Jungim Jang

Prevalence of Human Astrovirus in Patients with Acute Gastroenteritis

The prevalence of human astroviruses was tested in patients with acute gastroenteritis by using conventional duplex reverse transcription (RT)-PCR and electrophoresis. Diarrheal fecal samples were collected from 9,597 patients at local hospitals in Seoul. The prevalence of astroviruses was 1.0% (94/9,597 patients; mostly infants), and that of sapoviruses was 0.1% (14/9,597 patients). Age- and gender-wise analyses were carried out on 29 astrovirus-positive patients having complete information on file regarding their age, gender, and other particulars. The results were higher in patients of ages 0 to 14 yr, and 69.0% of the astrovirus-positive patients were females, of which 69.2% were infants (0 to 12 months), and 61.5% were 1-4 yr old. Notably, in the case of 5 to 78-yr-old acute gastroenteritis patients, 100% were females.

Epidemiological Characterization of Respiratory Viruses Detected from Acute Respiratory Patients in Seoul

Background: Viruses that cause acute respiratory infection include adenovirus (ADV), respiratory syncytial virus A and B (RSV(A), RSV(B)), influenza virus A and B (FluA, FluB), parainfluenza virus 1, 2 and 3 (PIV1, PIV2, PIV3), human metapneumovirus (hMPV), human coronavirus (hCoV), human rhinovirus (hRV), and enterovirus, among others. Methods: Viral incidence was evaluated in acute respiratory patients in Seoul, Korea from 2010 to 2012. A total of 2,544 oropharyngeal swab specimens were tested by real-time polymerase chain reaction (PCR) methods. RNA viruses (hRV, PIV, RSV, hCoV, and hMPV) and DNA viruses (ADV and bocavirus) were detected using the one-step reverse transcriptase PCR (RT-PCR) premix kit (SolGent, Korea) from January 2010 to June 2011, and using the real-time PCR kit (Kogenebiotech, Korea) from July 2011 to December 2012. Results: Thirty-two percent (813/2,544) of specimens were positive; 31.9% (294/923) in 2010, 31.4% (232/ 738) in 2011, and 32.5% (287/883) in 2012. The most frequently isolated virus was hRV (40.7%, 331/813), followed by ADV (23.9%, 194/813), RSV (14.1%, 115/ 813), PIV (12.3%, 100/813), and hCoV (8.7%, 71/813). PIV1 was the most commonly isolated PIV, followed by PIV3 and PIV2, respectively. hCo OC43 was the most commonly isolated hCoV, followed by hCoV NL63 and hCoV 229E, respectively. Conclusion: Information on respiratory viruses circulating in Seoul, Korea over the last three years will be helpful in the management of acute respiratory infections, and for larger-scale epidemiological studies. (Ann Clin Microbiol 2013;16:188-195)

No Detection of Severe Fever with Thrombocytopenia Syndrome Virus from Ixodid Ticks Collected in Seoul

Larvae, nymphs, and adult stages of 3 species of ixodid ticks were collected by tick drag methods in Seoul during June-October 2013, and their infection status with severe fever with thrombocytopenia syndrome (SFTS) virus was examined using RT-PCR. During the period, 732 Haemaphysalis longicornis, 62 Haemaphysalis flava, and 2 Ixodes nipponensis specimens were collected. Among the specimens of H. longicornis, the number of female adults, male adults, nymphs, and larvae were 53, 11, 240, and 446, respectively. Ticks were grouped into 63 pools according to the collection site, species, and developmental stage, and assayed for SFTS virus. None of the pools of ticks were found to be positive for SFTS virus gene.

Epidemiological Characterization of Influenza Viruses detected from Acute Respiratory Patients in Seoul during 2010-2012

Objectives: For our survey of the incidence of influenza viruses among respiratory viral infections in Seoul, we evaluated their prevalence among infectious acute respiratory viral patients in Seoul from 2010 to 2012 through regular surveillance. Methods: For influenza virus detection, we conducted real-time PCR analyses on 2,544 throat specimens collected from patients with respiratory viral infections in Seoul between 2010 and 2012. They were collected and then tested for the presence of influenza viruses through reverse transcription (RT) - polymerase chain reaction (PCR). Results: 19.1% (486/2,544) of the throat specimens were determined to be positive for influenza viruses. The incidences of influenza viral infection in the case of respiratory viral infections through regular surveillance in Seoul were 23.0% (212/923) in 2010, 6.4% (47/738) in 2011, and 25.7% (227/883) in 2012, and 10.8% (275/2,544) of type A, and 8.3% (211/2,544) type B influenza viruses. In addition, the greatest prevalence was in the 20-49 age group (51.6% ), which shows that influenza viruses constituted a major causative agent of acute respiratory viral infections. Conclusions: The distributions of influenza viruses and the epidemiologic patterns of the viral pathogen in acute respiratory viral infectious patients may provide potentially effective data for epidemiological studies in Seoul, Korea.

Genotypes and Infection Status of Human Enterovirus Associated with Enteric and Respiratory Patients in Seoul, Korea

Objective: Human enteroviruses (HEVs) are a common causative agent of gastrointestinal or respiratory infections. In this study, to examine the genotypic diversity and characteristics of HEVs associated with patients in Seoul, we collected and analyzed stool and throat swab samples taken from patients with acute gastroenteritis or a common cold from 2011 to 2012. We researched the difference in genetic characteristics of HEVs from gastroenteritis and respiratory patients. Methods: For genetic analysis, we amplified the 5’-noncoding region and partial VP1 region of HEVs by RTPCR. The genotypes of HEVs were further identified based on nucleotide sequences of the VP1 region. Results: The majority of the HEV infections in Seoul occurred from June to August. The molecular characteristic assay showed that although the majority of HEVs can be propagated by a fecal-oral route, Coxsackievirus A2 (n=13, 19.4%) , A4 (n=8, 11.9%), and A5 (n=4, 6.0%) can be preferentially transmitted by a respiratory route. Conclusions: This Enterovirus surveillance system plays an important role in preparing for a severe outbreak. The genotypic characteristics of HEV may provide potentially useful data needed for epidemiological studies.