• The Korean Journal of Ecology
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• v.21 no.1
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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.

• Parasites, Hosts and Diseases
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• v.35 no.3
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• pp.171-180
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• 1997

Studies on geographical distributions and relative population densities of the vector mites of tsutsugamushi disease were carried out in October 1996 at 12 locations of the mid south inland of the Korean peninsula, where chigger mites have been never studied. Of 177 field rodents and insectivores collected. 154 (87.0%) were Apodemus ngrarius. Total 25,707 chigger mites were collected and 14 species were identified. of which Leptotrombidium pnllidum was predominant (79.8%) and L. palpate the next (8.9%) . L. pallidum, the vector species, was widely distributed in all study areas, showing the highest density at Cho-o 2-dong, Sangju-si (chigger index 201.8), and the lowest at Tanwol-dong. Chungiu-si (chigger index 40.7) . The other vector species, L. scutellare was found only at the southern part of the study area such as Yobae and Mipyong, Kumrung gun and Vnsu , Kimchon-si. The northernmost areas of the L. scutellcre distribution were coincided with the areas where actual mean air temperature is above 10.0%. Among 157 A. ograrius sera tested, 48.3% was Karp, 1.7% william and 3.3% Kuroki. The rest of the sera were not able to determine the sexto-type because of the cross antigen-antibody reactions among the tested sero-types.

• Parasites, Hosts and Diseases
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• v.34 no.1
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• pp.27-34
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• 1996

The geographical distribution and population density of rodents and chigger mites at six localities of Chollanam-do were investigated from October to December in 1993. Among total 142 field rodents collected by the modified Chemin wooden traps, 131 rodents were Aponemw usrari,us (92.3%) and 11 were Crocidurc losiurc (7.7%). Out of 142 field rodents, 92 were parasitized by chiggers, showing 69.0% of the infestation rate and 74.2 of the chiggor index. Infestation rate and chigger index of A. omfernrius and C. lusiurc were 73.3%, 80.4 and 18.2%, 0.5, respectively. From the trapped field rodents, 10,532 chiggers were collected and identified with 11 species of 4 genera. Leptotrombidium pcLLinun. the vector 3pecies of tsutsugamushi disease, was the dominant species, showing 8,038 chi99ers (76.31%). L. scutellnre was the second dominant species showing 1,359 chiggers (12.9%). The distribution of chigger mites was clearly localized by the species, showing the different dominant species according to localities. The predominant species was 1. scutellare (100%) in Changhung-gun, 1. scutellcre (41.5%) in Posong-gun, 1. pnllidum (88.8%) in Hwasun- gun, 1. pnLlidunl (59.2%) in Koksong-gun, 1. zetum (77.3%) in Hampyong-gun, and 1. pclpcle (63.4%) in Tamyang-gun. Regarding to the geographical distribution of chigger population density, the infestation rate and chigger index was most high in Hwasun-gun as 62.4% and 216.2 respectively, and next high in Koksong-gun as 22.4% and 77.7%, respectively.

• Tuberculosis and Respiratory Diseases
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• v.63 no.4
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• pp.378-381
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• 2007

Tsutsugamushi disease (Scrub typhus) is an acute, febrile illness caused by Orientia tsutsugamushi, which is transmitted to humans through chigger bites. Leptospirosis, a febrile disease caused by various pathogenic Leptospira, and is acquired by exposure to contaminated water and soil. Both diseases have been the most common acute febrile diseases in the autumn in Korea for many years. Concomitant leptospirosis and scrub typhus is quite rare. We report a case of a coinfection with leptospirosis and scrub typhus in a 51-year-old male who presented with fever, abdominal pain and acute dyspnea. The patient was diagnosed with as acalculous cholecystitis, acute respiratory distress syndrome, and septic shock caused by the infection. This is the first case report of a coinfection with leptospirosis and scrub typhus in Korea.

• The Korean Journal of Zoology
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• v.2 no.1
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• pp.17-28
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• 1959

In Korea ,little attention was paid to chiggers until 1950 so only to reports on four species of chiggers were pulished before Korean War. Since 1950 (beginning of Korean War), a marked progress in the study of chiggers has been made in connection with investigations of Epidemic hemorrhagic fever occurring among the United Nations troops which was suspected as a chigger-borne infectious disease and the first report of tsutsugamushi disease in Korea called natives attention to chiggers as the vector mites of this newly known disease in Korea. This paper is mostly based on specimens of author's collections from 3269 Rodentia Insectivora, 9 Chiroptera, 24 Aves , 35 Amphibia and 3 Reptilia during the time from December 1955 to December 1956 but four species were introduced here from works of others . There are reported here five species of chiggers previously known only out of Korea and a new species also. This new species was collected by author but Lipovsky informed his colleague had collected the same one in Korea and they would publish it as new one in near future. This is the reason of describing the new species without specific name . Of course, this paper is incomplete in view of the geographic distribution, seosonal change and host relation etc, but will serve as a brief summary of the chiggers fauna of Korea up to the present. This species described here are as follows : Gahrliepia brennani var. ventralis Neoschongastia posekanyi Euschongastia kigtajimai Euschongastia miyagawai Euschongastia koreaensis Trombicula nagayoi Trombicula japonica Trombicula pomeranzevi Trombicula mitamurai Trombicula tamiyai Trombicula palpalis Trombicula orientalis Trombicula pallida Trombicula scutellaris Trobmicula miotis Trombicula hiranumai Trombicula sp. Trombicula hiranumai Trombicula sp. Trombicula subintermedius Shunsennia tarsalis . Euschongastia ikaoensis . Trombicula koomori Trombicul subakanushi

• Parasites, Hosts and Diseases
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• v.52 no.2
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• pp.225-229
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• 2014

A total of 9,281 larval chigger mites were collected from small mammals captured at Hwaseong-gun, Gyeonggi-do (Province) (2,754 mites from 30 small mammals), Asan city, Chungcheongnam-do (3,358 mites from 48 mammals), and Jangseong-gun, Jeollanam-do (3,169 for 62 mammals) from April-November 2009 in the Republic of Korea (= Korea) and were identified to species. Leptotrombidium pallidum was the predominant species in Hwaseong (95.8%) and Asan (61.2%), while Leptotrombidium scutellare was the predominant species collected from Jangseong (80.1%). Overall, larval chigger mite indices decreased from April (27.3) to June (4.9), then increased in September (95.2) and to a high level in November (169.3). These data suggest that L. pallidum and L. scutellare are the primary vectors of scrub typhus throughout their range in Korea. While other species of larval chigger mites were also collected with some implications in the transmission of Orientia tsutsugamushi, they only accounted for 11.2% of all larval chigger mites collected from small mammals.

• Proceedings of the Microbiological Society of Korea Conference
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• 2007.05a
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• pp.137-137
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• 2007

• Tuberculosis and Respiratory Diseases
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• v.61 no.4
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• pp.389-393
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• 2006

Tsutstugamushi disease is a major febrile disease that generally occurs in the fall in Korea with hemorrhagic fever with renal syndrome and leptospirosis. This disease is often accompanied by interstitial pneumonia, acute renal failure and liver failure. The causative agent, namely Orientia tsutsugamushi, is transmitted to humans through the bite of a laval trombiculid mite, which is commonly known as a chigger. A 78 year old man was admitted in October 2004 with intractable fever and a drowsy mentality. Two weeks earlier, he visited a private clinic complaining of a simple skin rash. He was treated with antihistamine and steroid, but his symptoms were aggravated and he was referred to our hospital. His physical examination and laboratory findings showed a septic shock status. The maculopapular rash had spread over his face, chest, abdomen and extremities. Eschar was observed in lower back area but it was too difficult to distinguish it from other skin rashes. His chest X-ray appeared as diffuse nodular patchy consolidations in the bilateral lung parenchyme. He was treated with a mechanical ventilator and doxycycline under th suspicion of Tsutstugamushi disease. However, he suffered multiorgan failure accompanied by acute respiratory distress syndrome, acute renal failure and acute hepatitis. He was treated in the intensive care unit for approximately 12 weeks and his general condition was recovered.

• Parasites, Hosts and Diseases
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• v.27 no.2
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• pp.141-144
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• 1989

During October-December 1987, chigger mites infested on the striped field mice (Apodemus agrarius cereae) collected at Pochun-gun, Gyeonggi Province and Chinhae city, Kyongnam Province were identified. . 1. Of 171 back-striped mice collected, chigger mites wire found from 58 mice, showing 33.9% of infestation rate. 2. Total 865 chigger mites collected were classified into seven species; Leptotrombidium pallidum (4.3%), L. palpate(23.0%), L. orienpalis(20.2%), L. xetum(19.0%), Neotrombicula tamiyai(32.9%), JV. japonica(0.25%) and Euschongastia koreaensis(0.3%). Though the most dominant species in number was N. tamiyai(32.9% of the total), this species was collected at very limited locality and for a short period. Therefore, most common species in Korea seems to be L. palpale which was found at all localities throughout the whole survey period. L. pallidum which is known as the vector species of tsutsugamushi disease in Korea was collected in a very low number(4.3% of the total chiggers collected). 3. The number of chigger mites infested on a host animal showed great variations from one chigger up to 207 chiggers. The present study has shown that there may be other Leptotrombidium species mite(s) for the vector and host of tsutsugamushi disease in Korea.

• Parasites, Hosts and Diseases
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• v.56 no.5
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• pp.521-525
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• 2018

Rodents are well-known reservoirs and vectors of many emerging and re-emerging infectious diseases, but little is known about their role in zoonotic disease transmission in Bhutan. In this study, a cross-sectional investigation of zoonotic disease pathogens in rodents was performed in Chukha district, Bhutan, where a high incidence of scrub typhus and cases of acute undifferentiated febrile illness had been reported in people during the preceding 4-6 months. Twelve rodents were trapped alive using wire-mesh traps. Following euthanasia, liver and kidney tissues were removed and tested using PCR for Orientia tsutsugamushi and other bacterial and rickettsial pathogens causing bartonellosis, borreliosis, human monocytic ehrlichiosis, human granulocytic anaplasmosis, leptospirosis, and rickettsiosis. A phylogenetic analysis was performed on all rodent species captured and pathogens detected. Four out of the 12 rodents (33.3%) tested positive by PCR for zoonotic pathogens. Anaplasma phagocytophilum, Bartonella grahamii, and B. queenslandensis were identified for the first time in Bhutan. Leptospira interrogans was also detected for the first time from rodents in Bhutan. The findings demonstrate the presence of these zoonotic pathogens in rodents in Bhutan, which may pose a risk of disease transmission to humans.