Genetic analysis of human parainfluenza virus type 4 associated with severe acute respiratory infection in children in Luohe City, Henan Province, China, during 2017-2018.

During 2017-2018, nasopharyngeal aspirates (NPAs) from 627 hospitalized patients with severe acute respiratory infection at Luohe Center Hospital were tested by RT-PCR for human parainfluenza virus 4 (HPIV-4). Fourteen (2.2%) of the 627 samples were positive for HPIV-4. The complete HN gene was amplified from nine positive samples and sequenced. Sequence comparisons showed that the HPIV-4 strains circulating in the city of Luohe are closely related to HPIV-4A strains. Our study indicated that there were multiple lineages of HPIV-4 circulating in Henan Province in China during the study period. This will improve our understanding of the epidemiological and clinical characteristics of HPIV-4.

Characteristics of human parainfluenza virus type 4 infection in hospitalized children in Korea.

BACKGROUND: The characteristics of human parainfluenza virus type 4 (hPIV4) infection are not thoroughly understood. We therefore clarified the characteristics of hPIV4 in Korea. METHOD: From January 2013 to December 2017, children admitted with respiratory tract infection at the Department of Pediatrics in Chung-Ang University Hospital were enrolled in the study. Nasopharyngeal aspirate specimens were obtained from patients and tested for hPIV types by multiplex reverse transcription polymerase chain reaction. We retrospectively reviewed subject medical records, focusing on epidemiological and clinical characteristics. RESULTS: Of the 12 423 NPA specimens, 8,406 were positive by multiplex reverse transcription polymerase chain reaction for nine respiratory viruses, and 1,018 were positive for one of the four types of hPIV: 1,018 specimens led to the detection of 1,029 hPIVs; 3ss (31.3%) were positive for hPIV1, 120 (11.7%) were positive for hPIV2, 356 (34.6%) were positive for hPIV3, and 231 (22.4%) were positive for hPIV4. Of the hPIV-positive patients, the mean age was 2.3 years (range, 0.1-12.7 years), 225 (97.4%) had no underlying disease, and 178 (77.1%) had a fever with a duration of 4.1 ± 2.3 days and a peak temperature of 39.0 ± 0.7 ℃. The most common diagnosis in hPIV4 infection was pneumonia (44.2%), followed by bronchiolitis (26.0%) and upper respiratory tract infection (24.3%). Only 2.2% of patients were diagnosed with croup. Although the most prevalent overall type of hPIV was hPIV3, hPIV4 generally caused acute respiratory tract infection in summer and early fall in an irregular annual pattern. CONCLUSIONS: Human parainfluenza virus type 4 is an important common pathogen of respiratory tract infections in pediatric patients in Korea.

Human parainfluenza virus surveillance in pediatric patients with lower respiratory tract infections: a special view of parainfluenza type 4 / Vigilância dos vírus parainfluenza humanos em pacientes pediátricos com infecções do trato respiratório inferior: uma visão especial do parainfluenza tipo 4

Abstract Objective: Characterize the role of human parainfluenza virus and its clinical features in Brazilian children under 2 years of age presenting with acute lower respiratory tract infections. Methods: Real-time assays were used to identify strains of human parainfluenza virus and other common respiratory viruses in nasopharyngeal aspirates. One thousand and two children presenting with acute lower respiratory tract illnesses were enrolled from February 2008 to August 2010. Results: One hundred and four (10.4%) patients were human parainfluenza virus positive, of whom 60 (57.7%) were positive for human parainfluenza virus-3, 30 (28.8%) for human parainfluenza virus-4, 12 (11.5%) for human parainfluenza virus-1, and two (1.9%) for human parainfluenza virus-2. Seven (6.7%) patients had more than one strain of human parainfluenza virus detected. The most frequent symptoms were tachypnea and cough, similar to other viral respiratory infections. Clinical manifestations did not differ significantly between human parainfluenza virus-1, -2, -3, and -4 infections. Human parainfluenza virus-1, -3, and -4 were present in the population studied throughout the three years of surveillance, with human parainfluenza virus-3 being the predominant type identified in the first two years. Conclusion: Human parainfluenza viruses contribute substantially to pediatric acute respiratory illness (ARI) in Brazil, with nearly 30% of this contribution attributable to human parainfluenza virus-4.

Resumo Objetivo: Caracterizar o papel do VPH-4 e suas características clínicas em crianças brasileiras com menos de dois anos de idade com infecções agudas do trato respiratório inferior. Métodos: Ensaios em tempo real foram utilizados para identificar tipos de VPH e outros vírus respiratórios comuns em aspirados nasofaríngeos. Mil e duas crianças com doença aguda do trato respiratório inferior foram inscritas para participar de fevereiro de 2008 a agosto de 2010. Resultados: 104 (10,4%) pacientes eram VPH positivos, dos quais 60 (57,7%) eram positivos para VPH-3, 30 (28,8%) para VPH-4, 12 (11,5%) para VPH-1 e dois (1,9%) para VPH-2. Sete (6,7%) pacientes apresentaram mais de um tipo de VPH detectado. Os sintomas mais frequentes foram tosse e taquipneia, semelhantes a outras infecções respiratórias virais. As manifestações clínicas não diferiram de forma significativa entre as infecções por VPH-1, -2, -3 e -4. Os VPH-1, -3 e -4 estavam presentes na população estudada ao longo dos três anos de vigilância, e o VPH-3 foi o tipo predominante identificado nos primeiros dois anos. Conclusão: Os VPHs contribuem substancialmente para a DRA pediátrica no Brasil com quase 30% dessa contribuição atribuível ao VPH-4.

Human parainfluenza virus surveillance in pediatric patients with lower respiratory tract infections: a special view of parainfluenza type 4.

OBJECTIVE: Characterize the role of human parainfluenza virus and its clinical features in Brazilian children under 2 years of age presenting with acute lower respiratory tract infections. METHODS: Real-time assays were used to identify strains of human parainfluenza virus and other common respiratory viruses in nasopharyngeal aspirates. One thousand and two children presenting with acute lower respiratory tract illnesses were enrolled from February 2008 to August 2010. RESULTS: One hundred and four (10.4%) patients were human parainfluenza virus positive, of whom 60 (57.7%) were positive for human parainfluenza virus-3, 30 (28.8%) for human parainfluenza virus-4, 12 (11.5%) for human parainfluenza virus-1, and two (1.9%) for human parainfluenza virus-2. Seven (6.7%) patients had more than one strain of human parainfluenza virus detected. The most frequent symptoms were tachypnea and cough, similar to other viral respiratory infections. Clinical manifestations did not differ significantly between human parainfluenza virus-1, -2, -3, and -4 infections. Human parainfluenza virus-1, -3, and -4 were present in the population studied throughout the three years of surveillance, with human parainfluenza virus-3 being the predominant type identified in the first two years. CONCLUSION: Human parainfluenza viruses contribute substantially to pediatric acute respiratory illness (ARI) in Brazil, with nearly 30% of this contribution attributable to human parainfluenza virus-4.

Etiology of respiratory tract infections in the community and clinic in Ilorin, Nigeria.

OBJECTIVE: Recognizing increasing interest in community disease surveillance globally, the goal of this study was to investigate whether respiratory viruses circulating in the community may be represented through clinical (hospital) surveillance in Nigeria. RESULTS: Children were selected via convenience sampling from communities and a tertiary care center (n = 91) during spring 2017 in Ilorin, Nigeria. Nasal swabs were collected and tested using polymerase chain reaction. The majority (79.1%) of subjects were under 6 years old, of whom 46 were infected (63.9%). A total of 33 of the 91 subjects had one or more respiratory tract virus; there were 10 cases of triple infection and 5 of quadruple. Parainfluenza virus 4, respiratory syncytial virus B and enterovirus were the most common viruses in the clinical sample; present in 93.8% (15/16) of clinical subjects, and 6.7% (5/75) of community subjects (significant difference, p < 0.001). Coronavirus OC43 was the most common virus detected in community members (13.3%, 10/75). A different strain, Coronavirus OC 229 E/NL63 was detected among subjects from the clinic (2/16) and not detected in the community. This pilot study provides evidence that data from the community can potentially represent different information than that sourced clinically, suggesting the need for community surveillance to enhance public health efforts and scientific understanding of respiratory infections.

[Detection and Analysis of Human Parainfluenza Virus Infection in Hospitalized Adults with Acute Respiratory Tract Infections].

OBJECTIVE: To investigate the prevalence and gene characteristics of different groups of human parainfluenza virus (HPIV) infection in hospitalized adults with acute respiratory tract infections (ARI). METHODS: RT-PCR was used to detect HPIV hemagglutinin (HA) DNA,which was extracted from sputum samples of 1 039 adult patients with ARI from March,2014 to June,2016. The HA gene amplified from randomly selected positive samples were sequenced to analyze the homology and variation. RESULTS: 10.6% (110/1 039) of these samples were positive for HPIV,including 8 cases of HPIV-1,22 cases of HPIV-2,46 cases of HPIV-3 and 34 cases of HPIV-4. Detectable rate varied among different groups of HPIV according to seasons of the year and ages of patients. No significant differences were found between the positive samples and the reference sequences. Compared with different reference strains of different regions,the genetic distance of nucleotide is the smallest between the strains tested in this study and the reference strains of other provinces and cities in China. CONCLUSION: In Chengdu region,HPIV virus is highly detected in ARI,all subtypes were detected with HPIV-3 being the main subtype.

Human parainfluenza virus infection in severe acute respiratory infection cases in Beijing, 2014-2016: A molecular epidemiological study.

BACKGROUND: Severe acute respiratory infection (SARI) threatens human health and even survival, causing a huge number of hospitalized patients every year. However, as one of the most common respiratory viruses circulated worldwide, the epidemiological and phylogenetic characteristics of human parainfluenza virus (HPIV) in these cases were not well known. OBJECTIVES: To reveal the epidemiological features of HPIV infection in SARIs in Beijing area from September 2014 to August 2016. METHODS: A total of 1229 SARI cases in Beijing area were enrolled, investigated, sampled, and tested by multiplex real-time PCR to identify HPIVs and other common respiratory viruses. Eighteen HPIV-3 viruses isolated from all HPIV-positive samples in these SARI cases were sequenced and analyzed. RESULTS: Among all enrolled cases, 0.81%, 0.73%, 4.48%, and 0.57% were positive for HPIV-1 to HPIV-4, respectively. The highest yield rate of HPIV infection occurred in children under 5 years old (9.07%), followed by the patients over 60 years old (6.02%). The phylogenetic information of HPIV-3 showed that all viruses belonged to Cluster C3a. CONCLUSIONS: Besides the young children, the elders older than 60 years also showed a relatively high infection rate of HPIVs, which should be given comparable attentions. Moreover, the HPIV-3 circulating in China undergoes continued evolution, suggesting the potential risk of evolved HPIV infection should not be overlooked.

Use of laboratory and administrative data to understand the potential impact of human parainfluenza virus 4 on cases of bronchiolitis, croup, and pneumonia in Alberta, Canada.

BACKGROUND: Human Parainfluenza Virus (hPIV) causes severe respiratory illness in infants and adults. Our study describes the association of hPIV1-4 with bronchiolitis, croup, and pneumonia using retrospective laboratory, administrative and public health data. Due to issues including the historic lack of hPIV4 in some commercial respiratory virus panels, the description of the impact of hPIV4 on croup, bronchiolitis, and pneumonia at population levels has often been limited. This study will use routine clinical laboratory data, and administrative data to provide a preliminary description of the impact of hPIV4 on these diseases in our population. METHODS: A three year cohort of patients positive for hPIV was linked with data from physician visits and hospital admissions to define cases and hospitalization status. International Classification of Disease (ICD-9) codes were used to determine if cases had croup, bronchiolitis, and pneumonia. We also looked at differences in hospitalization status, age and gender among hPIV1-4. All statistical analysis was done using SPSS (Version 19.0.0, IBM Corp© 2010) and Graphpad Prism V6 (GraphPad Software, Inc., 2012). RESULTS: Only hPIV1 and hPIV4 specimens had positivity rates greater than 5 % of all specimens sent for respiratory virus panel testing. hPIV1 exhibited a biennial pattern while the pattern for hPIV3 was less interpretable due to lower positivity rates. Circulation patterns for hPIV2 and hPIV4 were not assessed due to the low positivity rates of theses specimens. From 2010 to 2013, there were 2300 hPIV cases with hPIV3 (46 %) being the most common, followed by hPIV1 (27 %), hPIV4 (16 %) and hPIV2 (11 %). The median age was 2 years for all hPIV types. Males were slightly greater than females for hPIV1 and hPIV2, with an equal distribution for hPIV3 and slightly more females than males for hPIV4. hPIV1 and hPIV2 had the highest or proportion of croup while hPIV3 and hPIV4 had the highest proportion of pneumonia. Within hPIV4 cases, distributions of diseases were; pneumonia (21 %, 95 % CI 17.1-25.7), bronchiolitis (18 %, 95 % CI 14.3-22.5), croup (2 %, 95 % CI 0.8-3.9), mixed illness of any of pneumonia, bronchiolitis or croup (4 %, 95 % CI 2.5-7.0) or other respiratory diseases (54 %, 95 % CI 49.1-59.6). CONCLUSIONS: We used laboratory and administrative data to undertake a descriptive analysis of the association of hPIV1-4 with croup, bronchiolitis and pneumonia. hPIV4 appears to be more associated more with bronchiolitis and pneumonia and less with croup in our population.

Human parainfluenza virus types 1-4 in hospitalized children with acute lower respiratory infections in China.

Human parainfluenza viruses (HPIVs) are an important cause of acute lower respiratory tract infections (ALRTIs). HPIV-4, a newly identified virus, has been associated with severe ALRTIs recently. A total of 771 nasopharyngeal aspirate samples were collected from hospitalized children between March 2010 and February 2011. HPIVs were detected by Nest-PCR, and other known respiratory viruses were detected by RT-PCR and PCR. All amplification products were sequenced. HPIVs were detected in 151 (19.58%) patients, of whom 28 (3.63%) were positive for HPIV-4, 12(1.55%) for HPIV-1, 4 (0.51%) for HPIV-2, and 107 (13.87%) for HPIV-3. Only three were found to be co-infected with different types of HPIVs. All HPIV-positive children were under 5 years of age, with the majority being less than 1 year. Only the detection rate of HPIV-3 had a significant statistical difference (χ2 = 29.648, P = 0.000) between ages. HPIV-3 and HPIV-4 were detected during the summer. Sixty (39.74%) were co-infected with other respiratory viruses, and human rhinovirus (HRV) was the most common co-infecting virus. The most frequent clinical diagnosis was bronchopneumonia, and all patients had cough; some patients who were infected with HPIV-3 and HPIV-4 had polypnea and cyanosis. No significant difference was found in clinical manifestations between those who were infected with HPIV-4 and HPIV-3. Two genotypes for HPIV-4 were prevalent, although HPIV-4a dominated. HPIV-4 is an important virus for children hospitalized with ALRTIs in China. HRV was the most common co-infecting virus. Two genotypes for HPIV-4 are prevalent, HPIV-4a dominated. J. Med. Virol. 88:2085-2091, 2016. © 2016 Wiley Periodicals, Inc.

Análisis clínico y epidemiológico de las infecciones pediátricas causadas por los virus Parainfluenza tipos 1-4 durante el período 2013-2014 / Clinical and epidemiological analyses 01 pediatric infections caused by Parainfluenza viruses types 1-4 during the period of 2013-2014

Introducción. Las infecciones respiratorias víricas agudas son una entidad que afecta preferentemente a la población infantil. Los virus de la Parainfluenza (VPI) (tipos 1-4) son responsables de un porcentaje variable de estas infecciones. Pacientes y métodos. Se presenta un estudio prospectivo sobre las infecciones respiratorias agudas causadas por los diferentes tipos de los VPI. A los pacientes se les tomó una muestra respiratoria que fue estudiada mediante una RT-PCR múltiple comercial que permite la detección de 16 virus distintos y los cuatro tipos de los VPI. Resultados. En este estudio se han analizado 2.854 muestras, de las cuales 1.412 (49,5%) fueron positivas. Se han detectado 89 casos de infección por los VPI (6,3%). Los VIP correspondían a 34 VPI-1 (38,2%),9 VPI-2 (10,1 %),29 VPI-3 (32,5%) y 17 VPI-4 (19,1%). En el 78,6% de los casos el VPI se detectó solo y en el 21,4% en coinfección. El 68,5% de los casos se detectaron entre los meses de septiembre y octubre. Las edades de los pacientes estaban comprendidas entre los 21 días y 14 años (media 26,2 meses). El ingreso hospitalario ocurrió en 18 casos (20,2 %). Las patologías respiratorias observadas han ido desde el cuadro catarral hasta las bronquiolitis y neumonías. No se han detectado diferencias significativas entre los diferentes tipos vira les. Conclusiones. Las infecciones respiratorias agudas causadas por los VPI representan alrededor del 6% de los casos. La inespecificidad del proceso infeccioso obliga a realizar el estudio etiológico para poder ser atribuidas a un determinado agente viral (AU)

Introduction. The acute viral respiratory infections are an entity that preferentially affect children. Para influenza viruses (PIV) (types 1-4) are responsible for a varying percentage of these infections. Patients and methods. A prospective study of acute respiratory infections caused by different types of PIV is presented. AII patients were taking a respiratory sample that was studied with a commercial multiple RT-PCR which allows the detection of 16 different viruses, including the four types of the PIV. Results. In this study we have analyzed 2,854 samples, of which 1,412 (49.5%) were positive. We detected 89 cases of infection by PIV (6.3%). 34 corresponding to the VIP-1 (38.2%), 9 VPI -2 (10.1%),29 VPI-3 (32.5%) and 17 VPI-4 (19.1 %). In 78.6% of cases was detected only the PIV and 21.4% in coinfection. 68.5% of cases were detected between the months of September and October. The ages of the patients ranged from 21 days to 14 years (mean 26.2 months). Hospital admission occurred in 18 cases (20.2%). Respiratory diseases have been observed from cold symptoms to bronchiolitis and pneumonia. No significant differences were detected between the different viral types. Conclusions. Acute respiratory infections caused by PIV represent about 6% of cases. They affect both sexes equally and present with a variety of respiratory diseases. The specificity of the infectious process requires performing the etiologic study to be attributed to a specific viral agent (AU)

First report of severe parainfluenza virus 4B and rhinovirus C coinfection in a liver transplant recipient treated with immunoglobulin.

We describe the first reported case of severe pneumonia due to coinfection by parainfluenza virus type 4B and rhinovirus C in a liver transplant recipient. The patient responded promptly to intravenous immunoglobulin and timely infection control measures prevented spreading of the infections. This report highlights respiratory viral coinfections as a possible cause of severe morbidity in transplant recipients and the importance of efficient molecular diagnostic technologies with major impact on clinical practice in a transplant center. It also describes a potential therapeutic strategy for such patients.

Bacterial and viral etiology in hospitalized community acquired pneumonia with molecular methods and clinical evaluation.

INTRODUCTION: Polymerase chain reaction (PCR) method has improved the diagnosis rates for patients with community-acquired pneumonia (CAP). We aimed to evaluate the bacterial and viral etiology of hospitalized CAP cases and compare clinical and laboratory findings of patients with pure bacterial and bacterial and viral (mixed) infections. METHODOLOGY: A total of 55 patients hospitalized with CAP were enrolled into the prospective study between February 2010 and December 2010. Clinical and laboratory follow-up were performed on days 0, 7 and 14. Deep tracheal aspiration samples were examined for bacterial and viral pathogens by multiplex PCR, and standard bacteriological culture method. RESULTS: The etiological identification rate in 50 patients for bacteria, viruses and mixed virus-bacteria combination by PCR were 62%, 4%, 32%, respectively and 60% in 55 patients by bacterial culture method. Streptococcus pneumoniae concomitant with Haemophilus influenzae (36%) and rhinovirus (16%) was very common, whereas atypical pathogens (only Mycoplasma pneumoniae) were rare (6%). Rhinovirus was the most common viral agent (20%). Recently identified viruses, human coronavirus HKU1 and human bocavirus were not detected except for human metapneumovirus (one case). There was no significant difference in terms of mean age, immune status, leukocyte count, C-reactive protein (CRP) values, hospitalization duration and CURB-65 score between bacterial and mixed viral-bacterial detections. Advanced age (p < 0.01) and higher CURB-65 score (p = 0.01) were found to be associated with increased mortality. CONCLUSION: Concomitance of bacterial and viral agents is frequent and resemble with bacterial infections alone. Further studies are needed for the clinical significance of mixed detections.

Discovery of a divergent HPIV4 from respiratory secretions using second and third generation metagenomic sequencing.

Molecular detection of viruses has been aided by high-throughput sequencing, permitting the genomic characterization of emerging strains. In this study, we comprehensively screened 500 respiratory secretions from children with upper and/or lower respiratory tract infections for viral pathogens. The viruses detected are described, including a divergent human parainfluenza virus type 4 from GS FLX pyrosequencing of 92 specimens. Complete full-genome characterization of the virus followed, using Single Molecule, Real-Time (SMRT) sequencing. Subsequent "primer walking" combined with Sanger sequencing validated the RS platform's utility in viral sequencing from complex clinical samples. Comparative genomics reveals the divergent strain clusters with the only completely sequenced HPIV4a subtype. However, it also exhibits various structural features present in one of the HPIV4b reference strains, opening questions regarding their lifecycle and evolutionary relationships among these viruses. Clinical data from patients infected with the strain, as well as viral prevalence estimates using real-time PCR, is also described.

Epidemiology and clinical presentation of the four human parainfluenza virus types.

BACKGROUND: Human parainfluenza viruses (HPIVs) are important causes of upper respiratory tract illness (URTI) and lower respiratory tract illness (LRTI). To analyse epidemiologic and clinical characteristics of the four types of human parainfluenza viruses (HPIVs), patients with acute respiratory tract illness (ARTI) were studied in Guangzhou, southern China. METHODS: Throat swabs (n=4755) were collected and tested from children and adults with ARTI over a 26-month period, and 4447 of 4755 (93.5%) patients' clinical presentations were recorded for further analysis. RESULTS: Of 4755 patients tested, 178 (3.7%) were positive for HPIV. Ninety-nine (2.1%) samples were positive for HPIV-3, 58 (1.2%) for HPIV-1, 19 (0.4%) for HPIV-2 and 8 (0.2%) for HPIV-4. 160/178 (88.9%) HPIV-positive samples were from paediatric patients younger than 5 years old, but no infant under one month of age was HPIV positive. Seasonal peaks of HPIV-3 and HPIV-1 occurred as autumn turned to winter and summer turned to autumn. HPIV-2 and HPIV-4 were detected less frequently, and their frequency of isolation increased when the frequency of HPIV-3 and HPIV-1 declined. HPIV infection led to a wide spectrum of symptoms, and more "hoarseness" (p=0.015), "abnormal pulmonary breathing sound" (p<0.001), "dyspnoea" (p<0.001), "pneumonia" (p=0.01), and "diarrhoea" (p<0.001) presented in HPIV-positive patients than HPIV-negative patients. 10/10 (100%) HPIV-positive adult patients (≥14 years old) presented with systemic influenza-like symptoms, while 90/164 (54.9%) HPIV-positive paediatric patients (<14 years old) presented with these symptoms (p=0.005). The only significant difference in clinical presentation between HPIV types was "Expectoration" (p<0.001). Co-infections were common, with 33.3%-63.2% of samples positive for the four HPIV types also testing positive for other respiratory pathogens. However, no significant differences were seen in clinical presentation between patients solely infected with HPIV and patients co-infected with HPIV and other respiratory pathogens. CONCLUSIONS: HPIV infection led to a wide spectrum of symptoms, and similar clinical manifestations were found in the patients with four different types of HPIVs. The study suggested pathogenic activity of HPIV in gastrointestinal illness. The clinical presentation of HPIV infection may differ by patient age.

A novel duplex real-time PCR for HPIV-4 detects co-circulation of both viral subtypes among ill children during 2008.

The two subtypes of the human parainfluenzavirus type 4 (HPIV-4) are rarely sought in testing for acute respiratory illness (ARI) and this may be confounding our understanding of its role. This study presents a novel duplex real-time RT-PCR assay targeting the P gene that can detect and differentiate the two subtypes in a single reaction. Subtype-specific synthetic RNA positive controls were prepared and used to determine an analytical sensitivity of 10 copies per reaction with an 8log(10) dynamic range. The assays were validated using 1140 clinical specimens mostly nasopharyngeal aspirates collected from children during 2008. These included specimens previously determined to be positive for all commonly considered respiratory viruses. The novel assay did not cross-reaction with any other virus. Fourteen HPIV-4 positives, ten detected in the absence of any co-detections (four with rhinovirus), were identified in 2008 and their subtype confirmed by conventional RT-PCR and sequencing of P gene fragments. Most detections were in children two years of age or younger. Our assay proved suitably sensitive and specific for inclusion in future studies seeking to better understand the role HPIV-4 and other respiratory viruses in children with ARI.

Human parainfluenza virus type 4 infection in Chinese children with lower respiratory tract infections: a comparison study.

BACKGROUND: Human parainfluenza viruses (HPIVs) are a leading cause of acute respiratory tract infections (ARTIs). Although HPIV-4 has been associated with mild ARTIs for years, recent investigations have also associated HPIV-4 infection with severe respiratory syndromes and with outbreaks of ARTIs in children. OBJECTIVES: To characterize the role of HPIV-4 and its clinical features in children with acute lower respiratory tract infections (ALRTIs) in Beijing, China. STUDY DESIGN: Nasopharyngeal aspirates were collected from 2009 hospitalized children with ALRTIs between March 2007 and April 2010. RT-PCR and PCR analyses were used to identify HPIV types and other known respiratory viruses. RESULTS: HPIVs were detected in 246 (12.2%) patients, of whom 25 (10.2%) were positive for HPIV-4, 11 (4.5%) for HPIV-2, 51 (20.7%) for HPIV-1, 151 (61.4%) for HPIV-3, and 8 (3.3%) were co-detected with different types of HPIVs. Like HPIV-3, HPIV-4 was detected in spring, summer, and late fall over the study period. Seasonal incidence varied for HPIV-1 and -2. The median patient age was 20 months for HPIV-4 infections and 7-11 months for HPIV-1, -2, and -3 infections, but the clinical manifestations did not differ significantly between HPIV-1, -2, -3, and -4 infections. Moreover, co-detection of HPIV-4 (44%) with other respiratory viruses was lower than that of HPIV-1 (62.7%), HPIV-2 (63.6%), and HPIV-3 (72.7%). CONCLUSIONS: HPIV-4 plays an important role in Chinese paediatric ALRTIs. The epidemiological and clinical characteristics reported here improve our understanding of the pathogenesis associated with HPIV-4.