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Kim SY, Gill B, Song BG, Chu H, Park WI, Lee HI, Shin EH, Cho SH, Roh JY. Annual Fluctuation in Chigger Mite Populations and Orientia Tsutsugamushi Infections in Scrub Typhus Endemic Regions of South Korea. Osong Public Health Res Perspect 2019; 10:351-358. [PMID: 31897364 PMCID: PMC6927423 DOI: 10.24171/j.phrp.2019.10.6.05] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Objectives Chigger mites are vectors for scrub typhus. This study evaluated the annual fluctuations in chigger mite populations and Orientia tsutsugamushi infections in South Korea. Methods During 2006 and 2007, chigger mites were collected monthly from wild rodents in 4 scrub typhus endemic regions of South Korea. The chigger mites were classified based on morphological characteristics, and analyzed using nested PCR for the detection of Orientia tsutsugamushi. Results During the surveillance period, the overall trapping rate for wild rodents was 10.8%. In total, 17,457 chigger mites (representing 5 genera and 15 species) were collected, and the average chigger index (representing the number of chigger mites per rodent), was 31.7. The monthly chigger index was consistently high (> 30) in Spring (March to April) and Autumn (October to November). The mite species included Leptotrombidium pallidum (43.5%), L. orientale (18.9%), L. scutellare (18.1%), L. palpale (10.6%), and L. zetum (3.6%). L. scutellare and L. palpale populations, were relatively higher in Autumn. Monthly O. tsutsugamushi infection rates in wild rodents (average: 4.8%) and chigger mites (average: 0.7%) peaked in Spring and Autumn. Conclusion The findings demonstrated a bimodal pattern of the incidence of O. tsutsugamushi infections. Higher infection rates were observed in both wild rodents and chigger mites, in Spring and Autumn. However, this did not reflect the unimodal incidence of scrub typhus in Autumn. Further studies are needed to identify factors, such as human behavior and harvesting in Autumn that may explain this discordance.
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Affiliation(s)
- Seong Yoon Kim
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Byoungchul Gill
- Division of Laboratory Diagnosis Management, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Bong Gu Song
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Hyuk Chu
- Division of Bacterial Disease Research, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Won Il Park
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Hee Il Lee
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - E-Hyun Shin
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Shin-Hyeong Cho
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Jong Yul Roh
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
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Lee HJ, Park C. Distribution of Chigger Mites as Tsutsugamushi Vectors Sampled in Seogwipo. KOREAN JOURNAL OF CLINICAL LABORATORY SCIENCE 2019. [DOI: 10.15324/kjcls.2019.51.3.344] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Hyeok Jae Lee
- Department of Clinical Laboratory Science, Gwangju Health Science University, Gwangju, Korea
| | - Chul Park
- Department of Clinical Laboratory Science, Gwangju Health Science University, Gwangju, Korea
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Choi YJ, Lee IY, Song HJ, Kim J, Park HJ, Song D, Jang WJ. Geographical distribution of Orientia tsutsugamushi strains in chiggers from three provinces in Korea. Microbiol Immunol 2018; 62:547-553. [PMID: 30035807 DOI: 10.1111/1348-0421.12639] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/15/2018] [Accepted: 07/12/2018] [Indexed: 11/28/2022]
Abstract
Chiggers were collected from the central and southern parts of South Korea between April and November, 2009 with the aim of investigating the seasonal and geographical distribution of Or. A total of 1136 chiggers were identified. They included eight species belonging to four genera, as follows: Leptotrombidium scutellare (27.2%, n = 309), L. pallidum (54.6%, n = 621), L. orientale (6.25%, n = 71), L. palpale (1.59%, n = 18), L. zetum (2.0%, n = 23), Euschoengastia koreaensis (1.5%, n = 17), Cheladonta ikaoensis (0.08%, n = 1) and Neotrombicula japonica (1.05%, n = 12). The density of L. pallidum was high from April to May, whereas L. scutallare was not found in spring, being observed from October. Serotype-specific nested PCR targeting the 56 kDa protein gene and sequencing analysis identified that the strains of 1136 O. tsutsugamushi in the chiggers as Boryong (6.8%), Kanda (0.4%), Oishi (0.3%), Jecheon (0.1%), Youngworl (0.1%) and Wonju (0.1%). Our findings indicate that L. pallidum and L. scutellare are dominant species in Korea and have geographical and seasonal variations.
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Affiliation(s)
- Yeon-Joo Choi
- Department of Microbiology, College of Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143 701, Korea
| | - In-Yong Lee
- Department of Environmental Medical Biology, College of Medicine, Yonsei University, 50 Yonsei-ro, Seoul 120 752, Korea
| | - Hyeon-Je Song
- Department of Clinical Pathology, Gwangju Health College, 73 Bungmun Dae-ro, Gwangju 506 701, Korea
| | - Jeoungyeon Kim
- Department of Microbiology, College of Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143 701, Korea
| | - Hye-Jin Park
- Department of Microbiology, College of Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143 701, Korea
| | - Dayoung Song
- Department of Microbiology, College of Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143 701, Korea
| | - Won-Jong Jang
- Department of Microbiology, College of Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143 701, Korea
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Abstract
BACKGROUND The incidence rate of scrub typhus has been increasing in the Republic of Korea. Previous studies have suggested that this trend may have resulted from the effects of climate change on the transmission dynamics among vectors and hosts, but a clear explanation of the process is still lacking. In this study, we applied mathematical models to explore the potential factors that influence the epidemiology of tsutsugamushi disease. METHODS We developed mathematical models of ordinary differential equations including human, rodent and mite groups. Two models, including simple and complex models, were developed, and all parameters employed in the models were adopted from previous articles that represent epidemiological situations in the Republic of Korea. RESULTS The simulation results showed that the force of infection at the equilibrium state under the simple model was 0.236 (per 100,000 person-months), and that in the complex model was 26.796 (per 100,000 person-months). Sensitivity analyses indicated that the most influential parameters were rodent and mite populations and contact rate between them for the simple model, and trans-ovarian transmission for the complex model. In both models, contact rate between humans and mites is more influential than morality rate of rodent and mite group. CONCLUSION The results indicate that the effect of controlling either rodents or mites could be limited, and reducing the contact rate between humans and mites is more practical and effective strategy. However, the current level of control would be insufficient relative to the growing mite population.
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Affiliation(s)
- Kyung Duk Min
- Department of Public Health Science, Graduate School of Public Health, Seoul National University, Seoul, Korea
| | - Sung Il Cho
- Department of Public Health Science, Graduate School of Public Health, Seoul National University, Seoul, Korea
- Institute of Health and Environment, Seoul National University, Seoul, Korea.
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Choi MB, Lee WG, Kang HJ, Yang SC, Song BG, Shin EH, Kwon O. Seasonal prevalence and species composition of mosquitoes and chigger mites collected from Daegu, Gunwi and Sangju in South Korea, 2014. ACTA ACUST UNITED AC 2017. [DOI: 10.1186/s41610-017-0030-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Song H. Distribution and Population Density of Rodents and Chigger Mites in Gokseong-gun of Jeollanam-do, Korea. KOREAN JOURNAL OF CLINICAL LABORATORY SCIENCE 2016. [DOI: 10.15324/kjcls.2016.48.3.242] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Hyeonje Song
- Department of Clinical Pathology, Gwangju Health University, Gwangju 62287, Korea
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Park JW, Chung JK, Kim SH, Cho SJ, Ha YD, Jung SH, Park HJ, Song HJ, Lee JY, Kim DM, Pyus J, Ha DR, Kim ES, Lee JI. Seroepidemiological Survey of Zoonotic Diseases in Small Mammals with PCR Detection of Orientia tsutsugamushi in Chiggers, Gwangju, Korea. THE KOREAN JOURNAL OF PARASITOLOGY 2016; 54:307-13. [PMID: 27417085 PMCID: PMC4977789 DOI: 10.3347/kjp.2016.54.3.307] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 04/26/2016] [Accepted: 05/02/2016] [Indexed: 11/24/2022]
Abstract
Serosurveillance for zoonotic diseases in small mammals and detection of chiggers, the vector of Orientia tsutsugamushi, were conducted from September 2014 to August 2015 in Gwangju Metropolitan Area. Apodemus agrarius was the most commonly collected small mammals (158; 91.8%), followed by Myodes regulus (8; 4.6%), and Crocidura lasiura (6; 3.5%). The highest seroprevalence of small mammals for O. tsutsugamushi (41; 26.3%) was followed by hantaviruses (24; 15.4%), Rickettsia spp. (22; 14.1%), and Leptospira (2; 1.3%). A total of 3,194 chiggers were collected from small mammals, and 1,236 of 3,194 chiggers were identified with 7 species of 3 genera: Leptotrombidium scutellare was the most commonly collected species (585; 47.3%), followed by L. orientale (422; 34.1%), Euchoengastia koreaensis (99; 8.0%), L. palpale (58; 4.7%), L. pallidum (36; 2.9%), Neotrombicula gardellai (28; 2.3%), and L. zetum (8; 0.6%). L. scutellare was the predominant species. Three of 1,236 chigger mites were positive for O. tsutsugamushi by PCR. As a result of phylogenetic analysis, the O. tsutsugamushi strain of chigger mites had sequence homology of 90.1-98.2% with Boryong. This study provides baseline data on the distribution of zoonotic diseases and potential vectors for the development of prevention strategies of vector borne diseases in Gwangju metropolitan area.
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Affiliation(s)
- Jung Wook Park
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju City, Gwangju 61986, Korea
| | - Jae Keun Chung
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju City, Gwangju 61986, Korea
| | - Sun Hee Kim
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju City, Gwangju 61986, Korea
| | - Sun Ju Cho
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju City, Gwangju 61986, Korea
| | - Yi Deun Ha
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju City, Gwangju 61986, Korea
| | - So Hyang Jung
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju City, Gwangju 61986, Korea
| | - Hye Jung Park
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju City, Gwangju 61986, Korea
| | - Hyun Jae Song
- Clinical Pathology, Gwangju Health University, Gwangju 62287, Korea
| | - Jung Yoon Lee
- Clinical Pathology, Gwangju Health University, Gwangju 62287, Korea
| | - Dong Min Kim
- Department of Internal Medicine, School of Medicine, Chosun University, Gwangju 61452, Korea
| | - Jah Pyus
- Department of Internal Medicine, School of Medicine, Chosun University, Gwangju 61452, Korea
| | - Dong Ryong Ha
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju City, Gwangju 61986, Korea
| | - Eun Sun Kim
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju City, Gwangju 61986, Korea
| | - Jae Il Lee
- Department of Veterinary Public Health, College of Veterinary Medicine, Chonnam National University, Gwangu 62287, Korea
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Park GM, Shin HS. Geographical Distribution and Seasonal Indices of Chigger Mites on Small Mammals Collected on the East Coast of the Republic of Korea. J Parasitol 2015; 102:193-8. [PMID: 26653927 DOI: 10.1645/15-760] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The geographical distributions and relative population densities of scrub typhus vector mites collected from small mammals were determined for 5 locations on the east coast of the Republic of Korea. Collection sites included Goseong, Gangneung, and Hoengseong in Gangwon province and Uljin and Yeongdeok in Gyeongbuk province. A total of 275 small mammals including members of Rodentia (rodents) and Soricomorpha (shrews, such as Crocidura lasiura ) belonging to 4 genera and 4 species were captured in the field from 2012 to 2013. Apodemus agrarius was collected most frequently (220, 80%), followed by C. lasiura (25, 9.1%), Mus musculus (15, 5.5%), and Myodes regulus (15, 5.5%). A total of 23,436 larval chigger mites (Family Trombiculidae) belonging to 3 genera and 8 species (Leptotrombidium pallidum, Leptotrombidium scutellare, Leptotrombidium palpale, Leptotrombidium orientale, Leptotrombidium zetum, Neotrombicula tamiyai, Neotrombicula japonica, and Euschoengastica koreaensis) were collected from the small mammals. The predominant chigger species collected during the spring and fall seasons from A. agrarius were L. pallidum (57.6%), L. palpale (14.5%), and L. scutellare (7.9%). Leptotrombidium scutellare was collected only along the southeastern coast at Yeongdeok, Gyeongbuk province. The geographical distribution of scrub typhus vectors and reservoir hosts are important aspects of understanding the epidemiology of the disease as well as the potential impacts of climate change and health risks.
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Affiliation(s)
- Gab-Man Park
- Department of Environmental Medical Biology and Institute for Clinical and Translational Research, Catholic Kwandong University College of Medicine, 24 Beomil-ro 579 Beon-gil, Gangneung-si, Gangwon-do, Korea
| | - Ho-Sung Shin
- Department of Environmental Medical Biology and Institute for Clinical and Translational Research, Catholic Kwandong University College of Medicine, 24 Beomil-ro 579 Beon-gil, Gangneung-si, Gangwon-do, Korea
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Scrub Typhus Incidence Modeling with Meteorological Factors in South Korea. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:7254-73. [PMID: 26132479 PMCID: PMC4515655 DOI: 10.3390/ijerph120707254] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/17/2015] [Accepted: 06/18/2015] [Indexed: 11/30/2022]
Abstract
Since its recurrence in 1986, scrub typhus has been occurring annually and it is considered as one of the most prevalent diseases in Korea. Scrub typhus is a 3rd grade nationally notifiable disease that has greatly increased in Korea since 2000. The objective of this study is to construct a disease incidence model for prediction and quantification of the incidences of scrub typhus. Using data from 2001 to 2010, the incidence Artificial Neural Network (ANN) model, which considers the time-lag between scrub typhus and minimum temperature, precipitation and average wind speed based on the Granger causality and spectral analysis, is constructed and tested for 2011 to 2012. Results show reliable simulation of scrub typhus incidences with selected predictors, and indicate that the seasonality in meteorological data should be considered.
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Kim HC, Lee IY, Chong ST, Richards AL, Gu SH, Song JW, Lee JS, Klein TA. Serosurveillance of scrub typhus in small mammals collected from military training sites near the DMZ, Northern Gyeonggi-do, Korea, and analysis of the relative abundance of chiggers from mammals examined. THE KOREAN JOURNAL OF PARASITOLOGY 2010; 48:237-43. [PMID: 20877503 PMCID: PMC2945799 DOI: 10.3347/kjp.2010.48.3.237] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Revised: 07/09/2010] [Accepted: 07/09/2010] [Indexed: 11/23/2022]
Abstract
Comprehensive quarterly serosurveillance on scrub typhus in small mammals collected from military training sites located near the Demilitarized Zone (DMZ), northern Gyeonggi-do (Province), ROK was conducted to determine the potential rodent-borne and associated ectoparasite disease risks to military personnel. A total of 1,196 rodents and insectivores representing 8 species, Apodemus agrarius (87.3%, n = 1,044), Mus musculus (5.4%, n = 65), Crocidura lasiura (3.3%, n = 40), Microtus fortis (2.6%, n = 31), Micromys minutus (0.3%, n = 4), Tscherskia triton (0.3%, n = 4), Rattus norvegicus (0.3%, n = 4), and Myodes regulus (0.3%, n = 4) were assayed for the presence of antibodies to Orientia tsutsugamushi. O. tsutsugamushi antibodies were detected in 6 of 8 species and seroprevalence determined; A. agrarius (45.6%), M. musculus (23.1%), M. fortis (48.4%), M. minutus (50.0%), T. triton (50.0%), and R. norvegicus (25.0%). A total of 31,184 chigger mites collected from 508 rodents and insectivores were slide-mounted and 10 species belonging to 4 genera were identified. Leptotrombidium pallidum (53.4%) was the most frequently collected, followed by L. palpale (15.7%), Neotrombicula tamiyai (14.3%), L. orientale (10.7%), L. zetum (3.1%), Walchia fragilis (2.1%), and L. gemiticulum (0.8%), while the remaining 3 species, L. subintermedium, N. gardellai, and Euschoengastia koreaensis were rarely observed (prevalence < 10%). In contrast to previous surveys, higher chigger indices of the primary scrub typhus vectors, L. pallidum (165.4), L. orientale (45.0), and L. palpale (21.4), were observed during the spring season.
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Affiliation(s)
- Heung Chul Kim
- 5th Medical Detachment, 168th Multifunctional Medical Detachment, 65th Medical Brigade, Unit #15247, APO AP 96205-5247, USA
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Lee IY, Kim HC, Lee YS, Seo JH, Lim JW, Yong TS, Klein TA, Lee WJ. Geographical distribution and relative abundance of vectors of scrub typhus in the Republic of Korea. THE KOREAN JOURNAL OF PARASITOLOGY 2009; 47:381-6. [PMID: 19967086 DOI: 10.3347/kjp.2009.47.4.381] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 10/08/2009] [Accepted: 10/14/2009] [Indexed: 11/23/2022]
Abstract
A survey to determine the geographical distribution and relative abundance of potential vectors of scrub typhus was conducted from October to November 2006 at 13 localities throughout the Republic of Korea. Apodemus agrarius accounted for 97.6% (80/82) of all rodents, while only 2 Myodes regulus (2/82) were collected. A total of 10,860 chiggers were collected from A. agrarius belonging to 4 genera and 8 species, while only Walchia fragilis (40) was collected from Myodes regulus. Leptotrombidium pallidum (8,137; 74.9%), a vector of scrub typhus, was the predominant species collected from A. agrarius followed by Leptotrombidium scutellare (2,057, 18.9%), Leptotrombidium palpale (279; 2.7%), Leptotrombidium orientale (232; 2.1%), and Leptotrombidium zetum (79; 0.7%), Neotrombicula tamiyai (58; 0.5%), Euschoengastica koreaensis (16; 0.1%), and Cheladonta ikaoensis (2; < 0.1%). L. pallidum was the predominant chigger collected at collection sites in Gangwon (100%), Gyeonggi (87.2%), Chungnam (100%), Chungbuk (100%), Jeonbuk (73.9%), Jeonnam (77.0%), and Gyeongbuk (66.1%) provinces, whereas L. scutellare was the predominant chigger collected in Gyeongnam province (77.9%) and Jeju Island (62.3%). Data suggest a correlation between chigger population abundance and human cases of scrub typhus in Korea.
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Affiliation(s)
- In Yong Lee
- Department of Environmental Medical Biology, Yonsei University College of Medicine, Seoul 120-752, Korea
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Park SD, Chung MH, Lee HM, Kim MK, Kang JS. A Case of Scrub Typhus in Summer Presenting as Atypical Pneumonia. Infect Chemother 2008. [DOI: 10.3947/ic.2008.40.4.241] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Sang Don Park
- Department of Internal Medicine, Inha University College of Medicine, Inchon, Korea
| | - Moon-Hyun Chung
- Department of Internal Medicine, Inha University College of Medicine, Inchon, Korea
| | - Hye Myung Lee
- Clinical Research Center, Inha University College of Medicine, Inchon, Korea
| | - Mee-Kyung Kim
- Clinical Research Center, Inha University College of Medicine, Inchon, Korea
| | - Jae-Seung Kang
- Department of Microbiology, Inha University College of Medicine, Inchon, Korea
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Ree HI, Lee IY, Jeon SH, Yoshida Y. Geographical distribution of vectors and sero-strains of tsutsugamushi disease at mid-south inland of Korea. THE KOREAN JOURNAL OF PARASITOLOGY 1997; 35:171-9. [PMID: 9335182 DOI: 10.3347/kjp.1997.35.3.171] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Studies of 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 agrarius. Total 25,707 chigger mites were collected and 14 species were identified, of which Leptotrombidium pallidum was predominant (79.8%) and L. palpale 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. Chungju-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, Kumrunggun and Unsu, Kimchon-si. The northernmost areas of the L. scutellare distribution were coincided with the areas where anual mean air temperature is above 10.0 C. Among 157 A. agrarius sera tested, 48.3% was Karp, 1.7% Gilliam and 3.3% Kuroki. The rest of the sera were not able to determine the sero-type because of the cross antigen-antibody reactions among the tested sero-types.
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Affiliation(s)
- H I Ree
- Department of Parasitology, College of Medicine, Yonsei University, Seoul, Korea
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