Skip Navigation
Skip to contents

PHRP : Osong Public Health and Research Perspectives

OPEN ACCESS
SEARCH
Search

Articles

Page Path
HOME > Osong Public Health Res Perspect > Volume 4(3); 2013 > Article
Brief Report
Trends in the Incidence of Scrub Typhus: The Fastest Growing Vector-Borne Disease in Korea
Mi Ae Jeonga, Seung-Ki Younb, Young-Kwon Kimc, Hyungmin Leeb, Sun-Ja Kimb, Aeree Sohna
Osong Public Health and Research Perspectives 2013;4(3):166-169.
DOI: https://doi.org/10.1016/j.phrp.2013.04.007
Published online: April 30, 2013

aDepartment of Health, School of Public Health and Welfare, Sahmyook University, Seoul, Korea

bDivision of Epidemic Intelligence Service, Korea Centers for Disease Control and Prevention, Osong, Korea

cDepartment of Medical Science, Konyang University, Daejeon, Korea

∗Corresponding author. aeree@syu.ac.kr
• Received: February 12, 2013   • Revised: March 25, 2013   • Accepted: April 5, 2013

© 2013 Published by Elsevier B.V. on behalf of Korea Centers for Disease Control and Prevention.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

  • 2,696 Views
  • 20 Download
  • 15 Crossref
  • 12 Scopus
  • Scrub typhus, also called tsutsugamushi disease, is classified as a Group 3 disease in Korea according to the National Notifiable Diseases Surveillance Systems. It is an infectious disease transmitted to humans through the bite of mites that are infected with an intracellular parasite called Orientia tsutsugamushi (Family: Rickettsiaceae). This study aims to identify the demographic characteristics of the infected cases according to profession, region, gender, and onset period and provide a basic data for prevention and control of the disease in the infected patients. Between 2001 and 2010, 16,741 men (36.3%) and 29,373 women (63.7%) were reported to have been infected with scrub typhus, with men being 1.6 times less infected than women. When classified according to age, it was found that 4421 persons (9.6%) were under 40 years of age; 6601 (13.1%) in their 40s; 9714 (21.1%) in their 50s; 13,067 (28.3%) in 60s; 10,128 (22.0%) in their 70s; and 2723 (5.9%) aged 80 or more. The elderly (60 years or older) represented more than half of the infected cases. When the infections were classified according to region, it was found that the county residents had the major share of infection, with a total of 1583 infected cases (59.85).
Scrub typhus, also called tsutsugamushi disease, is an infectious disease transmitted to humans through the bite of mites that are infected with an intracellular parasite called Orientia tsutsugamushi (Family: Rickettsiaceae). The disease is common in rural and mountain areas [1,2]. Since 1994 the disease has been categorized under Group 3 of the National Notifiable Diseases Surveillance Systems [3]. Since then, approximately 300 incidences have been reported every year, with the number increasing over 1000 in 1998 and over 6000 in 2005, before flattening to approximately 5000 from 2009 onward. Majority of cases are reported in rural and mountain areas, with the southwestern part of Korea having a high incidence rate [4].
This study aims to identify the demographic characteristics of scrub typhus cases by classifying the infected cases according to profession, region, gender, and onset period and provide a basic data for prevention and control of the disease in the infected patients.
This study used the data reported by the National Infectious Report System of the Korea Centers for Disease Control and Prevention from 2001 to 2010. A total of 46,114 cases were analyzed according to demographic and social characteristics (age and gender), region, and month (Tables 1 and 2).
Between 2001 and 2010, 16,741 men (36.3%) and 29,373 women (63.7%) were reported to have been infected with scrub typhus, with men being 1.6 times less infected than women. Although the variation in gender is unchanging, there is a slight increase in the portion of men infected. When classified according to age, it was found that 4421 persons (9.6%) were under 40 years of age; 6601 (13.1%) in their 40s; 9714 (21.1%) in their 50s; 13,067 (28.3%) in 60s; 10,128 (22.0%) in their 70s; and 2723 (5.9%) were aged 80 or more. The elderly (60 years or older) represented more than half of the infected cases. When the infections were classified according to region, it was found that the county residents had the major share of infection, with a total of 1583 infected cases (59.85).
The disease has spread throughout the nation, with the provinces of Jeonbuk, Chungnam, Gyeongnam, and Jeonnam reportedly having relatively high incidence rates. Among the metropolitan cities, Busan has a prominent increase, whereas Daejeon has a fluctuated incidence rate. When the incidences reported in city and county were compared, it was found that 57% of the patients were shared. The difference between infected areas in county and city is more than 35% (data from 2002 to 2003); however, this difference has decreased since 2008 and in 2010 a difference of only 4.6% was reported, which is the smallest gap since 2001.
The peak months of infection were October (57.7%) and November (35.7%), representing a major portion (93.4%). The incidence rate starts to increase from September hitting peak in October and November and sharply decreases in December.
This study evaluated the characteristics of cases infected with scrub typhus in Korea in the last 10 years. In addition, the epidemiological characteristics of the national data were analyzed, based on the results of which it was found that there has been a change in the onset month and region. The number of infected cases of women cases is more than men, which is consistent with results of previous reports [4–8]. However, this difference in the rate of infection between the genders is not clearly identified. There is a similar difference between men and women in Thailand (approximately 60%) and Japan (approximately 50%). Women have higher chances of contacting the infection from mites than men, mainly because they spend more hours on the dry-field farms and tend more to kitchen garden plots than men in rural regions. In addition, when visiting relatives in rural areas, women are more willing to help in field farming. Min et al provided another possible reason for the difference in gender distribution among the elderly population; women are more than men in rural area and have more chance to go to the forests for dry-field farming [7]. Kong et al gave credit to the aspect of dry-field farming, which increased the chances of getting into contact with mite distributed on the grass, soil, and crops [9]. The farmers have the highest proportion of infected cases when the infection was classified by profession. More than of half of the cases (56%) are the elderly population, i.e., 60 years or more, which reflects the age distribution of the population. It is also to be noted that the level of immunity drops in the elderly population. Furthermore, the elderly people get physically weak with growing age, resting more on the ground or on grass during their field works, causing them to get bitten by the mites. By contrast, the infected cases in the city are relatively young compared with those of the counties. The cases are reported almost every month, with the numbers increasing in late spring and early summer and peaking from autumn to early winter. The reason is that mice, the host of the mites, are active from late August to early October when the mites are in their breeding season, thereby increasing their population in the field [10]. The proportion of the cases between January and March has steadily increased since 2005, and it is necessary to monitor the impact of change in vectors or climate change.
The limitation of this study is that the study group included only those cases infected with scrub typhus without reference group, and therefore, that we could not perform a statistical analysis of the risk factors. However, we have provided epidemiological characteristics based on the national data, which can serve as a basic evidence-based data for future prevention and control programs of scrub typhus in Korea.
Steady monitoring of the incidences with in-depth epidemiological investigation and research on risk factors such as behavior associated with infection, factors affecting sero-conversion, and identification of status of antibodies among healthy residents are necessary. The future studies could provide an effective prevention strategy and a systematic control program.
Acknowledgements
The authors thank the two scientists in the Division of Epidemic Intelligence Service in the Korea Centers for Disease Control and Prevention: Dr Chaeshin Chu for his work in translating the manuscript into English and Dr Donghyok Kwon for his meticulous review throughout the entire process in this article.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

  • 1. Jackson E.B., Danauskas J.X., Smadel J.E., Fuller H.S., Coale M.C., Bozeman F.M.. Occurrence of Rickettsia tsutsugamushi in Korean rodents and chiggers. Am J Hyg 66(3). 1957 Nov;309−320. PMID: 13478581.ArticlePubMed
  • 2. Ree H.I., Lee I.Y., Cho M.K.. Determination of the vector species of tsutsugamushi disease in Korea. Kisaengchunghak Chapchi 29(1). 1991 Mar;87−92. Korean. PMID: 1911628.ArticlePubMed
  • 3. Korea Centers for Disease Control and Prevention . Incidence of tsutsugamushi disease in 2004. Infect Dis Incid Rep 15(11). 2004;232−233. Korean.
  • 4. Choi J.S.. A study of effective management and prevention for tsutsugamushi disease. 2007. Korea Association of Agricultural Medicine, Seoul: Korea Centers for Disease Control and Prevention; Korean.
  • 5. Kim H.Y.. Clinical aspect of tsutsugamushi disease in Korea. Infect Dis Incid Rep 97(4). 2002;227−229. Korean.
  • 6. Jang J.G., Park B.G., Lee H.S.. The study of 46 cases of tsutsugamushi disease in Young-Dong region in Gang-Won-Do. J Infect Chemother 25(3). 2003;138−144. Korean.
  • 7. Min Y.S., Lim H.S., Lee K., Jung C., Cheong H.G.. A study on the epidemiologic characteristics of Scrub typhus in Gyeongsangbuk-do, 1999–2001. Korean J Epidemiol 27(2). 2005;70−79. Korean.
  • 8. Ryu S.Y.. Epidemiologic study for tsutsugamushi disease in Korea. 2006. Korea Centers for Disease Control and Prevention; Osong: Korean.
  • 9. Kong W.S., Shin E.H., Lee H.I.. Time-spatial distribution of scrub typhus and its environmental ecology. J Korean Geogr Soc 42(6). 2008;82−95. Korean.
  • 10. Clopton R.E., Gold R.E.. Distribution and seasonal and diurnal activity patterns of Eutrombicula alfreddugesi (Acari: Trombiculidae) in a forest edge ecosystem. J Med Entomol 30(1). 1993 Jan;47−53. PMID: 8433345.ArticlePubMed
Table 1
Incidence of scrub typhus in Korea, 2001–2010
Persons (%)
Month 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Gender
 Men 956 (36.1) 689 (36.0) 488 (34.6) 1669 (35.5) 2257 (34.4) 2287 (36.5) 2205 (36.8) 2217 (36.6) 1865 (37.6) 2108 (37.6)
 Women 1692 (63.9) 1227 (64.0) 923 (65.4) 3028 (64.5) 4305 (65.6) 3978 (63.5) 3790 (63.2) 3835 (63.4) 3097 (62.4) 3498 (62.4)
Age
 <40 315 (11.9) 197 (10.3) 126 (8.9) 511 (10.9) 650 (9.9) 610 (9.7) 593 (9.9) 484 (8.0) 423 (8.5) 512 (9.1)
 40–49 412 (15.6) 229 (12.0) 172 (12.2) 659 (14.0) 878 (13.4) 925 (14.8) 790 (13.2) 735 (12.1) 599 (12.1) 662 (11.8)
 50–59 562 (21.2) 366 (19.1) 264 (18.7) 926 (19.7) 1367 (20.8) 1324 (21.1) 1275 (21.3) 1324 (21.9) 1062 (21.4) 1244 (22.2)
 60–69 759 (28.7) 652 (34.0) 472 (33.5) 1376 (29.3) 1950 (29.7) 1743 (27.8) 1692 (28.2) 1662 (27.5) 1307 (26.3) 1454 (25.9)
 70–79 478 (18.1) 386 (20.1) 295 (20.9) 975 (20.8) 1364 (20.8) 1319 (21.1) 1295 (21.6) 1450 (24.0) 1231 (24.8) 1335 (23.8)
 ≥80 122 (4.6) 86 (4.5) 82 (5.8) 250 (5.3) 353 (5.4) 344 (5.5) 350 (5.8) 397 (6.6) 340 (6.9) 399 (7.1)
Region
 City 1065 (40.2) 590 (30.8) 455 (32.2) 1896 (40.4) 2883 (43.9) 2897 (46.2) 2623 (43.8) 2537 (41.9) 2218 (44.7) 2675 (47.7)
 County 1583 (59.8) 1326 (69.2) 956 (67.8) 2801 (59.6) 3679 (56.1) 3368 (53.8) 3372 (56.2) 3515 (58.1) 2744 (55.3) 2931 (52.3)
Total 2648 1916 1411 4697 6562 6265 5995 6052 4962 5606
Table 2
Incidence of scrub typhus by year and month, 2001–2010
Persons (%)
Month 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Jan 2 (0.1) 3 (0.2) 5 (0.4) 6 (0.1) 3 (0.0) 1 (0.0) 7 (0.1) 10 (0.2) 26 (0.5) 15 (0.3)
Feb 1 (0.0) 4 (0.2) 0 (0.0) 1 (0.0) 2 (0.0) 3 (0.0) 7 (0.1) 6 (0.1) 6 (0.1) 11 (0.2)
Mar 1 (0.0) 2 (0.1) 1 (0.1) 2 (0.0) 3 (0.0) 8 (0.1) 6 (0.1) 2 (0.0) 12 (0.2) 9 (0.2)
Apr 2 (0.1) 6 (0.3) 7 (0.5) 5 (0.1) 1 (0.0) 12 (0.2) 14 (0.2) 16 (0.3) 15 (0.3) 12 (0.2)
May 0 (0.0) 7 (0.4) 9 (0.6) 8 (0.2) 9 (0.1) 11 (0.2) 15 (0.3) 18 (0.3) 21 (0.4) 33 (0.6)
Jun 1 (0.0) 1 (0.1) 1 (0.1) 2 (0.0) 8 (0.1) 6 (0.1) 13 (0.2) 7 (0.1) 16 (0.3) 23 (0.4)
Jul 6 (0.2) 6 (0.3) 3 (0.2) 2 (0.0) 4 (0.1) 2 (0.0) 15 (0.3) 9 (0.2) 12 (0.2) 26 (0.5)
Aug 6 (0.2) 6 (0.3) 3 (0.2) 7 (0.2) 8 (0.1) 7 (0.1) 16 (0.3) 9 (0.2) 13 (0.3) 34 (0.6)
Sep 55 (2.1) 81 (4.3) 45 (3.2) 40 (0.9) 75 (1.2) 97 (1.6) 76 (1.3) 103 (1.7) 179 (3.7) 80 (1.5)
Oct 1646 (62.2) 1427 (75.3) 956 (67.8) 3402 (73.3) 3833 (60.9) 3553 (58.2) 2405 (40.5) 4232 (70.6) 2535 (51.9) 2623 (48.1)
Nov 898 (33.9) 344 (18.1) 360 (25.6) 1130 (24.3) 2290 (36.4) 2284 (37.4) 3275 (55.2) 1485 (24.8) 1943 (39.8) 2468 (45.2)
Dec 30 (1.1) 9 (0.5) 19 (1.3) 39 (0.8) 55 (0.9) 122 (2.0) 82 (1.4) 97 (1.6) 110 (2.3) 122 (2.2)
Total 2648 1896 1409 4644 6291 6106 5931 5994 4888 5456

Figure & Data

References

    Citations

    Citations to this article as recorded by  
    • Scrub typhus seroprevalence from an eastern state of India: findings from the state-wide serosurvey
      Debaprasad Parai, Matrujyoti Pattnaik, Jaya Singh Kshatri, Usha Kiran Rout, Annalisha Peter, Rashmi Ranjan Nanda, Subrat Kumar Sahoo, Asit Mansingh, Hari Ram Choudhary, Girish Chandra Dash, Ira Praharaj, Debdutta Bhattacharya, Sanghamitra Pati
      Transactions of The Royal Society of Tropical Medi.2023; 117(1): 22.     CrossRef
    • Epidemiological characteristics of cases with scrub typhus and their correlation with chigger mite occurrence (2019–2021): A focus on case occupation and activity locations
      Se‐Jin Jeong, Jin‐Hwan Jeon, Kyung won Hwang
      Entomological Research.2023; 53(7): 247.     CrossRef
    • Epidemiological Aspects of Tsutsugamushi Disease (Scrub Typhus) Outbreaks in Republic of Korea and Japan
      Myeong-Jin Lee, Bok Soon Han, Won-Chang Lee, Young Hwan Kwon
      The Korean Journal of Aerospace and Environmental .2022; 32(2): 65.     CrossRef
    • Scrub typhus and antibiotic-resistant Orientia tsutsugamushi
      Chin-Te Lu, Lih-Shinn Wang, Po-Ren Hsueh
      Expert Review of Anti-infective Therapy.2021; 19(12): 1519.     CrossRef
    • Seropositivity of Scrub Typhus Inpatients Attending a Tertiary Care Hospital in Western Odisha
      Shuvankar Mukherjee, Anshuman Dash, Shreekant Tiwari
      Journal of Evolution of Medical and Dental Science.2020; 9(04): 178.     CrossRef
    • Clinical and Laboratory Predictors associated with Complicated Scrub Typhus
      Mi-Hee Kim, Si-Hyun Kim, Jung-Hyun Choi, Seong-Heon Wie
      Infection & Chemotherapy.2019; 51(2): 161.     CrossRef
    • Molecular Epidemiology of an Orientia tsutsugamushi Gene Encoding a 56-kDa Type-Specific Antigen in Chiggers, Small Mammals, and Patients from the Southwest Region of Korea
      Jung Wook Park, Sun Hee Kim, Duck Woong Park, So Hyang Jung, Hye Jung Park, Mi Hee Seo, Hyeon Je Song, Jung Yoon Lee, Dong Min Kim, Choon-Mee Kim, Byong Chul Gill, Hang Jin Jeong, Jeong Min Lee, Dong Ryong Ha, Eun Sun Kim, Jae Keun Chung
      The American Journal of Tropical Medicine and Hygi.2018; 98(2): 616.     CrossRef
    • Clinical Aspects of Scrub Typhus Initially Misdiagnosed as Kawasaki Disease
      Sung Hoon Kim, Hae Jeong Lee, Ju Suk Lee
      Iranian Journal of Pediatrics.2018;[Epub]     CrossRef
    • Prevalence and risk factors for scrub typhus in South India
      Paul Trowbridge, Divya P., Prasanna S. Premkumar, George M. Varghese
      Tropical Medicine & International Health.2017; 22(5): 576.     CrossRef
    • Central Nervous System Infection Associated with Orientia tsutsugamushi in South Korea
      Kon Chu, Seon-Jae Ahn, Woo-Jin Lee, Jin-Sun Jun, Jung-Ah Lim, Keun-Hwa Jung, Kyung-Il Park, Jun-Sang Sunwoo, Han Sang Lee, Sang Kun Lee, Ki-Young Jung, Jangsup Moon, Soon-Tae Lee
      The American Journal of Tropical Medicine and Hygi.2017; 97(4): 1094.     CrossRef
    • Generation of protective immunity against Orientia tsutsugamushi infection by immunization with a zinc oxide nanoparticle combined with ScaA antigen
      Na-Young Ha, Hyun Mu Shin, Prashant Sharma, Hyun Ah Cho, Chan-Ki Min, Hong-il Kim, Nguyen Thi Hai Yen, Jae-Seung Kang, Ik-Sang Kim, Myung-Sik Choi, Young Keun Kim, Nam-Hyuk Cho
      Journal of Nanobiotechnology.2016;[Epub]     CrossRef
    • Immunization with an Autotransporter Protein of Orientia tsutsugamushi Provides Protective Immunity against Scrub Typhus
      Na-Young Ha, Prashant Sharma, Gwanghun Kim, Yuri Kim, Chan-Ki Min, Myung-Sik Choi, Ik-Sang Kim, Nam-Hyuk Cho, David H Walker
      PLOS Neglected Tropical Diseases.2015; 9(3): e0003585.     CrossRef
    • Current situation of scrub typhus in South Korea from 2001–2013
      Hyeong-Woo Lee, Pyo Yun Cho, Sung-Ung Moon, Byoung-Kuk Na, Yoon-Joong Kang, Youngjoo Sohn, Seung-Ki Youn, Yeongseon Hong, Tong-Soo Kim
      Parasites & Vectors.2015;[Epub]     CrossRef
    • 18F-FDG PET/CT Findings of Scrub Typhus
      Jahae Kim, Seong Young Kwon, Sae-Ryung Kang, Sang-Geon Cho, Ho-Chun Song
      Clinical Nuclear Medicine.2015; 40(10): e484.     CrossRef
    • Epidemiology of Scrub Typhus and the Eschars Patterns in South Korea from 2008 to 2012
      Ji-Hyuk Park, Sun-Ja Kim, Seung-Ki Youn, Kisoo Park, Jin Gwack
      Japanese Journal of Infectious Diseases.2014; 67(6): 458.     CrossRef

    • PubReader PubReader
    • Cite
      Cite
      export Copy
      Close
    • XML DownloadXML Download

    PHRP : Osong Public Health and Research Perspectives