Multiplex RT-PCR was used to detect respiratory viruses in 5,318 clinical samples referred to the laboratory of a tertiary teaching hospital from December 2006 to November 2010. The acquired data were analyzed with respect to types, ratio, and co-infection trends of infected respiratory viruses. Trends in respiratory viral infection according to sex, age, and period of infection were also analyzed. Of the 5,318 submitted clinical samples, 3,350 (63.0%) specimens were positive for at least one respiratory virus. The infection rates were 15.8% for human rhinovirus, 14.4% for human respiratory syncytial virus A, 9.7% for human respiratory syncytial virus B, 10.1% for human adenovirus, 5.4% for influenza A virus, 1.7% for influenza B virus, 4.7% for human metapneumovirus, 2.3% for human coronavirus OC43, 1.9% for human coronavirus 229E/NL63, 3.7% for human parainfluenza virus (HPIV)-1, 1.1% for HPIV-2, and 5.3% for HPIV-3. The co-infection analysis showed 17.1% of double infections and 1.8% of triple infections. The median age of virus-positive patients was 1.3 years, and 91.5% of virus-positive patients were under 10 years old. Human respiratory syncytial virus was the most common virus in children under 5 years of age, and the influenza A virus was the most prevalent virus in children over 5 years of age. These results help in elucidating the tendency of respiratory viral infections.

Candida spp. is an invasive infectious fungus, a major risk factor that can increase morbidity and mortality in hospitalized patients. In this study, 2,508 Candida spp. were isolated from various clinical specimens collected from university hospitals from July 2011 to October 2014. They were identified in order to determine isolation frequencies and characteristics by specimen, gender, age group, year, season, and month. The strain-specific isolation rate of Candida spp. is in the order of Candida albicans (1,218 strains, 48.56%), Candida glabrata (416 strains, 16.59%), Candida utilis (305 strains, 12.16%), Candida tropicalis (304 strains, 12.12%), and Candida parapsilosis (116 strains, 4.63%) and these five species accounted for more than 94% of the total strains. Of the specimens, Candida spp. were most frequently isolated from urine-catheter, followed by urine-voided, blood, sputum, other, open pus, vaginal discharge, Tip, ear discharge, bronchial aspiration and bile, in that order. Looking at the age distribution, the detection rate of patients in their 60s and older was significantly higher at 75.8% (1,900/2,508). The detection rate of patients in their 20s and younger was shown to be very low at 2.55% (64/2,508). By year, the detection rate of non-albicans Candida spp. showed a tendency to gradually increase each year compared with C. albicans. As isolation of Candida spp. from clinical samples at the specie level can vary depending on characteristics of the patient, sample, season, etc., continual studies are required.

Human respiratory coronaviruses (HCoV) are a broad and important group of RNA viruses that include the pathogens responsible for respiratory infections such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). HCoV possess unique molecular mechanisms for transcription and recombination, which lead to various etiologies and continually emerging pathogens [1]. In humans, HCoV infections primarily involve the upper respiratory and gastrointestinal tracts, and they vary from a mild, selflimiting disease, such as the common cold, to more severe manifestations, such as bronchitis and pneumonia with renal involvement [2].There are currently no commercial vaccines against most respiratory viruses, except for influenza A and B [3], and the prevention and effective control of viral infections remain difficult. Therefore, investigations into the viral etiology of respiratory infections that occur at various ages and times play an important role in the successful implementation of prevention, control, and treatment strategies [4].Three theories have been put forward to explain viral seasonality [5]: 1) the effect of climatic conditions on host resistance to infection (e.g., low vitamin D levels following lack of sun exposure can affect the ability to fight infection) [6,7]; 2) the effect of meteorological factors (e.g., temperature and humidity) on viral survival and infection rates [8]; and 3) the effect of behavioral changes on transmission (e.g., spending more time indoors and in close proximity to others or the aggregation of susceptible children at schools during the colder months) [9]. The study of climate and respiratory viral infections using big data may enable the recognition and interpretation of relationships between disease occurrence and climatic variables. In this study, realtime reverse transcription quantitative PCR (qPCR) methods were used to identify Human respiratory coronaviruses (HCoV). infections in patients below 10 years of age with respiratory infections who visitedDankook University Hospital in Cheonan, South Korea, from January 1, 2012, to December 31, 2018. Out of the 9010 patients who underwent respiratory virus real-time reverse transcription qPCR test, 364 tested positive for HCoV infections. Among these 364 patients, 72.8% (n = 265) were below 10 years of age. Data regarding the frequency of infections was used to uncover the seasonal pattern of the two viral strains, which was then compared with local meteorological data for the same time period. HCoV-229E and HCoV-OC43 showed high infection rates in patients below 10 years of age. There was a negative relationship between HCoV-229E and HCoV-OC43 infections with air temperature and wind-chill temperatures. Both HCoV-229E and HCoV-OC43 rates of infection were positively related to atmospheric pressure, while HCoV-229E was also positively associated with particulate matter concentrations. Our results suggest that climatic variables affect the rate in which children below 10 years of age are infected with HCo...

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BackgroundThe epidemic patterns of respiratory syncytial virus (RSV) infection and the factors determining its seasonality are not well studied in the local society of South Korea.