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.

Respiratory infections and coinfections: geographical and population patterns / Infecciones y coinfecciones respiratorias: patrón geográfico y de circulación poblacional

Abstract Introduction: Acute respiratory infections are the second cause of mortality in children younger than five years, with 150.7 million episodes per year. Human orthopneumovirus (hOPV) and metapneumovirus (hMPV) are the first and second causes of bronchiolitis; type 2 human orthorubulavirus (hORUV) has been associated with pneumonia in immunocompromised patients. Objective: To define hOPV, hMPV and hORUV geographical distribution and circulation patterns. Method: An observational, prospective cross-sectional pilot study was carried out. Two-hundred viral strains obtained from pediatric patients were genotyped by endpoint reverse transcription polymerase chain reaction (RT-PCR). Results: One-hundred and eighty-six positive samples were typed: 84 hOPV, 43 hMPV, two hORUV and 57 co-infection specimens. Geographical distribution was plotted. hMPV, hOPV, and hORUV cumulative incidences were 0.215, 0.42, and 0.01, respectively. Cumulative incidence of hMPV-hORUV and hMPV-hOPV coinfection was 0.015 and 0.23; for hOPV-hMPV-hORUV, 0.035; and for hORUV-hOPV, 0.005. The largest number of positive cases of circulating or co-circulating viruses occurred between January and March. Conclusions: This study successfully identified circulation and geographical distribution patterns of the different viruses, as well as of viral co-infections.

Resumen Introducción: Las infecciones respiratorias agudas constituyen la segunda causa de mortalidad en los niños menores de cinco años, con 150.7 millones de episodios anuales. Entre los principales agentes etiológicos están Orthopneumovirus (hOPV) y metapneumovirus (hMPV) humanos como primera y segunda causa de bronquiolitis, respectivamente; Orthorubulavirus humano tipo 2 (hORUV) se ha asociado a neumonía en pacientes inmunocomprometidos. Objetivo: Definir patrones de distribución geográfica y de circulación de hOPV, hMPV y hORUV. Método: Se llevó a cabo un estudio piloto transversal prospectivo observacional. Se genotipificaron 200 aislamientos virales de pacientes pediátricos mediante transcripción inversa seguida de reacción en cadena de la polimerasa en punto final (RT-PCR). Resultados: Se tipificaron 186 muestras positivas: 84 de hOPV, 43 de hMPV, dos de hORUV y 57 de coinfecciones. Se trazó la distribución geográfica. Las incidencias acumuladas de hMPV, hOPV y hORUV fueron de 0.215, 0.42 y 0.01, respectivamente. Las incidencias acumuladas de la coinfección de hMPV-hORUV y hMPV-hOPV fueron de 0.015 y 0.23; de hOPV-hMPV-hORUV, de 0.035; y de hORUV-hOPV, de 0.005. El mayor número de casos positivos de virus circulantes o cocirculantes se presentó entre enero y marzo. Conclusiones: Fue posible identificar patrones de circulación y distribución geográfica de los diferentes virus, así como de las coinfecciones virales.

Antimicrobial peptides in multiresistant respiratory infections / Péptidos antimicrobianos en infecciones respiratorias multiresistentes

Antimicrobial peptides are small cationic molecules present in almost all living organisms. They show direct or indirect (immunomodulation) activity in a wide range of pathogenic microorganisms as members of the humoral arsenal of innate immunity. In mammals they play a significant role in respiratory airways. The most abundant antimicrobial peptides in the respiratory tract of mammals are lysozymes, lactoferrin, histatins, defensins and cathelicidins. Respiratory and pulmonary infections are combated, primarily, by antimicrobial peptides like LL-37 against Gram-negative bacteria, histatin 5 against Candida albicans and human peptides from neutrophils against adenovirus, influenza and parainfluenza. This paper provides a review of the most important antimicrobial peptides in the respiratory tract and their use in the search for new effective agents against microorganisms that cause respiratory infections based on information published in MedLine, the Web of Science and Scopus in recent years(AU)

Los péptidos antimicrobianos son pequeñas moléculas catiónicas presentes en casi todos los organismos vivos. Muestran actividad directa o indirecta (inmunomodulación) en una amplia gama de microorganismos patógenos como miembros del arsenal humoral de la inmunidad innata. En los mamíferos juegan un papel importante en las vías respiratorias. Los péptidos antimicrobianos más abundantes en el tracto respiratorio son lisozima, lactoferrina, histatinas, defensinas y catelicidinas. Las infecciones respiratorias y pulmonares son combatidas, principalmente, por péptidos antimicrobianos como LL-37 contra bacterias gramnegativas, histatina 5 contra Candida albicans y péptidos humanos de neutrófilos contra adenovirus, influenza y parainfluenza. Este artículo proporciona una revisión sobre los péptidos antimicrobianos más importantes en el tracto respiratorio y su empleo en la búsqueda de nuevos agentes eficaces contra microorganismos causantes de infecciones respiratorias teniendo en cuenta la información publicada al respecto en MedLine, Web of Science y Scopus en los últimos años(AU)

Detection of avian metapneumovirus subtype A from wild birds in the State of São Paulo, Brazil / Detecção de metapneumovirus aviário subtipo A em aves silvestres no estado de São Paulo, Brasil

The present study investigated the circulation of avian metapneumovirus (aMPV) in wild birds in Brazil. To do so, 131 samples from 366 oropharyngeal or cloacal swabs collected from 18 species of birds were tested individually or in pools by RT-PCR. Samples detected by RT-PCR were selected for DNA sequencing. Thirteen (9.9%) samples were detected by the RT-PCR targeting the N gene and four out of 13 samples were sequenced. Sequencing results showed a high identity with the aMPV subtype A. Our results confirm the circulation of the aMPV subtype A in wild birds in Brazil even five years after its last detection.(AU)

O presente estudo investigou a circulação de metapneumovírus aviário em aves silvestres no Brasil. Para tanto, 131 amostras de 366 suabes orofaringeanos ou cloacais coletados de 18 espécies de aves foram testadas individualmente ou na forma de pools por RT-PCR. As amostras detectadas por RT-PCR foram selecionadas para sequenciamento. Treze (9,9%) das amostras foram detectadas por RT-PCR tendo o gene N como alvo; destas, quatro foram sequenciadas com sucesso. Resultados do sequenciamento mostraram alta identidade com o aMPV de subtipo A. Nossos resultados confirmam a circulação de aMPV subtipo A em aves silvestres no Brasil mesmo cinco anos após sua última detecção.(AU)

Evaluation of the Real-Q RV Detection Kit for the Identification of Viruses That Result in Respiratory Infections

Viral respiratory infections are one of the most common infections worldwide. It is important to detect the virus early and precisely. In this study, we evaluated the limit of detection (LoD) and usefulness of the Real-Q RV Detection kit (BioSewoom, Seoul, Korea). We measured the LoD of the Real-Q RV Detection kit using 10 strains of standard viruses. We then compared the detection results by the Allplex Respiratory Panel Assay kit (Seegene, Seoul, Korea) using 123 clinical specimens. The discrepant results were confirmed by sequencing. Among the 10 standard viruses, the LoD of human rhinovirus (HRV) was the lowest and that of parainfluenza virus 2 and 3 was relatively high as detected by Real-Q RV Detection kit. Agreements of the two kits ranged from 95.9% to 100%. Three specimens detected negative by the Allplex Respiratory Panel kit were detected as adenovirus (AdV) by the Real-Q RV Detection kit and were confirmed by sequencing. Similarly, a specimen detected negative by the Allplex Respiratory Panel kit was detected as HRV by the Real-Q RV Detection kit and was confirmed by sequencing. A specimen detected as human enterovirus by the Allplex Respiratory Panel kit was detected as HRV by the Real-Q RV Detection kit and was confirmed by sequencing. Real-Q RV Detection kit showed good diagnostic performance and can be useful for detecting major viruses that cause respiratory infections.

Seasonal patterns and etiologies of croup in children during the period 2010–2015: A multicenter retrospective study

PURPOSE: Croup is known to have epidemics in seasonal and biennial trends, and to be strongly associated with epidemics of parainfluenza virus. However, seasonal and annual epidemics of croup have not been clearly reported in Korea. This study aimed to examine the seasonal/annual patterns and etiologies of childhood croup in Korea during a consecutive 6-year period. METHODS: Pediatric croup data were collected from 23 centers in Korea from 1 January 2010 to 31 December 2015. Electronic medical records, including multiplex reverse transcription polymerase chain reaction (RT-PCR) results, demographics and clinical information were cross-sectionally reviewed and analyzed. RESULTS: Overall, 2,598 childhood croup patients requiring hospitalization were identified during the study period. Among them, a total of 927 who underwent RT-PCR were included in the analysis. Males (61.5%) predominated, and most (63.0%) of them were younger than 2 years of age (median, 19 months; interquartile range, 11–31 months). Peak hospitalization occurred in 2010 and 2012 in even-numbered years, and parainfluenza virus (PIV, 39.7%) was the most common cause of childhood croup requiring hospitalization, followed by respiratory syncytial virus (14.9%), human rhinovirus (12.5%), Mycoplasma pneumonaie (10.6%), and human coronavirus (7.3%). CONCLUSION: It is concluded that croup hospitalization has a biennial pattern in even-numbered years. PIV may be the most common cause of childhood croup; however, croup epidemics could be attributed to other viruses.

Viral etiology of acute respiratory infections in children in Southern Iran

Abstract INTRODUCTION: Prevalence of influenza A virus (Flu-A), respiratory syncytial virus (RSV), and human metapneumovirus (hMPV) was assessed in children with acute respiratory infections (ARIs). METHODS: Nasopharyngeal aspirates and throat swabs were subjected to real-time polymerase chain reaction (PCR) to detect RSV and Flu-A and to conventional PCR to detect hMPV. RESULTS: Of the 156 children assessed, 93 (59.6%) carried at least one virus, with 35.9% positive for RSV, 14.1% for hMPV, and 9.6% for Flu-A. The prevalence of co-infections was 2.6%. CONCLUSIONS: The high detection rate may reflect increased sensitivity of real-time PCR compared to traditional PCR and viral culture.

Influence of Fine Particulate Dust Particulate Matter 10 on Respiratory Virus Infection in the Republic of Korea

BACKGROUND: This study investigated the effect of fine dust concentrations in the air on the incidence of viral respiratory infections in the Republic of Korea.METHODS: A time series analysis using R statistics was performed to determine the relationship between weekly concentrations of fine dust in the air and the incidences of acute respiratory tract infections caused by the respiratory syncytial virus (RSV), adenovirus (HAdV), rhinovirus (HRV), human metapneumovirus (HMPV), human coronavirus (HCoV), human bocavirus (HBoV), human parainfluenza virus (HPIV), and influenza virus (IFV), from the beginning of 2016 to the end of 2017. Correlations between various meteorological factors and the amount of fine dust were analyzed using the Spearman's rank correlation coefficient. To analyze the relationship between viral infections and fine dust, a quasi-poisson analysis was performed.RESULTS: The incidence of the HAdV was proportional to fine dust and air temperature. The IFV was proportional to fine dust and relative humidity and was inversely proportional to temperature. The HMPV was proportional to fine dust, wind speed, and inversely proportional to relative humidity. The HCoV was proportional to micro dust, relative humidity, and inversely proportional to temperature. Both the HBoV and HPIV were directly proportional to fine dust, temperature, wind speed, and inversely proportional to relative humidity. The RSV was inversely proportional to fine dust, temperature, wind speed. A lag effect was observed for the influenza virus, in that its incidence increased 2–3 weeks later on the cumulative lag model.CONCLUSION: As the weekly average concentration of fine dust increases, the incidence of HAdV, HMPV, HCoV, HBoV, HPIV, and influenza increase.

Bacterial and Viral Identification Rate in Acute Exacerbation of Chronic Obstructive Pulmonary Disease in Korea

PURPOSE: The most common cause of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is respiratory infection. Most studies of bacterial or viral cause in AECOPD have been conducted in Western countries. We investigated bacterial and viral identification rates in AECOPD in Korea. MATERIALS AND METHODS: We reviewed and analyzed medical records of 736 cases of AECOPD at the Korea University Guro Hospital. We analyzed bacterial and viral identification rates and classified infections according to epidemiological factors, such as Global Initiative for Chronic Obstructive Lung Disease stage, mortality, and seasonal variation. RESULTS: The numbers of AECOPD events involving only bacterial identification, only viral identification, bacterial-viral co-identification, and no identification were 200 (27.2%), 159 (21.6%), 107 (14.5%), and 270 (36.7%), respectively. The most common infectious bacteria identified were Pseudomonas aeruginosa (13.0%), Streptococcus pneumoniae (11.4%), and Haemophilus influenzae (5.3%); the most common viruses identified were influenza virus (12.4%), rhinovirus (9.4%), parainfluenza virus (5.2%), and metapneumovirus (4.9%). The bacterial identification rate tended to be higher at more advanced stages of chronic obstructive pulmonary disease (p=0.020 overall, p=0.011 for P. aeruginosa, p=0.048 for S. pneumoniae). Staphylococcus aureus and Klebsiella pneumoniae were identified more in mortality group (p=0.003 for S. aureus, p=0.009 for K. pneumoniae). All viruses were seasonal (i.e., greater prevalence in a particular season; p < 0.050). Influenza virus and rhinovirus were mainly identified in the winter, parainfluenza virus in the summer, and metapneumovirus in the spring. CONCLUSION: This information on the epidemiology of respiratory infections in AECOPD will improve the management of AECOPD using antibiotics and other treatments in Korea.

Human metapneumovirus in Southern Brazil

INTRODUCTION Infections caused by respiratory viruses are important problems worldwide, especially in children. Human metapneumovirus (hMPV) is a respiratory pathogen and causes severe infections with nonspecific symptoms. This study reports the hMPV occurrence and dissemination in southern Brazil and compares the frequency of occurrence of this virus and the human respiratory syncytial virus (hRSV) in the epidemiological weeks in a three-year period (2009-2011). METHODS: In total, 545 nasopharyngeal (NP) specimens from individuals with Severe Acute Respiratory Syndrome (SARS) who were negative for other seven respiratory viruses were analyzed for the presence of hMPV. Human metapneumovirus was detected by direct immunofluorescence and real-time reverse transcription polymerase chain reaction. RESULTS: hMPV was detected in 109 patients from the main geographic regions of the southernmost state of Brazil, presenting similar overall prevalence in males (46.8%) and females (53.2%). Among children who were less than six years old, hMPV was detected in 99 samples of all age groups, with a higher frequency in infants who were less than one year old (45.7%) compared to all other age groups until six years. hMPV and hRSV infection occurred in almost the same epidemiological weeks (EWs) of each year, with peaks of incidence between EW 31/37 and EW 26/38 for the years 2009 and 2011, respectively. hMPV was further detected in several cases of SARS and it was the only virus detected in three deaths. CONCLUSIONS These findings indicate that hMPV is in circulation in southern Brazil and highlight the importance of diagnosing hMPV for influenza-like illness in the population. (AU)

Distribution and Characterization of Airborne Respiratory Pathogens in Public Facilities

Respiratory infections, which are caused by airborne pathogens, are the most common disease of all ages worldwide. This study was conducted to characterize the airborne respiratory pathogens in the public facilities in Busan, South Korea. A total of 260 public facilities were investigated in 2017, 52 seasonal indoor air from 2 hospitals and 208 indoor air samples from 208 randomly selected daycare centers. Among respiratory pathogen, 8 viral pathogens including human adenovirus (HAdV), human bocavirus (HBoV), human rhinovirus (HRV), human parainfluenza virus (HPIV), human respiratory syncytial virus (HRSV), human metapneumovirus (HMPV), human coronavirus (HCoV) and influenza virus (IFV), and 3 bacterial pathogens including Mycoplasma pneumoniae, Bordetella pertussis, and Chlamydophila pneumoniae, were investigated by multiplex real-time reverse transcription polymerase chain reaction. Pathogens were detected in 9 cases (3.4%). Among 9 positive samples, 6 (2.3%) cases were positive for HBoV and 3 (1.2%) cases were positive for IFV. All the positive cases were detected in daycare centers. Additionally, the concentration of HBoV was determined. In HBoV-positive samples, the cycle threshold (Ct) values of HBoV were 29.73~36.84, which are corresponding to the viral concentration of 4.91 × 10⁰ ~ 9.57 × 10² copies/ml. Serotype distribution of isolated HBoV was analyzed by sequencing of VP1/VP2 gene. All of the HBoV isolates were identified as HBoV type 1 with a high similarity among the isolates (>97%). No bacterial pathogen was identified in indoor air samples. Although virus concentration was not high in public facilities (daycare center), the presence of respiratory viral pathogens has been identified. Effective ventilation and air purification strategies are needed to reduce the indoor concentration of respiratory pathogens. A long-term and ongoing surveillance plan for respiratory pathogen management should be established.

Bronchiolitis severity according to the infected viruses

PURPOSE: The aim of this study was to evaluate the severity of disease in children with acute bronchiolitis according to the type of infected virus. METHODS: From November 2007 to May 2015, 768 patients under 2 years of age who underwent real time-polymerase chain reaction of nasopharyngeal aspirates admitted to the Department of Pediatrics of Dongguk University Ilsan Hospital for acute bronchiolitis were enrolled. Severe bronchiolitis was defined as presence of one or more kinds among tachypnea, chest retraction, needs of O2 inhalation or ventilator care. RESULTS: The severity of bronchiolitis was increased with shorter fever duration (P < 0.001) and previous wheezing episodes (P = 0.005). In the case of single infection, respiratory syncytial virus (RSV) A only increased the severity of acute bronchiolitis (P = 0.012). However, the severity of illness decreased when RSV A coinfected with adenovirus (P = 0.034), human rhinovirus (P = 0.038), or human coronavirus NL63 (P = 0.042). On the other hand, when human rhinovirus was coinfected with enterovirus (P = 0.013) or parainfluenza 3 (P = 0.019), the severity was increased. When human metapneumovirus coinfected with human bocavirus, the severity was increased (P = 0.038). CONCLUSION: Acute bronchiolitis was associated with increased severity only when RSV A infected solely, but several viruses increased or decreased the severity when coinfection occurred. Therefore, it may be helpful in predicting the course of the acute bronchiolitis according to the affected virus.

Clinical presentation of croup in children according to causative viruses

PURPOSE: We evaluated the clinical features of croup in children according to viral etiology. METHODS: This study enrolled pediatric patients with croup, who showed positive results on respiratory virus reverse transcriptase polymerase chain reaction performed between January 2012 and December 2017. We retrospectively reviewed the medical records. RESULTS: A total of 179 patients (119 boys and 60 girls) were enrolled with the mean age of 18.9±14.7 months. The viruses commonly identified were parainfluenza, respiratory syncytial virus, rhinovirus, and influenza. Among these 4 viruses, patients with rhinovirus infection showed significantly shorter fever and admission durations. Patients with parainfluenza infection showed significantly lower incidences of epinephrine nebulization and patients with influenza infections showed significantly higher incidences of steroid treatment. CONCLUSION: Clinical manifestations of croup differ according to causative viruses. Further studies should be conducted to evaluate the severity and prognosis of croup according to viral etiology.

Clinical Course of Neutropenia in Previously Healthy Children / 임상소아혈액종양

BACKGROUND: Neutropenia can be easily found in previously healthy children associated with various medical conditions, and the clinical course ranges from transient benign to life threatening. This study aimed to investigate the etiology, clinical characteristics, and clinical courses of neutropenia in previously healthy children. METHODS: We evaluated 215 previously healthy children under aged 18 years who diagnosed with neutropenia in two hospitals. Clinical and laboratory features were analyzed retrospectively based on the medical records. RESULTS: Transient infectious neutropenia (TIN) accounted for 97.7% of cases and chronic neutropenia (CN), for 2.3%. An infectious agent was identified in 128/210 (61%) patients with TIN, and the most frequent agents were viruses (46.5%). The most common viral agent was respiratory syncytial virus (RSV) (29%). TIN subgroups exhibited no differences in severity according to infectious agent (virus, bacteria, Mycoplasma); however, neutropenia severity differed among viral agents [mild-to-moderate neutropenia in the RSV group (857.3±293.3/µL) and moderate-to-severe neutropenia in the parainfluenza group (567.3±198.1/µL); P=0.017]. All patients with CN had anti-neutrophil antibody positivity (autoimmune neutropenia, AIN), and moderate-to-severe neutropenia predominated. The median duration of TIN was 8 days (range, 3–286 days), and it was significantly longer for AIN at 330 days (range, 217–730 days) (P=0.000). The median duration of neutropenia was also different according to each viral agent, with 4 days (range, 3–11 days) for the RSV group and longer durations for 3 other groups (influenza, parainfluenza, other respiratory viruses) (P=0.015). CONCLUSION: Neutropenia in previously healthy children is usually of transient infectious origin, with mild-to-moderate severity, and it resolves spontaneously without complications.

Serosurvey of Avian metapneumovirus, Orithobacterium rhinotracheale, and Chlamydia psittaci and Their Potential Association with Avian Airsacculitis / 生物医学与环境科学（英文）

Seasonal outbreaks of airsacculitis in China's poultry cause great economic losses annually. This study tried to unveil the potential role of Avian metapneumovirus (AMPV), Ornithobacterium rhinotracheale (ORT) and Chlamydia psittaci (CPS) in avian airsacculitis. A serological investigation of 673 breeder chickens and a case-controlled study of 430 birds were undertaken. Results showed that infection with AMPV, ORT, and CPS was highly associated with the disease. The correlation between AMPV and CPS were positively robust in both layers and broilers. Finally, we determined the co-infection with AMPV, ORT, and CPS was prevalent in the sampled poultry farms suffering from respiratory diseases and the outbreak of airsacculitis was closely related to simultaneous exposure to all three agents.

Epidemiology and Clinical Characteristics of Parainfluenza Virus Type 4 in Korean Children: a Single Center Study, 2015–2017

PURPOSE: We aimed to identify the epidemiology and the clinical characteristics of human parainfluenza virus type 4 (HPIV-4) infection compared to HPIVs 1–3 infections in Korean children. METHODS: We reviewed medical records of children with HPIV infection who visited Seoul National University Children's Hospital from 2015 to 2017. Detection of respiratory viruses was performed using real time-polymerase chain reaction (rt-PCR), which could differentiate HPIVs 1–4. Diagnosis was classified as a febrile illness, upper respiratory tract infection (URI), croup, bronchiolitis, or pneumonia. The epidemiology, demographic features, and clinical characteristics among HPIV types were compared. The clinical data were analyzed only for the previously healthy children. RESULTS: Of the 472 children diagnosed with HPIV infection, 108 (22.9%) were previously healthy: 24 (22.2%), 19 (17.6%), 39 (36.1%), and 26 (24.1%) in HPIV types 1, 2, 3, and 4, respectively. The median age of children with HPIV-4 infection was 11 (0–195) months: the proportion of children aged 0.05). CONCLUSIONS: We observed seasonal peak of HPIV-4 infection in 2015 and 2017. HPIV-4 was a common respiratory pathogen causing lower respiratory tract infection in hospitalized children.

Epidemiology and Clinical Severity of the Hospitalized Children with Viral Croup

PURPOSE: In this study, the clinical and epidemiological characteristics of patients admitted for viral croup were analyzed to evaluate disease severity based on the organism that caused the infection. METHODS: We retrospectively reviewed the medical records of 302 patients who were admitted to the Department of Pediatrics at the Wonju Severance Hospital between May 2013 and December 2016 for viral croup. Patients who showed positive results on multiplex polymerase chain reaction were subsequently diagnosed with respiratory virus infection. The Westley scoring system was used to evaluate the severity of viral croup. RESULTS: Of the 302 patients, 149 were admitted due to severe viral croup, including 88 boys and 61 girls, with a boy-to-girl ratio of 1.44:1. About 110 cases of parainfluenza virus infection have been reported, which accounted for almost half of the total cases. The other identified viruses included influenza virus, human rhinovirus, and respiratory syncytial virus. Analysis of the association between severe viral croup and causative pathogen revealed that only parainfluenza type 2 virus showed a significantly high risk. Parainfluenza type 2 virus did not show an age-based difference in frequency but showed relatively a higher frequency of infections during the summer and fall. CONCLUSIONS: In this study, parainfluenza virus type 2 was the only virus associated with severe viral croup. To facilitate proper preventive management, treatment, and prognosis evaluation of viral croup, prospective and multicenter studies should assess the additional variables and the severity of the virus. Additionally, further studies should be conducted to assess age-dependent influences, as well as the regional and seasonal incidence of viral infection.

Clinical and laboratory profiles of hospitalized children with acute respiratory virus infection / 소아과

PURPOSE: Despite the availability of molecular methods, identification of the causative virus in children with acute respiratory infections (ARIs) has proven difficult as the same viruses are often detected in asymptomatic children. METHODS: Multiplex reverse transcription polymerase chain reaction assays were performed to detect 15 common respiratory viruses in children under 15 years of age who were hospitalized with ARI between January 2013 and December 2015. Viral epidemiology and clinical profiles of single virus infections were evaluated. RESULTS: Of 3,505 patients, viruses were identified in 2,424 (69.1%), with the assay revealing a single virus in 1,747 cases (49.8%). While major pathogens in single virus-positive cases differed according to age, human rhinovirus (hRV) was common in patients of all ages. Respiratory syncytial virus (RSV), influenza virus (IF), and human metapneumovirus (hMPV) were found to be seasonal pathogens, appearing from fall through winter and spring, whereas hRV and adenovirus (AdV) were detected in every season. Patients with ARIs caused by RSV and hRV were frequently afebrile and more commonly had wheezing compared with patients with other viral ARIs. Neutrophil-dominant inflammation was observed in ARIs caused by IF, AdV, and hRV, whereas lymphocyte-dominant inflammation was observed with RSV A, parainfluenza virus, and hMPV. Monocytosis was common with RSV and AdV, whereas eosinophilia was observed with hRV. CONCLUSION: In combination with viral identification, recognition of virus-specific clinical and laboratory patterns will expand our understanding of the epidemiology of viral ARIs and help us to establish more efficient therapeutic and preventive strategies.

Innate Immune Response to Viral Infections in Primary Bronchial Epithelial Cells is Modified by the Atopic Status of Asthmatic Patients

PURPOSE: In order to gain an insight into determinants of reported variability in immune responses to respiratory viruses in human bronchial epithelial cells (HBECs) from asthmatics, the responses of HBEC to viral infections were evaluated in HBECs from phenotypically heterogeneous groups of asthmatics and in healthy controls. METHODS: HBECs were obtained during bronchoscopy from 10 patients with asthma (6 atopic and 4 non-atopic) and from healthy controls (n=9) and grown as undifferentiated cultures. HBECs were infected with parainfluenza virus (PIV)-3 (MOI 0.1) and rhinovirus (RV)-1B (MOI 0.1), or treated with medium alone. The cell supernatants were harvested at 8, 24, and 48 hours. IFN-α, CXCL10 (IP-10), and RANTES (CCL5) were analyzed by using Cytometric Bead Array (CBA), and interferon (IFN)-β and IFN-λ1 by ELISA. Gene expression of IFNs, chemokines, and IFN-regulatory factors (IRF-3 and IRF-7) was determined by using quantitative PCR. RESULTS: PIV3 and RV1B infections increased IFN-λ1 mRNA expression in HBECs from asthmatics and healthy controls to a similar extent, and virus-induced IFN-λ1 expression correlated positively with IRF-7 expression. Following PIV3 infection, IP-10 protein release and mRNA expression were significantly higher in asthmatics compared to healthy controls (median 36.03-fold). No differences in the release or expression of RANTES, IFN-λ1 protein and mRNA, or IFN-α and IFN-β mRNA between asthmatics and healthy controls were observed. However, when asthmatics were divided according to their atopic status, HBECs from atopic asthmatics (n=6) generated significantly more IFN-λ1 protein and demonstrated higher IFN-α, IFN-β, and IRF-7 mRNA expressions in response to PIV3 compared to non-atopic asthmatics (n=4) and healthy controls (n=9). In response to RV1B infection, IFN-β mRNA expression was lower (12.39-fold at 24 hours and 19.37-fold at 48 hours) in non-atopic asthmatics compared to atopic asthmatics. CONCLUSIONS: The immune response of HBECs to virus infections may not be deficient in asthmatics, but seems to be modified by atopic status.