Using atomic force microscope (AFM), we investigated the images of Pars influenza virus (PIV) under different treatment conditions and observed the different appearances of the virus and its ultra-microstructure from the exterior to the interior. From the 2D images under transmission electron microscope (TEM), we could see that the surfaces of PIV particles exhibited spherical and band-shaped 'tufts'; from the 3D images under AFM, we could further observe the whole spherical virus particles and their detailed surfaces, which exhibited round and band-shaped 'tufts'. Comparing the images under TEM with those under AFM, we found that the latter could reveal the surface topograph and ultramicrostructure of viruses more truly than did the former. The samples of viruses were treated by Tritonx-100, the lipid envelopes of virions were partly or completely resolved, and then most of their capsids were exposed. We could observe the different appearances of the virions under AFM, the lipid envelopes of which were gradually removed. The samples of viruses were also treated by SDS, and the RNA was released from the virions. From the AFM images, we could see the structure of the RNA. It was thus clear that AFM could be used to investigate the different appearances and ultramicrostructure of viruses rapidly and efficiently.
Microscopy, Atomic Force ; Parainfluenza Virus 1, Human ; ultrastructure ; Parainfluenza Virus 2, Human ; ultrastructure

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*

OBJECTIVEHuman parainfluenza virus (HPIV) types 1, 2 and 3 are major viral pathogens responsible for upper and lower respiratory tract infections. In this study, a real-time RT-PCR was developed using multiplex primers-probe (HPIV-1, 2, 3) for the simultaneous detection of both HPIV1, HPIV2 and HPIV3 genomes.

METHODSOptimal primers and probes were designed using specialized software. The conditions for multiplex real-time RT-PCR had been optimized. The synthesis of RNA standards of HPIV1, 2, 3 were used a T7 RNA polymerase. Check the specificity sensitivities and stability of one step RT-PCR assay.

RESULTSObtained in a 10-fold dilution series assay demonstrate a high sensitivity of the assay with a lowest detection limit of 10 copies for HPIV1, 100 copies for HPIV2 and 100 copies for HPIV3.

CONCLUSIONThe assays demonstrates an improved sensitivity and scope of detecting HPIV1, 2, 3 viruses relative to routine antigen detection assays while the quantitative utility may facilitate investigation of the pre-diagnosis and respiratory virus pathogenesis.

Humans ; Oligonucleotides ; genetics ; Parainfluenza Virus 1, Human ; isolation & purification ; Parainfluenza Virus 2, Human ; isolation & purification ; Parainfluenza Virus 3, Human ; isolation & purification ; Real-Time Polymerase Chain Reaction ; methods

PURPOSE: Croup, a common childhood respiratory illness with various severities, has many unanswered questions. Laryngotracheobronchopneumonitis (LTBP) is a disease entity considered to be an extension of croup to the lower respiratory tract. The object of this study was to compare epidemiology, clinical characteristics, and viral etiologic spectrum between croup and LTBP. METHODS: Patients hospitalized with croup at Gachon University Gil Hospital from January 2010 to April 2016 were recruited. LTBP was defined as pneumonia confirmed on radiographs of patients with croup. Clinical findings and demographic data were reviewed of patients whose nasopharyngeal swabs were done for viral analysis. RESULTS: A total of 371 patients with only croup and 63 patients with LTBP were included. Croup was found to be significantly associated with parainfluenza virus type 1 (P=0.006). LTBP was related to parainfluenza virus type 3, respiratory syncytial virus, and human bocavirus (P=0.001, P=0.030, and P=0.019, respectively). The duration of fever was longer in patients with LTBP than in those with croup (3.87±1.85 days vs. 2.86±1.80 days, P<0.001). CONCLUSION: Specific etiologic viruses might be associated with the progression from croup to LTBP. Pronged fever is also associated with progression from croup to LTBP.
Child* ; Croup* ; Epidemiology ; Fever ; Human bocavirus ; Humans ; Parainfluenza Virus 1, Human ; Parainfluenza Virus 3, Human ; Pneumonia ; Respiratory Syncytial Viruses ; Respiratory System

BACKGROUNDAlthough human parainfluenza virus (HPIV) has been determined as an important viral cause of acute respiratory infections (ARIs) in infants and young children, data on long-term investigation are still lacking to disclose the infection pattern of HPIV in China.

METHODSNasopharyngeal aspirates were collected from 25,773 hospitalized pediatric patients with ARIs from January 2004 through December 2012 for respiratory virus screen by direct immuno-fluorescence assay.

RESULTSOut of these specimens, 1675 (6.50%, 1675/25,773) showed HPIV positive, including 261 (1.01%, 261/25,773) for HPIV1, 28 (0.11%, 28/25,773) for HPIV2, and 1388 (5.39%, 1388/25,773) for HPIV3, 2 of the samples were positive for both HPIV1 and HPIV3, and 36 were co-detected with other viruses. The positive rates of HPIVs were higher in those younger than 3 years old. HPIV3 was detected from all age groups, predominantly from patients under 3 years of age, and the highest frequency was found in those 6 months to 1-year old (352/4077, 8.63%). HPIV3 was the dominant type in each of the years detected between May and July. HPIV1 showed a peak in every odd year, mainly in August or September. HPIV was detected most frequently from patients with upper respiratory infection (12.49%, 157/1257), followed by bronchitis (11.13%, 176/2479), asthma (9.31%, 43/462), bronchiolitis (5.91%, 150/2536), pneumonia (6.06%, 1034/17,068), and those with underlying diseases (1.0%, 15/1506). HPIV3 is the dominant type in these six disease groups referred above, especially in the asthma group.

CONCLUSIONSHPIV is one of the important viral causes of ARIs in infants and young children in Beijing based on the data from the hospitalized children covering a 9-year term. HPIV3 is the predominant type in all these years and in most of the disease groups. HPIVs with different types show different seasonality.

Beijing ; epidemiology ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Parainfluenza Virus 1, Human ; pathogenicity ; Parainfluenza Virus 3, Human ; pathogenicity ; Respirovirus ; pathogenicity ; Respirovirus Infections ; diagnosis ; virology

PURPOSE: Croup is a common respiratory disease in children. The aim of this study was to analyze the epidemiology, etiology, and seasonal variations of respiratory virus infections in children with croup. METHODS: From October 2009 to September 2017, children admitted with croup to Gachon University Gil Medical Center under the age of 18 years were enrolled in this study. We retrospectively reviewed patients' medical records. RESULTS: A total of 1,053 of 27,330 patients (3.9%) infected with lower respiratory infections were diagnosed as having croup. In the age distribution, croup was most common (50.0%) in children aged 1 to <2 years. There were 2 peaks, the major in summer (July to August) and the minor in spring (March to May). Parainfluenza virus type 1 (15.8%) was most prevalent and coincided with the summer peaks of croup. Influenza virus type B and parainfluenza virus type 3 were the most frequent etiologic agents in a spring peak of croup. Although parainfluenza virus type 1 was predominant of all ages, human coronavirus was a significant cause of croup in children younger than 1 year, whereas influenza virus played an important role in children above the age of 3 years. CONCLUSION: Seasonality and epidemiology of croup varied with age and regions. Two peaks of seasonal fluctuation were in summer and spring, which were related to the seasonality of respiratory viruses in croup. These results may be helpful in planning clinical and research needs.
Age Distribution ; Child ; Coronavirus ; Croup* ; Epidemiology ; Humans ; Medical Records ; Orthomyxoviridae ; Parainfluenza Virus 1, Human ; Parainfluenza Virus 3, Human ; Respiratory System* ; Respiratory Tract Infections* ; Retrospective Studies ; Seasons*

OBJECTIVETo understand the relationship of parainfluenza virus (PIV) and acute respiratory infections in infants and young children in Beijing, occurred in recent years.

METHODS3141 throat swab/nasopharyngeal aspirate specimens were collected from infants and young children with acute respiratory tract infections in Beijing from Jan 2001 to Dec 2003. All of these 3141 specimens were inoculated into MDCK cells for influenza virus and PIV isolation, since PIV had been isolated in MDCK cells in this laboratory from preliminary studies. Out of 3141 specimens, 702 were inoculated into MDCK as well as Vero cells to compare the sensitivity on virus isolation of these cell lines by micro plate method. Growth of PIV in cell culture were identified by haemoagglutination test and indirect immunofluorescent assay.

RESULTSThe PIV positive cases in Vero cells were also positive in MDCK cells, indicating that the sensitivity for PIV isolation in MDCK was equal to Vero cells. Out of these 3141 specimens, 94 (3.0%) were PIV positive, including 35 (35/1191, 2.9%) of PIV1, 11 (11/1191, 0.9%) of PIV3 in upper respiratory tract infections; 15 (15/1634, 0.9%) of PIV1, 24 (24/1634, 1.5%) of PIV3 in lower respiratory tract infections; 3 (3/207, 1.4%) of PIV in asthma; 1 (1/38) of PIV in patients with fever; 5 (5/71) of PIV in others. Data indicated that among upper respiratory tract infections caused by PIV, PIV1 was more commonly seen than PIV3.

CONCLUSIONMDCK cells could be used for PIV isolation from clinical samples while PIV was one of the important pathogenic viruses causing acute respiratory tract infections in infants and young children in Beijing for the recente years.

Acute Disease ; Animals ; Cell Line ; Cercopithecus aethiops ; Child, Preschool ; China ; Humans ; Infant ; Parainfluenza Virus 1, Human ; isolation & purification ; pathogenicity ; Parainfluenza Virus 3, Human ; isolation & purification ; pathogenicity ; Paramyxoviridae Infections ; diagnosis ; Respiratory Tract Infections ; virology ; Sensitivity and Specificity ; Vero Cells ; Virus Cultivation ; methods

BACKGROUND: Parainfluenza virus (PIV) is a significant cause of acute respiratory infections. Epidemiological information on PIV infection could be very helpful for patient management. The aim of this study was to investigate the epidemiology of PIV infection in Seoul and a neighboring area with regard to PIV type. METHODS: The diagnosis of PIV infection was made by virus isolation. The R-mix Too cell system (Diagnostic Hybrids, Inc., Athens, OH, USA) and D3 Ultra DFA Respiratory Virus Screening & ID kits (Diagnostic Hybrids, Inc.) were used for virus culture and identification. The medical records of patients with positive virus cultures were reviewed retrospectively. RESULTS: Seven hundred and ten PIV viruses (5.6%) were isolated from 12,723 specimens. The number of subjects with PIV type III, I and II was 357, 304 and 49, respectively. PIV infection showed a peak incidence in the first year of life regardless of subtypes. The most common diagnosis among all PIV subtypes was pneumonia. Lower respiratory tract infections constituted the majority (76.3%) of PIV infections. The most common diagnosis of PIV type I and II was croup and that of PIV type III was pneumonia. A difference in seasonal variation between subtypes was observed. PIV I (62.2%) was mainly isolated from July to September while PIV type III (86.8%) was isolated from April to July. CONCLUSION: Lower respiratory infection was most commonly found in hospitalized patients with PIV infection. Clinical features of PIV infection were similar those seen in Western PIV reports, with the exception of the seasonal outbreak pattern.
Chimera ; Croup ; Humans ; Incidence ; Mass Screening ; Medical Records ; Parainfluenza Virus 1, Human ; Paramyxoviridae Infections ; Pneumonia ; Respiratory Tract Infections ; Seasons ; Viruses

PURPOSE: Acute lower respiratory tract infections (ALRI) are one of the most common causes of morbidity in children. Most infections are known to be caused by virus and bacteria, greater percentage caused by virus than bacteria. This study was aimed to define the viral etiologic agents, age distribution, clinical manifestations, and seasonal occurrences of viral ALRI in Korean children, during 1996 and 2002. METHODS: A total of 4, 311 patients who had been hospitalized for ALRI at Samsung Medical Center, from March 1996 to September 2002, were studied. Nasopharyngeal aspirates were obtained for virus culture. Respiratory viruses were identified by indirect immunofluorescent staining. RESULTS: One or more viral agents were isolated in 14.8% (639 cases). The pathogens identified were RSV (21.8%), influenza virus type A (21.3%), adenovirus (20.7%), parainfluenza virus type 3 and 1 (17.4%, 8.3%), influenza virus type B (7.4%). The clinical patterns of viral ALRI were pneumonia (49%), bronchiolitis (22%), tracheobronchitis (15%) and croup (14%). The occurrence of viral ALRI was highest in the 1st year of life. Pneumonia was developed mostly by adenovirus. The most frequent cause of bronchiolitis was RSV. Croup was frequently caused by parainfluenza and influenza virus. Infections with influenza virus type A, B, parainfluenza virus type 1, 3, and RSV occurred in epidemics, whereas adenovirus was isolated throughout the study period. CONCLUSION: These data expand our understanding of the etiology of ALRI among pediatric inpatients in Seoul, Korea and may contribute to the prevention and control of viral respiratory tract infection.
Adenoviridae ; Age Distribution ; Bacteria ; Bronchiolitis ; Child ; Child, Hospitalized* ; Croup ; Epidemiologic Studies* ; Humans ; Inpatients ; Korea* ; Orthomyxoviridae ; Parainfluenza Virus 1, Human ; Parainfluenza Virus 3, Human ; Paramyxoviridae Infections ; Pneumonia ; Respiratory System* ; Respiratory Tract Infections* ; Seasons ; Seoul*

Laboratory diagnosis of respiratory viral infection has traditionally been based upon virus isolation and/or viral antigen identification. Recently, more sensitive and specific nucleic acid detection methods by reverse transcription- polymerase chain reaction (RT-PCR) have been developed, however, conventional RT-PCR can identify only a single suspected virus. To identify the causative agents which belong to Paramyxoviridae of respiratory virus infections, we have developed a single-tube multiplex RT-PCR using four primer sets which can amplify respiratory syncytial virus and parainfluenza virus type 1, 2 and 3 simultaneously. Assay sensitivity of single-tube multiplex RT-PCR allowed a detection in the range of 3~500 TCID50 and there were no cross amplification among other respiratory viral agents based on the test using reference virus stocks. The single-tube multiplex RT-PCR was able to directly detect viruses in respiratory specimens, with virus being detected 11 of 80 samples as compared to 9 of 80 samples detected by indirect immunofluorescence or antigen detection following shell vial culture. This result suggests that the single-tube multiplex RT-PCR can be established as a more sensitive and rapid diagnostic application than shell vial assay for the detection of respiratory infection of Paramyxoviridae.
Clinical Laboratory Techniques ; Fluorescent Antibody Technique, Indirect ; Humans* ; Parainfluenza Virus 1, Human* ; Paramyxoviridae ; Paramyxoviridae Infections* ; Polymerase Chain Reaction* ; Respiratory Syncytial Virus, Human* ; Respiratory Syncytial Viruses ; Reverse Transcription*