Adult ; Disease Outbreaks ; Humans ; Metapneumovirus ; Paramyxoviridae Infections ; epidemiology ; Respiratory Tract Infections ; epidemiology ; virology ; Students

Acute Disease ; Child ; China ; epidemiology ; Humans ; Paramyxoviridae Infections ; epidemiology ; virology ; Phylogeny ; Respiratory Tract Infections ; epidemiology ; virology ; Respirovirus ; genetics

OBJECTIVETo understand the epidemiological characteristics of human metapneumovirus (hMPV) infection in children with acute lower respiratory tract infection (ALRTI) in Changsha area, China.

METHODSA total of 2613 nasopharyngeal aspirate (NPA) specimens were collected from hospitalized children with ARTIs between September 2007 and February 2011 (a period of 3.5 years) in Changsha area, Hunan Province, China. Respiratory specimens were screened for hMPV M gene by reverse-transcription polymerase chain reaction (RT-PCR). All RT-PCR positive' amplification products were confirmed by sequencing or analyzed and compared with those in GenBank known hMPV reference strain.

RESULTShMPV was detected in 135 (5.2%) out of the 2613 children. The detected rate was significantly different between male and female (chi2 = 8.007, P = 0.003). The majority of the hMPV-positive patients (63.2%) were 0-1 year old infants. The majority of hMPV-positive patients were detected during spring season. Seasonal distribution showed that subtype A2b circulated predominantly in winter and spring, subtype B2 circulated predominantly in summer and spring. The most common genotype in 135 hMPV-positive patients were A and B in human subjects in Changsha. The predominant genotype of hMPV changed over the 3.5 year study period from genotype A2b to combined A2b and B2, and to B2. The 66 (48.9%) out of the 135 hMPV-positive patients were found to be co-infected with other respiratory viruses, and human bocavirus (HBoV) was the most common additional respiratory virus.

CONCLUSIONThese data suggest that some cases of acute lower respiratory infection in young children in Changsha area are related to hMPV and the majority of children infected with hMPV were less than 1 years old, the detected rate of boys was higher than that of girls. It circulated predominantly in spring. The subtype A2b genetic lineage and the subtype B1 genetic lineage of hMPV were revealed alternately in human subjects in Changsha area and the hMPV exhibited high co-infection rate with other respiratory viruses.

Acute Disease ; China ; epidemiology ; Female ; Humans ; Infant ; Male ; Metapneumovirus ; classification ; genetics ; Molecular Epidemiology ; Paramyxoviridae Infections ; epidemiology ; Respiratory Tract Infections ; virology ; Time Factors

OBJECTIVETo isolate and characterize the newly discovered human metapneumovirus (hMPV) in Chongqing, China and elucidate the clinical manifestations of hMPV infection.

METHODSEighty-six patients hospitalized for acute respiratory tract infection in Children's Hospital, Chongqing University of Medical Sciences from December 2004 to July 2005 were enrolled in the present study. Nasopharyngeal aspirates were collected for screening for common respiratory viruses by direct immunofluorescence assay, including respiratory syncytial virus, influenza virus types A and B, parainfluenza virus types 1, 2, 3 and adenovirus, and for inoculating onto Vero-E6 and LLC-MK2 cells for hMPV isolation. Cultures were maintained in the presence of trypsin and observed for development of cytopathic effect (CPE) for 3 weeks. Presence of hMPV was first indicated by positive CPE and subsequently confirmed by reverse transcription polymerase chain reaction targeting N and F genes. Sequence of amplified F fragments were analyzed and submitted to NCBI GenBank. The clinical findings of hMPV infection were collected and analyzed.

RESULTSOf the collected 86 NPAs, six showed CPE characterized by clustering of infected cells, increased granules and eventuall detachment from cell monolayer and obvious syncytium formation. Successful isolation of hMPVs was confirmed with RT-PCR targeting hMPV F and N genes. Of the six hMPV-positive specimens, two were collected in winter (December, January), two in spring (May) and the other two in autumn (June, July). All the six patients were younger than 2 years of age with disease spectrum of bronchiolitis (2/6), bronchopneumonia (2/6), infantile asthma (1/6) and upper respiratory tract infection (1/6). Clinical findings included fever, cough, wheezing, polypnea, cyanosis and rales. Parainfluenza 3 and adenovirus seemed to beviral pathogens of co-infection.

CONCLUSIONSix hMPVs were successfully isolated in the mainland of China for the first time. HMPV appears to be one important viral pathogen for acute lower respiratory tract infections in young children with a detection rate of 7% (6/86) by viral isolation. The virus causes respiratory diseases similar to those caused by respiratory syncytial virus. These findings highlight the need for future investigations to define disease burden of hMPV infection and molecular epidemiology among children in China.

Cell Line ; China ; epidemiology ; Genes, Viral ; Humans ; Infant ; Metapneumovirus ; genetics ; isolation & purification ; Paramyxoviridae Infections ; epidemiology ; virology ; Respiratory Tract Infections ; epidemiology ; virology ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo study the infection status and pathogenic features of human metapneumovirus (hMPV) among children with acute respiratory tract infection in Hangzhou.

METHODSA total of 372 children less than 14 years old with acute respiratory tract infections were recruited as subjects from the pediatric clinic or intensive care unit (ICU) of 3 hospitals in Hangzhou during November 2009 to January 2010, and November 2010 to January 2011. A total of 372 specimens were collected, including 351 respiratory swab, 9 nasopharyngeal aspirate material, 8 endotracheal aspirate material and 4 sputum. The total nucleic acid was then extracted from the specimens, and the nucleoprotein (N) gene of hMPV was amplified by RT-PCR, whose positive products were sequenced and analyzed. Africa green monkey kidney cells (Vero-E6) were applied to culture hMPV among the positive samples; meanwhile fluorescence quantitative RT-PCR was adopted to test other respiratory virus infection.

RESULTSOut of 372 patients, 42 (11.2%) were positive for N gene of hMPV. The positive rate of hMPV among boys was 11.5% (26/226), and correspondingly 10.9% (16/146) among girls. The difference showed no statistical significance (χ(2) = 0.026, P > 0.05). The youngest patient was only 2 month-old and the eldest patient was 14 years old. The median of the patients' age was 24 months. Fifteen positive samples amplified by RT-PCR were sequenced, and all turned out to be subtype B1; whose similarity to GD165 found in Guangdong was 98.1% - 99.5% and similarity to BJ1897 in Beijing was 87.8% - 89.2%. The co-infection rate between hMPV and other respiratory virus was 45.2% (19/42); most of which was between hMPV and respiratory syncytial virus, whose rate at 26.1% (11/42).

CONCLUSIONhMPV was the single genotype relevant with the acute respiratory tract infection disease among children in Hangzhou district; however, the co-infection with other respiratory virus did exist.

Adolescent ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Genotype ; Humans ; Infant ; Male ; Metapneumovirus ; genetics ; isolation & purification ; Paramyxoviridae Infections ; epidemiology ; virology ; Respiratory Tract Infections ; epidemiology ; virology

Human parainfluenza viruses (HPIVs) is one of the main causes of acute respiratory tract infections in children. HPIVs have been grouped into four serotypes (HPIV1~HPIV4) according to serological and genetic variation. Different serotypes of HPIVs have diverse clinical disease spectrum, epidemic characteristics and disease burden. Based on the nucleotide variation in structural protein genes, HPIVs can be further divided into distinct genotypes and subtypes with diverse temporal and spatial distribution features. The standard molecular typing methods are helpful to clarify the gene evolution and transmission patterns of HPIVs in the process of population transmission. However, the development of molecular epidemiology of HPIVs has been hindered by the lack of a standardized molecular typing method worldwide. Therefore, this study reviewed the viral characteristics, genome structure, existing genotyping methods and evolution of HPIVs, and screened the reference strains for molecular typing, so as to improve the understanding of gene characteristics and molecular typing of HPIVs, and provide an important scientific basis for the monitoring and research of molecular epidemiology of HPIVs in China.
Child ; Humans ; Molecular Typing ; Parainfluenza Virus 1, Human/genetics* ; Parainfluenza Virus 2, Human/genetics* ; Parainfluenza Virus 3, Human/genetics* ; Paramyxoviridae Infections/epidemiology* ; Respiratory Tract Infections/epidemiology*

PURPOSE: Acute respiratory tract infections are the most common illnesses in children. The great majority of these infections involving lower respiratory tracts infections(LRTIs) are caused by respiratory viruses such as respiratory syncytial virus(RSV), parainfluenza virus(PIV), influenza virus (Flu), and adenovirus(ADV), etc. Our purpose was to determine seasonal epidemiology and clinical characteristic features of each viral infection. METHODS: Nasopharyngeal aspirate(NPA)s were collected from 4,554 hospitalized children diagnosed as LRTIs on the first day of admission. The study period was from September 1998(Autumn) through May 2003(Spring). Respiratory viruses were detected in 881(19 percent) cases by isolation of the virus or by antigen detection method using indirect immunofluorescent staining. We reviewed the medical records of 837 cases retrospectively. RESULTS: The identified pathogens were RSV in 485 cases(55 percent), PIV in 152 cases(17 percent), FluA in 114 cases(13 percent), ADV in 79 cases(9 percent) and FluB in 51 cases(6 percent). Outbreaks of RSV occurred every year, mostly in the November through December period and of PIV in the April through June period. LRTIs by FluA reached the highest level in January, 2002. FluB infection showed an outbreak in April, 2002. The clinical diagnoses of viral LRTIs were bronchiolitis in 395 cases(47 percent), pneumonia in 305 cases(36 percent), croup in 73 cases(9 percent) and tracheobronchitis in 64 cases(8 percent). CONCLUSION: Viruses are one of the major etiologic agents of acute LRTIs in chidren. Therefore, we must continue to study their seasonal occurrence and clinical features to focus on management, and also for reasons of prevention.
Adenoviridae ; Bronchiolitis ; Child ; Child, Hospitalized ; Croup ; Diagnosis ; Disease Outbreaks ; Epidemiology* ; Humans ; Medical Records ; Orthomyxoviridae ; Paramyxoviridae Infections ; Pneumonia ; Respiratory Syncytial Viruses ; Respiratory System* ; Respiratory Tract Infections* ; Retrospective Studies ; Seasons

BACKGROUND: Studies on the incidence and seasonality of respiratory viruses that are the main cause of lower respiratory tract disease in children are insufficient in Korea. In the present study, the epidemiology of respiratory viruses in children was studied during the last 2 years and, the indirect immunofluorescent (IF) method was compared with the direct IF method. METHODS: A total of 814 pediatric inpatients hospitalized for lower respiratory tract infection at Hanyang University Hospital were studied from April, 1996 to July, 1998. Nasopharyngeal aspirates were obtained from these patients and indirect IF (Respiratory Panel I Viral Screening & Identification Kit, Light Diagnostics, Chemicon, Temecula, CA, USA) was performed for the following viruses : respiratory syncytial virus (RSV), parainfluenza virus type I, II and III, influenza virus A, B, and adenovirus. Sixty-nine of these samples were tested by direct IF (IMAGENTM, DAKO, UK) and indirect IF, simultaneously. RESULTS: 1) Viral pathogens were detected in 30.5% of nasopharyngeal aspirates. Among the positive cases, RSV was 60.6%, influenza A 35.3%, adenovirus 5.2%, influenza B 4.0%, and parainfluenza II 0.8%. 2) The occurrence rate of RSV in spring, summer, fall and winter was 7.3%, 13.6%, 31.45%, 33.45%, respectively, and showed a unique pattern in that the incidence rate in the summer of 1997 was 22.2%. A unique pattern was also observed for influenza A, which was continuously detected from December 1997 to July 1998. 3) The positive rate of indirect IF was statistically higher than that of direct IF. Excluding the results of the influenza A, there was no statistically significant difference between the two methods. CONCLUSION: RSV was the most frequently detected virus in viral respiratory infections in children. Infection usually began in the fall and most frequently detected in the winter and lasted until spring. High incidence of RSV in summer 1997 and continuous detection of influenza A till summer 1997 suggest some change of epidemic pattern. The discordance between direct and indirect IF was probably due to the difference in quality of the anti-influenza A reagent rather than a real difference in the two methods.
Adenoviridae ; Child* ; Epidemiologic Studies* ; Epidemiology ; Humans ; Incidence ; Influenza, Human ; Inpatients ; Korea ; Mass Screening ; Orthomyxoviridae ; Paramyxoviridae Infections ; Respiratory Syncytial Viruses ; Respiratory Tract Diseases ; Respiratory Tract Infections ; Seasons

BACKGROUND: The information on the incidence, seasonal variation and clinical pattern of respiratory virus infections is very important for clinicians in managing their patients. This study was aimed to define the epidemiology of respiratory viral pathogens in Seoul and the neighboring areas from March 2004 to February 2006. METHODS: A total of 6,533 specimens were cultured for respiratory viruses during the study period. Madin-Darby canine kidney (MDCK), LLC-MK2, and HEp-2 cells, or R-mix cells (Diagnostic Hybrids Inc., Athens, Ohio, USA) were used for culture. Influenza virus types A & B (Inf A & B), parainfluenza virus (PIV), respiratory syncytial virus (RSV), and adenovirus (ADV) were identified by indirect immuno-fluorescent staining. Medical records of the patients with positive virus cultures were reviewed retrospectively. RESULTS: One or more viral agents were isolated from 1682 specimens (25.7%). The pathogens identified were RSV 37.2%, ADV 19.9%, Inf A 18.9%, PIV 17.5% and Inf B 6.4%. The most frequent pathogen of pneumonia and acute bronchiolitis was RSV and that of croup was PIV. Upper respiratory tract infections were more prevalent in adults and the most frequently caused by influenza virus. Influenza virus itself was more frequently isolated in children less than six years old, which was different from previous reports. Influenza virus was mostly isolated in the winter and spring, while RSV was usually isolated from early fall with a peak incidence in the winter. Inf A and RSV showed a dampening effect on the occurrence of other viruses during their major epidemic. PIV was mostly detected in the spring and summer. ADV was isolated throughout the whole year. CONCLUSIONS: The epidemiological characteristics of respiratory virus infections in Seoul and the neighboring areas in 2004-2006, were similar to the findings of previous reports except for some minor changes. These findings could be useful to clinicians in managing their patients.
Adenoviridae ; Adult ; Bronchiolitis ; Child ; Croup ; Epidemiology* ; Humans ; Incidence ; Kidney ; Medical Records ; Ohio ; Orthomyxoviridae ; Paramyxoviridae Infections ; Pneumonia ; Respiratory Syncytial Viruses ; Respiratory Tract Infections ; Retrospective Studies ; Seasons ; Seoul

Human metapneumovirus (hMPV) is a recently isolated virus, mostly associated with acute lower respiratory infection in children, of which symptoms are similar to those of respiratory syncytial virus (RSV) infection. The aim of our study was to determine the frequency of hMPV in hospitalized children with acute respiratory tract disease in Korea. Nasal aspirates from hospitalized children with respiratory infections under 15 yr old between December 2003 and February 2005 were included in the study. Each sample was analyzed for RSV, adenovirus, influenza virus A and B, and parainfluenza virus by indirect fluorescent assay (IFA). F-gene sequences were used for PCR for the detection and sequencing of hMPV. In total 381 samples, negative samples in which any viral pathogen could not be identified by IFA were 231 cases. hMPV was detected using reverse transcriptase-PCR (RT-PCR) in 28 of 231 (12.1%) children who were not infected with another respiratory viruses. The hMPV-infected children were diagnosed as having pneumonia, bronchiolitis, bronchial asthma exacerbation, croup, and upper respiratory tract infection. Most of the RT-PCR positive samples for hMPV were collected in winter season. These results suggest that hMPV may be a responsible pathogen causing acute respiratory tract infection in Korean children.
Reverse Transcriptase Polymerase Chain Reaction ; Respiratory Tract Infections/*etiology ; Phylogeny ; Paramyxoviridae Infections/*epidemiology ; Metapneumovirus/classification/*isolation & purification ; Male ; Infant ; Humans ; Hospitalization ; Female ; Child, Preschool ; Child ; Acute Disease