Horses as a Potential Reservoir of Lyme Borreliosis in Jeju-do, Korea

Lyme borreliosis (LB) is the most common tick-borne infectious disease in North America, and it was designated as a national notifiable infectious disease in Korea in December 2010. While no cases in Jeju-do were recorded from 2012 to 2016, a recent survey reported that the seroprevalence of Borrelia burgdorferi using enzyme-linked immunosorbent assays in horses in Jeju-do was 19.0% (95% confidence interval, 12.0 to 28.3%). This fact suggests that horses may be a potential reservoir of LB in Jeju-do and that individuals in close contact with horses may be a high-risk group. Thus, a serological study in this high-risk group is urgently needed

Introduction of Phylodynamics for Controlling the HIV/AIDS Epidemic in Korea

As over 1000 new cases of HIV/AIDS occur in Korea annually, preventive health programs against HIV/AIDS are urgently needed. Since phylodynamic studies have been suggested as a way to understand how infectious diseases are transmitted and evolve, phylodynamic inferences can be a useful tool for HIV/AIDS research. In particular, phylodynamic models are helpful for dating the origins of an epidemic and estimating its basic reproduction number. Thus, the introduction of phylodynamics would be a highly valuable step towards controlling the HIV/AIDS epidemic in Korea

Prophylactic efficacy of probiotics on travelers’ diarrhea: an adaptive meta-analysis of randomized controlled trials

OBJECTIVES The 2017 guideline for the prevention of travelers’ diarrhea (TD) by the International Society of Travel Medicine suggested that ‘there is insufficient evidence to recommend the use of commercially available prebiotics or probiotics to prevent or treat TD.’ However, a meta-analysis published in 2007 reported significant efficacy of probiotics in the prevention of TD (summary relative risk [sRR], 0.85, 95% confidence interval [CI], 0.79 to 0.91). This study aimed to synthesize the efficacy of probiotics on TD by updating the meta-analysis of double-blind, placebo-controlled, randomized human trials. METHODS The search process was conducted by the adaptive meta-analysis method using the ‘cited by’ and ‘similar articles’ options provided by PubMed. The inclusion criteria were double-blind, placebo-controlled, randomized human trials with hypotheses of probiotics as intervention and TD as an outcome. The adaptive meta-analysis was conducted using Stata software using the csi, metan, metafunnel, and metabias options. RESULTS Eleven articles were selected for the meta-analysis. The sRR was 0.85 (95% CI, 0.79 to 0.91) and showed statistical significance. There was no heterogeneity (I-squared=28.4%) and no publication bias. CONCLUSIONS Probiotics showed statistically significant efficacy in the prevention of TD

Necessity of Epigenetic Epidemiology Studies on the Carcinogenesis of Lung Cancer in Never Smokers

Based on epidemiological and genomic characteristics, lung cancer in never smokers (LCNS) is a different disease from lung cancer in smokers. Based on current research, the main risk factor for LCNS may be air pollution. A recent case-control study in Koreans reported that nitrogen dioxide (NO2) may be a risk factor for LCNS. Additionally, a cohort study showed that exposure to NO2 was associated with significant hypomethylation. Thus, epigenetic epidemiology studies are needed in the near future to evaluate the carcinogenesis of LCNS according to chronic exposure to air pollution and/or viral infections

Epidemiological application of the cycle threshold value of RT-PCR for estimating infection period in cases of SARS-CoV-2

Epidemiological control of coronavirus disease 2019 (COVID-19) is needed to estimate the infection period of confirmed cases and identify potential cases. The present study, targeting confirmed cases for which the time of COVID-19 symptom onset was disclosed, aimed to investigate the relationship between intervals (day) from symptom onset to testing the cycle threshold (CT) values of real-time reverse transcription-polymerase chain reaction. Of the COVID-19 confirmed cases, those for which the date of suspected symptom onset in the epidemiological investigation was specifically disclosed were included in this study. Interval was defined as the number of days from symptom onset (as disclosed by the patient) to specimen collection for testing. A locally weighted regression smoothing (LOWESS) curve was applied, with intervals as explanatory variables and CT values (CTR for RdRp gene and CTE for E gene) as outcome variables. After finding its non-linear relationship, a polynomial regression model was applied to estimate the 95% confidence interval values of CTR and CTE by interval. The application of LOWESS in 331 patients identified a U-shaped curve relationship between the CTR and CTE values according to the number of interval days, and both CTR and CTE satisfied the quadratic model for interval days. Active application of these results to epidemiological investigations would minimize the chance of failing to identify individuals who are in contact with COVID-19 confirmed cases, thereby reducing the potential transmission of the virus to local communities

Trends of legionellosis reported in Jeju Province, Republic of Korea, 2015–2022

Objectives The number of reported cases of Legionnaires’ disease (LD) in the Republic of Korea surged nationally in 2016; however, in 2022, this number was higher in Jeju Province than the previous national peak. A descriptive epidemiological study was conducted to analyze trends in the incidence of reported LD cases in Jeju Island from 2015 to 2022. Methods The data for this study were obtained from case reports submitted to the Korea Disease Control and Prevention Agency through its Disease and Health Integrated Management System. The selection criteria were cases or suspected cases of LD reported among Jeju residents between 2015 and 2022. The 95% confidence interval of the crude incidence rate was calculated using the Poisson distribution. Results Since 2020, the incidence rate of LD in Jeju has risen sharply, showing a statistically significant difference from the national incidence rate. A particular medical institution in Jeju reported a significant number of LD cases. Screening with the urine antigen test (UAT) also increased significantly. Conclusion Our findings indicate that the rapid increase in cases of LD in Jeju Province since 2020 was due to the characteristics of medical-care use among Jeju residents, which were focused on a specific medical institution. According to their clinical practice guidelines, this medical institution conducted UATs to screen patients suspected of pneumonia

Vitamin D supplementation as a control program against latent tuberculosis infection in Korean high school students

The prevalence of latnet Mycobacterium tuberculosis infection (LTBI) in the first-grade high school students in South Korea was 2.1%, which was the lowest level at congregated settings in 2017. For LTBI cases refusing anti-tuberculosis (TB) medication or having poor compliance, additional support should be considered. Eight systematic reviews concluded that vitamin D (VD) deficiency is a risk factor for TB. While three of four South Korean adolescents were VD deficiency, VD supplementation could be a practical remedy to protect LTBI students of refusing anti-TB medication or having poor compliance

Seasonality of tuberculosis in the Republic of Korea, 2006-2016

OBJECTIVES While the seasonality of notified tuberculosis has been identified in several populations, there is not a descriptive epidemiological study on the seasonality of tuberculosis in Korea. This study aimed to evaluate the seasonality of tuberculosis in Korea from 2006 to 2016. METHODS Data regarding notified cases of tuberculosis by year and month was obtained from the Infectious Diseases Surveillance Yearbook, 2017 published by the Korea Centers for Disease Control and Prevention. Seasonal decomposition was conducted using the method of structural model of time series analysis with simple moving averages. RESULTS While the trough season was winter from 2006 to 2016, the peak season was summer between 2006 and 2012, but shifted to spring between 2013 and 2016. CONCLUSIONS Notified tuberculosis in Korea also showed seasonality. It is necessary to evaluate factors related to the seasonality of tuberculosis for controlling tuberculosis