Human bocavirus infection in children hospitalized with lower respiratory tract infections: Does viral load affect disease course?

Objective: To examine the effects of human bocavirus type 1 (HBoV1) on the course of lower respiratory tract infections in cases of monoinfection and coinfection, and the effects of HBoV1 viral load on the disease in children under six years old hospitalized with a diagnosis of HBoV1-associated lower respiratory tract infections. Methods: Children under six years of age, who were hospitalized with the diagnosis of lower respiratory tract infection due to HBoV1 between 1 January 2021 and 1 January 2022 were included in the study. Laboratory confirmation of the respiratory pathogens was performed using polymerase chain reaction (PCR). Results: Fifty-four (16.4%) children with HBoV1 among 329 children whose PCR was positive with bacterial/viral agent in nasopharyngeal swab samples were included in the study. There were 28 (51.9%) males and 26 (48.1%) females with a median age 23.4 months [interquartile range (IQR): 13.2, 30.0 months] (min-max:1 month-68 months). HBoV1 was detected as a monoinfecton in 26 (48.1%) children, and as a coinfection with other respiratory agents in 28 children (51.9%). In multiple regression analysis, coinfection (P=0.032) was associated with the length of hospitalization (P<0.001; R 2 =0.166). There was a negative correlation (r= 0.281, P=0.040) between cough and cycle threshold. Fever was found to be positively correlated with C-reactive protein (r=0.568, P<0.001) and procalcitonin (r=0.472; P=0.001). Conclusions: Although we found a higher HBoV1 viral load in children with more cough symptoms in our study, it had no effect on the severity of the disease, such as length of hospital stay and need for intensive care. Coinfection was found to affect the length of hospitalization.

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.

Establishment of stable cell line expressing human bocavirus type 1 non-structural protein NS1 and its trans-transcriptional activation / 生物工程学报

Human bocavirus 1 (HBoV1) non-structural protein NS1 is a multifunctional protein important for virus replication and induction of apoptosis in host cell. To better understand the function of the NS1 protein, it is urgent to address reducing the toxicity of NS1 to host cells. In the present study, we established a stable cell line that regulates expression of NS1 of HBoV1. The recombinant lentivirus plasmid containing a regulatable promoter fused with ns1 gene was constructed and transfected into HEK 293T cells using transfection reagent. The HEK 293T cell lines stably expressing NS1-100 and NS1-70 proteins were established by screening resistant cells with puromycin and inducing NS1 expression with doxycycline. The expression of NS1 protein was determined by fluorescent labeling protein and Western blotting. HBoV1 promoter was transfected into stably expressing NS1 cell line and its trans-transcriptional activity was analyzed. The results showed that NS1 protein was expressed stably in the established cell lines and had a strong activation activity on the HBoV1 promoter driving luciferase gene. Taken together, this study provides a solid basis for further research on the function of NS1 and the pathogenesis of human bocavirus.

Molecular prevalence and clinical characteristics of human metapneumovirus and human bocavirus in 333 hospitalized children with community-acquired pneumonia / 中华实验和临床病毒学杂志

Objective@#To study the molecular prevalence and clinical characteristics of human metapneumovirus and human bocavirus in hospitalized children with community-acquired pneumonia.@*Methods@#Total 333 throat swabs and clinical information of patients were collected between 2017 and 2018 at Department of Pediatrics of No.2 Clinical Teaching Hospital, Chengde Medical University. The IgM of adenovirus (AdV), respiratory syncytial virus (RSV), influenza virus-A/B (Influ-A/B), parainuenza viruses (PIVs)were tested by detection kit, and the positive samples of human metapneumovirus (hMPV), human bocavirus (HBoV), AdV, RSV and human coronavirus (HCoV) were detected by RT-PCR or PCR.@*Results@#43 cases, 19 cases, 3 cases and 2 cases were positive for Influ-B, PIV, RSV and AdV IgM, respectively. Total 80 cases were infected with hMPV (71 cases were single infection, 8 cases were double infection, and 1 case was triple infection), 22 cases were infected with HBoV (14 cases were single infection, 7 cases were double infection, and 1 case was triple infection), 6 cases were infected with AdV (4 cases were single infection, 1 case was double infection, and 1 case was triple infection), only 1 case was single infected with RSV or HCoV, respectively. 39 cases (11.7%) and 41 cases (12.3%) were distributed at <5 years group and ≥5 years group, respectively. 45.0%(18/40)in severe cases and 27.99%(82/293)in mild cases were positive for hMPV, HBoV, AdV, RSV and HCoV, the ratio of viral positive case was significant higher in severe cases than mild cases (P=0.042). The age (P=0.000), peak of fever (P=0.035), duration of hospitalization (P=0.000), neutrophils (P=0.000) and lymphocytes (P=0.000) were significant difference in severe cases compared with mild cases.@*Conclusions@#Multiple respiratory viruses can cause community-acquired pneumonia and more attention should be pay to the surveillance of hMPV and HBoV.

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.

Diffuse alveolar hemorrhage syndrome secondary to bocavirus and rhinovirus infection in a pediatric patient / Síndrome de hemorragia alveolar difusa secundaria a coinfección por Rhinovirus y Bocavirus en un paciente pediátrico

Abstract The diffuse alveolar hemorrhage syndrome is characterized by the presence of blood in the pulmonary alveolus from arterioles, venules and pulmonary capillaries, as a consequence of the lesion of the alveolar wall and without an endobronchial alteration. Its presentation includes a classic triad of hemoptysis, anemia and diffuse alveolar infiltrates. It's a rare but potentially fatal entity and there are no clear data on its real incidence in the pediatric population. We present the case of a previously healthy pediatric patient, immunocompetent, who presented diffuse alveolar hemorrhage syndrome with secondary ventilatory failure. After discarding all possible etiologies, coinfection by Rhinovirus and human Bocavirus was detected through the polymerase chain reaction, determining them as causal factors of the event. Recently, viral infections have been postulated as causing serious lung disease, especially coinfection in immunocompromised patients, in this case Rhinovirus and human Bocavirus; however there are no reports on the syndrome caused by these viruses.

Resumen El síndrome de hemorragia alveolar difusa se caracteriza por la presencia de sangre los alveolos pulmonar procedente de arteriolas, vénulas y capilares pulmonares, como consecuencia de la lesión de la pared alveolar y sin identificársele una alteración endobronquial. Su presentación incluye una triada clásica de hemoptisis, anemia e infiltrados alveolares difusos. Es una entidad poco frecuente aunque potencialmente fatal y no hay datos claros de su real incidencia en la población pediátrica. Se presenta el caso de un paciente pediátrico previamente sano, inmunocompetente, quien presentó síndrome de hemorragia alveolar difusa con falla ventilatoria secundaria. Después de descartar todas las posibles etiologías, se detectó, a través de reacción en cadena de polimerasa, coinfeccion por Rhinovirus y Bocavirus humano, determinándolos como causales del evento. Recientemente se postula las infecciones virales como causantes de enfermedad pulmonar grave, en especial la coinfeccion en pacientes inmunocomprometidos, en este caso Rhinovirus y Bocavirus humano, sin embargo no existen reportes sobre el síndrome causada por estos virus.

Three-dimensional Culture of Human Airway Epithelium in Matrigel for Evaluation of Human Rhinovirus C and Bocavirus Infections / 生物医学与环境科学（英文）

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.

Correlation between human bocavirus 2 infection in children and acute diarrhea in Beijing / 中华儿科杂志

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 (χ2=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 (1×109copies/L with cycle threshold (Ct) 25.8) was higher than that of control group (1×105copies/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.

Clinical characteristics of bocavirus infection in children with bronchiolitis / 中华实验和临床病毒学杂志

Objective@#To investigate the human bocavirus (HBoV) infection in the children diagnosed with brochiolitis, incomparison with the clinical characteristics of bronchiolitis of HBoV vs. respiratory syncytial virus (RSV) infection alone.@*Methods@#A total of 396 throat swabs were obtained from children diagnosed with bronchiolitis from January 2015 to December 2016 in Pediatric Asthma Center of Gansu Maternal and Child Health Care Hospital, Lanzhou. Specimens were tested for the nucleic acids of HBoV, RSV and other 6 common respiratory viruses by nested-polymerase chain reaction (nested PCR() and reverse transcription-polymerase chain reaction (RT-PCR), and the epidemic status, clinical characteristics of HBoV and RSV were analyzed and compared with each other.@*Results@#The positive rate of virus infection was 53.54%, and HBoV and RSV infections were 9.84% and 24.49% in 396 cases. The numbers of cases of HBoV single infection, RSV single infection, HBoV and RSV mixed infection were 29, 86 and 5. The number of boys infected with HBoV was 27. There was statistical significance in the difference between the genders. The statistical significance also existed in difference of age. The babies at ages ranging from 6 to 12 months had the hifgest positive rate. The first incidence peak of the infection of HBoV was in October 2015. The children with HBoV infection, compared with RSV patients, presented more often with vomiting, diarrhea (P<0.05), while symptoms such as the occurrence of dyspnea, hypoxemia and the hospitalization time were all lower.@*Conclusions@#HBoV is one of the possible causes of brochiolitis in infants, its infection distributed over the whole year. The clinical symptoms, laboratory and radio-graphic changes are similar between the HBoV and RSV infections, the only difference was that the HBoV infection was comparatively mild.

Clinical and epidemiological features of human Bocavirus infection in hospitalized children in Wuhan area / 中国感染控制杂志

Objective To understand infection status,clinical and epidemiological features of respiratory tract infection(RTI) with human Bocavirus(HBoV) in children in Wuhan area.Methods A total of 968 hospitalized children with acute RTI between January and December 2016 were recruited in the study.Sputum specimens were collected by sterile negative pressure suction method.HBoV,respiratory syncytial virus,adenovirus,A/B-type influenza virus,and parainfluenza virus Ⅰ/Ⅱ/Ⅲ were detected,the prevalence and clinical features of HBoV infection were analyzed.Results Among 968 cases,75(7.75％) were positive for HBoV.The detection rates of HBoV in boys and girls were 5.68％ and 2.07％ respectively,there was no significant difference in the detection rate of HBoV between different genders(x2 =2.083,P =0.140);53 (70.67 ％) HBoV-positive children were＜ 1 year old,63(84.00％) were＜3 years old,there was significant difference in the detection rate among all age groups(x2 =4.60,P =0.043).The detection rates in spring,summer,autumn,and winter were 9.78％,5.29％,2.86％,and 5.20％ respectively;except September and October,HBoV was found positive in the other months,detection rate was highest in March (33.33％).17 cases were simple HBoV infection and 58 were mixed infection,the main clini cal diagnosis of HBoV was bronchopneumonia(n =26,34.67％).The main clinical features of HBoV cases were fever(81.33 ％),cough(77.33 ％),and wheezing (77.33 ％).Conclusion HBoV is one of the important pathogens causing RTI in hospitalized children in Wuhan area,HBoV infection can occur throughout the year,the peak season are spring and summer,there is no difference between different genders.The most common clinical diagnosis of HBoV in hospitalized children is bronchopneumonia,the main manifestations are fever,coughing,and wheezing.

Clinical analysis of human bocavirus infection in children with severe lower respiratory tract infection / 中华实用儿科临床杂志

Objective To explore the clinical characteristics of human bocavirus (HBoV) infection in the children with severe lower respiratory tract infection.Methods The clinical data of the hospitalized children with sputum HBoV-positive were analyzed retrospectively,who were hospitalized at the Pediatric Intensive Care Unit of Children's Hospital Affiliated to Capital Institute of Pediatrics from September 1,2016 to March 31,2017.Results A total of 17 children were included in the study.The ratio of male to female was 15 ∶ 2.The diagnostic age ranged from 4 months to 4 years and 10 months old.82.4％ (14/17 cases) of the patients were infants less than 2 years old.Autumn and winter were high-occurrence seasons.Pediatric Critical Illness Scores(PCIS) were 68-88 scores(median 82 scores).PCIS was less than 70 scores in 1 case,and between 70 scores and 80 scores in 7 cases,and more than 80 scores in 9 cases.The main clinical manifestations were respiratory system involvement,including dyspnea in 17 cases (100％),fever in 14 cases (82.4％),cough in 16 cases (94.1％),wheezing in 13 cases (76.5％),and moist rales in 13 cases (76.5％).The main abnormal chest radiological findings showed patchy shadows in 7 cases (41.2％) and consolidation in 6 cases (35.3％).The oxygenation index was 73.9-296.0 mmHg(1 mmHg =0.133 kPa),and median was 176 mmHg.The oxygenation index was between 100-200 mmHg in 7 cases(41.2％),and less than 100 mmHg in 2 cases(11.7％).Type Ⅰ respiratory failure occurred in 11 cases (64.7％),while type Ⅱ respiratory failure occurred in 6 cases (35.3 ％).All of the patients need respiratory support with mechanical ventilation.Among them,6 patients (35.3％) were treated by non-invasive ventilation and their ventilation time were 25-128 h(median 65 h),while 11 patients (64.7％) were treated by invasive ventilation and their ventilation time was 42-178 h(median 70 h).Other organ or system dysfunction is mild.The length of hospital stay ranged from 3 days to 13 days.The cure rate was 100％.Conclusions HBoV infection in the children with severe lower respiratory tract infection is common in infants under 2 years old,with acute onset and rapid recovery.The obvious clinical symptoms are fever,cough,wheezing and dyspnea.Although respiratory failure is common,other organ or system dysfunction is mild,which may bring about a good prognosis.

Clinical research of Qingfei Oral Liqulid and Xiyanping Injection in treatment of children with human bocavirus pneumonia / 中草药

Objective To observe the clinical effect of Qingfei Oral Liqulid and Xiyanping Injection in the treatment of children with human bocavirus pneumonia. Methods Children with human bocavirus pneumonia (59 cases) were randomly divided into treatment group and control group. The cases in the treatment group were treated with Qingfei Oral Liqulid and Xiyanping Injection, and those in the control group were given Ambroxol and Clenbuterol oral solution and Ribavirin injection. The comprehensive efficacy, before and after treatment of primary symptoms scores, secondary symptoms scores, and total scores of symptoms were observed. Results The treatment group had superior comprehensive efficacy over the control group (P < 0.05). Both groups had reduced scores for primary symptoms and secondary symptoms and total scores for symptoms after treatment (P < 0.05). The decreases in the scores for primary symptoms and secondary symptoms and the total scores for symptoms after treatment were larger in the treatment group than those in the control group (P < 0.05). Conclusion Qingfei Oral Liqulid and Xiyanping Injection had definitive efficacy in the treatment of human bocavirus pneumonia in children.

Epidemiological characteristics and genetic evolution of human bocavirus infection in hospitalized children with severe acute respiratory infection in Hangzhou / 中华临床感染病杂志

Objective To study the epidemiological characteristics and genetic evolution of human bocavirus ( HBoV ) infection in hospitalized children with severe acute respiratory infection ( SARI ) in Hangzhou.Methods A total of 1388 clinical specimens were collected from children with SARI admitted in Affiliated Children' s Hospital, Zhejiang University School of Medicine from January 2011 to December 2014.HBoV1-4 and other respiratory pathogens were identified by fluorescent real -time polymerase chain reaction (fRT-PCR).The VP1 gene in HBoV1 positive samples was amplified and sequenced for genetic analysis with Clustal X and MEGA 6.0.Chi-square test and Fisher exact probability were used to analyze the data.Results Eighty five HBoV positive samples were detected from 1388 samples (6.12％), among which 83 (97.65％) were HBoV1 positive and 2 (2.35％) were HBoV2 positive.The positive rates of HBoV in males and females were 6.54％and 5.35％(χ2 =0.780, P>0.05).The posititve detection rate of HBoV in all age groups was statistically significant (χ2 =47.446,P <0.01).The detection rate in children aged 6 months-1 year was highest (12.84％), in children aged >3 years was lowest (1.64％), in children aged ≤6 months and aged 1-3 years was 3.04％ and 3.33％, respectively.The detection rate of HBoV in summer was the highest (14.97％), followed by that in autumn (7.14％), spring (3.19％) and winter (1.97％) (χ2 =58.807, P<0.01).The detection rates of HBoV in 2011 to 2014 were 7.39％, 7.31％, 5.58％ and 4.72％ (χ2 =3.447, P >0.05 ).The co-infection rate with other respiratory pathogens was 62.35％.The main pathogens were human rhinovirus (33.96％), parainfluenza virus (28.30％) and respiratory syncytial virus (20.75％).The incidence of anhelation and wheezing in HBoV positive group was higher than that in HBoV negative group (χ2 =15.161 and 13.914, P <0.01). Sequence analysis of VP 1 gene showed that 44 isolates belonged to the same branch ( clade 1 ) as Swedish strain ST2, and 2 isolates HZ12-S32 and HZ12-S199 belonged to a separated branch.Conclusion HBoV is an important causative agent of hospitalized children with SARI in Hangzhou area and has high co -infection with other respiratory pathogens.Most of the strains belong to the same clade as the Swedish strain ST 2, and two strains of HZ12-S32 and HZ12-S199 are identified in a separated clade.

Bocavirus en niños menores de 5 años con infección respiratoria aguda: Provincia del Chaco, 2014 / Bocavirus in infants under 5 years with acute respiratory infection. Chaco Province, Argentina, 2014

La infección respiratoria aguda (IRA) es la patología más frecuente a lo largo de la vida de una persona y es la causa más común de morbi-motalidad en menores de 5 años. El objetivo de este trabajo fue determinar la frecuencia de bocavirus (BoV) en pacientes menores de 5 años con diagnóstico presuntivo de IRA en una ciudad capital del norte argentino (Resistencia, Chaco). Se analizaron aspirados nasofaríngeos correspondientes a 488 niños durante el año 2014. Los mismos fueron testeados por PCR en tiempo real hallándose BoV en 36 casos (7.4%), de los cuales 26 (72.2%) fueron infantes de 6-18 meses de vida. La mayor concentración de positivos se registró en el período junio-septiembre con un total de 28 pacientes (77.8%). Los casos positivos para BoV se observaron como infección única en el 50% de los mismos y el resto como infecciones concomitantes con otros microorganismos. No conocemos que haya otro estudio de epidemiología molecular de BoV en el norte argentino y destacamos la importancia de investigar los nuevos virus capaces de generar infección respiratoria aguda, y difundir el conocimiento de su circulación en la comunidad.

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.

Detección de bocavirus humano en la población infantil de Tucumán y Santa Fe, Argentina / Detection of human bocavirus in children from Tucuman and Santa Fe, Argentina

Background: A large proportion of acute respiratory tract infections (ARTI) remain without etiologic diagnosis, reason why new pathogens are investigated continuously. Human bocavirus (HBoV) was discovered in 2005, as a new member of Parvoviridae family and proposed to cause ARTI. Aim: To know the prevalence of HBoV among pediatric populations hospitalized for ARTI in two provinces of Argentina: Santa Fe and Tucuman; and to describe epidemiological and clinical aspects associated to its detection. Materials and Methods: We studied nasopharyn-geal aspirates of patients younger than 5 years old that were hospitalized during 2013 due ARTI. HBoV DNA was assayed using PCR described by Allander et al. Traditional virnses were studied by immunofluorescence. Personal, clinical and epidemiological data were collected in a standardized form. Results: The HBoV was detected in 7% of the samples and was prevalent in spring and summer and in children younger of 2 years old. Other respiratory viruses were detected in 22% of HBoV positive samples. Discussion: We detected HBoV in these two provinces of Argentina. Further studies should be performed to determine if it’s a recent infection or prolonged viral shedding.

Introducción: Un alto porcentaje de las infecciones respiratorias agudas (IRA) permanece sin diagnostico etiológico, por lo cual se investigan nuevos patógenos continuamente. Bocavirus humano (HBoV) fue descubierto en 2005, como un nuevo miembro de la familia Parvoviridae y propuesto como causante de IRA. Objetivos: Investigar la prevalencia de HBoV en niños bajo 5 años de edad, hospitalizados por IRA en dos provincias de Argentina: Santa Fe y Tucumán y describir aspectos epidemiológicos y clínicos asociados a su detección. Materiales y Métodos: Se estudiaron retrospectivamente los aspirados nasofaríngeos (ANF) de pacientes bajo 5 años de edad, con diagnóstico de IRA, hospitalizados durante el año 2013. La presencia de HBoV se detectó mediante la RPC de punto final descripta por Allander y cols. Los virus tradicionales se estudiaron mediante inmunofluorescencia. Datos personales, clínicos y epidemiológicos se recolectaron en una planilla estandarizada. Resultados: HBoV fue detectado en 7% de las muestras con prevalencia en primavera y verano; y principalmente en pacientes bajo 2 años de edad. Se registró co-detecciones en 22% de los casos. Discusión: Hemos detectado HBoV en estas dos provincias de Argentina; estudios posteriores deberán efectuarse para determinar si se trata de una infección reciente o una excreción prolongada del virus.

Severe lower respiratory infections in children related to human Bocavirus 1 / 国际儿科学杂志

Human bocavirus 1 ( HBoV1 ) is closely related to lower respiratory infections in children. Respiratory symptoms elicited by HBoV1 include cough, tachypnea, wheezing and dyspnea, which are of mild degree and haven′t found to be distinguished. Few single infected patients with dyspnea needing mechanical ven-tilation were reported,however,the number of severe cases caused by HBoV1 is increasing in recent years. Here we reviewed the epidemiological characteristics, clinical manifestations, treatment and prognosis of HBoV1 in-duced severe lower respiratory infections.

Clinical features of human metapneumovirus and human bocavirus infections among children with acute respiratory ;tract infections in Taiyuan / 临床儿科杂志

Objective To investigate the status and clinical and epidemiological characteristics of human metapneumovirus (hMPV) and human bocavirus (HBoV) infections in children with acute respiratory tract infections (ARTIs) in Taiyuan. Methods A total of 549 children with ARTIs from November 2012 to May 2013 and November 2013 to May 2014 were recruited. The pharyngeal swab specimens were collected. The hMPV and HBoV were detected by using real-time PCR. Results In 549 children, 56 children (10.2%) were hMPV positive on swab specimens, 15 children (2.7%) were HBoV positive on swab specimens. The detection rates of hMPV and HBoV in November 2012 to May 2013 were 12.3%and 2.0%, respectively, and in November 2013 to May 2014 were 6.5%and 4.0%, respectively. The detection rate of hMPV was signiifcantly different between two periods (P<0.05), while the detection rate of HBoV has no signiifcant difference between two periods. In different months, the detection rate of hMPV and HBoV showed no signiifcant difference. The highest detection rates of hMPV and HBoV were all in children younger than two years old. The highest detection rate of hMPV was in children with asthmatic bronchitis or bronchiolitis. Conclusion In Taiyuan, during the monitoring periods, the ARITS are associated with childhood hMPV and HBoV infection especially in infants and toddlers. hMPV is one of the most important pathogens in infants and toddlers with wheezing.

Effect of alum on immune response in mice induced by HBoV1 VP2 VLPs / 中国免疫学杂志

Objective:To study the effect of alum on immune response in mice induced by HBoV1 VP2 VLPs.Methods:BABL/c mice were randomly divided into VLPs experimental group, alum adjuvant experimental group, PBS control group and alum adjuvant control group,the experimental group mice were intramuscular immunization with HBoV1 VP2 VLPs and HBoV1 VP2 VLPs added alum,control group mice were immunization with alum or PBS buffer,then to study the effect of alum on immune response in mice induced by HBoV1 VP2 VLPs by cellular and humoral immune strength.Results: Alum adjuvant decreased cellular immune response induced by HBoV1 VP2 VLPs(P<0.001),enhance the HBoV1 VP2 VLPs immuned serum IgG titer(P<0.05)and IgG activity(P<0.01).Conclusion:Alum adjuvant can enhance humoral immune response induced by HBoV1 VP2 VLPs,but weaken cellular immune response induced by HBoV1 VP2 VLPs,when HBoV1 VP2 VLPs used as a prophylactic vaccine it should add alum adjuvant,when used as a therapeutic vaccine,it should not add alum adjuvant.

Expression of recombinant protein VP2 of human bocavirus and detection by indirect ELISA / 实用医学杂志

Objective By prokaryotic expression and purifying the human bocavirus recombinant protein VP2, to establish the indirect enzyme-linked immunoassay for detection of virus. Methods We amplified the human bocavirus recombinant protein VP2 gene fragments from WHL-1 template by PCR , and cloned into the expression vector pET28a, then conversed into the BL21 (DE3) and expressed the fusion protein detected by Western Blot detection , the obtained the antibody and detected the human bocavirus in serum in Guanghzhou area in healthy people. Results The Recombinant prokaryotic expression identified correct by double enzyme, and it could occur specific reaction with the virus positive serum. The best optimal antigen coating concentration were serum multiples and blocking BSA was 2 mg/mL , 1 ∶ 200 and 1%. The best working dilution of enzyme-labeled secondary antibody was 1 ∶ 4 000. The best working hours was 1h. This detection method had good specificity and reproducibility. The cut-off of the indirect ELISA method was 0.1 and the sensitivity and specificity of the developed ELISA method were 92% and 98% respectively. The coincidence rate of determination results by the developed kit and control kit was 97%. Conclusion The competitive ELISA established by prokaryotic expressing and purifying the human bocavirus protein VP2 protein , provides a basis in detecting the human bocavirus serum antibody.

Genetic variation and molecular evolution of human bocavirus 1 strains isolated during 2009 to 2014 in Hangzhou, China / 中华微生物学和免疫学杂志

Objective To investigate the genetic variation and molecular evolution of human bo-cavirus 1 (HBoV1) strains isolated during 2009 to 2014 in Hangzhou, China.Methods Throat swab sam-ples were collected from children with acute respiratory tract infections in the Children′s Hospital Affiliated to the Zhejiang University School of Medicine from 2009 to 2014.Real-time PCR was performed for the detec-tion of HBoV1 strains.Fifteen HBoV1 strains with high virus load were screened out for the amplification and sequencing of complete genomes.The complete genomes were submitted to GenBank for further analysis with bioinformatics software.Results A total of 48 nucleotide mutations were detected in the complete genomes of 15 HBoV1 strains, resulting in 11 amino acid mutations with 5 of them located in the active region of phospholipase A2 ( PLA2) .The 15 HBoV1 isolates along with 16 HBoV1 strains in GenBank were classified into three clusters as indicated by the phylogenetic analysis based on their complete coding sequences.All of the 15 strains were belonged to clusterⅠ, the representative strain of which was the Sweden prototype strain ST2.The phylogenetic trees constructed using genes encoding the capsid proteins VP1 and VP2 were highly similar to those based on the complete coding sequences.The estimated mean evolutionary rate of HBoV1 with regard to the complete coding sequence was 3.03×10-4(95%HPD, 2.14×10-4-3.92×10-4 ) substitu-tions per site per year.With regard to each gene, the NS1 gene was considered to the most conserved gene while the NP1 gene showed the highest substitution rate.The dN/dS ratios (ω) of the four genes were all less than 1, indicating that all of them were under negative selection.Moreover, the VP2 gene was under the strongest negative selection, while the NP1 gene was under the weakest negative selection.Conclusion All of the HBoV1 isolates circulating in Hangzhou province during 2009 to 2014 were belonged to ST2 genotype with a relatively high mutation in the area of PLA2.Despite the complete genome was conservative, its evo-lutionary rate was high.Among the four genes, the NP1 gene showed the highest substitution rate.All of the four genes were under negative selection, of which the VP2 gene was under the strongest negative selection.