• The Korean Journal of Ecology
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• 제21권1호
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• pp.97-103
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• 1998

Yedang lake has so plentiful pondage and many species of fresh-walter-fish that a large number of people crowd around there all the year round. Most of them are not used to prevent tsutsugamushi disease spreading by chigger(T-mite). Accordingly, this study was carried out in order to obtain basic materials for prevention of this disease and the results are summarized as follows. The number of wild rat that captured in surveyed areas was sixty five(apodemus agrarius: 63, Rattus norvegicus: 2) during the period of a year and ration of captured rats to trap was about 8%. The dominant species of T-mite in all the surveyed areas were Leptotrombidium pallidum and L. palpale and the total number collected was 5782.9 with one family, two genra, eight species. The density of T-mites that collected from rats in three areas(Nodongri, Hatanbangri, Kyochonri) appeared $743.3{\pm}80.4,\;847.2{\pm}86.2\;and\;869.6{\pm}86.4,\;and\;in\;soil\;149.5{\pm}13.9,;154.7{\pm}14.7\;and\;182.4{\pm}20.8$ respectively. On the whole, the number of T-mite that collected from the rats was about three times as much as it in soil. The comparison of individual number of T-mite per a rat collected in three surveyed sites(A,B and C) showed 126.7, 243.1, 258.6 and per $2,000cm^3$ of soil 12.7, 12.7, 54.6, 103.5 respectively. In other word, the number of T-mite at site A and B is smaller than that at area C, thus comparing habitats of three sites each other, C is better living environment of rat and mite than that of A or B. Seasonl occuarance of t-mite that is from rat gradually was increased toward winter and showed the peak to January, and decreased since March but it in soil was inverse proportion to it from rats, because the larvae of T-mite that was hatched in soil was transmited to host in order to suck the body fluid.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1994년도 한국생물과학협회 학술발표대회
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• pp.133.2-133
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• 1994

• Parasites, Hosts and Diseases
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• 제58권4호
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• pp.445-450
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• 2020

Trombiculid "chigger" mites (Acari) are ectoparasites that feed blood on rodents and another animals. A crosssectional survey was conducted in 7 ecosystems of southern Vietnam from 2015 to 2016. Chigger mites were identified with morphological characteristics and assayed by polymerase chain reaction for detection of rickettsiaceae. Overall chigger infestation among rodents was 23.38%. The chigger index among infested rodents was 19.37 and a mean abundance of 4.61. A total of 2,770 chigger mites were identified belonging to 6 species, 3 genera, and 1 family, and pooled into 141 pools (10-20 chiggers per pool). Two pools (1.4%) of the chiggers were positive for Orientia tsutsugamushi. Ricketsia spp. was not detected in any pools of chiggers. Further studies are needed including a larger number and diverse hosts, and environmental factors to assess scrub typhus.

• 대한임상검사과학회지
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• 제52권4호
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• pp.364-371
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• 2020

질병관리본부에서는 매개체로 인한 전파 확산에 대처하고자 전국 권역별 기후변화 매개체 감시사업을 실시하고 있으며 일환으로 전북 진안지역의 쯔쯔가무시 매개체인 털진드기 분포 조사와 병원체 검사를 위해 채집기와 야생설치류 포획을 실시하였다. 털진드기 종 분류를 위해 9~12월 둘째주까지 매주 1회씩, 총 20개의 채집기를 이용하여 채집한 결과 총 개체수는 8종 611마리가 채집되었다. 종 분류 결과는 둥근혀털진드기(N. tamiyai) 434마리(71.0%)로 가장 많이 분리되었다. 야생설치류 포획으로 털진드기 채집은 66마리의 설치류를 포획해서 털진드기 총 3,050마리 채집되어 chigger index는 46.2로 나타났다. 월별 chigger index는 11월 206.1로 가장 높았다. 병원체 보유여부 검사결과 총 85개의 pools중 5월과 9월에 각각 1개의 pools에서 양성을 확인하였다. 이러한 결과는 쯔쯔가무시증 환자가 빈번히 발생하는 봄과 가을철의 시기와도 일치하였다.

• 대한의생명과학회지
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• 제17권4호
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• pp.367-370
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• 2011

Studies on the relative abundance of potential vectors of scrub typhus was conducted from April to October 2009 at the Jangseong of Jeonnam Province, Korea. Among the total 62 field rodents collected by the Sherman collapsible traps, 56 rodents were $Apodemus$ $agrarius$ (90.3%), 4 were $Crocidura$ $lasiura$ (6.4%) and 2 were $Cricetulus$ $triton$ $nester$ (3.2%). Out of the 62 field rodents, 39 were parasitized by chiggers, showing 62.9% of the infestation rate and 80.0 of the chigger index. Chigger index of $A.$ $agrarius$ and $C.$ $triton$ $nester$ were 79.9, 82.0, respectively. But chigger mite was not collected from $C.$ $lasiura$. From the trapped field rodents, 3,120 chiggers were collected and identified with 6 species of 2 genera. $Leptotrombidium$ $scutellare$, the vector species of tsutsugamushi disease, was the dominant species, showing 2,276 chiggers (72.9%). $L.$ $pallidum$ was the second dominant species showing 346 chiggers (11.0%). The distribution of chigger mites was showed the different dominant species according to seasons. $L.$ $pallidum$ was the predominant chigger collected in April (34.8%), May (77.8%) and Jun (39.3%), whereas $L.$ $scutellare$ was the predominant chigger collected in September (78.78%) and October (76.8%).

• 대한임상검사과학회지
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• 제48권3호
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• pp.242-246
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• 2016

2013년 4월부터 11월까지 전라남도 곡성군 지역을 대상으로 들쥐를 포획하고 기생하는 털진드기의 분포를 조사하였다. 597개의 trap에서 79마리를 포획하여 포획률은 13.2%였고, 종류별로는 등줄쥐가 92.4%를 차지하여 절대 우점종이었다. 79마리의 들쥐중 68마리에 털진드기가 기생하고 있어 86.0%의 기생률을 보였고, 74.5개체의 chigger index를 보였다. 5,063개체의 채집한 털진드기는 2속 6종으로 동정되었고, 활순털진드기가 3,535개체(69.8%)로 절대적인 우점종이었다. 계절별로 봄철에는 대잎털진드기, 가을철에는 활순털진드기가 높은 밀도로 채집되어 진드기종의 분포가 채집시기에 따라 차이가 있었다.

• Parasites, Hosts and Diseases
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• 제59권5호
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• pp.473-479
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• 2021

A nationwide survey of chigger mites causing scrub typhus and an investigation of epidemiologic factors for chigger mites was conducted at 16 localities in 8 provinces in Korea during autumn 2009, 2012, and 2013. A total of 233 Apodemus agrarius were captured, and all were infested with chigger mites. The chigger index was highest in Chungcheongbuk-do in 2009 (358.3) and 2012 (290.1) and Chungcheongnam-do in 2013 (294.4). The predominant chigger mite species was Leptotrombidium pallidum in the northern and central parts and L. scutellare in the southern and western parts, Korea. L. pallidum was not found in Jellanam-do and Gyeongsangnam-do and the distribution of L. scutellare had been expanded in the northern parts of Korea. The chigger index of L. pallidum was positively correlated with temperature and negatively correlated with humidity. The incidence of scrub typhus is dependent on L. scutellare index. These findings could be helpful to monitor the distribution of chigger mites and to develop a preventive measures for scrub typhus in Korea.

• Parasites, Hosts and Diseases
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• 제58권2호
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• pp.153-159
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• 2020

The chigger mite Leptotrombidium sialkotense is one of the 6 main vectors of scrub typhus in China. Before present study, L. sialkotense was found in some parts of Hunan province, China with a narrow geographical distribution. During field investigation 2016-2017, we found L. sialkotense in Jingha, southern Yunnan, China. Of 15 small mammal host species, L. sialkotense were collected from 6 species of the hosts. Rattus brunneusculus was a dominant host of L. sialkotense, from which 98.3% of the mites were collected. The chigger mite showed a relatively high infestation prevalence (P_M =11.7%) and mean abundance (MA=0.5) in comparison with the rest 5 host species. These results reveal a certain host specificity of L. sialkotense to a rat R. brunneusculus. The mite L. sialkotense showed an aggregated distribution on the host (P<0.05). A positive correlation observed between L. sialkotense and the body length of hosts. There was a positive interspecific association between L. sialkotense and 2 other dominant vectors, L. deliense and L. scutellare.

• Parasites, Hosts and Diseases
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• 제31권4호
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• pp.341-346
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• 1993

1992년 10월부터 1993년 8월에 걸쳐 경기도 강화도와 인천직할시 영종도 2개 섬에서 털진드기에 관한 조사를 실시하였다. 포획한 42마리의 들쥐로부터 1,290개체의 털진드기를 채집하여 4속 8종을 동정하였다. 강화도에서는 전 계절을 통하여 Leptotrombidium pallidum이 93.0%를 차지하여 우점종으로 나타났으며, 영종도에서는 L. palpale가 38.4%를 차지하여 우점종이었고, L. pallidum은 한 마리도 채집되지 않았다.

• Parasites, Hosts and Diseases
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• 제59권6호
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• pp.625-634
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• 2021

Based on the field investigations in 91 investigation sites (counties) in southwest China between 2001 and 2019, the present paper reported the chigger mites on A. agrarius mice in southwest China for the first time by using a series of statistical methods. From 715 striped field mice captured in 28 of 91 investigated sites, only 255 chiggers were collected, and they were identified as 14 species, 6 genera in 3 subfamilies under 2 families. Of 715 A. agrarius mice, only 24 of them were infested with chigger mites with low overall prevalence (P_M=3.4%), overall mean abundance (M_A=0.36 mites/host) and overall mean intensity (M_I=10.63 mites/host). The species diversity and infestation of chiggers on A. agrarius were much lower than those previously reported on some other rodents in southwest China. On a certain species of rodent, A. agrarius mouse in southwest China seems to have a very low susceptibility to chigger infestations than in other geographical regions. Of 14 chigger species, there were 3 dominant species, Leptotrombidium sialkotense, L. rupestre and Schoengastiella novoconfuciana, which were of aggregated distribution among different individuals of A. agrarius hosts. L. sialkotense, one of 6 main vectors of scrub typhus in China, was the first dominant on A. agrarius. The species similarity of chigger mites on male and female hosts was low with C_SS=0.25, and this reflects the sex-bias of different genders of A. agrarius mice in harboring different chigger species.