• The Korean Journal of Nuclear Medicine
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• v.30 no.1
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• pp.118-125
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• 1996

Scrub typhus의 발현증상에는 저알부민혈증, 단백뇨, 전신 부종 등을 들 수 있다. 그러나, 저알부민혈증에 비해 단백뇨와 부종 등은 심하지 않은 경우가 많다. 본 연구에서는 저알부민혈증이 장내에서의 단백질 소실에 의한 것인지를 확인하고자 하였다. Scrub typhus가 의심되는 25명의 환자를 대상으로 (1) 저알부민혈증의 원인 장내 단백질 소실에 의한 것인지 여부와 (2) $^{99m}Tc$-HSA 신티그램의 진단적 유용성을 알아보고자 하였다. 신티그램은 혈청학적 검사상 Scrub typhus로 확인된 18명의 환자에서 (13예는 항생제 치료 개시후 1일에서 8일 사이에, 5예는 치료 전에 시행하였으며, 11예에서는 대변에서 alpha-1- antitrypsin (${\alpha}AT$)배설 여부를 확인하였다. 촬영방법은 $^{99m}Tc$-HSA 30mCi를 정맥 주사한 후, 2, 4, 6, 24시간에 복부 전면상을 얻었다. 판정은 소장과 대장의 주행 위치에서의 혈관외 방사능 소견을 장내 단백질 소실로 간주하였다. 13예에서 양성으로 판정하였는데, 이중 8예는 대변에서의 ${\alpha}AT$치도 높게 나왔다. 신티그램상 음성을 보인 5예중 2예에서는 대변중 ${\alpha}AT$치가 매우 높게 나왔는데 그 이유는 신티그램 검사는 치료 도중에 하였고, 대변 검사는 치료 전에 하였기 때문인 것으로 간주하였다. 결론적으로 전체 18예중 15예에서 신티그램이나 대변검사로 Scrub typhus로 진단하였다. 한편, 13예 (72%)에서 저알부민혈증을 보였는데 이중 4예는 장내단백질 소실과 단백뇨를, 5예는 장내단백질 소실만을, 3예에서는 단백뇨만을 보였고, 1예는 아무 소견이 없었다. 요약하면, 장내단백질 소실 소견은 Scrub typhus환자의 83%에서 보여, 혈중 알부민치가 저하되는 원인으로 추정된다. 따라서 $^{99m}Tc$-HSA 신티그램은 장내단백질 소실의 진단에 매우 유용한 검사방법이다. 또한, 검사방법이 다소 어렵지만 대변에서의 ${\alpha}AT$측정도 동위원소 검사상 음성 소견을 보이는 환자에게는 어느 정도 진단에 도움을 주리라 보여진다.

• Journal of Medicine and Life Science
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• v.15 no.2
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• pp.84-88
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• 2018

The aim was to evaluate different results from using crude incidence rate (CIR) instead of agestandardized incidence rate (AIR) when comparing groups having different age structures. After selecting a report using CIRs, AIRs and their 95% confidence intervals(CI) was calculated from the raw data. The statistically significant difference between CIR and AIR was decided based on AIR's 95% CI. Comparing with CIRs, AIRs were under-estimated. In addition, there were no statistical significance of annual trends(P=0.59). These findings are an additional evidence using AIR when comparing level of occurring infectious diseases on groups with different age structures.

• Journal of Preventive Medicine and Public Health
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• v.43 no.5
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• pp.436-444
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• 2010

Objectives: Infectious diseases are known to be affected by climate change. We investigated if the infectious diseases were related to meteorological factors in Korea. Methods: Scrub typhus, hemorrhagic fever with renal syndrome (HFRS), leptospirosis, malaria and Vibrio vulnificus sepsis among the National Notifiable Infectious Diseases were selected as the climate change-related infectious diseases. Temperature, relative humidity and precipitation were used as meteorological factors. The study period was from 2001 through 2008. We examined the seasonality of the diseases and those correlations with meteorological factors. We also analyzed the correlations between the incidences of the diseases during the outbreak periods and monthly meteorological factors in the hyper-endemic regions. Results: All of the investigated diseases showed strong seasonality; malaria and V. vulnificus sepsis were prevalent in summer and scrub typhus, HFRS and leptospirosis were prevalent in the autumn. There were significant correlations between the monthly numbers of cases and all the meteorological factors for malaria and V. vulnificus sepsis, but there were no correlation for the other diseases. However, the incidence of scrub typhus in hyper-endemic region during the outbreak period was positively correlated with temperature and humidity during the summer. The incidences of HFRS and leptospirosis had positive correlations with precipitation in November and temperature and humidity in February, respectively. V. vulnificus sepsis showed positive correlations with precipitation in April/May/July. Conclusions: In Korea, the incidences of the infectious diseases were correlated with meteorological factors, and this implies that the incidences could be influenced by climate change.

• Parasites, Hosts and Diseases
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• v.48 no.3
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• pp.237-243
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• 2010

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. pal pale (15.7%), Neotrombicula tam/yai (14.3%), L. orientate (10.7%), L. zetum (3.1%), Walchia fragilis (2.1%), and L. gemiticutum (0.8%), while the remaining 3 species, L subintennedium, 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. palpate (21.4), were observed during the spring season.

• IMMUNE NETWORK
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• v.21 no.2
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• pp.14.1-14.17
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• 2021

Scrub typhus develops after the individual is bitten by a trombiculid mite infected with Orientia tsutsugamushi. Since it has been reported that pneumonia is frequently observed in patients with scrub typhus, we investigated whether intranasal (i.n.) vaccination with the outer membrane protein of O. tsutsugamushi (OMPOT) would induce a protective immunity against O. tsutsugamushi infection. It was particular interest that when mice were infected with O. tsutsugamushi, the bacteria disseminated into the lungs, causing pneumonia. The i.n. vaccination with OMPOT induced IgG responses in serum and bronchoalveolar lavage (BAL) fluid. The anti-O. tsutsugamushi IgA Abs in BAL fluid after the vaccination showed a high correlation of the protection against O. tsutsugamushi. The vaccination induced strong Ag-specific Th1 and Th17 responses in the both spleen and lungs. In conclusion, the current study demonstrated that i.n. vaccination with OMPOT elicited protective immunity against scrub typhus in mouse with O. tsutsugamushi infection causing subsequent pneumonia.

• Clinical and Experimental Pediatrics
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• v.46 no.2
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• pp.188-191
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• 2003

Tsutsugamushi fever is a serious febrile disease outwardly similar to malaria and various arboviral infections. The endemic area is Asia-Pacific. This disease are generally associated with disturbed habitats favoring large populations of vector larval trombiculid mites. Therapy with tetracycline, chloramphenicol or ciprofloxacin is currently recommanded. Unfortunately these drugs is suboptimal for children and pregnant women. Recently, azithromycin has been proven to be effective in therapy of scrub typhus. There is no evidence that azithromycin causes adverse reaction to developing fetus or children. We report four cases of tsutsugamushi fever in children successfully treated with azithromycin. This is the first report describing clinical application of azithromycin to tsutsugamushi fever in Korean children.

• Biomedical Science Letters
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• v.17 no.4
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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%).

• Journal of Microbiology
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• v.39 no.3
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• pp.186-194
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• 2001

Scrub typhus, caused by Orientia tsutsugamushi infection, is clinically and histopathologically characterized by local as well as systemic inflammatory reactions, indicating that orientiae induce mechanisms that amplify the inflammatory response. To reveal underlying mechanisms of chemoattraction and activation of responding leukocytes, expression of chemokine and tumor necrosis factor alpha (TNF-$\alpha$) genes in murine peritoneal macrophages after infection with the obligate intracellular bacterium Ο.tsutsugamushi was investigated. The genes that were unregulated included macrophage inflammatory proteins l$\alpha$/$\beta$(MIP-l$\alpha$/$\beta$), MIP-2, monocyte chemoattractant protein 1(MCP-1), RANTES (regulated upon activation, normal T-cell expressed and secreted), gamma-interferon-inducible protein 10(IP-10) and TNF-$\alpha$. Peak expression of these chemokines and TNF-$\alpha$ was observed between 1 and 3 h after infection. These responses returned to or approached baseline preinfection levels 6 h after challenge. Semiquantitative reverse transcription (RT)-PCR analysis revealed dramatic Increases during infection in the steady-state levels of mRNA ceding for the inhibitory subunit of NF-kB (IkB$\alpha$), whose transcription is enhanced by binding of NF-kB within the IkB$\alpha$promoter region. Thus, Ο. tsutsugamushi appears to be a stung inducer of chemokines and TNF-$\alpha$ which may significantly contribute to inflammation and tissue damage observed in scrub typhus by attracting and activating phagocytic leukocytes.

• Parasites, Hosts and Diseases
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• v.56 no.4
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• pp.313-324
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• 2018

This article reviews Leptotrombidium deliense, including its discovery and nomenclature, morphological features and identification, life cycle, ecology, relationship with diseases, chromosomes and artificial cultivation. The first record of L. deliense was early in 1922 by Walch. Under the genus Leptotrombidium, there are many sibling species similar to L. deliense, which makes it difficult to differentiate L. deliense from another sibling chigger mites, for example, L. rubellum. The life cycle of the mite (L. deliense) includes 7 stages: egg, deutovum (or prelarva), larva, nymphochrysalis, nymph, imagochrysalis and adult. The mite has a wide geographical distribution with low host specificity, and it often appears in different regions and habitats and on many species of hosts. As a vector species of chigger mite, L. deliense is of great importance in transmitting scrub typhus (tsutsugamushi disease) in many parts of the world, especially in tropical regions of Southeast Asia. The seasonal fluctuation of the mite population varies in different geographical regions. The mite has been successfully cultured in the laboratory, facilitating research on its chromosomes, biochemistry and molecular biology.

• The Journal of Korean Society of Virology
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• v.28 no.2
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• pp.193-201
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• 1998

In Sprague Dawley (SD) rats, antibodies against strains of Orientia tsutsugamushi, Kato, Karp and Gilliam, were produced in order to investigate their longevity and cross-reactivities to their corresponding homologous and heterologous antigens. By immunofluorescence assay (IFA) of IgG and IgM, it was shown that the immunity to the homologous strains persisted at a higher level (longevity of at least 34 weeks with higher IFA titers). On the other hand, the immunity to the heterologous strains persisted at a lower level (longevity of 10 to 34 weeks with lower IFA titers). Since infection with one strain of O. tsutsugamushi does not preclude reinfection with other strains, understanding of the antigenic diversity of O. tsutsugamushi and duration of the immunity to both homologous and heterologous strain is very important in diagnosis of scrub typhus.