Analysis of hemagglutinin-neuraminidase gene characteristics of human parainfluenza virus type 3 among children with acute respiratory tract infection in Qingdao city / 中华预防医学杂志

The purpose was to discuss the infection status of human parainfluenza virus type 3 (HPIV-3) in children with acute respiratory tract infection(ARTI) in Qingdao, Shandong province, and to analyze the gene characteristics of HPIV-3 hemagglutinin-neuraminidase protein (HN). This study was a cross-sectional study. A total of 1 674 throat swab samples were collected randomly from children with ARTI, in the three hospitals (Qingdao Women and Children's Hospital, West Coast Branch of Affiliated Hospital of Qingdao University, Laoshan Branch of Affiliated Hospital of Qingdao University) from January 2018 to December 2019. Multiplex real-time fluorescence RT-PCR was performed to screen HPIV-3 positive specimens. For HPIV-3 positive specimens, nested PCR was used to amplify the full-length HN gene of HPIV-3. The HN gene was sequenced and compared with the representative strains of HPIV-3 in GenBank, and the phylogenetic tree was established. As results, this study collected 1 674 samples, in which there were 90 HPIV-3 positive samples showed and the detection rate was 5.37%. Among positive specimens, the number of samples from children under 6 years old was 88, accounting for 97.78%. HPIV-3 positive cases were mainly distributed in spring and summer. The full-length sequences of 44 HPIV-3 HN genes were obtained by nested PCR method. Sequence alignment and evolutionary analysis showed that the HPIV-3HN gene belonged to the C3a and C3b branches of C3 genotype, with 30 strains of subtype C3a and 14 strains of subtype C3b. The nucleotide and amino acid homology of the amplified 44 strains of the HPIV-3 HN gene in Qingdao were 97.0%-100.0% and 98.5%-100.0%, respectively. In conclusion, from 2018 to 2019, the C3a and C3b branches of HPIV-3 C3 genotype were circulating prevalent in Qingdao, Shandong province. HN gene variation rate was low, but showed certain regional characteristics in evolution.

Advances on molecular typing methods and evolution of human parainfluenza virus / 中华预防医学杂志

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.

Seasonality and etiology of croup in pediatric patients hospitalized with lower respiratory tract infections: A long-term study between 2009 and 2017

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.

Comparison of etiology and clinical presentation between children with laryngotracheobronchopneumonitis and croup

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.

Analysis of pathogenic features and infection status of human parainfluenza virus type 3 among children in Hangzhou / 中华预防医学杂志

<p><b>OBJECTIVE</b>To determine the level of genetic variation of human parainfluenza virus type 3 (HPIV-3), and to describe infection and co-infection characteristics of HPIV-3 in children.</p><p><b>METHODS</b>Single respiratory samples from 856 pediatric patients with acute respiratory tract infection (ARI) in Hangzhou were collected from December 2009 to March 2013. All samples were screened for HPIV-3 by real-time RT-PCR and followed by HN sequencing and phylogenetic analysis. In all RSV positive specimens, we screened for the other pathogens, and co-infection characteristics were evaluated.</p><p><b>RESULTS</b>A total of 9.6% of 856 samples were positive for HPIV-3, the nucleotide among the strains ranged from 96.9% to 100%. All Hangzhou strains were placed in C3 subgroup based on HN gene analysis. 49% (n=41) of all HPIV-3-positive children with ARI were found to be co-infected with at least one of the other pathogen. The highest co-infection rate of HPIV-3 was with HRV (n=17). Children in the younger groups (≤12 months old) were significantly more prone to be co-infected with other pathogen (χ(2)=4.78, P=0.029). Pneumonia infection rate was significantly higher in the mono-infection group than the co-infection group (χ(2)=3.92, P=0.048).</p><p><b>CONCLUSION</b>HPIV-3 was an important pathogen in children with ARI in Hangzhou. HN gene variation rate was low, but showed a more local pattern. The co-infections with other respiratory viruses were popular. Except for pneumonia, no significant differences in other clinical presentation between the HPIV-3 mono-infection and co-infection groups were observed.</p>

Detection of respiratory viruses in children with acute lower respiratory tract infection: an analysis of 5,150 children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the distribution of respiratory viruses on throat swabs in hospitalized children with acute lower respiratory tract infection (ALRTI).</p><p><b>METHODS</b>A total of 5,150 children with ALRTI who were admitted to Hebei Children's Hospital between March 2014 and February 2015 were enrolled to investigate the distribution of respiratory viruses in children with ALRTI. Direct immunofluorescence assay was performed for throat swabs from these children to detect influenza virus A (FA), influenza virus B (FB), adenovirus (ADV), respiratory syncytial virus (RSV), and parainfluenza virus types 1, 2, and 3 (PIV-1, PIV-2, and PIV-3).</p><p><b>RESULTS</b>Of all the 5,150 throat swabs from hospitalized children, 2,155 (41.84%) had positive virus detection results. RSV had the highest detection rate (1,338 cases/25.98%), followed by PIV-3 (439 cases/8.52%) and FA (166 cases/3.22%), and 29 patients had mixed infection with 2 viruses. With the increasing age, the detection rates of viruses tended to decrease (χ2=279.623; P<0.01). The positive rate of RSV increased gradually from September, and reached the peak value (60.09%) in November; the lowest positive rate occurred in June (1.51%). The positive rate of PIV-3 was the highest in May (21.38%) and the lowest in November (1.77%).</p><p><b>CONCLUSIONS</b>The distribution of viruses in children with ALRTI varies with age and season, with RSV prevalence in autumn and winter and PIV-3 prevalence in spring and summer. RSV is the most common viral pathogen that causes ALRTI in hospitalized children.</p>

Parainfluenza Virus Types 1, 2, and 3 in Pediatric Patients with Acute Respiratory Infections in Beijing During 2004 to 2012 / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Although 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.</p><p><b>METHODS</b>Nasopharyngeal 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.</p><p><b>RESULTS</b>Out 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.</p><p><b>CONCLUSIONS</b>HPIV 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.</p>

Study on functions of N-carbohydrate chains in human parainfluenza virus type 3 hemagglutinin-neuraminidase protein / 病毒学报

To determine the functions of N-carbohydrate chains in human parainfluenza virus type 3 hemagglutinin-neuraminidase(HN) protein, a PCR-based site-directed mutagenesis method was used to obtain N-glycan mutants. Protein electrophoresis rate, cell surface expression,receptor binding activity, neuraminidase activity and cell fusion promotion activity were determined. The HN proteins of single mutants (G1, G2, and G4) and multiple mutants (G12, G14, G24 and G124) migrated faster than the wild-type (wt) HN protein on polyacrylamide gels, while G3-mutated protein and wt HN protein migrated at the same position. There was no statistic difference in cell surface expression and neuraminidase activity between wt and each mutant HN protein (P>0.05), but receptor binding activity and cell fusion promotion activity of each mutant protein was reduced to significant extent (P<0.05). G1, G2 and G4 mutants exhibited re duced receptor binding activity, which was 83.94%, 76.45% and 55.32% of the wt level, respectively. G1, G2 and G4-mutated proteins also showed reductions in fusion promotion activity, which was 80.84%, 77.83% and 64.16%, respectively. Multiple mutants with G12-, G14-, G24- and G124- substitutions could further reduce receptor binding activities, 33.07%, 20.67%, 19.96% and 15.11% of the wt HN level, respectively. G12, G14, G24 and G124 mutants exhibited levels of fusion promotion activity that were only 46.360, 12.04%, 13.43% and 4.05% of the wt amount, respectively. As N-glycans of hPIV3 HN protein play an important role in receptor binding activity and cell fusion promotion activity of HN protein. We propose that the loss of N-glycans change the conformation or orientation of globular domain that is responsible for receptor binding and lower receptor binding activity and cell fusion promotion activi ty.

Genetic characterization of human parainfluenza virus 3 circulating in Gansu and Shaanxi Provinces from 2009 to 2011 / 病毒学报

To investigate the genetic characterization of Human parainfluenza virus-3 (HPIV-3) circulating in Gansu and Shaanxi Provinces of China, 719 throat swabs were collected from pediatric patients with acute respiratory infections from 2009-2011. Multiplex RT-PCR was used to screen common respiratory viral pathogens. For HPIV-3-positive specimens, nested RT-PCR was used to amplify the HN gene of HPIV-3. The nucleotides of Hemagglutinin-neuraminidase(HN)gene of 13 HPIV-3 positive strains identified in Gansu and Shaanxi Provinces were successfully sequenced and compared with those downloaded from GenBank. The phylogenetic analysis based on the nucleotides sequence of HN gene showed that 13 HPIV-3 strains belonged to sub-cluster C3 with little sequence variation (overall nucleotide divergence of 0.2%-2.3% and amino acid divergence at 0-1.1%). Compared with the complete gene of HPIV-3 strains from U.S.A., Canada, and Australia, the biggest divergence of the nucleotide and amino acid lovels was 6.0% and 3.4%, respectively. The nucleotide divergence between shaanxi09-2 and shaanxi10-H0091 was 0.9%, while the nucleotide divergence between shaanxi10-H005 and gansull-62110372 was 0.5%, between shaanxi09-2 and BJ/291/09 was 0.6%. However, there was no amino acid divergence among them. It is likely that HPIV-3 virus had been transmitting in Gansu and Shaanxi Provinces for several years. Human parainfluenza virus-3 (HPIV-3) circulated in Gansu and Shaanxi Provinces from 2009 to 2011 belonged to sub-cluster C3.

Viral agents causing acute lower respiratory tract infections in hospitalized children at a tertiary care center in Saudi Arabia

To determine the load and importance of respiratory viruses in hospitalized Saudi children with acute lower respiratory tract infections [ALRIs]. A retrospective study was performed in the Departments of Pediatrics, Pathology/Microbiology, King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia from January 2005 to December 2010. Nasopharyngeal aspirates were collected from 643 children with ALRI. Viruses were detected by direct immunofluorescence, respiratory syncytial virus [RSV], adenovirus [ADV], type 1 to 3 parainfluenza viruses [PIV], and type A and B influenza virus [flu]. Of the 643 children with ALRI, viruses were detected in 309 [48.1%] specimens. The viruses that were identified included RSV [n=295, 95.5%], PIV [n=8, 1.2%], ADV [n=2, 0.3%], flu A [n=2, 0.3%], and flu B [n=2, 0.3%]. The RSV was predominated in 231 [75%] children less than one year of age. Only younger age and male gender were associated with severe illness. The peak frequency of the viruses detected was in the winter. Of the 309 virus positive samples, bronchiolitis was detected in 81.2% [n=251], and pneumonia in 14.2% [n=44] [p<0.0001]. Viruses are an important cause of ALRIs in Saudi children constituting approximately 48.1% of the total cases. The RSV is the most common pathogen [95.5%] causing ALRIs. Most of the children were younger than one year of age, and were more likely to present with bronchiolitis than pneumonia

Respiratory Viral Infections after Hematopoietic Stem Cell Transplantation in Children

This study was performed to characterize respiratory viral infections in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT). Study samples included 402 respiratory specimens obtained from 358 clinical episodes that occurred in the 116 children of the 175 consecutive HSCT cohort at Seoul National University Children's Hospital, Korea from 2007 to 2010. Multiplex reverse-transcription polymerase chain reactions were performed for rhinovirus, respiratory syncytial virus (RSV), parainfluenza viruses (PIVs), adenovirus, human coronavirus (hCoV), influenza viruses and human metapneumovirus. Viruses were identified in 89 clinical episodes that occurred in 58 patients. Among the 89 clinical episodes, frequently detected viruses were rhinovirus in 25 (28.1%), RSV in 23 (25.8%), PIV-3 in 16 (18.0%), adenovirus in 12 (13.5%), and hCoV in 10 (11.2%). Lower respiratory tract infections were diagnosed in 34 (38.2%). Neutropenia was present in 24 (27.0%) episodes and lymphopenia was in 31 (34.8%) episodes. Sixty-three percent of the clinical episodes were hospital-acquired. Three patients died of respiratory failure caused by respiratory viral infections. Respiratory viral infections in pediatric patients who have undergone HSCT are common and are frequently acquired during hospitalization. Continuous monitoring is required to determine the role of respiratory viruses in immunocompromised children and the importance of preventive strategies.

Simultaneous detection of human parainfluenza viruses 1, 2, 3 by multiplex real-time reverse transcription-polymerase chain reaction with LNA probes / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>Human 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.</p><p><b>METHODS</b>Optimal 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.</p><p><b>RESULTS</b>Obtained 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.</p><p><b>CONCLUSION</b>The 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.</p>

Morbidity of parainfluenza 3 outbreak in preterm infants in a neonatal unit

<p><b>INTRODUCTION</b>Parainfluenza type 3 virus (PIV-3) is an important nosocomial pathogen which causes pneumonia and bronchiolitis in infants. We report an outbreak of PIV-3 respiratory infection which occurred in the neonatal unit of KK Hospital in June 2005. This is the second PIV-3 outbreak in our unit after the fi rst in December 1994.</p><p><b>MATERIALS AND METHODS</b>The clinical characteristics and outcome of 7 infants tested positive for PIV-3 on nasopharyngeal aspirate in June 2005 were reviewed retrospectively.</p><p><b>RESULTS</b>Seven cases were infected with PIV-3 during this outbreak. The median birthweight of affected infants was 970 g (range, 740 to 2585 g), gestational age was 27 weeks and 4 days (range, 24 to 35 weeks), and postnatal age was 84 days (range, 28 to 250 days). Apnoeas and bradycardias were significant symptoms in 3 infants, 5 infants had progressive respiratory distress while the remaining 2 infants had flu-like illness. Five infants required ventilatory support and there were no deaths. The index case was an infant with chronic lung disease who was on oxygen supplementation and subsequently required ventilatory support with nasal CPAP. Despite implementation of control measures to prevent the spread of infection through early identification with strict cohorting of infected cases, contact tracing/screening, and reinforcement of hand hygiene precautions, the outbreak lasted for 24 days.</p><p><b>CONCLUSION</b>PIV-3 respiratory infection in preterm infants can present with non-specific symptoms, leading to significant morbidity especially in those with underlying pulmonary pathology. Early recognition of symptoms and diagnosis by physicians, and prompt institution of control measures are necessary to prevent the spread of infection.</p>

Comparison of Nasopharyngeal Aspirates and Nasal Swabs for the Detection of Respiratory Viruses by Multiplex RT-PCR / 소아알레르기및호흡기학회지

PURPOSE: Although the nasopharyngeal aspirate (NPA) is more commonly used because of relatively higher accuracy, the nasal swab (NS) is a less painful and easier method than NPA. A few recent reports have shown that NS is more effective than NPA for the detection of respiratory virus using immunofluorescence or viral culture. The objective of the present study was to compare the results of NPA and NS sampling specimens in children for respiratory viruses detection using multiplex RT-PCR. METHODS: From December 2008 to June 2009 Paired NPA and NS specimens were collected from 250 children admitted with symptoms of acute respiratory infections at the Department of Pediatrics, Soonchunhyang University Cheonan Hospital, Cheonan, Korea. The sensitivity and agreement of virus detection between NPA and NS using multiplex RT-PCR were compared and analyzed. RESULTS: The median age of the subjects was 1.3 years (range, 20 days to 16.5 years), and 228 patients (91.2%) were under the age of 5 years. The agreement of virus detection between NPA and NS was excellent (Cohen's kappa >0.8) for parainfluenza virus type 3 or substantial (0.6 to 0.8) for rhinovirus A, RSV A and RSV B, moderate (0.4 to 0.6) for adenovirus and metapneumovirus and poor (<0.4) for influenza A. The overall sensitivity of detection of respiratory viruses was significantly higher in NPA (0.96) than in NS (0.59, P<0.05). CONCLUSION: We recommend NPA may be more accurate specimen for detection of respiratory viruses in hospitalized children. NS might be used in limited cases at a office setting or for larger epidemiological studies. However, results obtained from NS for influenza virus type A, metapneumovirus and adenovirus, should be interpreted carefully.

Comparison of Nasopharyngeal Aspirates and Nasal Swabs for the Detection of Respiratory Viruses by Multiplex RT-PCR / 소아알레르기및호흡기학회지

PURPOSE: Although the nasopharyngeal aspirate (NPA) is more commonly used because of relatively higher accuracy, the nasal swab (NS) is a less painful and easier method than NPA. A few recent reports have shown that NS is more effective than NPA for the detection of respiratory virus using immunofluorescence or viral culture. The objective of the present study was to compare the results of NPA and NS sampling specimens in children for respiratory viruses detection using multiplex RT-PCR. METHODS: From December 2008 to June 2009 Paired NPA and NS specimens were collected from 250 children admitted with symptoms of acute respiratory infections at the Department of Pediatrics, Soonchunhyang University Cheonan Hospital, Cheonan, Korea. The sensitivity and agreement of virus detection between NPA and NS using multiplex RT-PCR were compared and analyzed. RESULTS: The median age of the subjects was 1.3 years (range, 20 days to 16.5 years), and 228 patients (91.2%) were under the age of 5 years. The agreement of virus detection between NPA and NS was excellent (Cohen's kappa >0.8) for parainfluenza virus type 3 or substantial (0.6 to 0.8) for rhinovirus A, RSV A and RSV B, moderate (0.4 to 0.6) for adenovirus and metapneumovirus and poor (<0.4) for influenza A. The overall sensitivity of detection of respiratory viruses was significantly higher in NPA (0.96) than in NS (0.59, P<0.05). CONCLUSION: We recommend NPA may be more accurate specimen for detection of respiratory viruses in hospitalized children. NS might be used in limited cases at a office setting or for larger epidemiological studies. However, results obtained from NS for influenza virus type A, metapneumovirus and adenovirus, should be interpreted carefully.

Viral pathogens of acute lower respiratory tract infection in China.

OBJECTIVES: To document the viral etiology of acute lower respiratory tract infection (ALRIs) in Chinese children. SETTING: Children Hospital, Zhejiang University, China. STUDY DESIGN: Cross-sectional. PARTICIPANTS: 34885 children with ALRI between January 2001 to December 2006. METHODS: Nasopharyngeal aspirates were collected from all subjects. Respiratory syncytial virus (RSV), adenovirus (ADV), type 1 to 3 parainfluenza viruses (PIV), and type A and B influenza virus (Flu) were detected by direct immunofluorescence. RESULTS: Viruses were identified in 32.3% cases, including RSV (23.6%), PIV 3 (4.3%), Flu A (2.0%), ADV (1.7%), PIV I (0.6%), Flu B (0.2%) and PIV 2 (0.1%). RSV and PIV 3 predominated in younger children while Flu A and Flu B predominated in older children (P<0.001, respectively). PIV 1 was more prevalent in children aged 1 to 3 years. The peak frequency of RSV, PIV 3 and Flu A were in early spring, June to August, and August and September, respectively. Flu B had a peak in the winter and spring. Adenovirus infections occurred in all seasons with a relatively constant frequency. CONCLUSIONS: Viruses are an important cause of ALRIs in Chinese children constituting 1/3 of total cases. RSV is the most common pathogen.

An Epidemiological Study of Acute Viral Lower Respiratory Tract Infections in Hospitalized Children from 2002 to 2006 in Seoul, Korea / 소아알레르기및호흡기학회지

PURPOSE: Acute lower respiratory tract infections (ALRI) in children are mostly caused by viruses. This study aimed to define the causative viruses, and clinical manifestations during 4 years (2002-2006) and to determine seasonal occurrence of viral ALRI in Korean children by using our cumulative 10 year data (1996-2006). METHODS: A total of 3,854 hospitalized patients due to viral ALRI at Samsung Medical Center, from October 2002 to July 2006, were analyzed. Nasopharyngeal aspirate was obtained for virus cultures. Respiratory viruses were identified using indirect immunofluorescent staining. RESULTS: Viral agents were isolated in 9.8% (378 cases). The common identified pathogens were parainfluenza virus type 3 (32.3%), respiratory syncytial virus (RSV) (29.6%) and adenovirus (14.0%). The clinical patterns of viral ALRI were pneumonia (73.0%), bronchiolitis (20.9%), croup (3.7%) and tracheobronchitis (2.4%). The occurrence of viral ALRI was highest under 2 years of age. Pneumonia developed mostly by parainfluenza virus type 3 and RSV. The most frequent cause of bronchiolitis was RSV. Croup was frequently caused by parainfluenza virus. During the past 10 years, infections with parainfluenza virus type 3 and RSV epidemically occurred, whereas adenovirus was isolated throughout the study period. CONCLUSION: We could look through the etiological aspect of ALRI among pediatric inpatients during 10 years in Seoul by adding this 4 year data to the former 6 years data in our hospital. Our results may contribute to prevention and control of viral respiratory tract infections.

Parainfluenza virus infections in pediatric patients with acute respiratory infections in Beijing during 2001 - 2003 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To understand the relationship of parainfluenza virus (PIV) and acute respiratory infections in infants and young children in Beijing, occurred in recent years.</p><p><b>METHODS</b>3141 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.</p><p><b>RESULTS</b>The 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.</p><p><b>CONCLUSION</b>MDCK 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.</p>

Vigilancia seroepidemiológica de los Parainfluenza virus humano (PIVh) tipos 2 y 3 en una población infantil seleccionada en Ciudad de La Habana / Seroepidemiological surveillance of human parainfluenza viruses (HPIVs) types 2 and 3 in an infantile population selected in Havana City

Se estudió la presencia de anticuerpos contra los virus Parainfluenza humanos tipos 2 y 3 en 1 793 sueros de una población infantil menor de 14 años de edad. Para el pesquisaje de las muestras clínicas se empleó como sistema la técnica de inhibición de la hemaglutinación. Del total de sueros analizados fueron positivos 1 382 (77,1 por ciento), de estos se confirmó la presencia de anticuerpos contra el tipo 2 en 320 (17,8 por ciento), para el tipo 3 en 334 (18,6 por ciento) y predominó la seropositividad simultánea en 805 (44,9 por ciento). Se constató la circulación de los virus Parainfluenza humanos durante todos los meses del año y en todos los grupos de edades analizados, con aumento en los porcentajes de positividad con la edad

Bronquiolitis / Bronchiolitis

Es una enfermedad aguda de etiología viral, que afecta al aparato respratorio en forma difusa y bilateral y puede determinar en capacidad ventilatoria obstructiva. Si bien para algunos autores puede presentarse en niños de hasta 2 años, la mayoría considera como edad límite de presentación el primer año de vida