Vol. 8 No. 16 PUBLIC HEALTH WEEKLY REPORT, KCDC 중증열성혈소판감소증후군매개작은소피참진드기의특성 Biological Characteristics of Haemaphysalis longicornis (Acari: Ixodidae), a Vector of Severe Fever with Thrombocytopenia Syndrome (SFTS) Abstract Haemaphysalis longicornis is known as the vector of Sever Fever with Thrombocytopenia Syndrome (SFTS), and has become recognized in Korea recently as the murderer tick. The body length of this species ranges from 0.5mm (very small) to 4mm (small). The tick s body is dorsoventrally flattened, oval and hardened with yellow brown to brown color. The feeding behavior of this species at every stage of its life cycle is parasitic. The tick feeds on the blood of its host and transmits pathogens during feeding. This study provided information on the morphological and biological characteristics of H. longicornis. Anyone unfamiliar with ticks should read this document so as to identify this parasite and to learn some general information about this species. High resolution stereo and scanning electron microscopic pictures of H. longicornis endemic in the Republic of Korea were also attached in this for identification purposes. 질병관리본부국립보건연구원면역병리센터질병매개곤충과이학선, 양성찬, 신이현, 주영란 1) 작은소피참진드기 (Haemaphysalis longicornis Neumann, 1901) 는 bunyaviridae에속하는 virus에의해발병하는중증열성혈소판감소증후군 (Severe Fever with Thrombocytopenia Syndrome, SFTS) 의주요매개체로국내언론보도를통해 살인진드기 로주목받았던종이다. 중증열성혈소판감소증후군을매개하는진드기를보다쉽게식별하고이해함으로서사람과진드기의접촉을줄이기위한기초적인정보를제공하고자작은소피참진드기에대한형태적인특징과생태에대한정보를제시하였다. 작은소피참진드기는곤충이아닌, 분류학적으로동물계 (Kingdom Animalia), 절지동물문 (Phylum Athropoda), 거미강 (Class Arachnida), 진드기목 (Order Acari), 후기문아목 (Suborder Ixodida), 참진드기과 (Ixodidae) 에속한다. 또한일반적으로 hard tick이라고도불리우는참진드기 (Ixodid ticks) 의범주에포함된다 [1]. 생활사에따라알, 유충, 약충, 성충순으로성장하며성충의경우약 2-4mm, 약충의경우 1-2mm, 유충의경우 0.5mm 내외이며보통짙은갈색부터황갈색의색상을보인다 (Figure 1-4). 알은작은타원형모양으로길이약 0.6mm, 너비약 0.4mm 이며밝은갈색을띤다. 유충, 약충, 성충의전체적인형태는위아래로납작한타원형으로유충은 3쌍의다리를갖고있고약충과성충은 4쌍의다리를갖고있다. 특히성충은피참진드기속 (Genus Haemaphysalis) 진드기들의특징이잘나타나는데그특징은다음과같다. 1) 주둥이는원추형태로촉수두번째마디가의두기부보다폭이더넓음, 2) 순판에무늬가없음, 3) 눈이없음, 4) 다리부절에가시 (spur) 가없음, 5) 항문선이항문뒤쪽에위치함 (Figure 1-6). 암컷성충의경우특이하게흡혈시 10mm 가량커지며, 흡혈전의형태와전혀다른모습을나타낸다. 온대기후지역에주로분포하는작은소피참진드기는우리나라전역을포함한일본, 중국, 극동러시아, 호주, 뉴질랜드, 피지, 뉴칼레도니아, 하와이에서식하는것으로알려져있으며 [2]. 1) 교신저자 (juyran@korea.kr/043-719-8560) www.cdc.go.kr 351
주간건강과질병 제 8 권제 16 호 2011년부터 2014년까지질병매개곤충과에서조사한채집데이터에서도전국에걸쳐고르게분포하는것으로나타났다 (Figure 7). 계절별작은소피참진드기의발생은성충의경우 6-8월사이, 약충의경우 4-6월사이인것으로확인되었고, 유충의경우 8월에높은밀도로채집되어 9월에가장많은수가채집되었으며 10월에는상대적으로적은수가채집되는것으로나타났다 [3]. 작은소피참진드기는 3숙주진드기 (three host tick) 로유충, 약충및성충단계에서숙주동물을바꾸어가며흡혈한다. 흡혈대상을찾아다니기보다는식물에기어올라숙주를기다렸다가달라붙는습성을갖고있으며, 흡혈을위해숙주동물에붙어있는시간이외에는일반적으로지면이나식물에서지낸다. 가장일반적인숙주동물로서가축으로기르는 소를선호하는것으로알려져있으며사람, 말, 사슴, 양, 고양이, 개, 돼지, 염소, 다람쥐등의포유동물과일부닭, 오리등의조류에서도발견된기록이있다 [2, 4]. 성충암컷은 5-6일가량숙주동물의혈액을충분히흡혈한후성숙기간을거쳐대략 1,000-2,000 개의알을낳으며알은 37-90일사이에유충으로부화하게된다. 유충은숙주동물에게붙은뒤 4일가량의충분한흡혈을한후땅으로떨어져 19-22일후에약충으로탈피한다. 약충은숙주동물에게붙은뒤 4-5 일가량흡혈하며땅으로떨어져 23-95일후에성충으로탈피한다. 야생의환경에서흡혈하지않은상태로얼마나생존하는지는아직알려지지않았으나실험적환경에서흡혈하지않은유충은 217일, 흡혈하지않은약충은 263일, 흡혈하지않은성충은 249일가량을생존한기록이있으며온도와습도에따라 Figure 1. Stereo microscopic pictures of Haemaphysalis longicornis (A-F, Adult, Body length 2.61 mm). A, Body in dorsal view; B, Body in ventral view; C, Mouth part in dorsal view; D, Mouth part in ventral view; E, Coxae and genital aperture; F, Anus, ventral plates and stigma. 352 www.cdc.go.kr
Vol. 8 No. 16 PUBLIC HEALTH WEEKLY REPORT, KCDC 생존기간이달라지는것으로알려져있다 [5]. 작은소피참진드기는이처럼다양한숙주동물에붙어지내면서 혈액등의체액을흡혈하는과정을통하여중증열성혈소판 감소증후군, 진드기매개뇌염, 바베시아증, 아나플라즈마증, 리케치아성질병등을매개할능력이있는것으로알려져있다 [6, 7, 8]. Figure 2. Stereo microscopic pictures of Haemaphysalis longicornis (A-F, Adult, Body length 3.37 mm). A, Body in dorsal view; B, Body in ventral view; C, Mouth part in dorsal view; D, Mouth part in ventral view; E, Coxae and genital aperture; F, Anus, ventral plates and stigma. www.cdc.go.kr 353
주간건강과질병 제 8 권제 16 호 Figure 3. Stereo microscopic pictures of Haemaphysalis longicornis (A-F, Nymph, Body length 1.52 mm). A, Body in dorsal view; B, Body in ventral view; C, Mouth part in dorsal view; D, Mouth part in ventral view; E, Coxae and genital aperture; F, Anus, ventral plates and stigma. Figure 4. Stereo microscopic pictures of Haemaphysalis longicornis (A-B, Larva, Body length 0.53 mm). A, Hole body in dorsal view; B, Hole body in ventral view. 354 www.cdc.go.kr
Vol. 8 No. 16 PUBLIC HEALTH WEEKLY REPORT, KCDC Figure 5. Scanning electron microscope observation of adult H. longicornis Female (A, C, E, G and H) and Male (B, D and F). H. longicornis has Palpal segment III with dorsal retrograde spur (A and B) and it was observed coxa I with long and sharply spur in both sexes (G). Their male genital aperture shape was sawtooth like shape (E) and female was round shape (F). H. longicornis has circular shape spiracular plates (H). Figure 6. Scanning electron microscope observation of nymph stage (A-C) and larva stage (D-F). Dorsal view of their capitulum, palpal segment III without dorsal retrograde spur (A and D), and showed projectioned irregularly capitilum in nymph stage (A) than larva stage (D). Their basis capituli was gently round shape (B and E). It was observed coxa I with long and sharply spur in H. longicornis Nymph than larval stage (C and F). www.cdc.go.kr 355
주간건강과질병 제 8 권제 16 호 4. Yamaguti N, Tipton VJ, Keegan HL, Toshioka S. 1971. Ticks of Japan, Korea, and Ryukyu islands. Brigham Young University Science Bulletin, Biological Series. 15(1):94-100. 5. Barker SC, Walker AR. 2014. Ticks of Australia. Zootaxa. 3816(1):1-144. 6. Heath ACG. 2002. Vector competence of Haemaphysalis longicornis with particular reference to blood parasites. Surveillance. 29(4):12-14. 7. Kim SY, Yeong YE, Yun SM, Lee IY, Han MG, Ju YR. 2009. Molecular evidence for tick-borne encephalitis virus in south Korea. Medical and Veterinary Entomology. 23(1):15-20. 8. Yu XJ, Liang MF, Zhang SY, Liu Y, Li JD, Sun YL, Zhang L, Zhang QF, Popov VL, Li C, Qu J, Li Q, Zhang YP, Hai R, Wu W, Wang Q, Zhan FX, Wang XJ, Kan B, Wang SW, Yin WW, Zhou H, Guan XH, Liu JF, Bi ZQ, Liu GH, Ren J, Wang H, Zhao Z, Song JD, He JR, Wan T, Zhang JS, Fu XP, Sun LN, Dong XP, Feng ZJ, Yang WZ, Hong T, Zhang Y, Walker DH, Wang Y, Li DX. 2011. Fever with thrombocytopenia associated with a novel bunyavirus in China. The New England Journal of Medicine. 364(16):1523-1532. Figure 7. Collecting area of Haemaphysalis longicornis in the Republic of Korea from 2011 to 2014. 참고문헌 1. Walker AR, Bouattour A, Camicas J-L, Estrada-Peña A, Horak IG, Latif AA, Pegram RG, Preston PM. 2003. Ticks of domestic animals in Africa: a guide to identification of species. Bioscience Reports, Edinburgh. p.21. 2. Hoogstraal H, Roberts FHS, Kohls GM, Tipton VJ. 1968. Review of Haemaphysalis (Kaiseriana) longicornis Neuman (resurrected) of Australia, New Zealand, New Caledonia, Fiji, Japan, Korea, and Northeastern China and USSR, and its parthenogenetic and bisexual populations (Ixodoidea, Ixodidae). The Journal of Parasitology. 54(6):1197-1213. 3. Chong ST, Kim HC, Lee IY, Kollars TM Jr., Sancho AR, Sames WJ, Chae JS, Klein TA. 2013. Seasonal distribution of ticks in four habitats near the demilitarised zone, Gyeonggi-do (province), republic of Korea. Korean journal of parasitology. 51(3):319-325. 356 www.cdc.go.kr