Search

Background Severe fever with thrombocytopenia syndrome (SFTS) virus was first isolated in China in 2009 and has since spread to several Asian countries. SFTS is closely related to environmental factors that accelerate vector growth. We evaluated the associations of SFTS and deforestation with environmental variables. Methods For this observational study, we generated multiple Poisson models using national SFTS outbreak data (2013–2018) and official environmental data for Korea. We included established risk factors as variables. Deforestation was used as the main variable. All variables were analyzed according to their spatial characteristics using the R-INLA package. Results SFTS cases increased over time and peaked in 2017, at 272, followed by a decrease in 2018. Disease mapping showed a high incidence of SFTS nationwide, with particular risks in Gangwon and Gyeonggi Provinces in the north, and Jeju in the south of South Korea. Deforestation was significantly associated with a higher risk of SFTS in the final model (relative risk, 1.751 [95% confidence interval, 1.125–2.743]). Conclusions SFTS outbreaks are associated with deforestation. Therefore, deforestation in Gyeonggi, Gangwon, and Jeju provinces of South Korea needs to be considered in vector-control strategies and active surveillance of SFTS occurrence. [ABSTRACT FROM AUTHOR]

Background: Severe fever with thrombocytopenia syndrome (SFTS), which was first discovered in China in 2009, is an infectious disease with a high mortality rate, particularly in East Asia. This study aimed to investigate the epidemiological and clinical characteristics and risk factors for mortality by analyzing SFTS cases accumulated for up to ten years in Jeju, Korea. Materials and Methods: Medical records of patients diagnosed with SFTS between March 2013 and August 2022 at a tertiary hospital in Jeju were analyzed retrospectively. We investigated data of patients with SFTS on the epidemiologic and clinical characteristics, laboratory findings, and administered treatments and compared the differences between fatal and non-fatal groups. Results: We enrolled 91 SFTS-confirmed patients. The median age of patients was 62 years, and the fatality rate increased with age (P = 0.004). Fever was the most common symptom (84.6%), and diarrhea (37.4%) was also present in some cases. The overall fatality rate was 10.9%. Dyspnea (20.0% vs. 0.0%, P = 0.009) and changes in mental status (70.0% vs. 11.0%, P <0.001) were more frequent in fatal cases. Risk factor assessment revealed that a high aspartate aminotransferase /alanine aminotransferase ratio (odds ratio [OR]: 39.568, 95% confidence interval [CI]: 1.479 – 1,058.639, P = 0.028) and elevated total bilirubin levels (OR: 53.037, 95% CI: 1.064 - 2,643.142, P = 0.046) were also significantly associated with fatal cases. Plasma exchange (40.7%) was the most commonly administered treatment. Conclusion: SFTS has a high mortality rate; therefore, awareness of SFTS must be raised among physicians and citizens living in tick-inhabited areas, such as Jeju. [ABSTRACT FROM AUTHOR]

Background: Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne zoonotic disease that is caused by the SFTS virus (SFTSV), and exhibits an overall mortality rate of approximately 20.0% in Korea. Most cases of this disease have been reported in Korea, East China, and japan, and it mostly affects outdoor workers and farmers. This study aimed to investigate the seroprevalence of SFTSV among healthy farmers on Jeju Island, Korea. Materials and Methods In this prospective cross-sectional study, we analyzed 421 blood samples obtained from 254 farmers (mean age, 59.9 years; 68.9% male) to determine the seroprevalence of SFTSV in 16 rural areas of the Jeju Special Self-Governing Province over a period of 3 years (January 2015-December 2017). We used an enzyme-linked immunosorbent assay to detect immunoglobulin (Ig) G antibodies against SFTSV in the collected samples. Results The seroprevalence of the SFTSV IgG among farmers on Jeju Island was observed to be 2.4%. One subject showed seroposidvity over the entire 3-year study period. The areas with the highest SFTSV IgG seropositivity rates were Seonheul-ri in Jocheon-eup, followed by Namwon-eup. Fruit farmers were at a higher risk of exposure to SFTSV than other farmers. Conclusion The seroprevalence of SFTSV in the healthy agricultural population of Jeju Island was not high. However, personal hygiene management should be implemented for the agricultural population in the endemic areas. Surveillance of mild or asymptomatic infections is required in the endemic regions. [ABSTRACT FROM AUTHOR]

배경: Severe fever with thrombocytopenia syndrome virus (SFTSV) is transmitted through tick bites. Q fever is transmitted by inhaling contaminated aerosols, contacting an infected animal, and consuming contaminated dairy products. Ticks are considered a potential Coxiella burnetii vector. This study aimed to analyze SFTSV and C. burnetii infection rates in ticks in rural areas on Jeju Island, South Korea, monthly from 2016 to 2019. 방법: Free ticks were collected from the natural environment, and SFTSV RNA was extracted from the collected ticks. Ribosomal RNA gene sequencing was used to identify Coxiella species, and phylogenetic analyses were conducted. 결과: From the 3,187 ticks collected during the study period, the most common species was Haemaphysalis longicornis (n=3,139; 98.4%), followed by Haemaphysalis flava (n=48; 1.6%). Tick number gradually increased from April, peaked in August (12.4%), and was lowest in March. Of all collected ticks, 2,597 (81.3%) were nymphs; the remaining ticks were adults (18.6%) and larvae (0.1%). SFTSV-infected ticks comprised 390/3,187 (12.2%) of all ticks. The SFTSV-infected ticks were lowest in November–December and increased from January. SFTSV-infected ticks were mostly identified in the adult stage during June–August. Of the SFTSV-infected ticks, C. burnetii co-infection was seen in H. longicornis (4.9%), with the highest infection rate in January, followed by December and November. 결론: Coxiella burnetii-infected ticks were mainly identified in the nymph stage. This region is at high SFTSV risk and potential Q fever endemic. This study provides important information on SFTSV and Q fever risk to humans, according to Korean tick developmental stage. [ABSTRACT FROM AUTHOR]