Ju-Young Chung

Detection of Human Bocavirus in Children Hospitalized because of Acute Gastroenteritis

Abstract The idea that human bocavirus (hBoV) infection possibly plays a role in gastroenteritis has been suggested because of the frequent manifestation of gastrointestinal symptoms. The purpose of this study was to investigate the prevalence of hBoV in children with gastroenteritis. We studied the etiologic agents in 962 children hospitalized with gastroenteritis. Viral etiologic agents were detected by enzyme-linked immunosorbent assay or reverse-transcriptase polymerase chain reaction. A viral agent was found in 44.4% of the study population: rotavirus, norovirus, adenovirus, and astrovirus were detected in 25.7%, 13.7%, 3.0%, and 1.1% of the study population, respectively; hBoV was detected in 0.8%, which suggests that it might play a minor role in gastroenteritis.

Bocavirus infection in hospitalized children, South Korea.

This study presents the first evidence of human bocavirus infection in South Korean children. The virus was detected in 27 (8.0%) of 336 tested specimens, including 17 (7.5%) of 225 virus-negative specimens, collected from children with acute lower respiratory tract infection.

WU Polyomavirus in Children with Acute Lower Respiratory Tract Infections, South Korea

In South Korea, WU polyomavirus (WUPyV) was detected in 34 (7%) of 486 children with acute lower respiratory tract infections, 3 (4.2%) of 72 asymptomatic children, and as coinfection with other respiratory viruses in 23 (67.6%) children. Although WUPyV was frequently detected, its clinical role has not been distinguished from that of coinfecting viruses.

Detection of viruses identified recently in children with acute wheezing

The etiologic role of recently identified respiratory viruses for acute wheezing in children is not yet clear. The purpose of this study was to investigate the prevalence of recently identified viruses, including human metapneumovirus (hMPV), human bocavirus (hBoV), human coronavirus NL63 (hCoV‐NL63), and human coronavirus HKU1 (hCoV‐HKU1) in children with acute wheezing. Viral etiology was identified in 231 children hospitalized with acute wheezing, aged from 1 month to 5 years. Viral antigens for common respiratory viruses were detected by IFA or multiplex PCR. RT‐PCR was used to detect respiratory rhinoviruses, hCoV‐NL63, hCoV‐HKU1, and hMPV. PCR assays for hBoV DNA were performed using the primer sets for noncapsid protein (NP1) and nonstructural protein (NS1) genes. Viruses were found in 61.5% (142/231) of the study population and a single virus was detected in 45.5% (105/231) of the study population. Rhinovirus (33.3%), human respiratory syncytial virus (hRSV; 13.8%), and hBoV (13.8%) were the most frequently detected viruses. hMPV and hCoV‐NL63 were detected in 7.8% and 1.3% of wheezing children, respectively. HCoV‐HKU1 was not detected. In 16.0% of the study population, more than one virus was detected. In children with acute wheezing, rhinovirus, hRSV, and hBoV were most frequently detected. Further studies including healthy control subjects are needed to define the clinical significance of hBoV in acute wheezing. J. Med. Virol. 79: 1238–1243, 2007.

Human Coronavirus-NL63 infections in Korean children, 2004–2006

Abstract Background Human coronavirus-NL63 (HCoV-NL63) has been isolated from children with respiratory tract infections and its prevalence in Korea has not been reported. Objectives This study was designed to investigate the presence and the clinical features of HCoV-NL63 during two winter seasons. Study design During April 2004–April 2006, nasopharyngeal specimens from children hospitalized with acute respiratory disease were tested for common respiratory viruses, including RSV, influenza A, influenza B, parainfluenza viruses, and adenovirus by IFA. hMPV infection was excluded by nested RT-PCR using primers for F-gene. To detect HCoV-NL63, previously described nested PCR assays for 1a and 1b were used. PCR products of the 1a gene for HCoV-NL63 were sequenced. Results Out of 872 nasopharyngeal aspirate from children aged under 16 years, 14 (1.7%) were positive for HCoV-NL63. Most of the patients had croup (64.2%) or bronchiolitis (21.4%). The peak prevalence was found in November (28.5%). Most were collected between November 2004 and February 2005. Conclusions HCoV-NL63 may be one of the causative agents of acute respiratory tract infection, especially croup.

Clinical and Epidemiological Comparison of Human Metapneumovirus and Respiratory Syncytial Virus in Seoul, Korea, 2003-2008

Human metapneumovirus (HMPV) shares clinical and epidemiological characteristics with well-known respiratory syncytial virus (RSV). The aim of this study was to investigate the clinical and epidemiological differences between HMPV- and RSV-induced wheezing illnesses. A total of 1,008 nasopharyngeal aspirate specimens was collected from 1,008 pediatric patients hospitalized with acute respiratory tract infection at Inje University Sanggye Paik Hospital from December 2003 to April 2008, and tested for seven common respiratory viruses. Conditions classified as wheezing illness were bronchiolitis, reactive airways disease, and bronchial asthma. HMPV caused a significantly lower proportion of wheezing illness when compared to RSV (48.1% vs. 82.2%, P<0.05). HMPV-induced wheezing illness occurred predominantly in older patients when compared to RSV patients (P<0.001). RSV infections peaked in the fall and winter followed by peaks of HMPV infection in winter and spring. Eosinophil counts were significantly higher (P<0.01) in RSV patients when compared to HMPV patients. These results show that human metapneumovirus patients exhibit several different clinical and epidemiological characteristics, such as higher proportion of wheezing illness, age and seasonal incidence, and eosinophil counts, when compared to RSV patients.

Detection of human rhinovirus C in children with acute lower respiratory tract infections in South Korea

Recently, HRV-C was identified as a new species of HRV, but its spectrum of clinical disease is still not clear. The purpose of this study was to investigate the molecular epidemiology of HRVs in children with acute lower respiratory tract infections (LRTIs). A total of 54 HRV-positive samples that were negative for other respiratory viruses were sequenced. HRV-A was detected in 33, HRV-B in 4, and HRV-C in 17 of these samples. All HRV-C-positive patients showed favorable clinical outcomes. We confirmed the presence of HRV-C in children with LRTIs, but its association with clinical severity is not clear.

Detection of GII-4/2006b Variant and Recombinant Noroviruses in Children With Acute Gastroenteritis, South Korea

Norovirus (NoV), a single‐stranded, positive RNA virus, is an important etiologic agent of acute gastroenteritis in children worldwide. In this study, a total of 434 fecal samples collected from 434 children with acute gastroenteritis in Seoul, between September 2007 and July 2008 were tested to determine the molecular epidemiology of NoVs and characterize recombinant strains by using RT‐PCR followed by sequencing. Of the 434 specimens, NoV, rotavirus, and adenovirus were detected in 155 (35.8%), 72 (16.6%), and 19 specimens (4.3%), respectively. NoV GI was detected in 7 specimens (1.6%) and GII in 148 (34.1%) specimens. Phylogenetic analysis of capsid sequences in the GII‐positive specimens revealed the presence of the following strains: GII‐4, 111 (75.0%); GII‐3, 35 cases (23.6%); GII‐6b, 1 case; and GII‐16, 1 case. Most of the GII‐4 strains were grouped with the GII‐4/2006b variant with 98–100% nucleotide identity. Eleven strains were identified as recombinant (GII‐4/GII‐3 in 10 cases and GII‐b polymerase/GII‐16 capsid in 1 case) by sequencing based on the RdRP and capsid genes. The putative recombination point in the recombinant strains was the ORF‐1/ORF2 overlap, located at nucleotide 5,046 with reference to Lordsdale. In conclusion, GII‐4/2006b variants were detected predominantly and a new recombinant strain (GII‐4/GII‐3) was found in the Korean children with gastroenteritis. Continuous monitoring of the genetic diversity of NoVs is important to determine the trend of the predominant genotype and new recombinant strain. J. Med. Virol. 82:146–152, 2010.

Detection of Human Bocavirus-2 in children with acute Gastroenteritis in South Korea

Human bocavirus (HBoV)-2, a new parvovirus, has been identified in stool samples and is suggested to be one of the etiologic agents of acute gastroenteritis (GE). The purpose of this study was to investigate the prevalence of HBoV-2 in children with GE. Stool samples were collected from 358 children hospitalized with GE. HBoV-2 was detected in 3.6% of the patients. HBoV-2 was co-detected with other viral agents in 53.8% of the patients. These findings suggest that HBoV-2 may be an etiologic agent in GE, but further studies are needed due to frequent co-detection with other enteric viruses.

Respiratory picornavirus infections in Korean children with lower respiratory tract infections

Recently, human rhinoviruses (RVs) and enteroviruses have been suggested as important etiological agents in young children with lower respiratory tract infections (LRTIs). We investigated the role of respiratory picornaviruses in hospitalized children with LRTI. A total of 233 nasopharyngeal samples were collected from hospitalized children with LRTIs from July 2004 to January 2006. All specimens were tested for the presence of human respiratory syncytial virus (hRSV), influenza virus A, influenza B, parainfluenzavirus, and adenovirus using direct immunofluorescent assay, and for human metapneumovirus (HMPV) by RT-PCR. Detection of RV was performed in nasopharyngeal samples by a RT-PCR assay that incorporated a BglI restriction enzyme digestion of the picornavirus RT-PCR amplicon, and detection of enterovirus was accomplished by hemi-nested RT-PCR using specific primers. Viral agents were detected in 70.4% (164/233) of the study population. The most frequently detected viruses were RV (64/233, 27.4%), hRSV (48/233, 20.6%), and enterovirus (43/233, 18.4%). Picornaviruses were detected as the sole viral agents in 27.0% (63/233) of children, whereas mixed viral infection was detected in 12.0%. These results suggest that picronavirus infection is an important etiological cause of LRTIs in Korean children.