PMID: 19381259 PMCID: PMC2663820 DOI: 10.1371/journal.ppat.1000391]

Longitudinal analysis of the enteric virome in paediatric subjects from the Free State Province, South Africa, reveals early gut colonisation and temporal dynamics

The gut of healthy neonates is devoid of viruses at birth, but rapidly becomes colonised by normal viral commensals that aid in important physiological functions like metabolism but can, in some instances, result in gastrointestinal illnesses. However, little is known about how this colonisation begins, its variability and factors shaping the gut virome composition. Thus, understanding the development, assembly, and progression of enteric viral communities over time is key. To explore early-life virome development, metagenomic sequencing was employed in faecal samples collected longitudinally from a cohort of 17 infants during their first six months of life. The gut virome analysis revealed a diverse and dynamic viral community, formed by a richness of different viruses infecting humans, non-human mammals, bacteria, and plants. Eukaryotic viruses were detected as early as one week of life, increasing in abundance and diversity over time. Most of the viruses detected are commonly associated with gastroenteritis and include members of the Caliciviridae, Picornaviridae, Astroviridae, Adenoviridae, and Sedoreoviridae families. The most common co-occurrences involved asymptomatic norovirus-parechovirus, norovirus-sapovirus, sapovirus-parechovirus, observed in at least 40 % of the samples. Majority of the plant-derived viruses detected in the infants' gut were from the Virgaviridae family. This study demonstrates the first longitudinal characterisation of the gastrointestinal virome in infants, from birth up to 6 months of age, in sub-Saharan Africa. Overall, the findings from this study delineate the composition and variability of the healthy infants' gut virome over time, which is a significant step towards understanding the dynamics and biogeography of viral communities in the infant gut.

Development of RPA-Cas12a-fluorescence assay for rapid and reliable detection of human bocavirus 1

Human bocavirus (HBoV) 1 is considered an important pathogen that mainly affects infants aged 6-24 months, but preventing viral transmission in resource-limited regions through rapid and affordable on-site diagnosis of individuals with early infection of HBoV1 remains somewhat challenging. Herein, we present a novel faster, lower cost, reliable method for the detection of HBoV1, which integrates a recombinase polymerase amplification (RPA) assay with the CRISPR/Cas12a system, designated the RPA-Cas12a-fluorescence assay. The RPA-Cas12a-fluorescence system can specifically detect target gene levels as low as 0.5 copies of HBoV1 plasmid DNA per microliter within 40 min at 37°C without the need for sophisticated instruments. The method also demonstrates excellent specificity without cross-reactivity to non-target pathogens. Furthermore, the method was appraised using 28 clinical samples, and displayed high accuracy with positive and negative predictive agreement of 90.9% and 100%, respectively. Therefore, our proposed rapid and sensitive HBoV1 detection method, the RPA-Cas12a-fluorescence assay, shows promising potential for early on-site diagnosis of HBoV1 infection in the fields of public health and health care. The established RPA-Cas12a-fluorescence assay is rapid and reliable method for human bocavirus 1 detection. The RPA-Cas12a-fluorescence assay can be completed within 40 min with robust specificity and sensitivity of 0.5 copies/μl.

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.

Human bocavirus respiratory infection: Tracing the path from viral replication and virus-cell interactions to diagnostic methods

Human bocaviruses were first described between 2005 and 2010, identified in respiratory and enteric tract samples of children. Screening studies have shown worldwide distribution. Based on phylogenetic analysis, they were classified into four genotypes (HBoV1-4). From a clinical perspective, human bocavirus 1 (HBoV1) is considered the most relevant, since it can cause upper and lower acute respiratory tract infection, mainly in infants, including common cold, bronchiolitis, and pneumonia, as well as wheezing in susceptible patients. However, the specific processes leading to structural, biochemical, and functional changes resulting in the different clinical presentations have not been elucidated yet. This review surveys the interactions between the virus and target cells that can potentially explain disease-causing mechanisms. It also summarises the clinical phenotype of cases, stressing the role of HBoV1 as an aetiological agent of lower acute respiratory infection in infants, together with laboratory tests for detection and diagnosis. By exploring the current knowledge on the epidemiology of HBoV1, insights into the complex scenario of paediatric respiratory infections are presented, as well as the potential effects that changes in the circulation can have on the dynamics of respiratory agents, spotlighting the benefits of comprehensively increase insights into incidence, interrelationships with co-circulating agents and potential control of HBoV1.

Prevalence, molecular characterization, and clinical features of human bocavirus in children under 5 years of age with acute gastroenteritis admitted to a specialized children's hospital in Iran: A cross-sectional study

Background and Aims

Although some reports have confirmed the role of human bocavirus (HBoV) in respiratory infections, the importance of this virus in causing acute gastroenteritis has not yet been proven. This study aimed to determine the molecular prevalence of HBoV in children under 5 years old with gastroenteritis and to compare the clinical symptoms of HBoV-positive and -negative gastroenteritis cases.

Methods

A total of 100 stool samples were collected from children with gastroenteritis hospitalized in a pediatric hospital in Tehran, Iran. Demographic and clinical data were collected from patients' medical records. Viral genomic DNA was extracted from stool samples and amplified using the PCR assay. Finally, sequencing was used to determine the genotype of HBoV.

Results

The HBoV genome was detected in 14 samples (14%). The highest prevalence of HBoV was observed in the age range of 24-60 months (n = 5; 35.7%); However, no statistically significant relationship was observed between the prevalence of HBoV and age groups (p = 0.09). Nine (64.3%) and 5 (35.7%) HBoV-positive cases were boys and girls, respectively (p = 0.45). Fever, vomiting, and heartache were seen in 5 (35.7%), 3 (21.4%), and 1 (7.1%) HBoV-positive patients, respectively. Overall, no significant difference was observed in any of the investigated clinical manifestations between patients positive or negative for HBoV. Five HBoV-positive samples were subjected to sequencing and all five sequenced samples were genotype 3.

Conclusion

HBoV infections can be considered a risk factor for causing at least a portion of acute gastroenteritis cases in children under 5 years of age.

Human bocavirus 1 and 2 genotype-specific antibodies for rapid antigen testing in pediatric patients with acute respiratory infections

BACKGROUND

Previous serological studies of human bocavirus (HBoV) 1 could not exclude cross-reactivity with the other three HBoVs, particularly HBoV2.

METHODS

To search for genotype-specific antibodies against HBoV1 and HBoV2, the divergent regions (DRs) located on the major capsid protein VP3 were defined through viral amino acid alignment and structure prediction. DR-deduced peptides were used as antigens to harvest corresponding anti-DR rabbit sera. To determine their genotype specificities for HBoV1 and HBoV2, these sera samples were used as antibodies against the antigens VP3 of HBoV1 and HBoV2 (expressed in Escherichia coli) in western blotting (WB), enzyme-linked immunosorbent assay (ELISA), and bio-layer interferometry (BLI) assays. Subsequently, the antibodies were evaluated with clinical specimens from pediatric patients with acute respiratory tract infection by indirect immunofluorescence assay (IFA).

RESULTS

There were four DRs (DR1-4) located on VP3 with different secondary and tertiary structures between HBoV1 and HBoV2. Regarding the reactivity with VP3 of HBoV1 or HBoV2 in WB and ELISA, high intra-genotype cross-reactivity of anti-HBoV1 or HBoV2 DR1, DR3, and DR4, but not anti-DR2, was observed. Genotype-specific binding capacity of anti-DR2 sera was confirmed by BLI and IFA, in which only anti-HBoV1 DR2 antibody reacted with HBoV1-positive respiratory specimens.

CONCLUSION

Antibodies against DR2, located on VP3 of HBoV1 or HBoV2, were genotype specific for HBoV1 and HBoV2, respectively.

Breaking Bad: Inflammasome Activation by Respiratory Viruses

The nucleotide-binding domain leucine-rich repeat-containing receptor (NLR) family is a group of intracellular sensors activated in response to harmful stimuli, such as invading pathogens. Some NLR family members form large multiprotein complexes known as inflammasomes, acting as a platform for activating the caspase-1-induced canonical inflammatory pathway. The canonical inflammasome pathway triggers the secretion of the pro-inflammatory cytokines interleukin (IL)-1β and IL-18 by the rapid rupture of the plasma cell membrane, subsequently causing an inflammatory cell death program known as pyroptosis, thereby halting viral replication and removing infected cells. Recent studies have highlighted the importance of inflammasome activation in the response against respiratory viral infections, such as influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While inflammasome activity can contribute to the resolution of respiratory virus infections, dysregulated inflammasome activity can also exacerbate immunopathology, leading to tissue damage and hyperinflammation. In this review, we summarize how different respiratory viruses trigger inflammasome pathways and what harmful effects the inflammasome exerts along with its antiviral immune response during viral infection in the lungs. By understanding the crosstalk between invading pathogens and inflammasome regulation, new therapeutic strategies can be exploited to improve the outcomes of respiratory viral infections.

Epidemiologic and Clinical Characteristics of Human Bocavirus Infection in Children with or without Acute Gastroenteritis in Acre, Northern Brazil

Human bocavirus (HBoV) is an emerging virus detected around the world that may be associated with cases of acute gastroenteritis (AGE). However, its contribution to AGE has not been elucidated. This study aimed to describe the frequency, clinical features, and HBoV species circulation in children up to 5 years with or without AGE symptoms in Acre, Northern Brazil. A total of 480 stool samples were collected between January and December 2012. Fecal samples were used for extraction, nested PCR amplification, and sequencing for genotyping. Statistical analysis was applied to verify the association between epidemiological and clinical characteristics. Overall, HBoV-positivity was 10% (48/480), with HBoV-positive rates of 8.4% (19/226) and 11.4% (29/254) recorded in diarrheic and non-diarrheic children, respectively. The most affected children were in the age group ranging between 7 and 24 months (50%). HBoV infection was more frequent in children who live in urban areas (85.4%), use water from public networks (56.2%), and live with adequate sewage facilities (50%). Co-detection with other enteric viruses was 16.7% (8/48) and the most prevalent coinfection was RVA+ HBoV (50%, 4/8). HBoV-1 was the most frequent species detected in diarrheic and non-diarrheic children, responsible for 43.8% (21/48) of cases, followed by HBoV-3 (29.2%, 14/48) and HBoV-2 (25%, 12/48). In this study, HBoV infection was not always associated with AGE, as most HBoV cases belonged to the non-diarrheal group. Future studies are warranted in order to determine the role of HBoV in causing acute diarrhea disease.

Longitudinal Detection of Twenty DNA and RNA Viruses in Allogeneic Hematopoietic Stem Cell Transplant Recipients Plasma

Metagenomics revealed novel and routinely overlooked viruses, representing sources of unrecognized infections after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We aim to describe DNA and RNA virus prevalence and kinetics in allo-HSCT recipients' plasma for one year post HSCT. We included 109 adult patients with first allo-HSCT from 1 March 2017 to 31 January 2019 in this observational cohort study. Seventeen DNA and three RNA viral species were screened with qualitative and/or quantitative r(RT)-PCR assays using plasma samples collected at 0, 1, 3, 6, and 12 months post HSCT. TTV infected 97% of patients, followed by HPgV-1 (prevalence: 26-36%). TTV (median 3.29 × 10⁵ copies/mL) and HPgV-1 (median 1.18 × 10⁶ copies/mL) viral loads peaked at month 3. At least one Polyomaviridae virus (BKPyV, JCPyV, MCPyV, HPyV6/7) was detected in >10% of patients. HPyV6 and HPyV7 prevalence reached 27% and 12% at month 3; CMV prevalence reached 27%. HSV, VZV, EBV, HHV-7, HAdV and B19V prevalence remained <5%. HPyV9, TSPyV, HBoV, EV and HPg-V2 were never detected. At month 3, 72% of patients had co-infections. TTV and HPgV-1 infections were highly prevalent. BKPyV, MCPyV and HPyV6/7 were frequently detected relative to classical culprits. Further investigation is needed into associations between these viral infections and immune reconstitution or clinical outcomes.

Detection and Molecular Characterization of Enteric Viruses in Bivalve Mollusks Collected in Arraial do Cabo, Rio de Janeiro, Brazil

Viral bivalve contamination is a recognized food safety hazard. Therefore, this study investigated the detection rates, seasonality, quantification, and genetic diversity of enteric viruses in bivalve samples (mussels and oysters). We collected 97 shellfish samples between March 2018 and February 2020. The screening of samples by qPCR or RT-qPCR revealed the detection of norovirus (42.3%), rotavirus A (RVA; 16.5%), human adenovirus (HAdV; 24.7%), and human bocavirus (HBoV; 13.4%). There was no detection of hepatitis A virus. In total, 58.8% of shellfish samples tested positive for one or more viruses, with 42.1% of positive samples contaminated with two or more viruses. Norovirus showed the highest median viral load (3.3 × 10⁶ GC/g), followed by HAdV (median of 3.5 × 10⁴ GC/g), RVA (median of 1.5 × 10³ GC/g), and HBoV (median of 1.3 × 10³ GC/g). Phylogenetic analysis revealed that norovirus strains belonged to genotype GII.12[P16], RVA to genotype I2, HAdV to types -C2, -C5, and -F40, and HBoV to genotypes -1 and -2. Our results demonstrate the viral contamination of bivalves, emphasizing the need for virological monitoring programs to ensure the quality and safety of shellfish for human consumption and as a valuable surveillance tool to monitor emerging viruses and novel variants.

Gut virome in early life: origins and implications

The human body is colonized by a multitude of bacteria, fungi, and viruses, which play important roles in health and disease. Microbial colonization during early life is thought to be a particularly important period with lasting consequences for health. Viral populations in the gut are particularly dynamic in early life before they stabilize in adulthood. The composition of the early-life virome is increasingly recognized as a determinant of disease later in life. Here, we review the development of the virome in healthy infants, as well as the role of the early-life virome in the development of disease states including diarrhea, malnutrition, and autoimmune diseases.

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.

Human Bocavirus infection among children with respiratory tract infection in Ibadan, Nigeria

Background. Human Bocavirus (HBoV), which is an ssDNA virus of the family Parvoviridae, is responsible for 21.5 % of childhood respiratory tract infections (RTIs) annually. Among the four genotypes currently known, HBoV-1 has been associated with acute RTI. Although there have been studies on HBoV in some countries, there is limited information on this virus in sub-Saharan Africa where there is the highest burden of RTI. This study aimed to characterize the circulating strains of HBoV in Ibadan, Nigeria.

Methods. Nasopharyngeal and oropharyngeal swab samples were collected from 333 children ≤5 years old presenting with RTI attending hospitals in Ibadan, whose parents assented, from 2014 to 2015. Twenty-three HBoV isolates were sequenced after a nested PCR and phylogenetic analysis was carried out using mega 6 software.

Gut Virome: Role and Distribution in Health and Gastrointestinal Diseases

The study of the intestinal microbiome is an evolving field of research that includes comprehensive analysis of the vast array of microbes – bacterial, archaeal, fungal, and viral. Various gastrointestinal (GI) diseases, such as Crohn’s disease and ulcerative colitis, have been associated with instability of the gut microbiota. Many studies have focused on importance of bacterial communities with relation to health and disease in humans. The role of viruses, specifically bacteriophages, have recently begin to emerge and have profound impact on the host. Here, we comprehensively review the importance of viruses in GI diseases and summarize their influence in the complex intestinal environment, including their biochemical and genetic activities. We also discuss the distribution of the gut virome as it relates with treatment and immunological advantages. In conclusion, we suggest the need for further studies on this critical component of the intestinal microbiome to decipher the role of the gut virome in human health and disease.

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

Aim

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

Methods

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

Results

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

Conclusion

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

Viral metagenomics reveals diverse viruses in the fecal samples of children with diarrhea

Diarrhea is the third leading cause of death in developing countries in children under the age of five. About half a million children die of diarrhea every year, most of which in developing countries. Viruses are the main pathogen of diarrhea. In China, the fecal virome of children with diarrhea has been rarely studied. Using an unbiased viral metagenomics approach, we analyzed the fecal virome in children with diarrhea. Many DNA or RNA viruses associated with diarrhea identified in those fecal samples were mainly from six families of Adenoviridae, Astroviridae, Caliciviridae, Parvoviridae, Picornaviridae, and Reoviridae. Among them, the family of Caliciviridae accounts for the largest proportion of 78.42%, following with Adenoviridae (8.94%) and Picornaviridae (8.36%). In addition to those diarrhea-related viruses that have already been confirmed to cause human diarrhea, the viruses not associated with diarrhea were also identified including anellovirus and picobirnavirus. This study increased our understanding of diarrheic children fecal virome and provided valuable information for the prevention and treatment of viral diarrhea in this area.

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Many DNA or RNA viruses associated with diarrhea were identified in this study.

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Viruses belonging to the family of Caliciviridae were the most main pathogen that induced children diarrhea.

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In addition to those diarrhea-related viruses, the viruses not associated with diarrhea were also identified.

Best of most possible worlds: Hybrid gene therapy vectors based on parvoviruses and heterologous viruses

Parvoviruses and especially the adeno-associated virus (AAV) species provide an exciting and versatile platform for the rational design or molecular evolution of human gene-therapy vectors, documented by literature from over half a century, hundreds of clinical trials, and the recent commercialization of multiple AAV gene therapeutics. For the last three decades, the power of these vectors has been further potentiated through various types of hybrid vectors created by intra- or inter-genus juxtaposition of viral DNA and protein cis elements or by synergistic complementation of parvoviral features with those of heterologous, prokaryotic, or eukaryotic viruses. Here, we provide an overview of the history and promise of this rapidly expanding field of hybrid parvoviral gene-therapy vectors, starting with early generations of chimeric particles composed of a recombinant AAV genome encapsidated in shells of synthetic AAVs or of adeno-, herpes-, baculo-, or protoparvoviruses. We then dedicate our attention to two newer, highly promising types of hybrid vectors created via (1) pseudotyping of AAV genomes with bocaviral serotypes and capsid mutants or (2) packaging of AAV DNA into, or tethering of entire vector particles to, bacteriophages. Finally, we conclude with an outlook summarizing critical requirements and improvements toward clinical translation of these original concepts.

Prevalence of human pathogenic viruses in wastewater: A potential transmission risk as well as an effective tool for early outbreak detection for COVID-19

Millions of human pathogenic viral particles are shed from infected individuals and introduce into wastewater, subsequently causing waterborne diseases worldwide. These viruses can be transmitted from wastewater to human beings via direct contact and/or ingestion/inhalation of aerosols. Even the advanced wastewater treatment technologies are unable to remove pathogenic viruses from wastewater completely, posing a serious health risk. Recently, coronavirus disease 2019 (COVID-19) has been urged globally due to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which has resulted in >4.1 million deaths until July 2021. A rapid human-to-human transmission, uncertainties in effective vaccines, non-specific medical treatments, and unclear symptoms compelled the world into complete lockdown, social distancing, air-travel suspension, and closure of educational institutions, subsequently damaging the global economy and trade. Although, few medical treatments, rapid detection tools, and vaccines have been developed so far to curb the spread of COVID-19; however, several uncertainties exist in their applicability. Further, the acceptance of vaccines among communities is lower owing to the fear of side effects such as blood-clotting and heart inflammation. SARS-CoV-2, an etiologic agent of COVID-19, has frequently been detected in wastewater, depicting a potential transmission risk to healthy individuals. Contrarily, the occurrence of SARS-CoV-2 in wastewater can be used as an early outbreak detection tool via water-based epidemiology. Therefore, the spread of SARS-CoV-2 through fecal-oral pathway can be reduced and any possible outbreak can be evaded by proper wastewater surveillance. In this review, wastewater recycling complications, potential health risks of COVID-19 emergence, and current epidemiological measures to control COVID-19 spread have been discussed. Moreover, the viability of SARS-CoV-2 in various environments and survival in wastewater has been reviewed. Additionally, the necessary actions (vaccination, face mask, social distancing, and hand sanitization) to limit the transmission of SARS-CoV-2 have been recommended. Therefore, wastewater surveillance can serve as a feasible, efficient, and reliable epidemiological measure to lessen the spread of COVID-19.

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.

Small but mighty: old and new parvoviruses of veterinary significance

In line with the Latin expression "sed parva forti" meaning "small but mighty," the family Parvoviridae contains many of the smallest known viruses, some of which result in fatal or debilitating infections. In recent years, advances in metagenomic viral discovery techniques have dramatically increased the identification of novel parvoviruses in both diseased and healthy individuals. While some of these discoveries have solved etiologic mysteries of well-described diseases in animals, many of the newly discovered parvoviruses appear to cause mild or no disease, or disease associations remain to be established. With the increased use of animal parvoviruses as vectors for gene therapy and oncolytic treatments in humans, it becomes all the more important to understand the diversity, pathogenic potential, and evolution of this diverse family of viruses. In this review, we discuss parvoviruses infecting vertebrate animals, with a special focus on pathogens of veterinary significance and viruses discovered within the last four years.

Global molecular prevalence and genotype distribution of Sapovirus in children with gastrointestinal complications: A systematic review and meta-analysis

Sapovirus (SaV) is an emerging cause of children gastrointestinal complications such as acute gastroenteritis (AGE). The aim of the present systematic review and meta-analysis was to estimate the global prevalence of the SaV in children and association of infection with SaVs and AGE in children based on case-control studies. Four international databases (PubMed, Scopus, Web of Sciences and Google Scholar) were used to retrieve English-language studies published between January 2000 and December 2020. Comprehensive Meta-Analysis software was applied to estimate the overall prevalence, publication bias and heterogeneity index. The pooled prevalence of SaV infection among children with gastroenteritis was 3.4% [95% confidence interval (CI): 2.9%-3.9%] based on a random-effects meta-analysis. Genogroup I was the dominant genogroup of SaV in children with gastroenteritis [2.2% (95% CI: 1.6%-3.0%)], association analysis showed that SaV was associated with gastroenteritis [OR: 1.843 (95% CI: 1.27-2.66)]. Given the significant prevalence of the virus in children, it is necessary to pay more attention to this situation. Therefore, preventive health measures in children should be a priority.

Prevalence and Molecular Characterization of Human Bocavirus Detected in Croatian Children with Respiratory Infection

Human bocavirus (HBoV) 1 is considered an important respiratory pathogen, while the role of HBoV2-4 in clinical disease remains somewhat controversial. Since, they are characterized by a rapid evolution, worldwide surveillance of HBoVs’ genetics is necessary. This study explored the prevalence of HBoV genotypes in pediatric patients with respiratory tract infection in Croatia and studied their phylogeny. Using multiplex PCR for 15 respiratory viruses, we investigated 957 respiratory samples of children up to 18 years of age with respiratory tract infection obtained from May 2017 to March 2021 at two different hospitals in Croatia. Amplification of HBoV near-complete genome or three overlapping fragments was performed, sequenced, and their phylogenetic inferences constructed. HBoV was detected in 7.6% children with a median age of 1.36 years. Co-infection was observed in 82.2% samples. Sequencing was successfully performed on 29 HBoV positive samples, and all belonged to HBoV1. Croatian HBoV1 sequences are closely related to strains isolated worldwide, and no phylogenetic grouping based on mono- or co-infection cases or year of isolation was observed. Calculated rates of evolution for HBoV1 were 10⁻⁴ and 10⁻⁵ substitutions per site and year. Recombination was not detected among sequences from this study.

Etiology of diarrheal disease among children under 5 years in Egypt: a high incidence of human bocavirus

BACKGROUND

Human bocavirus (HBoV) is globally distributed and associated with respiratory and enteric infections. Limited data are available about the incidence of HBoV in Egyptian children. We aimed to investigate the association of HBoV genotypes in children with diarrheal disease and also to determine the possibility of HBoV co-infections with other human enteric pathogens.

METHODS

A total of 102 stool samples were collected from children under five years old with diarrhea. Samples were analyzed for the presence of HBoV by real-time PCR. HBoV positive samples were tested for adenovirus (AdV), rotavirus (RoV), parasitic helminths, and enteric protozoa.

RESULTS

HBoV was detected in 58% of examined cases. HBoV-3 was the most prevalent genotype observed (44%; 45 of 102), followed by HBoV-2/4 (33%; 34 of 102) and HBoV-1 (30%; 31 of 102). Although the incidence of HBoV was higher in males (66.6%; 34 of 51) than females (49%; 25 of 51), the analysis showed no significant difference for HBoV between genders. The average HBoV concentrations were 5.3 × 10⁴ GC/g in males and 1.03 × 10⁵ GC/g in females. Among the HBoV-positive samples, the single infection of HBoV was 52.5% (31/59), while the co-infections with multiple viruses were found in 1.7% (1/59) for HBoV and AdV, 33.9% (20/59) for HBoV and RoV, and 11.9% (7/59) for HBoV, and RoV and AdV. No co-infection with parasitic helminths or enteric protozoa was found.

CONCLUSIONS

The single infection of HBoV in some children suffering from acute gastroenteritis indicated that HBoV could be the main etiologic agent of the disease. The study highlights the high incidence of HBoVs genotypes with remarkable multiple co-infections in the pre-school children in Egypt.

Prevalence of human bocavirus infections in Europe. 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.

Porcine Bocavirus: A 10-Year History since Its Discovery

Porcine bocavirus (PBoV) is a single-stranded DNA virus, belongs to the genus Bocaparvovirus of family Parvoviridae. It was discovered along with porcine circovirus 2 (PCV 2) and torque tenovirus (TTV) in the lymph nodes of pigs suffering from postweaning multisystemic wasting syndrome (PMWS) in Sweden in 2009. PBoV has been reported throughout the world, mostly in weaning piglets, and has a broad range of tissue tropism. Since PBoV is prevalent in healthy as well as clinically infected pigs and is mostly associated with coinfection with other viruses, the pathogenic nature of PBoV is still unclear. Currently, there are no cell lines available for the study of PBoV, and animal model experiments have not been described. This review summarizes the current state of knowledge about PBoV, including the epidemiology, evolution analysis, detection methods, pathogenesis and public health concerns.

pH-Induced Conformational Changes of Human Bocavirus Capsids

Human bocavirus 1 (HBoV1) and HBoV2-4 infect children and immunocompromised individuals, resulting in respiratory and gastrointestinal infections, respectively. Using cryo-electron microscopy and image reconstruction, the HBoV2 capsid structure was determined to 2.7 Å resolution at pH 7.4 and compared to the previously determined HBoV1, HBoV3, and HBoV4 structures. Consistent with previous findings, surface variable region (VR) III of the capsid protein VP3, proposed as a host tissue-tropism determinant, was structurally similar among the gastrointestinal strains HBoV2-4, but differed from HBoV1 with its tropism for the respiratory tract. Towards understanding the entry and trafficking properties of these viruses, HBoV1 and HBoV2 were further analyzed as species representatives of the two HBoV tropisms. Their cell surface glycan-binding characteristics were analyzed, and capsid structures determined to 2.5-2.7 Å resolution at pH 5.5 and 2.6, conditions normally encountered during infection. The data showed that glycans with terminal sialic acid, galactose, GlcNAc or heparan sulfate moieties do not facilitate HBoV1 or HBoV2 cellular attachment. With respect to trafficking, conformational changes common to both viruses were observed at low pH conditions localized to the VP N-terminus under the 5-fold channel, in the surface loops VR-I and VR-V and specific side-chain residues such as cysteines and histidines. The 5-fold conformational movements provide insight into the potential mechanism of VP N-terminal dynamics during HBoV infection and side-chain modifications highlight pH-sensitive regions of the capsid.IMPORTANCE Human bocaviruses (HBoVs) are associated with disease in humans. However, the lack of an animal model and a versatile cell culture system to study their life cycle limits the ability to develop specific treatments or vaccines. This study presents the structure of HBoV2, at 2.7 Å resolution, determined for comparison to the existing HBoV1, HBoV3, and HBoV4 structures, to enable the molecular characterization of strain and genus-specific capsid features contributing to tissue tropism and antigenicity. Furthermore, HBoV1 and HBoV2 structures determined under acidic conditions provide insight into capsid changes associated with endosomal and gastrointestinal acidification. Structural rearrangements of the capsid VP N-terminus, at the base of the 5-fold channel, demonstrate a disordering of a "basket" motif as pH decreases. These observations begin to unravel the molecular mechanism of HBoV infection and provide information for control strategies.

Characterization of the GBoV1 Capsid and Its Antibody Interactions

Human bocavirus 1 (HBoV1) has gained attention as a gene delivery vector with its ability to infect polarized human airway epithelia and 5.5 kb genome packaging capacity. Gorilla bocavirus 1 (GBoV1) VP3 shares 86% amino acid sequence identity with HBoV1 but has better transduction efficiency in several human cell types. Here, we report the capsid structure of GBoV1 determined to 2.76 Å resolution using cryo-electron microscopy (cryo-EM) and its interaction with mouse monoclonal antibodies (mAbs) and human sera. GBoV1 shares capsid surface morphologies with other parvoviruses, with a channel at the 5-fold symmetry axis, protrusions surrounding the 3-fold axis and a depression at the 2-fold axis. A 2/5-fold wall separates the 2-fold and 5-fold axes. Compared to HBoV1, differences are localized to the 3-fold protrusions. Consistently, native dot immunoblots and cryo-EM showed cross-reactivity and binding, respectively, by a 5-fold targeted HBoV1 mAb, 15C6. Surprisingly, recognition was observed for one out of three 3-fold targeted mAbs, 12C1, indicating some structural similarity at this region. In addition, GBoV1, tested against 40 human sera, showed the similar rates of seropositivity as HBoV1. Immunogenic reactivity against parvoviral vectors is a significant barrier to efficient gene delivery. This study is a step towards optimizing bocaparvovirus vectors with antibody escape properties.

Human bocavirus genotypes 1, 2, and 3 circulating in pediatric patients with acute gastroenteritis in Chiang Mai, Thailand, 2012-2018

BACKGROUND

Global distribution of human bocavirus (HBoV) has been known to associate with viral gastroenteritis in pediatric population. This study was conducted in Chiang Mai, Thailand from 2012 to 2018 to investigate epidemiology and genotype distribution of HBoV in pediatric patients less than 5 years old hospitalized with diarrhea.

METHODS

A total of 2727 fecal specimens were investigated for the presence of HBoV using nested-PCR targeting partial VP1 capsid region. The detected HBoV strains were further characterized by nucleotide sequencing and phylogenetic analysis.

RESULTS

Detection rate of HBoV infection in pediatric patients with acute diarrhea was 5.2%. Three genotypes of HBoV were detected with the most predominance of HBoV1 (50.4%), followed by HBoV2 (42.5%), and HBoV3 (7.1%). The majority of HBoV positive cases were children of 1 to <2 years old (31.9%) with high detection rate of HBoV1 and HBoV2. HBoV infection occurred all year-round. Phylogenetic analysis revealed that majority of HBoV1 displayed the genetic relationship with HBoV1 strains reported previously from Asia whereas only a few were related to the strains from Europe, South America, and Middle East. The HBoV2 and HBoV3 were also mainly closely related to the strains reported from Asia and a few from South America and North Africa.

CONCLUSIONS

This study highlights distribution of HBoV genotypes circulating in pediatric patients with acute gastroenteritis in Chiang Mai, Thailand. Overall, three genotypes of HBoV were detected with equally high prevalence of HBoV1 and HBoV2 whereas HBoV3 was detected with much lower prevalence.

Detection and genetic characteristics of porcine bocavirus in central China

To investigate the epidemic profile and genetic diversity of porcine bocavirus (PBoV), 281 clinical samples, including 236 intestinal tissue samples and 45 fecal samples were collected from diarrheic piglets on 37 different pig farms in central China, and two SYBR Green I-based quantitative PCR assays were developed to detect PBoV1/2 and PBoV3/4/5, respectively. One hundred forty-eight (52.67%) of the 281 clinical samples were positive for PBoV1/2, 117 (41.63%) were positive for PBoV3/4/5, 55 (19.57%) were positive for both PBoV1/2 and PBoV3/4/5, and 86.49% (32/37) of the pig farms were positive for PBoV. Overall, the prevalence of PBoV was 74.73% (210/281) in central China. Subsequently, nearly full-length genomic sequences of two PBoV strains (designated CH/HNZM and PBoV-TY) from two different farms were determined. Phylogenetic analysis demonstrated that the two PBoV strains obtained in this study belonged to the PBoV G2 group and had a close relationship to 10 other PBoV G2 strains but differed genetically from PBoV G1, PBoV G3, and seven other bocaviruses. CH/HNZM and PBoV-TY were closely related to the PBoV strain GD18 (KJ755666), which may be derived from the PBoV strains 0912/2012 (MH558677) and 57AT-HU (KF206160) through recombination. Compared with reference strain ZJD (HM053694)-China, more amino acid variation was found in the NS1 proteins of CH/HNZM and PBoV-TY. These data extend our understanding of the molecular epidemiology and evolution of PBoV.

Microfluidic sample preparation for respiratory virus detection: A review

Techniques used to prepare clinical samples have been perfected for use in diagnostic testing in a variety of clinical situations, e.g., to extract, concentrate, and purify respiratory virus particles. These techniques offer a high level of purity and concentration of target samples but require significant equipment and highly trained personnel to conduct, which is difficult to achieve in resource-limited environments where rapid testing and diagnostics are crucial for proper handling of respiratory viruses. Microfluidics has popularly been utilized toward rapid virus detection in resource-limited environments, where most devices focused on detection rather than sample preparation. Initial microfluidic prototypes have been hindered by their reliance on several off-chip preprocessing steps and external laboratory equipment. Recently, sample preparation methods have also been incorporated into microfluidics to conduct the virus detection in an all-in-one, automated manner. Extraction, concentration, and purification of viruses have been demonstrated in smaller volumes of samples and reagents, with no need for specialized training or complex machinery. Recent devices show the ability to function independently and efficiently to provide rapid, automated sample preparation as well as the detection of viral samples with high efficiency. In this review, methods of microfluidic sample preparation for the isolation and purification of viral samples are discussed, limitations of current systems are summarized, and potential advances are identified.

History of paediatric gastroenterology in Australia

Paediatric gastroenterology in Australia has undergone remarkable changes over the more than six decades since Charlotte Anderson's pioneering work, and is now a well-established specialty in its own right. Australian paediatric gastroenterologists have made important contributions nationally and internationally.

Beyond Cytomegalovirus and Epstein-Barr Virus: a Review of Viruses Composing the Blood Virome of Solid Organ Transplant and Hematopoietic Stem Cell Transplant Recipients

Viral primary infections and reactivations are common complications in patients after solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT) and are associated with high morbidity and mortality. Among these patients, viral infections are frequently associated with viremia. Beyond the usual well-known viruses that are part of the routine clinical management of transplant recipients, numerous other viral signatures or genomes can be identified in the blood of these patients. The identification of novel viral species and variants by metagenomic next-generation sequencing has opened up a new field of investigation and new paradigms. Thus, there is a need to thoroughly describe the state of knowledge in this field with a review of all viral infections that should be scrutinized in high-risk populations. Here, we review the eukaryotic DNA and RNA viruses identified in blood, plasma, or serum samples of pediatric and adult SOT/HSCT recipients and the prevalence of their detection, with a particular focus on recently identified viruses and those for which their potential association with disease remains to be investigated, such as members of the Polyomaviridae, Anelloviridae, Flaviviridae, and Astroviridae families. Current knowledge of the clinical significance of these viral infections with associated viremia among transplant recipients is also discussed. To ensure a comprehensive description in these two populations, individuals described as healthy (mostly blood donors) are considered for comparative purposes. The list of viruses that should be on the clinicians' radar is certainly incomplete and will expand, but the challenge is to identify those of possible clinical significance.

Detection and phylogenetic analysis of Human bocavirus in children diagnosed with acute respiratory tract infection

Introduction. Human bocavirus (HBoV) is a recently discovered parvovirus; it has been shown to be a common cause of respiratory infections and gastroenteritis in children. Since its identification, HBoV has been detected worldwide in nasopharyngeal swabs, serum and stool samples particularly those obtained from young children suffering from respiratory or gastrointestinal tract infections.Aim. The aim of this work was to determine HBoV prevalence among children with acute respiratory tract infection in Egypt, to detect the most prevalent HBoV genotype and to compare PCR and ELISA as diagnostic techniques for HBoV infection.Methods. Nasopharyngeal swabs and blood samples were obtained within the first day of admission from 75 children diagnosed with acute respiratory tract infection in El-Shatby University Hospital for Children in Alexandria, Egypt from October 2018 to March 2019. Conventional PCR was used to detect HBoV DNA, ELISA was used to detect HBoV IgM antibodies and sequencing of the VP1/2 genes was used for genotyping.Results. Seven (9.3%) of the 75 nasopharyngeal swabs obtained from patients with acute respiratory tract infection were positive for HBoV by PCR, while 5 (6.7 %) of the 75 serum samples were positive for HBoV IgM antibodies using ELISA. The correlation between PCR and ELISA results showed a highly significant association between PCR and ELISA techniques (X ²=52.041, P<0.01) and a highly significant agreement between the two methods (Kappa=81.9 %, P<0.01). Phylogenetic analysis showed that all positive samples were related to the HBoV-1 genotype.Conclusion. Human bocavirus was detected at 9.3 % prevalence in nasopharyngeal swabs obtained from children with acute respiratory tract infection. The HBoV-1 genotype was the only genotype detected, suggesting that a single genetic lineage of HBoV is circulating in Egypt. PCR and ELISA are two reliable methods for detection and diagnosis of HBoV.

Human Bocavirus in Brazil: Molecular Epidemiology, Viral Load and Co-Infections

Human bocavirus (HBoV) is an emerging virus and has been detected worldwide, especially in pediatric patients with respiratory and gastrointestinal infection. In this study, we describe HBoV prevalence, genotypes circulation and DNA shedding, in stool samples from children up to two years of age in Brazil. During 2016 and 2017, 886 acute gastroenteritis (AGE) stool samples from ten Brazilian states were analyzed by TaqMan^®-based qPCR, to detect and quantify HBoV. Positive samples were genotyped by sequencing the VP1/2 overlap region, followed by phylogenetic analysis and co-infections were accessed by screening other gastroenteric viruses. HBoV was detected in 12.4% (n = 110) of samples, with viral load ranging from 1.6 × 10² to 1.2 × 10⁹ genome copies per gram of stool. From these, co-infections were found in 79.1%, and a statistically lower HBoV viral load was found compared to viral loads of rotavirus, norovirus and adenovirus in double infected patients (p < 0.05). No significant differences were found between HBoV viral load in single or co-infections, age groups or genotypes. Phylogenetic analysis identified the circulation of HBoV-1 in 38%, HBoV-2 in 40% and HBoV-3 in 22%. Continuous HBoV monitoring is needed to clarify its role in diarrhea disease, especially in the absence of classic gastroenteric viruses.

Human Bocavirus infection and respiratory tract disease identified in a UK patient cohort

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Human Bocavirus 1 (HBoV1) was commonly detected in a survey of circa 13,000 UK respiratory samples between 2015 and 2019.

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Co-infection with other viruses was observed in approximately three quarters of samples.

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However, mono-infection was also prevalent, and associated with clinically relevant disease.

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Intensive care was required in 31% of HBoV1 mono-infections and ventilation in 17%.

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Fatal multi-organ failure was observed in an apparently HBoV1 mono-infected and otherwise healthy child.

Background

Since its first isolation in 2005, Human Bocavirus (HBoV) has been repeatedly associated with acute respiratory tract infections, although its role in pathogenicity remains unclear due to high co-infection rates.

Objectives

To assess HBoV prevalence and associated disease in a cohort of respiratory patients in the East Midlands, UK between 2015 and 2019.

Study design

We initially investigated the undiagnosed burden of HBoV in a retrospective paediatric cohort sampled between 2015 and 2017 using an in-house PCR assay. HBoV was subsequently incorporated into the standard respiratory diagnostic pathway and we audited a calendar year of HBoV positive results between 2018 and 2019.

Results

Our retrospective PCR screening of previously routine diagnostic-negative samples from juvenile patients identified a 9% (n = 30) prevalence of HBoV type 1. These apparent HBoV1 mono-infections were frequently associated with respiratory tract symptoms, often severe requiring ventilation, oxygen and steroid intervention with 31% (n = 9) of individuals requiring intensive care. When HBoV screening was subsequently adopted into the routine respiratory diagnostic pathway, year-round infections were observed in both children and adults peaking in February. 185 of 9098 (2.03%) individuals were found to be HBoV positive with children aged 12–24 months the principally infected group. However, HBoV infection was also observed in patients aged over 60, predominantly as a mono-infection. 23% of the 185 unique patients were HBoV monoinfected and persistent low-level DNA positivity was observed in 15 individuals up to 6-months after initial presentation.

Conclusion

HBoV1 is a prevalent respiratory infection in the UK capable of causing serious monoinfections.

Parvovirus Capsid-Antibody Complex Structures Reveal Conservation of Antigenic Epitopes Across the Family

The parvoviruses are small nonenveloped single stranded DNA viruses that constitute members that range from apathogenic to pathogenic in humans and animals. The infection with a parvovirus results in the generation of antibodies against the viral capsid by the host immune system to eliminate the virus and to prevent re-infection. For members currently either being developed as delivery vectors for gene therapy applications or as oncolytic biologics for tumor therapy, efforts are aimed at combating the detrimental effects of pre-existing or post-treatment antibodies that can eliminate therapeutic benefits. Therefore, understanding antigenic epitopes of parvoviruses can provide crucial information for the development of vaccination applications and engineering novel capsids able to escape antibody recognition. This review aims to capture the information for the binding regions of ∼30 capsid-antibody complex structures of different parvovirus capsids determined to date by cryo-electron microscopy and three-dimensional image reconstruction. The comparison of all complex structures revealed the conservation of antigenic regions among parvoviruses from different genera despite low sequence identity and indicates that the available data can be used across the family for vaccine development and capsid engineering.

Human Bocavirus genotypes 1 and 2 detected in younger Amazonian children with acute gastroenteritis or respiratory infections, respectively

OBJECTIVES

This study aimed to verify the frequency, genotypes, and etiological role of Human Bocavirus (HBoV) in younger Amazonian children with either acute gastroenteritis (AGE) or respiratory infections (ARI). The influence of Rotarix™ vaccination and co-infection status was also investigated.

DESIGN

HBoV quantitative polymerase chain reaction (qPCR) testing was done on both fecal and saliva (1468 samples) from 734 children < 5 months old living in the Amazon (Brazil, Guyana, and Venezuela). High and median HBoV viral load samples were used for extraction, nested PCR amplification, and sequencing for genotyping. HBoV mRNA detection was done by reverse transcription following DNA amplification.

RESULTS

The overall HBoV frequencies were 14.2% (69/485; AGE) and 14.1% (35/249; ARI) (p = 0.83). HBoV exclusively infected 4.5% (22/485; AGE) and 4% (10/249) of the Amazonian children (Odds ratios 1.13, 95% confidence interval= 2.42-0.52). HBoV 1 was mainly detected in feces and saliva from AGE children; and HBoV2, from ARI children. HBoV mRNA was detected only in feces. The Rotarix™ vaccination status did not affect the HBoV frequencies.

CONCLUSIONS

We suggest that, after entry into the air/oral pathways, HBoV1 continues infecting toward the intestinal tract causing AGE. HBoV2 can be a causative agent of AGE and ARI in younger Amazonian children.

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.

Genetic Diversity and Phylogenetic Analysis of Human Bocavirus 2 in Pediatric Patients with Acute Gastroenteritis in Taiwan

Human bocavirus (HBoV) is a causative agent of respiratory and gastrointestinal diseases worldwide. Four HBoV species (HBoV1-4) have been identified so far. Although a previous report has documented the HBoV association with acute gastroenteritis (AGE) in Taiwan, their epidemiology, genetic diversity, and phylogenetic relationships remain unclear. In this study, we focused on an investigation of these unsolved issues, which will help to reveal molecular epidemiology and phylogeny of the circulating HBoV2 in Taiwan. A total of 176 stool samples were collected from children with AGE for this study. PCR amplification and sequencing on the VP1 gene region were used to identify species. Phylogenetic analysis was conducted by maximum-likelihood and neighbor-joining methods. Selection pressure was also estimated to obtain HBoV evolutionary information. Our results showed the prevalence of HBoV in AGE children was 8.5%, of which HBoV1 was the predominant species (6.3%), followed by HBoV2 (2.3%). Phylogenetic analysis showed those Taiwanese HBoV2 strains have significant genetic variability and can be divided into two clusters. One belongs to HBoV2 genotype A and the other forms an independent unclassified cluster. The nucleotide distance between that independent cluster and the known HBoV2 genotypes was more than 5%, suggesting a new HBoV2 genotype. No positive selection site was found and the virus was under purifying selection. This is the first report to reveal HBoV2 genetic diversity and phylogenetic relationships among AGE children in Taiwan. We find that HBoV2 may have been introduced into the country by multiple origins, and a potential new HBoV2 genotype is proposed.

Detection, genetic, and codon usage bias analyses of the VP2 gene of mink bocavirus

Mink bocavirus 1 (MiBoV1), a novel virus detected from the feces of domestic minks in China in 2016, may be related to gastrointestinal diseases. However, its prevalence and genetic characteristics are poorly described. In this study, we examined 192 samples collected from minks in the major mink industry province from northern China. PCR results showed that 10 samples (5.2%) were positive for MiBoV1, and 60% of MiBoV1-positive samples were co-infected with Aleutian mink disease virus or mink circovirus. MiBoV1 was detected in six serum samples. Sequence analysis demonstrated that the VP2 gene of MiBoV1 was highly conserved and had low viral diversity over the VP2 region and unique nucleotide mutations. Phylogenetic analysis of the VP2 sequence demonstrated that MiBoV1 strains formed two clades and were grouped with California sea lion bocavirus, Canine bocavirus, and Feline bocavirus. Codon usage analysis revealed that most of the preferentially used codons in MiBoV1 were A- or U-ended codons, and no evident codon usage bias was found. This study provides evidence that MiBoV1 has a low prevalence in Jilin and Hebei provinces in China. Moreover, it contributes information regarding the expansion of the limited mink bocavirus sequence and determines the codon usage bias of the VP2 gene for the first time. Epidemiological surveillance is necessary to understand the importance and evolution of MiBoV1.

Environmental monitoring of Aichi virus and human bocavirus in samples from wastewater treatment plant, drain, and River Nile in Egypt

Wastewater plays a major role in water pollution causing transmission of several viral pathogens, including Aichi virus (AiV) and human bocavirus (HBoV), associated with gastrointestinal illness in humans. In this study, we investigated the presence of AiV and HBoV in aquatic, sludge, sediment matrices collected from Abu-Rawash wastewater treatment plant (WWTP), El-Rahawy drain, Rosetta branch of the River Nile in Egypt by conventional polymerase chain reaction (PCR). AiV RNA was detected in 16.6% (2/12), 8.3% (1/12), 8.3% (1/12), 22% (16/72), 12.5% (3/24), 4% (1/24), and 0/24 (0%) of untreated raw sewage, treated sewage, sewage sludge, drainage water, drain sediment, river water, and river sediment, respectively. On the other hand, HBoV DNA was detected in 41.6% (5/12), 25% (3/12), 16.6% (2/12), 48.6% (35/72), 29% (7/24), 3/24 (12.5%), 4% (1/24) of untreated raw sewage, treated raw sewage, sewage sludge, drainage water, drain sediment, river water, and river sediment, respectively. This study provides data on the presence of these viruses in various types of water samples that are valuable to environmental risk assessment. In addition, the current study demonstrates the importance of environmental monitoring as an additional tool to investigate the epidemiology of AiV and HBoV circulating in a given community.

Waterborne Transmission of Enteric Viruses and Their Impact on Public Health

Viruses of human or animal origin can spread in the environment and infect people via water and food. These viruses are released into the environment by various routes including water runoffs and aerosols. Furthermore, zoonotic viruses may infect humans exposed to contaminated surface waters.

Viruses are emerging pathogens and are able to adapt by mutation, recombination, and reassortment and can thus become able to infect new hosts and to adjust to new environments. Enteric viruses are among the commonest and most hazardous waterborne pathogens, causing both sporadic and outbreak-related illness.

While considerable research has documented the risk of enteric viruses to human health from contact with contaminated water, the current bacterial indicator-based methods for the evaluation of water quality are often ineffectual proxies for pathogenic viruses, but no correlation was established between the enteric bacteria and viruses studied.

The present chapter will focus on viral pathogens shown to be transmitted through water. It will also provide an overview of viruses that had not been a concern for waterborne transmission in the past, but that may represent potentially emerging waterborne pathogens due to their occurrence and persistence in water environments.

Monitoring effluents from wastewater treatment plants is important to preventing both environmental contamination and the spread of disease.

Identification of a Novel Ichthyic Parvovirus in Marine Species in Hainan Island, China

Parvoviruses are a diverse group of viruses that are capable of infecting a wide range of animals. In this study, we report the discovery of a novel parvovirus, tilapia parvovirus HMU-HKU, in the fecal samples of crocodiles and intestines of tilapia in Hainan Province, China. The novel parvovirus was firstly identified from crocodiles fed with tilapia using next-generation sequencing (NGS). Screening studies revealed that the prevalence of the novel parvovirus in crocodile feces samples fed on tilapia (75–86%) was apparently higher than that in crocodiles fed with chicken (4%). Further studies revealed that the prevalence of the novel parvovirus in tilapia feces samples collected at four areas in Hainan Province was between 40 and 90%. Four stains of the novel parvovirus were identified in this study based on sequence analyses of NS1 and all the four strains were found in tilapia in contrast only two of them were detected in crocodile feces. The nearly full-length genome sequence of the tilapia parvovirus HMU-HKU-1 was determined and showed less than 45.50 and 40.38% amino acid identity with other members of Parvoviridae in NS1 and VP1 genes, respectively. Phylogenetic analysis based on the complete helicase domain amino acid sequences showed that the tilapia parvovirus HMU-HKU-1 formed a relatively independent branch in the newly proposed genus Chaphamaparvovirus in the subfamily Hamaparvovirinae according to the ICTV’s most recent taxonomic criteria for Parvoviridae classification. Tilapia parvovirus HMU-HKU-1 likely represented a new species within the new genus Chaphamaparvovirus. The identification of tilapia parvovirus HMU-HKU provides further insight into the viral and genetic diversity of parvoviruses and its infections in tilapia populations need to be evaluated in terms of pathogenicity and production losses in tilapia farming.

Molecular epidemiology of human bocavirus infection in hospitalized children with acute gastroenteritis in South Africa, 2009-2015

Human bocavirus (HBoV) is known to be associated with a variety of clinical manifestation including acute gastroenteritis (AGE). Despite their global prevalence, no data is available on the epidemiology of HBoV associated with AGE in South Africa (SA). Between April 2009 and April 2015, 3765 stool specimens were collected from children less than 5 years of age hospitalized with diarrhea. Specimens were screened for selected enteric viruses by enzyme immunoassay and quantitative polymerase chain reaction, bacteria by culture and parasites by staining and microscopy. HBoV was detected in 5.63% (212 of 3765) of cases, the majority of which were children ≤2 years (92%, 195 of 212), and were common in the summer and autumn months (60%; 128 of 212). Further investigations of coinfections showed that bacteria (adjusted odds ratio [aOR] = 2.20; 95% confidence interval [CI], 1.41-3.45; P = .001) and sapovirus (aOR = 2.05; 95% CI, 1.08-3.86; P = .027) were significantly associated with HBoV in multivariate analysis. HBoV genotyping was successful in 191 of the 212 samples with HBoV-1 being the most prevalent genotype observed (79.6%; 152 of 191) followed by HBoV-3 (13.6%; 26 of 191), HBoV-2 (5.2%; 10 of 191), and HBoV-4 (1.6%; 3 of 191). The high prevalence of HBoV-1, a virus known to be associated with respiratory infections, and the association between HBoV-positive specimens and already established AGE agents, suggests that HBoV may play a limited role in the observed AGE cases in SA.

iTRAQ-based high-throughput proteomics analysis reveals alterations of plasma proteins in patients infected with human bocavirus

Human bocavirus (HBoV) is a member of the genus Bocavirus, family Parvoviridae, and subfamily Parvovirus and was first identified in nasopharyngeal aspirates of Swedish children with acute respiratory tract infection (ARTI) in 2005. It is the causative agent of nasopharyngeal aspirate disease and death in children. The HboV genomic structure is a linear single-stranded DNA (ssDNA). Its clinical pathogenic characteristics have been extensively studied, however, at present the molecular mechanism underlying the pathogenesis of HBoV infection is not completely clear. In this study, a total of 293 differentially expressed proteins (DEPs) between ARTI cases and healthy plasma samples were characterized using isobaric tags for relative and absolute quantitation (iTRAQ)-coupled bioinformatics analysis, among which 148 were up-regulated and 135 were down-regulated. Gene Ontology (GO) and Cluster of Orthologous Groups of proteins (COG) annotated an enrichment of DEPs in complement activation and biological processes like immunity, inflammation, signal transduction, substance synthesis, and metabolism. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis enriched DEPs mainly in the Wnt signaling pathway (ko04310), PPAR signaling pathway (ko03320), intestinal immune network for IgA production (ko04672), complement and coagulation cascades (ko04610), Toll-like receptor signaling pathway (ko04620) and B cell receptor signaling pathway (ko04662). Further, expression levels of three candidate proteins (upregulated PPP2R1A and CUL1, and downregulated CETP) were validated using western blotting. Our investigation is the first analysis of the proteomic profile of HBoV-infected ARTI cases using the iTRAQ approach, providing a foundation for a better molecular understanding of the pathogenesis of ARTI in children.

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.

Are Community Acquired Respiratory Viral Infections an Underestimated Burden in Hematology Patients?

Despite a plethora of studies demonstrating significant morbidity and mortality due to community-acquired respiratory viral (CRV) infections in intensively treated hematology patients, and despite the availability of evidence-based guidelines for the diagnosis and management of respiratory viral infections in this setting, there is no uniform inclusion of respiratory viral infection management in the clinical hematology routine. Nevertheless, timely diagnosis and systematic management of CRV infections in intensively treated hematology patients has a demonstrated potential to significantly improve outcome. We have briefly summarized the recently published data on CRV infection epidemiology, as well as guidelines on the diagnosis and management of CRV infections in patients intensively treated for hematological malignancies. We have also assessed available treatment options, as well as mentioned novel agents currently in development.

Description of a human Bocavirus recombinant strain in the Americas

Human bocaviruses (HBoV) are mainly associated with respiratory and gastroenteric infections. These viruses belong to the family Parvoviridae, genus Bocaparvovirus and are classified in four subtypes (HBoV1-4). Recombination and point mutation have been described as basis of parvovirus evolution. In this study three viral sequences were obtained from positives HBoV sewage samples collected in two Uruguayan cities and were characterised by different methods as recombinant strains. This recombination event was localised in the 5’ end of VP1 gene and the parental strains belonged to subtypes 3 and 4. These three Uruguayan strains are identical at the nucleotide sequences in the analysed genome region of the virus. As far as we known, this study represents the first detection of HBoV recombinants strains in the Americas.