{'fraction_non_alphanumeric': 0.044499562299387216, 'fraction_numerical': 0.029909541873358623, 'mean_word_length': 4.789695945945946, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 1, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Laboratory Investigation of Human Rhinovirus Infection in Cheonan, Korea 천안지역 대학병원에서의 라이노바이러스 감염 양상에 연구

Annually, millions of children die from respiratory virus infections. Human rhinovirus (HRV) is a causative agent of severe respiratory infections in young, elderly, and asthmatic patients with weak immunity. In this study, 9,010 respiratory virus specimens were collected from January 2012 to December 2018 at Dankook University Hospital, Cheonan and examined by real-time reverse transcription polymerase chain reaction. Twelve respiratory viruses were detected. The mean detection rate was 21.3% (N=1,920/9,010), and the mean age of HRV-positive patients was 6.5 years (median age: 1.6 years, range: 0.0 ∼ 96.0). The detection rate was the highest in July (32.4%) and the lowest in February (8.3%). When the detection rate was analyzed by age group, the detection rate was the second highest in patients aged 10 ∼ 19 years. The co-infection rate of HRV was 35.3%, and the most common combination was with Adenovirus. Respiratory virus infections are known to occur in children and elderly people with weak immunity. However, in this study, the detection rate was second highest in patients aged 10 ∼ 19 years. Indeed, the detection rate in this age group was more than 15%, except in January and February. These results suggested that steady-state studies on the infection patterns of HRV are required.


INTRODUCTION
Respiratory viruses are one of the most common infectious diseases in children, accounting for 30∼50% of the total number of hospitalized patients worldwide, and are responsible for the deaths of millions of children each year [1,2]. The major causative agents of respiratory virus infections are Adenovirus, Coronavirus, Human rhinovirus, Influenza A and B viruses, Metapneumovirus, Parainfluenza viruses (1∼3), and Respiratory syncytial viruses A and B.
Human rhinovirus (HRV) is a species of the Picornaviridae family, Enterovirus genus. HRV is currently classified into three species, HRV-A, -B, and -C, and there are more than 100 serotypes of HRVs [3]. Recent studies have reported that HRV-A and -C are detected more frequently than HRV-B. Real-time reverse transcription polymerase chain reaction (RT-PCR) can be used to detect all three species of HRV (HRV-A, -B, and -C). HRV is the most common cause of respiratory infections, regardless of age. Headache, sore throat, and cough are the main symptoms, and 50% of cold cases in adults are caused by HRV [4,5]. HRV has also been reported to cause severe respiratory infections in patients that are immunocompromised due to age, tumors, or asthma and can aggravate asthma, leading to chronic obstructive airway infection [6]. This virus is also associated with all types of upper and lower respiratory diseases, but is of particular concern when causing lower respiratory tract infections in children, infants, immunocompromised patients, and the elderly. Thus, because of the risk posed by these respiratory viruses, the Korea Center for Disease Control and Prevention (KCDC) has developed the Influenza and Respiratory Viruses Surveillance System (KINRESS), which includes surveillance of HRV [7].
In this study, we investigated the patterns of infection for HRV, including annual, monthly, and overlapping infections at a local university hospital for 7 years.
Although common colds are not associated with major health concerns, they can result in enormous costs to society in the form of missed school and work and unnecessary medical care.

Collection of samples
The patients in this study provided 9,010 respiratory specimens (nasopharyngeal aspirates, nasal swabs, and throat swabs), which were sent to the Department of Laboratory Medicine, Dankook University Hospital, Cheonan for real-time RT-PCR, from January 2012 to December 2018. The samples were immediately tested, or if they were not immediately available, they were refrigerated at 4°C and tested within 24 h.

Extraction of RNA
The collected respiratory specimens were treated with a QIAamp MinElute Virus Spin Kit (Qiagen, Hilden, Germany) to extract the RNA.

Statistical analysis
HRV detected by real-time RT-PCR was analyzed by various criteria, including overlapping infection, sex, age, year, and month. Results with P values of less than 0.05 were significant.

Ethics
This study was approved by the IRB Committee of Dankook University (No. 2019-04-006).

RESULTS
Among the 9,010 respiratory specimens collected during the study period, 12 respiratory viruses were detected in 5,081 specimens, with a detection rate of 56.4%; 1,920 specimens were positive for HRV (detection     was the lowest (13.9%; N=119/1435) during the study period ( Figure 1). The detection rate in July was the highest (32.4%; N=191/590), and the detection rate in February was the lowest (8.3%; Figure 2, Table 1). The detection rate for patients 2∼3 years old was the highest (36.5%; N=212/581), and the detection rate for patients 40∼49 www.kjcls.org were the most frequent multiple infections found (Tables 3   and 4).

DISCUSSION
In this study, we evaluated the detection rates of HRV in a cohort of 9,010 patients. Our results showed that HRV infections were most common in patients ages under 10.
Our findings provided insights into the prevalence of HRV in Korean populations.
During the period evaluated in our study, we observed two peaks in 2012 and 2015. Another study conducted over a similar period reported similar results, albeit with higher rates in 2011 and 2015 [8]. In Cheonan, HRV appeared to be an epidemic for a period of 2∼3 years. The prevalence period depends on the subtype of HRV [9]. For this reason, it seems to be an epidemic for a period of 2∼3 years.
The detection rate in July was the highest, followed by that in September. Detection rates averaged more than 15% per year, except for those (9.0% and 8.3%) in January and February, respectively. In previous studies, the incidence of HRV has been reported to increase in autumn and late spring, with lower rates during the other periods [10,11]. In contrast, high detection rates were reported in summer months (June and July), in Korea [10]. Moreover, the detection rates of HRV in June and July were higher than 20%. Seasonal differences in respiratory viruses have been well documented [12]; however, the reason for this seasonality is unknown, and few studies have examined this topic [2,13]. As previously noted, we found that HRV was most active in Korea in the summer, which was unusual because another study reported that HRV is more likely to cause severe illness in winter and spring [12]. This may be because of unrelated factors; for example, yellow dust, which causes severe respiratory problems in the Asia-Pacific region, could cause an increase in the rate of HRV infection [14]. Although this has not yet been studied