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.
Child ; Coronavirus ; Croup ; Demography ; Electronic Health Records ; Hospitalization ; Humans ; Korea ; Male ; Mycoplasma ; Paramyxoviridae Infections ; Polymerase Chain Reaction ; Respiratory Syncytial Viruses ; Retrospective Studies ; Reverse Transcription ; Rhinovirus ; Seasons

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.
Adenoviridae ; Air Pollution ; Coronavirus ; Dust ; Human bocavirus ; Humans ; Humidity ; Incidence ; Influenza, Human ; Metapneumovirus ; Meteorological Concepts ; Orthomyxoviridae ; Paramyxoviridae Infections ; Particulate Matter ; Republic of Korea ; Respiration Disorders ; Respiratory Syncytial Viruses ; Respiratory Tract Infections ; Rhinovirus ; Wind

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.
Anti-Bacterial Agents ; Bacteria ; Epidemiology ; Haemophilus influenzae ; Klebsiella pneumoniae ; Korea ; Medical Records ; Metapneumovirus ; Mortality ; Orthomyxoviridae ; Paramyxoviridae Infections ; Prevalence ; Pseudomonas aeruginosa ; Pulmonary Disease, Chronic Obstructive ; Respiratory Tract Infections ; Rhinovirus ; Seasons ; Staphylococcus aureus ; Streptococcus pneumoniae

OBJECTIVE: To study the expression of interferon-λ1 (IFN-λ1) in respiratory epithelial cells in children with human rhinovirus (HRV) infection. METHODS: Sputum samples and nasopharyngeal swabs were collected from the children who were hospitalized due to acute respiratory infection from February to October, 2017. Bacterial culture was performed, and nucleic acid test was performed for 11 respiratory pathogens. A total of 90 children with positive HRV alone were enrolled as the HRV infection group, and 95 children with positive respiratory syncytial virus (RSV) alone were enrolled as the RSV infection group. A total of 50 healthy children who underwent outpatient physical examination during the same period of time and had negative results for all pathogen tests were enrolled as the healthy control group. Nasopharyngeal swabs were collected from all groups, and quantitative real-time PCR was used to measure viral load and the mRNA expression of IFN-λ1. RESULTS: In the HRV infection group, there was no significant difference in the mRNA expression of IFN-λ1 between boys and girls and across all age groups (P>0.05). In the HRV infection group, there was no correlation between the mRNA expression of IFN-λ1 and HRV load (P>0.05). The mRNA expression of IFN-λ1 in the HRV infection group was significantly higher than that in the healthy control group (P<0.05), but significantly lower than that in the RSV infection group (P<0.05). CONCLUSIONS HRV can induce the expression of IFN-λ1 in respiratory epithelial cells, suggesting that IFN-λ1 may play an important role in anti-HRV infection in children.
Antiviral Agents ; Child ; Epithelial Cells ; Female ; Humans ; Interferons ; Male ; Picornaviridae Infections ; Respiratory Tract Infections ; Rhinovirus

OBJECTIVE: Viral infections are being identified increasingly in patients with pneumonia and can be fatal, particularly in immune-compromised patients. This study examined the seasonal trend and mortality in adult patients with viral pneumonia. METHODS: Retrospective data of adult patients who visited the emergency room and were diagnosed with viral pneumonia was collected between January 2012 and December 2015 at a tertiary referral center. The monthly incidence of each viral pathogen and in-hospital mortality were analyzed. RESULTS: A total of 1,179 patients were analyzed. The mean age was 66.0 years and male comprised 60.0% of cases. Multiple viral infections and viral-bacterial co-infection were found in 5.2% and 24.7% of patients, respectively. The underlying diseases were as follows: diabetes mellitus in 32.8%, malignancy in 30.3%, and chronic lung disease in 30.9%. In-hospital mortality occurred in 7.9% of the total patients. Rhinovirus was the most common viral pathogen throughout the year. Influenza A was the most common from January to March and rhinovirus was the most common from September to November. Among the viral pathogens, a coronavirus infection resulted in the highest mortality of 12.6% but there was no significant difference in mortality among the viral pathogens. Multivariate analysis for in-hospital mortality revealed a viral-bacterial co-infection (odds ratio [OR], 1.46; 95% confidence interval [CI], 1.02–2.34), malignancy (OR, 2.34; 95% CI, 1.48–3.71), C-reactive protein (CRP; OR, 1.04; 95% CI, 1.02–1.07), CURB-65 score 2 (OR, 2.46; 95% CI, 1.47–4.12), and CURB-65 score ≥3 (OR, 4.60; 95% CI, 2.31–9.16) to be significantly associated with mortality. CONCLUSION: The outcome from viral pneumonia was poor in adult patients. A viral-bacterial co-infection, malignancy, elevated CRP, and CURB-65 score were significant predictors of mortality.
Adult ; C-Reactive Protein ; Coinfection ; Coronavirus Infections ; Diabetes Mellitus ; Emergency Service, Hospital ; Hospital Mortality ; Humans ; Incidence ; Influenza, Human ; Lung Diseases ; Male ; Mortality ; Multivariate Analysis ; Pneumonia ; Pneumonia, Viral ; Retrospective Studies ; Rhinovirus ; Risk Factors ; Seasons ; Tertiary Care Centers

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.
Adenoviridae ; Enterovirus ; Humans ; Limit of Detection ; Paramyxoviridae Infections ; Respiratory Tract Infections* ; Rhinovirus ; Seoul

PURPOSE: Respiratory syncytial virus (RSV) and human rhinovirus (hRV) are the most common causes of child respiratory viral infections. We aimed to investigate epidemiological and clinical characteristics of RSV and hRV single infections and coinfections. METHODS: Nasopharyngeal aspirates of hospitalized children aged <5 years were tested using multiplex reverse transcription polymerase chain reaction (RT-PCR) from October 2014 to April 2017. Their medical records were retrospectively reviewed. RESULTS: RSV or hRV was detected in 384 patients who divided into 3 groups: patients with RSV (R group, n=258); patients with hRV (H group, n=99); and patients with both (RH group, n=27). The R group (median age, 6 months) consisted of 248 (96.1%) patients with lower respiratory tract infection (LRTI), and 14 (5.4%) needed oxygen inhalation. Infants aged <12 months (63.2%) had respiratory difficulty and were supplied oxygen more often. The H group (median age, 16 months) consisted of 56 (56.6%) patients with LRTI, 4 (4%) required oxygen inhalation, and 1 (1.0%) required mechanical ventilation. Infants (40.4%) showed longer hospitalization compared to patients aged ≥12 months (5 vs. 4 days, P<0.05). The RH group consisted of 24 (88.9%) patients with LRTI, and 2 (7.4%) needed oxygen inhalation. Hospitalization days and oxygen inhalation and mechanical ventilation rates did not differ between single infections (R and H groups) and coinfections (RH group). CONCLUSIONS: RSV was detected more often in younger patients and showed higher LRTI rates compared to hRV. Single infections and coinfections of RSV and hRV showed no difference in severity.
Child ; Child, Hospitalized ; Coinfection ; Epidemiology ; Hospitalization ; Humans ; Infant ; Inhalation ; Korea ; Medical Records ; Multiplex Polymerase Chain Reaction ; Oxygen ; Polymerase Chain Reaction ; Respiration, Artificial ; Respiratory Syncytial Viruses ; Respiratory Tract Infections ; Retrospective Studies ; Reverse Transcription ; Rhinovirus

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.
Adenoviridae ; Bronchiolitis ; Child ; Coinfection ; Coronavirus NL63, Human ; Enterovirus ; Fever ; Hand ; Human bocavirus ; Humans ; Infant ; Inhalation ; Metapneumovirus ; Paramyxoviridae Infections ; Pediatrics ; Respiratory Sounds ; Respiratory Syncytial Viruses ; Rhinovirus ; Tachypnea ; Thorax ; Ventilators, Mechanical

Ecthyma gangrenosum (EG) is a rare skin manifestation which starts with a maculopapular eruption and followed by a necrotic ulcer covered with black eschar. EG usually occurs in immunosuppressed patients with Pseudomonas aeruginosa sepsis. We present a previously healthy 12-month-old girl with EG by P. aeruginosa and agranulocytosis due to influenza A and then rhinovirus infection, without bacteremia. It is important for allergists to culture wound and differentiate EG from other skin disorders including Tsutsugamushi disease and initiate appropriate empiric antipseudomonal antibiotic treatment, and to evaluate for possible immunodeficiency, even in a healthy child.
Agranulocytosis* ; Bacteremia ; Child ; Ecthyma* ; Female* ; Humans ; Infant* ; Influenza, Human ; Pseudomonas aeruginosa ; Rhinovirus ; Scrub Typhus ; Sepsis ; Skin ; Skin Manifestations ; Ulcer ; Wounds and Injuries

PURPOSE: Lower respiratory tract infection (LRTI) is one of the most common causes of hospitalization in the pediatric population. In this study, we investigated the clinical characteristics of LRTI, particularly in low birth weight children. METHODS: We reviewed medical records of children at ages 0–6 years with LRTI in Korea University Anam Hospital between January and December of 2014. Clinical data including age, sex, birth history, viral pathogens, blood test results, and clinical courses were collected. RESULTS: In the 828 eligible cases, 617 (74.5%) were pneumonia and followed by bronchiolitis 180 (21.7%) and bronchitis 31 (3.7%). The median age of the subjects was 17 months (interquartile range [IQR], 7–28 months), the median gestational age was 39.0 weeks (IQR, 38.0–40.0 weeks) and the median birth weight was 3,200 g (IQR, 2,900–3,480 g). Sixty-four children (7.7%) were low birth weight (< 2,500 g) and their median gestational age and birth weight were 33.0 weeks (IQR, 30.0–36.0 weeks) and 2,045 g (IQR, 1,565–2,300 g), respectively. The rates of oxygen supplement (17.2% vs. 4.6%, P < 0.001) and systemic steroid use (20.3% vs. 4.7%, P < 0.001) were significantly higher in low birth weight children than normal birth weight children. Respiratory viruses were identified in 82.6% (519 of 628 subjects); RSV was detected in 240 subjects (38.2%), followed by rhinovirus 168 (26.8%) and adenoviruses 75 (11.9%). The distribution of respiratory viruses was not different between normal birth weight children and low birth weight children. CONCLUSION: Low birth weight children show more severe clinical manifestations than normal birth weight children during hospitalization for LRTI, although respiratory viral pathogens were not different. Clinicians should be aware that the severity may be increased when low birth weight children were hospitalized due to low respiratory tract infection.
Adenoviridae ; Birth Weight ; Bronchiolitis ; Bronchitis ; Child* ; Gestational Age ; Hematologic Tests ; Hospitalization ; Humans ; Infant, Low Birth Weight* ; Infant, Newborn ; Korea ; Medical Records ; Oxygen ; Pneumonia ; Reproductive History ; Respiratory System* ; Respiratory Tract Infections* ; Rhinovirus