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The prevalence of eight respiratory viruses detected in patients with acute respiratory infections (ARIs) in Korea was investigated through analysis of data recorded by the Korea Influenza and Respiratory Viruses Surveillance System (KINRESS) from 2013 to 2015. Nasal aspirate and throat swabs specimens were collected from 36 915 patients with ARIs, and viral nucleic acids were detected by real-time (reverse-transcription) polymerase chain reaction for eight respiratory viruses, including human respiratory syncytial viruses (HRSVs), influenza viruses (IFVs), human parainfluenza viruses (HPIVs), human coronaviruses (HCoVs), human rhinovirus (HRV), human adenovirus (HAdV), human bocavirus (HBoV), and human metapneumovirus (HMPV). The overall positive rate of patient specimens was 49.4% (18 236/36 915), 5% of which carried two or more viruses simultaneously. HRV (15.6%) was the most predominantly detected virus, followed by IFVs (14.6%), HAdV (7.5%), HPIVs (5.8%), HCoVs (4.2%), HRSVs (3.6%), HBoV (1.9%), and HMPV (1.6%). Most of the ARIs were significantly correlated with clinical symptoms of fever, cough, and runny nose. Although HRV and HAdV were frequently detected throughout the year in patients, other respiratory viruses showed apparent seasonality. HRSVs and IFVs were the major causative agents of acute respiratory diseases in infants and young children. Overall, this study demonstrates a meaningful relationship between viral infection and typical manifestations of known clinical features as well as seasonality, age distribution, and co-infection among respiratory viruses. Therefore, these data could provide useful information for public health management and to enhance patient care for primary clinicians.

Serological and virological studies were carried out of a mumps outbreak which occurred in one region, Yoeju County, Southeast of Seoul in Korea from September to December, 1999. Sera from 736 children at 8–13 years of age of patients with mumps and healthy children were tested for mumps-specific antibodies by enzyme immunoassay. The overall IgM positive rate was 7.6% (56/736), compared with 69.8% (514/736) for IgG. Of the 49 children with both IgG and IgM, 32 were also confirmed by both clinical and serological diagnosis. IgM antibodies were detected even in the samples collected up to 3 months after the onset of symptoms. Although 436 children had been vaccinated before the outbreak, 27 (6.2%) were found to be IgM positive, particularly 6 (4.4%) of 136 were positive serologically despite a second-dose vaccinees. Sequence analysis of the small hydrophobic (SH) gene of 4 mumps viruses isolated from 42 saliva specimens revealed that these were related to the genotype H, but distinguishable from European strains. This is the first study on the outbreak due to mumps virus genotype H and provides information to assess the understanding of recent outbreaks of mumps in Korea. J. Med. Virol. 73:85–90, 2004. © 2004 Wiley-Liss, Inc.

During the influenza pandemic of 2009-2010, rapid influenza diagnostic tests (RIDTs) were used to detect influenza viral infections because they are quick and simple to use. However, retrospective studies showed that RIDTs performed poorly when used to diagnose pandemic viral infections. Determining how amino acid sequence changes in pandemic or epidemic influenza viral antigens impact clinical value of RIDTs has not been possible, because the viral epitopes recognized by RIDTs have been not mapped. In this study, the effect of escape-variations or mutations in influenza viral antigens upon the sensitivity and specificity of an RIDT was investigated by characterizing the immunological properties of the antibodies used in the RIDT. Escape-mutants were generated by cultivating A/Korea/01/2009 in the presence of an excess of the same antibodies used in the RIDT. Escape-mutants not recognized by the RIDT were selected. Epitopes recognized by the RIDT were mapped by comparing the sequence and immunological analysis of the escape-variants and wild-type isolates. The RIDT antibodies recognized epitopes on the Sa antigenic site and in the F subdomain in hemagglutinin. Variants bearing mutations in these epitopes were not detected by the RIDT. The frequency of escape-variants emerging since the 2009-2010 pandemic was calculated as 1.27% using in silico surveillance of influenza sequence databases. These results suggest that mapping the relevant epitopes of RIDTs and making such information available to clinics would be helpful for determining whether RIDTs match newly emergent strains and subtypes prior to retrospective re-evaluation of the RIDTs using clinical specimens.

Despite the marked reduction in the incidence of measles in Korea by the introduction of measles vaccine, a large measles epidemic occurred during 2000-2001. During the epidemic, more than 55,000 measles cases were reported and at least 7 children were dead. In this study, we analyzed the genetic and antigenic properties of 15 measles viruses that isolated during the epidemic. Sequence analyses of entire hemagglutinin (H) and nucleoprotein (N) genes of the viruses indicated that all Korean isolates had a high degree of homology (>99.8%) when compared with each other. They differed from other wild-type viruses by as much as 6.8% in the H gene and 6.5% in the N gene at the nucleotide level. The deduced amino acid variability was up to 6.4% for the H protein and up to 6.5% for the N protein. Phylogenetic analysis of nucleotide sequences and deduced amino acid sequences of the H and N genes revealed that all Korean viruses were grouped into the genotype H1. This strongly demonstrated that single genotype of measles virus has been circulated in Korea during the 2000-2001 epidemic. Plaque reduction neutralizing antibody titers against vaccine strains, Edmonston and Schwarz, and recently isolated Korean strains were measured using sera from vaccinees and recently infected children. Although sera of recently infected children demonstrated higher neutralizing antibody titers against wild-type strains than against vaccine strains, both sera neutralized both strains and the reciprocal geometric mean titers (GMTs) were not significantly different against both strains.

A multiplex polymerase chain reaction (PCR) assay that is capable of detecting and typing six serotypes of respiratory adenovirus (Ad) was developed, using multiple sets of type-specific primers. The detection of each different serotype depended on distinguishing different numbers and sizes of amplification products on agarose gels following PCR. The multiplex PCR was tested with 26 clinical Ad isolates and other respiratory viruses including influenza viruses, parainfluenza viruses, and respiratory syncytial viruses as well as respiratory bacterial pathogens such as Chlamydia pneumoniae, Streptococcus pneumoniae, Haemophilus influenzae, and Mycoplasma pneumoniae. The multiplex PCR for the detection and typing of Ads gave an excellent correlation with the results by conventional typing with type-specific antisera. This assay may serve as a rapid means of confirming Ad with simultaneous serotype identification of the isolates. It will also have relevance as an adjunctive tool to conventional serotyping for diagnostic and epidemiological purposes.