• Journal of Korean Medical Science
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• v.33 no.50
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• pp.319.1-319.5
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• 2018

The incidence of severe fever with thrombocytopenia syndrome (SFTS) has increased in Korea since a first report in 2013. We investigated whether SFTS existed before 2013 using real-time reverse transcription polymerase chain reaction and stored blood samples from febrile patients with thrombocytopenia. Four cases of SFTS were identified, with the earliest occurring in 2008.

• Journal of Veterinary Science
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• v.23 no.6
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• pp.83.1-83.7
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• 2022

Severe fever with thrombocytopenia syndrome (SFTS) is a zoonotic disease, and its clinical information and prevalence are important. This study was conducted on 22 feline patients from the Republic of Korea (ROK), suspected to suffer from a tick-borne disease. Four cats were positive for SFTS, and genotypes B-1, B-3, D, and F were identified. Clinical symptoms, such as anorexia, jaundice, thrombocytopenia, leukopenia, and hyperbilirubinemia, were detected. This is the first report of SFTS virus genotypes B-1, D, and F from cats in the ROK. Moreover, our results suggest that jaundice may be an indicator of SFTS in cats.

• Journal of Preventive Medicine and Public Health
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• v.52 no.3
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• pp.195-199
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• 2019

Objectives: Jeju Province is well known as the region showing the highest incidence of severe fever with thrombocytopenia syndrome (SFTS) in South Korea. The aim of this study was to evaluate the epidemiological and clinical characteristics of SFTS patients in Jeju Province. Methods: The primary data for this study were obtained from the Integrated Diseases and Health Control System of the Korea Centers for Disease Control and Prevention (KCDCIS). The selection criteria were confirmed cases of SFTS with a residence listed in Jeju Province at the time of diagnosis, reported to the KCDCIS between July 16, 2014 and November 30, 2018. Results: Of 55 confirmed cases of SFTS, the case fatality rate was 10.9% (95% confidence interval [CI], 4.1 to 22.2). The most common presenting symptoms at diagnosis of severe fever, myalgia, and diarrhea had incidences of 83.6% (95% Cl, 71.2 to 92.2), 45.5% (95% Cl, 32.0 to 59.5), and 40.0% (95% CI, 27.0 to 54.1), respectively. Conclusions: Compared to SFTS patients nationwide in 2013-2015, the subjects of this study exhibited a lower case fatality rate and had a lower incidence of severe fever, myalgia, and confusion.

• Parasites, Hosts and Diseases
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• v.52 no.2
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• pp.221-224
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• 2014

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.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.2
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• pp.143-149
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• 2020

The study examined the seasonal pattern of larvae, nymph, and adult life stages for Haemaphysalis longicornis and the rate of infection with severe fever from the thrombocytopenia syndrome virus in ticks collected from 12 sections (Jichukdong), 14 sections (Uldaeri), and 18 sections (Howondong) in Bukhansan dullegil for April-October 2019. Haemaphysalis longicornis ticks have been considered the main vector for severe fever with thrombocytopenia syndrome (SFTS). Haemaphysalis flava and Ixodes nipponensis were collected using the dragging and flagging method. The ratios of Haemaphysalis longicornis of the collected ticks were 91% (Jichukdong), 94% (Uldaeri), and 98% (Howondong). Monthly distributional studies of Haemaphysalis longicornis based on the developmental stage showed that the adults peaked in September while nymphs were collected more frequently from April through June. The larvae peaked in September and October. SFTS virus detection was performed using 2 × OneStep RT-PCR and nested PCR. On the other hand, no SFTS virus-specific gene was detected in 1,158 ticks of Haemaphysalis longicornis. This result provides estimates of the population densities for the life stages of Haemaphysalis longicornis and the associated disease risk in Bukhansan dullegil, where many people have visited since opening in 2010.

• Korean Journal of Veterinary Service
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• v.39 no.2
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• pp.75-80
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• 2016

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease characterized by fever and thrombocytopenia. Haemaphysalis longicornis ticks comprise the major population of ticks in the environment and have been considered as the main vector for SFTS virus (SFTSV). Here we investigated the distribution of ticks carrying SFTSV collected from the environment using the dragging or sweeping methods during April~October 2015 in Jeollanam-do, Korea. Sampling was taken from Songjeong, Omi, Bangkwang, Sandong areas in Jiri walking trails. Among the total 3,869 ticks collected, 3,823 ticks (98.8%) were H. longicornis, 41 (1.1%) were Amblyomma testudinarium, and 5 (0.1%) were Ixodes nipponensis. Classification results by regional groups of H. longicornis indicated that 1,613 ticks were collected in Sandong, 1,190 ticks in Omi, 603 ticks in Bangkwang, and 417 ticks in Songjeong. In monthly distributional studies of H. longicornis based on the developmental stages, nymph (325 ticks) was collected from May to October, 94% of larvae from April to June, and 94% of adult from June to August. These results showed the different dominant stage of ticks according to seasons. However, no SFTSV-specific gene was detected in 3,823 ticks of H. longicornis, 41 of A. testudinarium and 5 of I. nipponensis.

• Korean journal of aerospace and environmental medicine
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• v.30 no.2
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• pp.75-79
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• 2020

This study focuses on the comparative and quantitative analysis of the epidemiologic trends and aspects of severe fever with thrombocytopenia syndrome (SFTS) outbreaks between Korea and Japan from 2013 to 2017. The following factors were analyzed; cumulative incidence rate (CIR), cases-fatality rate (CFR), and the epidemic aspects, including cases related to gender, male-to-female morbidity ratio (MFMR), age, seasonal, and geographical distributions. We observed 607 SFTS cases with CIR in Korea during the period 2013 to 2017 were as 0.24 per 100,000 populations and with a 127 fatal-cases (F.C.s), corresponding to a CFR of 20.9%, respectively. During the same period in Japan, 319 SFTS cases with a CIR of 0.05 and with 60 F.C.s to a CFR of 18.8% observed. When compared, the CIR of SFTS in Korea was significantly higher than in Japan (P<0.01), but there were no significant differences levels of the CFR and MFMR between Korea and Japan. Also, a higher incidence of SFTS was observed in people aged over 50-years or elders in Korea and those of 60-years or elders in Japan (P<0.01). The seasonal distribution of SFTS outbreak cases showed that the incidence in summer through autumn in Korea (92.4% of total cases) was higher than in Japan (65.2%), while the outbreaks of SFTS in spring was much higher in Japan (31.0%) than in Korea (7.4%), (P<0.01). The regional distribution revealed no significant difference between the eastern area (44.8%) and the western area (46.8%) of the Korean peninsula except Jeju-island (8.4%). However, in Japan, the incidence only occurred in Chubu-Kinki-Chugoku (30.3%), Shikoku (25.7%), Kyushu (42.6%) and Okinawa (0.3%), which are the western and southern areas of Japan. These differences in SFTS occurrence may reflect the influences of vector/hosts, climate, and geographical and cultural characteristics between the two countries.

• Korean Journal of Veterinary Research
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• v.57 no.3
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• pp.169-174
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• 2017

This study was performed to investigate the distribution of ticks and the rate of infection with severe fever with thrombocytopenia syndrome (SFTS) virus in ticks collected at Mt. Gwanak and the Seoul National University campus, Korea. Ticks (n = 273) were collected from May to October and included 76 Haemaphysalis longicornis (4 adult females, 72 nymphs), 49 Haemaphysalis flava (9 adult females, 3 adult males, 37 nymphs), and 148 Haemaphysalis spp. larvae. SFTS virus detection was performed by using one-step RT PCR and nested PCR. The SFTS virus was detected in 7 samples (1 Haemaphysalis longicornis nymph, 3 Haemaphysalis flava nymphs, and 3 Haemaphysalis spp. larva). The overall minimum field infection rate was 2.6%, whereas the minimum field infection rates of adult, nymphal, and larval ticks were 0%, 3.2%, and 2.0%, respectively. For a more accurate indication of the prevalence of SFTS virus in Korea, further in-depth investigations of tick species and SFTS virus occurrence over a larger area and longer period are needed.

• Korean journal of applied entomology
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• v.59 no.3
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• pp.233-241
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• 2020

Several hard tick species in Ixodidae are medically important pests that transmit infectious disease including severe fever with thrombocytopenia syndrome (SFTS). In Korea, the number of SFTS patients continues to steadily increase since its first report in 2013, and Gyeongsangbuk-do (province) is the second most frequent area of SFTS patient occurrence. In order to investigate the distribution of ticks in Sangju city, we collected ticks using the flagging method from 26 sites comprising urban green area, vulnerable area of management, and rural area, and examined SFTS virus from the collected ticks in 2019. Based on Collection Index (CI = tick number / 1 h / 2 people), CI 143 ticks, including Haemaphysalis longicornis, Haemaphysalis flava, and Ixodes nipponensis, were collected; the most abundant species among the three tick species was H. longicornis (CI 138, 96.5%). Ninety two percent (CI 131) of ticks were collected in vulnerable area of management, where people cannot easily enter and are not managed by city hall, whereas only 8.4% (CI 12) were collected in the urban green area and rural area. Regarding SFTS virus detection, virus was not investigated from 26 pools containing CI 143 ticks. The results of this study are expected to be used as a recommendation for ensuring the safety of local residents from tick-borne diseases.

• Parasites, Hosts and Diseases
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• v.59 no.3
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• pp.281-289
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• 2021

This study aimed to characterize the seasonal abundance of hard ticks that transmit severe fever with thrombocytopenia syndrome virus from April to November 2019 and 2020 on Ganghwa-do, Incheon Metropolitan City, Korea. The ticks were collected at grassland, grave site, copse and mountain road using a collection trap method. The ixodid hard ticks comprising three species (Haemaphysalis longicornis, H. flava, and Ixodes nipponensis) collected were 6,622 in 2019 and 3,811 in 2020. H. longicornis was the most frequent (97.9% in 2019 and 96.0% in 2020), followed by H. flava (2.0% and 3.0% in 2019 and 2020, respectively) and I. nipponensis (less than 0.1%). Our study demonstrated that seasonal patterns of the tick populations examined for two years were totally unsimilar. The hard ticks tested using RT-qPCR were all negative for severe fever with thrombocytopenia syndrome virus.