Human Coronavirus NL63 Infection Research Articles

The Impact of Physiotherapy on Motor Function in a Child Recovering from Human Coronavirus NL63: A Case Report

Backgrounds: This case report aims to investigate potential neurological complications in children following Human Coronavirus NL63 (HCoV-NL63) infection and evaluate the effectiveness of 12-week physiotherapy intervention in improving motor function in this child. Methods: This case study examines a four-year-old male patient with multiple health dysfunctions following an HCoV-NL63 infection. A 12-week rehabilitation program including whole body vibration, lower extremities strengthening exercise, stairs climbing, balance exercise, and obstacles course was performed. The evaluation included the Pediatric Balance Scale (PBS), the Denver Developmental Screening Test (DDST), and the 10-Meter Walking Test (10MWT) to assess motor abilities and walking speed. Results: The participant demonstrated clinically meaningful improvement in motor function. The PBS score increased from 33 at baseline to 49 at 12 weeks. Walking speed increased from 0.56 meters/second at baseline to 1.43 meters/second. The DDST revealed improvement in fine motor skills such as copying a circle and drawing a person with three body parts Conclusions: This case report demonstrates that a 12-week physiotherapy program can lead to substantial improvements in motor function, including balance and walking speed, in a child with developmental delays following a severe HCoV-NL63 infection. However, the study also highlights the broader neurological and developmental populations. While respiratory symptoms are typically the focus of HCoV-NL63 treatment, this case report suggests that clinician should also consider potential long-term neurological effects, especially in severe cases. The child’s history of seizures and global developmental delay points to the need for more research into the virus’s impact on brain function and development.

Developing a mouse model of human coronavirus NL63 infection: comparison with rhinovirus-A1B and effects of prior rhinovirus infection.

Human coronavirus (HCoV)-NL63 causes respiratory tract infections in humans and uses angiotensin-converting enzyme 2 (ACE2) as a receptor. We sought to establish a mouse model of HCoV-NL63 and determine whether prior rhinovirus (RV)-A1B infection affected HCoV-NL63 replication. HCoV-NL63 was propagated in LLC-MK2 cells expressing human ACE2. RV-A1B was grown in HeLa-H1 cells. C57BL6/J or transgenic mice expressing human ACE2 were infected intranasally with sham LLC-MK2 cell supernatant or 1 × 105 tissue culture infectious dose (TCID50) units HCoV-NL63. Wild-type mice were infected with 1 × 106 plaque-forming units (PFU) RV-A1B. Lungs were assessed for vRNA, bronchoalveolar lavage (BAL) cells, histology, HCoV-NL63 nonstructural protein 3 (nsp3), and host gene expression by next-generation sequencing and qPCR. To evaluate sequential infections, mice were infected with RV-A1B followed by HCoV-NL63 infection 4 days later. We report that hACE2 mice infected with HCoV-NL63 showed evidence of replicative infection with increased levels of vRNA, BAL neutrophils and lymphocytes, peribronchial and perivascular infiltrates, and expression of nsp3. Viral replication peaked 3 days after infection and inflammation persisted 6 days after infection. HCoV-NL63-infected hACE2 mice showed increased mRNA expression of IFNs, IFN-stimulated proteins, and proinflammatory cytokines. Infection with RV-A1B 4 days before HCoV-NL63 significantly decreased both HCoV-NL63 vRNA levels and airway inflammation. Mice infected with RV-A1B prior to HCoV-NL63 showed increased expression of antiviral proteins compared with sham-treated mice. In conclusion, we established a mouse model of HCoV-NL63 replicative infection characterized by relatively persistent viral replication and inflammation. Prior infection with RV-A1B reduced HCoV-NL63 replication and airway inflammation, indicative of viral interference.NEW & NOTEWORTHY We describe a mouse model of human coronavirus (HCoV) infection. Infection of transgenic mice expressing human angiotensin-converting enzyme 2 (ACE2) with HCoV-NL63 produced a replicative infection with peribronchial inflammation and nonstructural protein 3 expression. Mice infected with RV-A1B 4 days before HCoV-NL63 showed decreased HCoV-NL63 replication and airway inflammation and increased expression of antiviral proteins compared with sham-treated mice. This research may shed light on human coronavirus infections, viral interference, and viral-induced asthma exacerbations.

Comparative assessment of favipiravir and remdesivir against human coronavirus NL63 in molecular docking and cell culture models

Human coronavirus NL63 (HCoV-NL63) mainly affects young children and immunocompromised patients, causing morbidity and mortality in a subset of patients. Since no specific treatment is available, this study aims to explore the anti-SARS-CoV-2 agents including favipiravir and remdesivir for treating HCoV-NL63 infection. We first successfully modelled the 3D structure of HCoV-NL63 RNA-dependent RNA polymerase (RdRp) based on the experimentally solved SARS-CoV-2 RdRp structure. Molecular docking indicated that favipiravir has similar binding affinities to SARS-CoV-2 and HCoV-NL63 RdRp with LibDock scores of 75 and 74, respectively. The LibDock scores of remdesivir to SARS-CoV-2 and HCoV-NL63 were 135 and 151, suggesting that remdesivir may have a higher affinity to HCoV-NL63 compared to SARS-CoV-2 RdRp. In cell culture models infected with HCoV-NL63, both favipiravir and remdesivir significantly inhibited viral replication and production of infectious viruses. Overall, remdesivir compared to favipiravir is more potent in inhibiting HCoV-NL63 in cell culture. Importantly, there is no evidence of resistance development upon long-term exposure to remdesivir. Furthermore, combining favipiravir or remdesivir with the clinically used antiviral cytokine interferon-alpha resulted in synergistic effects. These findings provided a proof-of-concept that anti-SARS-CoV-2 drugs, in particular remdesivir, have the potential to be repurposed for treating HCoV-NL63 infection.

Crystal structures of human coronavirus NL63 main protease at different pH values.

Human coronavirus NL63 (HCoV-NL63), which belongs to the genus Alphacoronavirus, mainly infects children and the immunocompromized and is responsible for a series of clinical manifestations, including cough, fever, rhinorrhoea, bronchiolitis and croup. HCoV-NL63, which was first isolated from a seven-month-old child in 2004, has led to infections worldwide and accounts for 10% of all respiratory illnesses caused by etiological agents. However, effective antivirals against HCoV-NL63 infection are currently unavailable. The HCoV-NL63 main protease (Mpro), also called 3C-like protease (3CLpro), plays a vital role in mediating viral replication and transcription by catalyzing the cleavage of replicase polyproteins (pp1a and pp1ab) into functional subunits. Moreover, Mpro is highly conserved among all coronaviruses, thus making it a prominent drug target for antiviral therapy. Here, four crystal structures of HCoV-NL63 Mpro in the apo form at different pH values are reported at resolutions of up to 1.78 Å. Comparison with Mpro from other human betacoronaviruses such as SARS-CoV-2 and SARS-CoV reveals common and distinct structural features in different genera and extends knowledge of the diversity, function and evolution of coronaviruses.

Potential Effect of Previous Human Coronavirus NL63 Infection on the Rate of Infection and the Clinical Course of Coronavirus Disease 2019.

Potential Effect of Previous Human Coronavirus NL63 Infection on the Rate of Infection and the Clinical Course of Coronavirus Disease 2019.

Study of respiratory viruses and their coinfection with bacterial and fungal pathogens in acute exacerbation of chronic obstructive pulmonary diseases.

Background:Patients with chronic obstructive pulmonary disease (COPD) develop acute exacerbations (AE), with varying natural history. The exacerbation is triggered by infection, leading to increased morbidity and mortality. The study on infectious aetiology of AECOPD is largely restricted to only viral or only bacterial aetiology. There are no studies from India that have investigated multiple viral, bacterial, and fungal associations from the same group of patients. This prospective study was conducted over 2 years to estimate the incidence and profile of viral infections in AECOPD patients, their coinfection with other bacterial and fungal agents, and association of the type and pattern of infective agent with the clinical severity.Materials and Methods:Seventy-four AECOPD cases were included in the study. Multiplex polymerase chain reaction was performed from nasopharyngeal swab using Fast Track Diagnostics Respiratory Pathogens 21 Plus Kit. Ziehl–Neelsen (ZN) stain, Modified ZN, and potassium hydroxide (KOH) mount were performed for Mycobacteria, Nocardia, and fungal elements. Bacterial cultures and fungal cultures were done as per the standard techniques. Serum samples were tested for Mycoplasma and Chlamydia pneumoniae immunoglobulin M enzyme-linked immunosorbent assay.Results:The number of AECOPD events involving only viral infection, only bacterial infection, bacterial–viral coinfection, and no infection were 43 (58.1%), 32 (43.2%), 20 (27%), and 19 (25.7%), respectively. Influenza A virus was the most common virus (22/43, 51%) identified. In 26 patients, monoviral infections were found, and in 17 patients, polyviral infections were identified, the most common pattern being influenza A and B virus, followed by human rhinovirus and human parainfluenza. The most common bacteria isolated were Pseudomonas aeruginosa (9/32,28%) followed by Acinetobacter baumanii and Klebsiella pneumoniae (7/32, 21%). Among the viral–bacterial coinfection, human coronavirus NL63 infection was always associated with a bacterial infection.Conclusion:This information on the various viral and bacterial etiologies of respiratory infections in AECOPD in this part of India will improve the understanding of the management of AECOPD using a timely institution of antivirals and reduce the overuse of antibiotics and the implementation of routine influenza vaccination.

Seasonality of Human Coronavirus OC43, NL63, HKU1, and 229E Infection in Yamagata, Japan, 2010-2019.

Seasonality of Human Coronavirus OC43, NL63, HKU1, and 229E Infection in Yamagata, Japan, 2010-2019.

Antiviral Action of Tryptanthrin Isolated from Strobilanthes cusia Leaf against Human Coronavirus NL63.

Strobilanthes cusia (Nees) Kuntze is a Chinese herbal medicine used in the treatment of respiratory virus infections. The methanol extract of S. cusia leaf contains chemical components such as β-sitosterol, indirubin, tryptanthrin, betulin, indigodole A, and indigodole B that have diverse biological activities. However, the antiviral action of S. cusia leaf and its components against human coronavirus remains to be elucidated. Human coronavirus NL63 infection is frequent among immunocompromised individuals, young children, and in the elderly. This study investigated the anti-Human coronavirus NL63 (HCoV-NL63) activity of the methanol extract of S. cusia leaf and its major components. The methanol extract of S. cusia leaf effectively inhibited the cytopathic effect (CPE) and virus yield (IC50 = 0.64 μg/mL) in HCoV-NL63-infected cells. Moreover, this extract potently inhibited the HCoV-NL63 infection in a concentration-dependent manner. Among the six components identified in the methanol extract of S. cusia leaf, tryptanthrin and indigodole B (5aR-ethyltryptanthrin) exhibited potent antiviral activity in reducing the CPE and progeny virus production. The IC50 values against virus yield were 1.52 μM and 2.60 μM for tryptanthrin and indigodole B, respectively. Different modes of time-of-addition/removal assay indicated that tryptanthrin prevented the early and late stages of HCoV-NL63 replication, particularly by blocking viral RNA genome synthesis and papain-like protease 2 activity. Notably, tryptanthrin (IC50 = 0.06 μM) and indigodole B (IC50 = 2.09 μM) exhibited strong virucidal activity as well. This study identified tryptanthrin as the key active component of S. cusia leaf methanol extract that acted against HCoV-NL63 in a cell-type independent manner. The results specify that tryptanthrin possesses antiviral potential against HCoV-NL63 infection.

Entry of Human Coronavirus NL63 into the Cell.

The first steps of human coronavirus NL63 (HCoV-NL63) infection were previously described. The virus binds to target cells by use of heparan sulfate proteoglycans and interacts with the ACE2 protein. Subsequent events, including virus internalization and trafficking, remain to be elucidated. In this study, we mapped the process of HCoV-NL63 entry into the LLC-Mk2 cell line and ex vivo three-dimensional (3D) tracheobronchial tissue. Using a variety of techniques, we have shown that HCoV-NL63 virions require endocytosis for successful entry into the LLC-MK2 cells, and interaction between the virus and the ACE2 molecule triggers recruitment of clathrin. Subsequent vesicle scission by dynamin results in virus internalization, and the newly formed vesicle passes the actin cortex, which requires active cytoskeleton rearrangement. Finally, acidification of the endosomal microenvironment is required for successful fusion and release of the viral genome into the cytoplasm. For 3D tracheobronchial tissue cultures, we also observed that the virus enters the cell by clathrin-mediated endocytosis, but we obtained results suggesting that this pathway may be bypassed.IMPORTANCE Available data on coronavirus entry frequently originate from studies employing immortalized cell lines or undifferentiated cells. Here, using the most advanced 3D tissue culture system mimicking the epithelium of conductive airways, we systematically mapped HCoV-NL63 entry into susceptible cells. The data obtained allow for a better understanding of the infection process and may support development of novel treatment strategies.

Structure of Main Protease from Human Coronavirus NL63: Insights for Wide Spectrum Anti-Coronavirus Drug Design.

First identified in The Netherlands in 2004, human coronavirus NL63 (HCoV-NL63) was found to cause worldwide infections. Patients infected by HCoV-NL63 are typically young children with upper and lower respiratory tract infection, presenting with symptoms including croup, bronchiolitis, and pneumonia. Unfortunately, there are currently no effective antiviral therapy to contain HCoV-NL63 infection. CoV genomes encode an integral viral component, main protease (Mpro), which is essential for viral replication through proteolytic processing of RNA replicase machinery. Due to the sequence and structural conservation among all CoVs, Mpro has been recognized as an attractive molecular target for rational anti-CoV drug design. Here we present the crystal structure of HCoV-NL63 Mpro in complex with a Michael acceptor inhibitor N3. Structural analysis, consistent with biochemical inhibition results, reveals the molecular mechanism of enzyme inhibition at the highly conservative substrate-recognition pocket. We show such molecular target remains unchanged across 30 clinical isolates of HCoV-NL63 strains. Through comparative study with Mpros from other human CoVs (including the deadly SARS-CoV and MERS-CoV) and their related zoonotic CoVs, our structure of HCoV-NL63 Mpro provides critical insight into rational development of wide spectrum antiviral therapeutics to treat infections caused by human CoVs.

Epidemiology of human coronavirus NL63 infection among hospitalized patients with pneumonia in Taiwan.

Background/PurposeHuman coronavirus (HCoV) NL63 is recognized in association with upper or lower respiratory tract illnesses in children. This study surveyed the prevalence of HCoV-NL63 and influenza viruses in patients with influenza-like illness in Taiwan during 2010–2011.MethodsThroat samples from 107 hospitalized patients with pneumonia and 175 outpatients with influenza-like illness were examined using real-time polymerase chain reaction assays with virus-specific primers, and then virus-positive specimens were confirmed by sequencing the polymerase chain reaction products.ResultsHCoV-NL63 infection was identified in 8.4% (9/107) of hospitalized patients with pneumonia, but not found in outpatients with influenza-like illness. Age distribution of HCoV-NL63 infection in hospitalized patients with pneumonia indicated that the group aged 16–25 years (20%) had the highest positive rate compared with the other groups, and exhibited a similar age-specific pattern to influenza A/H1N1 infection, but not influenza A/H3N2 and B infections in hospitalized patients. Seasonal prevalence of HCoV-NL63 infection was late winter, overlapping the highest peak of the influenza A/H1N1 epidemic during December 2010 to March 2011 in Taiwan. Co-infection of HCoV-NL63 and influenza A/H1N1 was detected in three hospitalized patients. Clinical manifestation analysis indicated that the main symptoms for HCoV-NL63 infection included fever (88.9%), cough (77.8%), and pneumonia (100%). Co-infection caused significantly higher rates of breathing difficulties, cough, and sore throat than those of single infection with HCoV-NL63 and influenza A/H1N1. Phylogenetic analysis indicated a low level of heterogeneity between Taiwan and global HCoV-NL63 strains.ConclusionUnderstanding epidemiology of HCoV-NL63 in Taiwan provides an insight for worldwide surveillance of HCoV-NL63 infection.

Human coronavirus NL63 utilizes heparan sulfate proteoglycans for attachment to target cells.

Human coronavirus NL63 (HCoV-NL63) is an alphacoronavirus that was first identified in 2004 in the nasopharyngeal aspirate from a 7-month-old patient with a respiratory tract infection. Previous studies showed that HCoV-NL63 and the genetically distant severe acute respiratory syndrome (SARS)-CoV employ the same receptor for host cell entry, angiotensin-converting enzyme 2 (ACE2), but it is largely unclear whether ACE2 interactions are sufficient to allow HCoV-NL63 binding to cells. The present study showed that directed expression of angiotensin-converting enzyme 2 (ACE2) on cells previously resistant to HCoV-NL63 renders them susceptible, showing that ACE2 protein acts as a functional receptor and that its expression is required for infection. However, comparative analysis showed that directed expression or selective scission of the ACE2 protein had no measurable effect on virus adhesion. In contrast, binding of HCoV-NL63 to heparan sulfates was required for viral attachment and infection of target cells, showing that these molecules serve as attachment receptors for HCoV-NL63. ACE2 protein was proposed as a receptor for HCoV-NL63 already in 2005, but an in-depth analysis of early events during virus infection had not been performed thus far. Here, we show that the ACE2 protein is required for viral entry but that it is not the primary binding site on the cell surface. Conducted research showed that heparan sulfate proteoglycans function as adhesion molecules, increasing the virus density on cell surface and possibly facilitating the interaction between HCoV-NL63 and its receptor. Obtained results show that the initial events during HCoV-NL63 infection are more complex than anticipated and that a newly described interaction may be essential for understanding the infection process and, possibly, also assist in drug design.

Characterization of Human Coronavirus OC43 and Human Coronavirus NL63 Infections Among Hospitalized Children <5 Years of Age

Multiplex molecular assays now make it possible for clinical laboratories to detect human coronaviruses (HCoVs). We investigated the clinical characteristics of HCoV-OC43 and HCoV-NL63 in patients <5 years of age during a recent coronavirus season. Respiratory viruses were detected using a multiplex molecular assay at St. Louis Children`s Hospital starting in November 2012. We analyzed demographic and clinical data from all patients <5 years of age with solo detection of HCoV-OC43 (n = 52) and HCoV-NL63 (n = 44) and for comparison, samples of children with respiratory syncytial virus, parainfluenza virus and picornaviruses. During the study period, HCoV-OC43 (4%) was the 5th and HCoV-NL63 the 8th (2%) most common respiratory virus. Coinfections were detected in 35% and 38% of children with HCoV-OC43 and HCoV-NL63, respectively. Croup was more common with HCoV-NL63 (30%) than with HCoV-OC43 (2%). Lower respiratory tract infection occurred in 33% of children with HCoV-OC43 and 25% of children with HCoV-NL63. Severe illness was less common in HCoV-NL63, HCoV-OC43 and parainfluenza virus (14%, each) compared with respiratory syncytial virus (30%) and picornaviruses (26%; P = 0.055 for HCoVs combined compared with the other respiratory viruses) and occurred mainly in those with underlying medical conditions. Infections caused by HCoV-OC43 and HCoV-NL63 are common and include some with lower respiratory tract involvement and severe disease, especially in children with underlying medical conditions. Overall, a substantial burden of disease associated with both HCoV-OC43 and HCoV-NL63 was observed for hospitalized children <5 years of age.

The dominance of human coronavirus OC43 and NL63 infections in infants

Background It is unknown to what extent the human coronaviruses (HCoVs) OC43, HKU1, 229E and NL63 infect healthy children. Frequencies of infections are only known for hospitalized children. Objectives Comparing infection frequencies in children who have mild infections with frequencies in children needing hospital uptake will determine whether infection by one of the four HCoVs leads to more severe disease. In addition, the sequence of seroconversions can reveal whether infection by one HCoV protects from infection by other HCoVs. Study design Two distinct study groups were monitored: healthy children and children hospitalized due to respiratory infection. HCoV natural infection rates in healthy children were obtained by serology in 25 newborns (followed 0–20 months). The frequencies of severe HCoVs infection was determined by real time RT-PCR among 1471 hospitalized infants (<2-years old) with acute respiratory tract disease. Results The majority of healthy children seroconverted for HCoV-OC43 ( n = 19) and HCoV-NL63 ( n = 17), less for HCoV-HKU1 ( n = 9) and HCoV-229E ( n = 5). Notably, HCoV-HKU1 seroconversion was absent after HCoV-OC43 infection. Also HCoV-229E infection was rarely observed after HCoV-NL63 infection (1 out of 5). In the hospital 207 (14%) out of 1471 children were HCoV positive. Again we observed most infection by HCoV-OC43 ( n = 85) and HCoV-NL63 ( n = 60), followed by HCoV-HKU1 ( n = 47) and HCoV-229E ( n = 15). Conclusions HCoV-NL63 and HCoV-OC43 infections occur frequently in early childhood, more often than HCoV-HKU1 or HCoV-229E infections. HCoV-OC43 and HCoV-NL63 may elicit immunity that protects from subsequent HCoV-HKU1 and HCoV-229E infection, respectively, which would explain why HCoV-OC43 and HCoV-NL63 are the most frequently infecting HCoVs. There are no indications that infection by one of the HCoVs is more pathogenic than others.

Human coronavirus NL-63 infection in a Brazilian patient suspected of H1N1 2009 influenza infection: Description of a fatal case

Human coronaviruses (HCoVs) cause upper respiratory tract and occasionally lower respiratory tract diseases. The recently described human coronavirus NL63 has not been well investigated among Brazilian patients. We reported the clinical course of an HCoV-NL63 infection in a hospitalised patient suspected of H1N1 2009 infection during the second pandemic wave of influenza activity. A 46-year-old female, health care worker with diabetes and presenting with influenza-like illness (ILI) was admitted to the hospital. During 9 days of influenza-like symptoms, the patient had diabetes decompensation, haemorrhagic pneumonia, rhabdomyolysis, respiratory and renal failure, pericarditis, and brain edema and died. HCoV-NL63 may be a causative agent of previously unexplained respiratory illnesses.

Human metapneumovirus and human coronavirus infection and pathogenicity in Saudi children hospitalized with acute respiratory illness

BACKGROUND AND OBJECTIVES:Human metapneumovirus (hMPV) and the Netherlands human coronavirus (HCoV-NL63) have been isolated from children with respiratory tract infection. The prevalence of these viruses has not been reported from Saudi Arabia. We sought to determine whether hMPV and HCoV-NL63 are responsible for acute respiratory illness and also to determine clinical features and severity of illness in the hospitalized pediatric patient population.DESIGN AND SETTING:Prospective hospital-based study from July 2007 to November 2008.PATIENTS AND METHODS:Nasopharyngeal specimens from children less than 16 years old who were suffering from acute respiratory diseases were tested for hMPV and HCoV-NL63 by reverse transcriptase–polymerase chain reaction. Samples were collected from July 2007 to November 2008.RESULTS:Both viruses were found among Saudi children with upper and lower respiratory tract diseases during the autumn and winter of 2007 and 2008, contributing to 11.1% of all viral diagnoses, with individual incidences of 8.3% (hMPV) and 2.8% (HCoV-NL63) among 489 specimens. Initial symptoms included fever, cough, and nasal congestion. Lower respiratory tract disease occurs in immunocompromised individuals and those with underlying conditions. Clinical findings of respiratory failure and culture-negative shock were established in 7 children infected with hMPV and having hematologic malignancies, myelofibrosis, Gaucher disease, and congenital immunodeficiency; 2 of the 7 patients died with acute respiratory failure. All children infected with HCoV-NL63 had underlying conditions; 1 of the 4 patients developed respiratory failure.CONCLUSION:hMPV and HCoV-NL63 are important causes of acute respiratory illness among hospitalized Saudi children. hMPV infection in the lower respiratory tract is associated with morbidity and mortality in immunocompromised children. HCoV-NL63 may cause severe lower respiratory disease with underlying conditions.

Infection with human coronavirus NL63 enhances streptococcal adherence to epithelial cells.

Understanding the mechanisms of augmented bacterial pathogenicity in post-viral infections is the first step in the development of an effective therapy. This study assessed the effect of human coronavirus NL63 (HCoV-NL63) on the adherence of bacterial pathogens associated with respiratory tract illnesses. It was shown that HCoV-NL63 infection resulted in an increased adherence of Streptococcus pneumoniae to virus-infected cell lines and fully differentiated primary human airway epithelium cultures. The enhanced binding of bacteria correlated with an increased expression level of the platelet-activating factor receptor (PAF-R), but detailed evaluation of the bacterium-PAF-R interaction revealed a limited relevance of this process.

Role of Human Coronavirus NL63 in Hospitalized Children With Croup

Background: Human coronavirus NL63 (HCoV-NL63) has recently been implicated as a common cause of croup in children. This study was performed to evaluate viruses associated with croup in children, with an emphasis on HCoV-NL63. Methods: Nasopharyngeal aspirates were prospectively collected from 182 children hospitalized with croup at Seoul National University Bundang Hospital from January 2005 to June 2009. Multiplex reverse-transcriptase polymerase chain reaction was conducted for detection of 11 respiratory viruses, and medical records were reviewed. Results: Viruses were identified in 147 (80.8%) of the 182 croup patients. The 3 most commonly detected viruses were parainfluenza virus type 1 (PIV1) in 44 (24.2%) patients, HCoV-NL63 in 30 (16.5%) patients, and influenza A virus in 25 (13.7%) patients. Other detected viruses were rhinovirus in 22 (12.1%) patients, PIV type 3 and respiratory syncytial virus in 15 (8.2%) patients, human bocavirus in 8 (4.4%) patients, and several others in a few patients. Coinfections with ≥2 viruses were found in 20 (11%) patients. HCoV-NL63 was identified primarily in winter, which coincides with the peak occurrence of croup. Patients with HCoV-NL63 infection were younger than those who were positive for PIV1 (median age 13 months versus 21 months, P = 0.006) and had shorter fever duration than influenza A virus infection (median 1.5 days versus 4 days, P = 0.000). Conclusions: PIV1 and HCoV-NL63 were most commonly associated with patients who were hospitalized with croup. HCoV-NL63 is prevalent in winter and is associated with younger age and with shorter fever duration.

The Pediatric Infectious Diseases Society Annual Awards, 2010

Human coronavirus NL63 (HCoV-NL63) has recently been implicated as a common cause of croup in children. This study was performed to evaluate viruses associated with croup in children, with an emphasis on HCoV-NL63. Nasopharyngeal aspirates were prospectively collected from 182 children hospitalized with croup at Seoul National University Bundang Hospital from January 2005 to June 2009. Multiplex reverse-transcriptase polymerase chain reaction was conducted for detection of 11 respiratory viruses, and medical records were reviewed. Viruses were identified in 147 (80.8%) of the 182 croup patients. The 3 most commonly detected viruses were parainfluenza virus type 1 (PIV1) in 44 (24.2%) patients, HCoV-NL63 in 30 (16.5%) patients, and influenza A virus in 25 (13.7%) patients. Other detected viruses were rhinovirus in 22 (12.1%) patients, PIV type 3 and respiratory syncytial virus in 15 (8.2%) patients, human bocavirus in 8 (4.4%) patients, and several others in a few patients. Coinfections with > or = 2 viruses were found in 20 (11%) patients. HCoV-NL63 was identified primarily in winter, which coincides with the peak occurrence of croup. Patients with HCoV-NL63 infection were younger than those who were positive for PIV1 (median age 13 months versus 21 months, P = 0.006) and had shorter fever duration than influenza A virus infection (median 1.5 days versus 4 days, P = 0.000). PIV1 and HCoV-NL63 were most commonly associated with patients who were hospitalized with croup. HCoV-NL63 is prevalent in winter and is associated with younger age and with shorter fever duration.

Burden of disease due to human coronavirus NL63 infections and periodicity of infection

Background The disease burden caused by recently identified respiratory viruses like HCoV-NL63 is unknown. Objectives We determined the burden of disease due to HCoV-NL63 infections using the population-based PRI.DE cohort of children under the age of 3 with lower respiratory tract infections (LRTIs). Study design In total 1756 respiratory samples, from hospitalized children or children who visited the outpatient clinic, were tested for HCoV-NL63. Sampling covered a period of 2 years and the frequency of infection in different years was compared to other Western European studies that tested for this virus in 2 or more consecutive years. Results Sixty-nine samples were HCoV-NL63 positive, 35 were with high loads, and of these 25 were single HCoV-NL63 infections. Based on the number of children with high HCoV-NL63 infection and no additional infection, the overall annual incidence in outpatients was 7 per 1000 children per year (95% confidence interval (CI) 3–13 per 1000 children per year), which can be extrapolated to an absolute number of 16,929 visits to the physician due to an HCoV-NL63 infection in Germany per year. The estimated hospitalization rate is 22 per 100,000 children (95% CI: 7–49 per 100,000 children per year). This number reflects 522 HCoV-NL63 children in Germany per year. A large year-to-year difference in HCoV-NL63 infection frequency was observed. Combining these data with those of other studies in Western Europe revealed that HCoV-NL63 infections follow a 2-year inter-epidemic period with peaks of infection in the winters of 2000/2001, 2002/2003 and 2004/2005 ( p < 0.0001). Conclusions HCoV-NL63 infection in children below 3 years of age often requires a visit to the physician in an outpatient clinic, especially during peak-years, but hospitalizations are relatively infrequent.