We monitored the population of Haemaphysalis longicornis, in Andong, Gyungbuk from April to November, 2018. Among total 2,994 ticks collected for 8 months, H. longicornis 1,677(56%), H. spp Larva 1,074(35.9%), H. flava 213(7.1%), Ixodes nipponensis 30(1.0%) were identified. In addition, considering the environment, 1,727(57.7%), 907(30.3%), 192(6.4%) and 168(5.6%) ticks were collected in the grassland, graves, copse, mountain path, respectively. In the pathogen diagnosis with PCR using SFTS virus specific primers, positive viruses were detected in H. longicornis, H. flava and H. spp from June to October. The minimum field infection rate of June, July, August, September and October were 0.4%, 0.8%, 1.2%, 0.8% and 2.3%. respectively.

A tick survey was conducted to monitor ticks using tick traps attached dry ice and a flagging method at each four sites in Busan, Ulju, and Geoje areas of Gyeongnam Province from April to November, 2018. Haemaphysalis longicornis was the most frequently collected, representing 99.8% in Ulju. A total of 27,247 ticks were collected as H. longicornis (Trap Index; TI 283.2), H. flava (TI 0.3), and Ix. nipponensis (TI 0.3). In the collection environment, a total number of 15,672, 5,798, 4,876, and 901 ticks were collected from glassland, tump, tomb, and mountain path, respectively. On the other hand, H. longicornis and Ix. nipponensis were collected with flaggings at the four sites in Ulju, Busan, and Geoje in May and June, 2018. A total of 1,517 ticks collected H. longicornis (Flagging Index; FI 9.3) and Ix. nipponensis (FI 0.1) in Ulju. Haemaphysalis longicornis were collected 2,183 (FI 13.6) and 1,596 (FI 10.0) in Geoje and Busan, respectively. In the results of the isolation of Severe Fever with Thrombocytopenia Syndrome (SFTS) from the ticks, no pathogens detected from RNA of 557 pools of the ticks using a Polymerase Chain Reaction method in 2018.

Heamaphysalis longicornis is a major vector for Severe Fever with Thrombocytopenia Syndrome (SFTS) virus and the density of the vector has been increasing because of the climate change. The incidence of fatalities due to SFTS is increasing every year. In this study, to evaluate the SFTS transmission by ticks, the density of ticks mediating SFTS was monitored. Tick was collected every month from four different sites (Grass land, Mountain path, Grave, Copse) in Andong with the traps containing dry ice as CO2 attractants. Among 2,572 ticks of 3 species; H. longicornis, H. flava, and Ixodes nipponensis were most abundantly collected from April to August. H. longicornis is the richest species (92.8%), whereas Ixodes nipponensis was the least species (0.8%). The 54.5% of the sample were nymph stage and female/male ratio was 64.3%. According to the pathogene analysis, SFTS virus was detected from H. longicornis adult and larvae stages collected in July and August. In July samples, SFTS virus was detected only from grassland site, but the virus was observed in the sample from all four sites in August. For effective prevention of SFTS, the tick density should be continuously monitored based on the onset time of SFTS with the consideration of habitate, habit & life history of ticks.

Longhorned tick, Haemaphysalis longicornis (Ixodida: Ixodidae) is one of the vectors of severe fever with thrombocytopenia syndrome virus (SFTSV) in human. The tick occurs in mostly grass fields, and the use of pyrethroid insecticides induced pest resistance and environmental residual toxicity. Particularly the use of chemicals near residential areas where persons live become a big issue, so environmentally safe control agents need to be considered. Here in this work, our interest was given to the selection of highly virulent fungi against H. longicornis. A total of 101 fungal pathogens collected from mountainous areas were assayed by a dipping the nymph stage of ticks into a conidial suspension (1×107conidia/ml). Interestingly among several species, one species showed high virulence and mycosis were observed in 7-15 days. Most of the selected isolates produced a large amount of conidia in Italian millet, rice and millet with thermotolerance at 40-45°C. Based on these results, we selected a couple of isolates with high virulence against H. longicornis and they could be used for the control of the ticks after the set-up of a practical application strategy in fields by optimizing fungal colonization in soil and phyllosphere.

국내에서 발생하는 진드기 매개질환 중에서 SFTS(중증열성혈소판감소증후군)는 법정감염병으로 지정된 2013년이후 지속적인 환자 증가뿐만 아니라 사망자가 늘고 있어 국민적 관심이 높은 질환이다. 또한 대표적인 가을철발열성 질환인 쯔쯔가무시증도 2013년 이후 1만 여명 내외의 환자가 지속적으로 발생하는 대표적인 질환의 하나이다.SFTS를 매개하는 참진드기(tick)는 우리나라 전역에 서식하고 있고, 모든 성장단계에서 숙주를 흡혈하여 병원체를감염시키고 있어 감염병 발생 차단을 위한 방제 전략수립에 어려움이 많은 매개체로 알려져 있다. 쯔쯔가무시증을매개하는 털진드기(chigger mite)도 야생 설치류와 사람 등 포유동물에 기생하며 흡혈을 통해 병원체를 전파하는것으로 알려져 있다. 질병관리본부에서는 이들 진드기의 국내 발생양상을 감시하기 위해 전국적인 감시망을 구축하여시기별 발생밀도 및 국내 분포조사를 실시하고 진드기의 병원체 보유여부 확인을 통해 분석한 자료를 대국민홍보자료를 제공하고 있어 이를 소개하고자 한다.

The purpose of this monitoring is to survey the geographical distribution of tick species using dry ice bait traps and flagging methods at each ten provinces (GangwonⅠ,GangwonⅡ, Gyeonggi, Chungbuk, Chungnam, Gyeongbuk, Gyeongnam, Jeonbuk, Jeonnam and Jeju area) and one Metropolitan area in the Republic of Korea for eight months from April through November, 2016. A total of 65,339 ixodid ticks (8,200 females, 1,988 males, 31,453 nymphs and 23,698 larvae) was collected, belonging to three genera (Haemaphysalis, Ixodes and Amblyomma). Haemaphysalis longicornis was the most commonly collected species, which is represented for 96.88% of all the collected ticks and followed by H. flava (2.69%), I. nipponensis (0.35%), A. testudinarium (0.05%) and H. japonica (0.03%) in the Republic of Korea for the study period. Haemaphysalis longicornis was a dominant species observed in these eleven areas.

Previous laboratory repellent assessment with three plant essential oils against Haemaphysalis longicornis, a major vector for Severe fever with thrombocytopenia syndrome, revealed high repellency of Lavendual angustifolia and high synergic effects of Cinnamomum zeylinicam and Juniperus verginiana. Based on the previous laboratory repellent assessment field studies on repellency of the three plant oils were carried out with formulations such as cream type and spray type. 10% spray type of Cinnamomum zeylinicam demonstrated > 70% of repellency against H. longicornis. 10% spray type of Lavendual angustifolia showed > 80% of repellency. 10% spray type of binary mixture containing Cinnnamomum zeylinicam and Juniperus verginiana showed > 98% repellency against H. longicornis. Further studies on repellency of cream type of the plant oils might be carried out and compared with two commercial repellents.

Haemaphysalis longicornis is a major vector for Severe fever with thrombocytopenia syndrome (SFTS) throughout Republic of Korea (ROK). The ticks distribute at vast open fields and various kind of habitate. Control of the ticks with pesticides is almost impossible and personal protection such as use of commercial repellents is very critical for control. However occasional toxic effects of the commercial repellents have been reported that include central nervous system depression and urticaria. In our studies, repellency of three plant essential oils was assessed and was compared with two commercial repellents. Lavendual angustifolia demonstrated the highest repellency and higher repellency than DEET when was individually tested, but binary mixture of Cinnamomum zeylinicam and Juniperus verginiana showed significantly higher repellency with synergic effects than mixture of Lavendula angustifolia and Juniperus verginiana. Further study on repellency of the C. zelinicam in field need.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne zoonosis and SFTS virus is transmitted to humans by tick bites. The aim of this study was to monitor tick population and its SFTS virus infection. During March 2014 to October 2015, ticks were monthly sampled using dry-ice bait trap and flag method from 4 collecting points in Boeun-gun. A total of 16,500 ticks, including 14,646 Haemaphysalis longicornis (88.7%), 1,825 H. flava (11.1%), and 29 Ixodes nipponensis (0.2%), were collected. Ticks were pooled (5,156 ticks in 456 pools) and tested by RT-PCR and nested PCR and the minimum infection rate of ticks was 0.27% (14 pools) consisting of 0.13% H. longicornis (6 pools), 1.19% H. flava (8 pools). This annual surveillance study will be needed for long-term monitoring of ixodid ticks in Korea.