Child ; Humans ; Respiratory Syncytial Virus Infections ; immunology ; virology ; Respiratory Syncytial Virus, Human ; immunology ; pathogenicity

Humans ; Molecular Epidemiology ; Respiratory Syncytial Virus Infections ; epidemiology ; virology ; Respiratory Syncytial Virus, Human ; genetics

The respiratory syncytial virus (RSV) is one of the most common causes of acute infection of the lower respiratory tract among children. For viruses in the Paramyxoviridae subfamily, membrane fusion requires a specific interaction between two glycoproteins: the fusion protein and attachment protein. Membrane fusion of the RSV appears to be unique among paramyxoviruses in that fusion is accomplished by the fusion protein alone without help from the attachment protein. Here, we review recent achievements and advances in the study of membrane fusion triggered by the RSV published in high-impact-factor journals. We also review and make a comparative analysis of the popular hypotheses regarding membrane fusion of the RSV. Finally, we discuss the "hot topics" in current research and controversial data published in recent years in the hope of providing references for Chinese researchers.
Animals ; Humans ; Respiratory Syncytial Virus Infections ; virology ; Respiratory Syncytial Viruses ; genetics ; physiology ; Viral Fusion Proteins ; genetics ; metabolism ; Virus Internalization

OBJECTIVETo investigate human coronaviruses (HCoVs) infection in children with acute lower respiratory tract infection(ALRTI)and to explore the clinical features of ALRTI caused by HCoVs in children.

METHODTotally 4 371 children with clinical diagnosis of ALRTI during the period from March 2007 to February 2015 seen in Beijing Children's Hospital were recruited into this study. Patients were divided into 4 groups by age, including 1 890 cases in < 1 year group, 788 cases in 1-3 years group, 553 cases in 3-6 years group, 1140 cases in ≥6 years group. One nasopharyngeal aspirate specimen was collected from each patient. RT-PCR methods were applied to detect 9 common respiratory viruses including HCoVs (including HCoV-OC43, HCoV-229E, HCoV-NL63 and HCoV-HKU1), respiratory syncytial virus (RSV) and so on. Clinical features of ALRTI with single HCoVs infection were analyzed and compared with hospitalized ALRTI cases with single RSV infection in the same period.

RESULT(1) Totally 2 895 cases were positive for at least one virus in this study in 4 371 ALRTI patients (positive rate 66.23%), in which 147 cases were positive for HCoVs infection (positive rate 3.36%). (2) Positive rates of HCoVs in each year from 2007 to 2014 were 6.11%, 3.79%, 4.69%, 4.31%, 2.38% 2.10%, 0.77% and 2.65%, respectively. The mean positive rates of HCoVs for each month from January to December were 2.53%, 2.12%, 3.63%, 6.68%, 1.53%, 3.77%, 3.92%, 3.00%, 2.15%, 5.26%, 3.01% and 2.80%. (3) Detection results of each subtypes of HCoVs in total 4 371 pediatric ALRTI patients were: 48 cases positive for HCoV-OC43(1.10%), 32 cases positive for HCoV-229E(0.73%), 25 cases positive for HCoV-NL63 (0.57%), 27 cases positive for HCoV-HKU1 (0.62%). (4) Positive rates of HCoVs infection in <1 year group, 1-3 years group, 3-6 years group and ≥ 6 years group were 4.13%, 5.08%, 2.71% and 1.23%, respectively. There were significant differences in positive rates of HCoV among groups (χ² = 27.218, P<0.01). (5) There were 16 hospitalized cases with single infection of HCoVs in this study, of which 12 cases were diagnosed as bronchopneumonia, 3 cases developed acute laryngeal obstruction, 2 cases had acute bronchial asthma attack. Common clinical manifestations included cough (14 cases), gasping (13 cases), dyspnea (9 cases), fever (6 cases), hoarseness (4 cases), laryngeal stridor (4 cases) and abnormality on chest X-ray (including fuzzy lung texture, patchy shadow and consolidation) (12 cases). (6) There were no significant differences in the incidence of clinical manifestations (including cough, gasping, dyspnea, fever and abnormality on chest X-ray), complications (including respiratory failure, myocardial damage, and acute bronchial asthma attack) and mechanical ventilation between hospitalized ALRTI patients with single HCoV infection and 193 patients with single RSV infection in the same period.

CONCLUSIONHCoVs are pathogens of ALRTI in children, The overall positive rate of HCoVs was 3.36% in this study. The clinical manifestations and severity of ALRTI caused by single HCoVs was comparable to that of ALRTI with single RSV infection in children.

Acute Disease ; Beijing ; Child ; Child, Preschool ; Coronavirus ; Coronavirus Infections ; epidemiology ; Humans ; Incidence ; Infant ; Respiratory Syncytial Virus Infections ; epidemiology ; Respiratory Syncytial Viruses ; Respiratory Tract Infections ; epidemiology ; virology

Human metapneumovirus (HMPV) shares clinical and epidemiological characteristics with well-known respiratory syncytial virus (RSV). The aim of this study was to investigate the clinical and epidemiological differences between HMPV- and RSV-induced wheezing illnesses. A total of 1,008 nasopharyngeal aspirate specimens was collected from 1,008 pediatric patients hospitalized with acute respiratory tract infection at Inje University Sanggye Paik Hospital from December 2003 to April 2008, and tested for seven common respiratory viruses. Conditions classified as wheezing illness were bronchiolitis, reactive airways disease, and bronchial asthma. HMPV caused a significantly lower proportion of wheezing illness when compared to RSV (48.1% vs. 82.2%, P<0.05). HMPV-induced wheezing illness occurred predominantly in older patients when compared to RSV patients (P<0.001). RSV infections peaked in the fall and winter followed by peaks of HMPV infection in winter and spring. Eosinophil counts were significantly higher (P<0.01) in RSV patients when compared to HMPV patients. These results show that human metapneumovirus patients exhibit several different clinical and epidemiological characteristics, such as higher proportion of wheezing illness, age and seasonal incidence, and eosinophil counts, when compared to RSV patients.
Bronchiolitis/physiopathology/virology ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Korea/epidemiology ; Male ; Metapneumovirus/pathogenicity ; Nasopharynx/virology ; Paramyxoviridae Infections/*epidemiology/*physiopathology/virology ; Respiratory Sounds/*physiopathology ; Respiratory Syncytial Virus Infections/*epidemiology/*physiopathology/virology ; Respiratory Syncytial Viruses/pathogenicity ; Retrospective Studies ; Seasons

OBJECTIVETo study the epidemiological characteristics of respiratory virus infection and its relations to climatic factors in Suzhou.

METHODSFrom 2006 to 2009, viral etiology surveillance was conducted among 6655 children hospitalized with acute respiratory tract infections (ARIs). Direct immunofluorescence method was used to test respiratory secretion samples for respiratory syncytial virus (RSV), influenza viruses A and B (Inf-A, Inf-B), parainfluenza virus types I, II, and III (Pinf-I, Pinf-II, Pinf-III) and adenovirus. Samples were tested for human metapneumovirus (hMPV) with reverse transcription polymerase chain reaction (RT-PCR). Samples from Jan 2006 to Dec 2009 were also tested for human bocavirus (HBoV). Climatic factors, including mean temperature, relative humidity, rainfall amount, sum of sunshine and mean wind velocity were collected monthly. The relationship between activity of each virus and climatic factors were analyzed by linear regression and stepwise regression analysis.

RESULTSFrom 2006 to 2009, in the total virus detection rate was 32.2% (2142/6655) in Suzhou. RSV was the most common virus and the average detection rate was 15.7% (1048/6655), followed by hMPV 8.9% (596/6655), HBoV 7.8% (148/1883), Pinf-III 2.7% (183/6655), Inf-A 2.4% (161/6655), ADV 1.3% (89/6655), Pinf-I 0.4% (29/6655), Inf-B 0.37% (25/6655) and Pinf-II 0.16% (11/6655). The positive rates of RSV, hMPV and ADV were significantly different in four years (χ(2) = 17.71, 33.23, 8.42, all P values < 0.05). Different virus has different epidemiological characteristics and distinct seasonality. The detection rate of RSV, hMPV, Inf-A were higher in Winter as 37.2%, 13.2%, 4.4%, respectively. ADV and Pinf-III were higher in summer as 2.3% and 4.6% respectively. The peak of HBoV existed in Autumn as 3.3%. The total virus detection rate showed significant inverse correlation with month average temperature (r = -0.732, P < 0.001) and a weak inverse correlation with average wind velocity was also found (r = -0.36, 0.01 < P < 0.05). The highest month total virus detection rate was from 47.6% to 84.4% when average temperature was from 3.2°C to 9.4°C and mean wind velocity was from 1.2 - 1.9 m/s. The associations of average temperature, sum of sunshine and wind velocity with RSV activity were statistical significant (r = -0.88, P < 0.001; r = -0.43, P < 0.01; r = -0.47, P < 0.01). The highest rate was from 24.3% to 58.2%, when mean temperature was from 5.3°C to 19.9°C, mean wind velocity was from 1.3 - 2.4 m/s and sum of sunshine was 61.0 to 153.4 hours. hMPV detection rate was inversely correlated with mean temperature and rain account (r = -0.43, P < 0.01; r = -0.29, P < 0.05). The rate was highest from 11.7% to 31.6% when mean temperature was from 5.3°C to 21.9°C and rain account was from 27.5 millimeter to 150.9 millimeter. Only mean temperature was positively correlated with Pinf-III (r = 0.53, P < 0.001). The rate was from 2.8% to 7.2% when mean temperature was between 11.9°C and 30.4°C. ADV detection rate was positively correlated with mean temperature and sum of sunshine, but negatively correlated with wind velocity (r = 0.35, P < 0.05; r = 0.30, P < 0.05; r = -0.32, P < 0.05). The rate was from 2.2% to 6.6% when mean temperature was between 15.9°C and 30.4°C, and sum of sunshine between 93 hours to 240.7 hours and mean wind velocity was from 1.1 - 2.8 m/s. Average temperature and relative humidity showed interactions on the detection rate of ADV (r = 0.36, P = 0.0093; r = -0.34, P = 0.016), but temperature showed higher effect on ADV detection rate. ADV detection rate was high at higher temperature (15.9 - 30.4°C) and low humidity (56% - 71%).

CONCLUSIONRSV was one of the most common viruses among hospitalized children in Suzhou, and hMPV and HBoV also played an important role in respiratory tract infection of children. Different virus has different cycle and seasonality. Climatic factors, especially mean temperature, was the main factor affecting the virus prevalence.

Child ; Child, Hospitalized ; Child, Preschool ; China ; epidemiology ; Climate ; Female ; Human bocavirus ; Humans ; Infant ; Male ; Metapneumovirus ; Prevalence ; Respiratory Syncytial Virus Infections ; epidemiology ; virology ; Respiratory Syncytial Virus, Human ; Respiratory Tract Infections ; epidemiology ; virology

OBJECTIVETo probe the epidemiological trend of respiratory syncytial virus (RSV) and cellular immunological change of RSV bronchopneumonia among children in Suzhou in the past five years.

METHODS10,205 children with acute respiratory tract infection from January 2001 to December 2005 were enrolled into the study. Nasopharyngeal aspirates were obtained from the respiratory tract by aseptic vacuum aspiration. Direct immuno-fluorescence assay was employed to detect seven kinds of virus antigens including RSV antigen. CD3, CD4, CD8, CD19, CD16 and CD56 in peripheral blood mononuclear cells of 30 patients with RSV bronchopneumonia (1.5-24.0 months old group) were analyzed by flow cytometry analysis, and 15 normal infants (1.5-24.0 months old group) were enrolled as control group.

RESULTSThe annual positive rate of RSV was 24.94%, 25.83%, 24.05%, 25.39% and 27.30% respectively from 2001 to 2005. It also found that the peak season for RSV infection was spring or winter (January to March or November to December). The positive rate of RSV was significantly higher in 1-12 months old group than that in > 12 months old group (chi2 = 97.320, P < 0.01), as well as the groups between 1-12 months old (chi2 = 7.804, P < 0.05, the highest positive rate was occurred at 3-6 months old group). The positive rate of RSV was significantly higher in boys than that in girls (chi2 = 9.693, P < 0.01). The percentages of CD3+, CD4+, CD8+ and NK (CD16 + 56)+ cells were significantly lower in RSV bronchopneumonia than those in control group (t = 3.199, P < 0.01; t = 2.215, P < 0.05; t = 2.619, P < 0.05 and t = 5.240, P < 0.01, respectively). While the percentage of CD19+ cells was significantly elevated in RSV bronchopneumonia than that in control group (t = 2.875, P < 0.01).

CONCLUSIONRSV infection is of obvious seasonal changes. The younger the patient, the higher positive rates of RSV infection is, while and the cellular immunity function is lower. The effective measures for preventing RSV infection are important, especially for the infants. Further investigation is necessary to understand the causes of the variations for RSV infections between boys and girls.

Adolescent ; Bronchopneumonia ; epidemiology ; immunology ; virology ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Respiratory Syncytial Virus Infections ; epidemiology ; immunology ; Respiratory Syncytial Viruses

The respiratory syncytial virus (RSV) belongs to the family Paramyxoviridae and subfamily Pneumovirinae. The RSV can cause acute infections of the lower respiratory tract in infants. The F gene of the RSV is a conservative gene and varies only slightly in its expression. Few studies focusing on the variability of the F gene have been carried out. F protein (fusion glycoprotein) is a transmembrane glycoprotein that mediates fusion and penetration between the virus and host cells. Neutralizing antibody against the F protein can protect against infection by RSV subtypes A and B. Hence, F protein has become the main target for the development of a monoclonal antibody and vaccine against the RSV. An effective vaccine is not available, so a monoclonal antibody against F protein is now the most important method to reduce the morbidity and severity associated with RSV infection in high-risk children. However, a monoclonal antibody can lead to the production of drug-resistant strains of the RSV. This review focuses on genetic variation of the F gene of the RSV as well as progress in the development of a monoclonal antibody against F protein and a vaccine in the last decade.
Animals ; Antibodies, Monoclonal ; immunology ; Humans ; Respiratory Syncytial Virus Infections ; immunology ; prevention & control ; virology ; Respiratory Syncytial Viruses ; genetics ; immunology ; Viral Fusion Proteins ; genetics ; immunology ; Viral Vaccines ; genetics ; immunology

To understand the role of respiratory syncytial virus (RSV) in children with acute respiratory infections (ARI) in Tibet Autonomous Region and the contribution of two major groups of RSV, nasopharyngeal aspirates (NPA) were collected from hospitalized children with ARI in Department of Pediatrics, Tibet People's Hospital in Lasa, Tibet from April to July in 2011 and tested for seven common respiratory viruses and human metapneumovirus (hMPV) by direct immunofluorescence assay (DFA). Total RNAs were extracted from RSV positive samples by DFA and reverse transcripted to cDNA. Nested-PCR was employed to determine the genogroups of RSV, which were confirmed by real time-PCR and sequence analysis for G protein encoding gene. The Characteristics and variations of G genes from RSV in this project were identified by sequence comparison with those G genes in GenBank. Out of 167 samples, 65 were positive for respiratory viruses with a total positive rate of 38.9%, including 45 (69.2%, 45/65)positive samples for RSV. Among 42 samples that were positive for RSV and genotyped, 40 were identified as group A and 2 as group B. Sequence analysis of full-length G genes for 7 RSV of group A indicated that all of these belonged to subgroup GA2. The nucleotide identities between RSVs from Tibet and prototype A2 strain were 90.7%-91.8%, with 86.5%-87.2% identities of amino acid. The mutations of amino acids were mainly located in both ends of a highly conserved region in the ectodomain of the G proteins. The data indicated that RSV was the most important viral etiologic agent of ARI in spring of 2011 in Tibet and group A of RSV was predominant during the study period. High divergence existed in the ectodomain of G proteins of RSVs from Tibet.
Acute Disease ; Amino Acid Sequence ; Female ; Humans ; Infant ; Male ; Molecular Sequence Data ; Phylogeny ; Respiratory Syncytial Virus Infections ; virology ; Respiratory Syncytial Viruses ; chemistry ; classification ; genetics ; isolation & purification ; Respiratory Tract Infections ; virology ; Sequence Alignment ; Tibet ; Viral Proteins ; chemistry ; genetics

OBJECTIVETo characterize the prevalence and occurrence of subgroups of human respiratory syncytial virus (RSV) in infants and young children with acute respiratory infections (ARI) in Beijing area.

METHODSRSVs were identified from nasopharyngeal aspirates and throat swabs collected from infants and children with ARI who visited the Children's Hospital Affiliated to Capital Institute of Pediatrics during the period of November 2000 to March 2006, by virus isolation in Hep-2 cells and antigen detection by indirect immunofluorescence assay (IFA). RT-PCR was used to differentiate subgroups A and B of RSV from part of the positive specimens.

RESULTSOut of 10 048 specimens including 7176 nasopharyngeal aspirates from inpatients and 2872 throat swabs from outpatients, 2286 (22.8%) were RSV positive. The positive rate for RSV identification were 30.0% (2153/7176) in specimens from the hospitalized patients, which was higher than that from outpatients (4.6%, 133/2872). The youngest of the RSV positive patients was 1 day after birth and the oldest was 15 years of age, with 73.0% younger than 1 year. Among those RSV positives, only 1.6% were older than 5 years. The ratio of male to female who were RSV positive was 2.4:1 (1598:674). The clinical diagnosis for 91.2% (1991) of those RSV positive patients was severe lower respiratory infections including bronchiolitis and pneumonia, whereas in only 8.8% (192) the diagnosis was upper respiratory infections. The data revealed that RSV started to be detected in October each year during the survey period and November to next April was the RSV season. The detection rate declined in May and almost no RSV could be found in summer. Positive rates for RSV detection were 42.3%, 41.0% and 40.5% in the seasons of 2001 - 2002, 2003 - 2004, 2005 - 2006, which were higher than those in seasons of 2000 - 2001 (14.0%), 2002 - 2003 (18.2%), 2004 - 2005 (20.4%). Subtyping of A and B during the surveillance period showed that 73.7% (691/938) were subgroup A and 26.3% (247/938) were subgroup B. Subgroup B was predominant in the 2000 - 2001 and 2004 - 2005 seasons, whereas subgroup A predominated in the 2001 - 2002, 2002 - 2003 and 2003 - 2004 seasons. Almost equal proportions of subgroup A and B appeared in 2005 - 2006 seasons.

CONCLUSIONThe data indicate that RSV is an important etiological agent for lower respiratory infections in infants and young children in winter and spring during the survey period. The pattern of RSV circulation varied alternately with higher rate every other year. The predominant subgroup changed between A and B, and co-circulated in equal proportion in some years.

Adolescent ; Cell Line, Tumor ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Population Surveillance ; Prevalence ; Respiratory Syncytial Virus Infections ; diagnosis ; epidemiology ; Respiratory Syncytial Virus, Human ; genetics ; isolation & purification ; Respiratory Tract Infections ; diagnosis ; epidemiology ; virology ; Seasons