• Journal of agricultural medicine and community health
• /
• v.29 no.1
• /
• pp.177-184
• /
• 2004

Objectives: Tsutsugamushi disease is one of the most significant acute febrile illnesses, increasing in frequency of occurrence during the late autumn in rural areas of Korea. Methods: I have conducted a case-control study on 30 cases who had the fever as a chief complaint, then had been ruled out as having the Tsutsugamushi disease. Data was collected retrospectively by review of chart regarding their general characteristics, clinical and laboratory findings, then was analysed by chi-test. Results: Of 30 cases, 16 cases were seropositive and 14 cases were seronegative against O. tsutsugamushi. Of seropositive for tsutsugamushi disease, 56.3% were female; 37.5% were in their seventies; 50.0% were farmers; 62,6% had chances of exposure to fields or mountains. And 75.0% occurred in November. The main symptoms and signs were fever and chill(100.0%), headache(75.0%). weakness and fatigue(93.8%), and eschar(68.8%). The characteristic laboratory findings were elevated AST(50.0%), ALT(62.5%), and abnormal urinalysis(56.3%). On the other hand, of seronegative cases, 57.1% were male; 50.0% were in their fifties; 42.9% were farmers; 57.2% had chances of exposure to fields or mountains. And 71.4% occurred in November. The symptoms and signs were fever and chill(100.0%), headache(85.7%), eschar(64.3%). weakness, fatigue and skin(57.1%). The laboratory findings were elevated AST(71.4%) and ALT(64.3%), and abnormal urinalysis(42.9%). However, there were no significant differences between the seropositive and seronegative cases(P>.05). Conclusions: Acute febrile community inhabitants who have the epidemiological, clinical as well as laboratory features should be focused upon for the early diagnosis and treatment for tsutsugamushi disease whether or not possessing the serological antibody against O. tsutsugamushi.

• Journal of agricultural medicine and community health
• /
• v.19 no.2
• /
• pp.119-128
• /
• 1994

This study was performed on 302 cases of leptospirosis, tsutsugamushi disease and hemorrhagic fever with renal syndrome(HFRS) which occurred in Chonnam(Do) in 1991 through 1993. The results were as follows : 1. 81.8% of the patients with Leptospirosis and 54.5% of the HFRS patients were men while 61.4% of the patients with tsutsugamushi disease were women. 2. Most patients lived in rural areas(Gun), their educational level was elementary School or lower and their occupations were either farmer or jobless. 3. Peak ages were 40s for leptospirosis(36.4%) and 50s for tsutsugamushi disease and HFRS(32.9% and 36.4% respectively). 4. The high incidence areas of tsutsugamushi disease were northern, eastern and a diagonal line, from northeast to southwest, of the Chonnam area, and these are consistent with a mountainous district. 5. In monthly distribution leptospirosis was higher in Sep. and Oct., and tsutsugamushi disease and HFRS were higher in Oct. and Nov. 6. The first case is occurring and the last case shows up later than in past years.

• Korean Journal of Veterinary Service
• /
• v.35 no.3
• /
• pp.183-189
• /
• 2012

Tsutsugamushi disease or scrub typhus cause by Orientia tsutsugamushi is an endemic disease in Korea. Chigger mites and field rodents play roles in transmission of the disease by the vector and host of the agent. The purpose of this study is to investigate the density of the chigger mites and field rodents due to environmental factors such as temperature, relative humidity, soil thickness and the various vegetations to the 9 field rodent collection sites. The total 62 field rodents was captured by the Sherman collapsible traps from April to October 2009 at the Jangseong of Jeonnam Province, Korea. The trapping rate of the field rodents by the different collecting sites was dominant at subside storage water (24%), bush near by dam (22%), bank around field (20%), followed by 18% of grassy field and surround cattle shed. The distribution of chigger mites by the different collecting sites was the highest at Bush near by dam (28.7%). And the sites of subside storage water, bank around field and surround cattle shed were 20.4%, 18.8%, 16.4%, respectively. On the other hand the collecting sites of stream bank and ridges between rice paddies were not collected. The temperature to the collecting sites was showed $24.1^{\circ}C$ in June and $24.2^{\circ}C$ in October which was higher than April ($10.6^{\circ}C$), whereas lower than May ($25.3^{\circ}C$) and September ($26.8^{\circ}C$). The highest number of mites was collected at $24.2^{\circ}C$ and 46.6% relative humidity in October. The chigger mites and field rodents were highly collected between 18 and 24% at the sites where are loosely in the superficial layers of the soil from 8.0 cm to 10.2 cm. Total 25 species of vegetation were distributed at the collecting sites. In the present study, strong evidence was found that bank around field and grassy field were provided for the prevalence sites of tsutsugamushi disease.

• Korean journal of applied entomology
• /
• v.47 no.3
• /
• pp.287-292
• /
• 2008

Repellent and acaricidal activities of eucalyptus oil, permethrin, and DEET against Leptotrombidium pallidum larvae, which are a vector transmitting tsutsugamushi disease, were evaluated under laboratory conditions using a filter paper impregnated method. The $LD_{50}$ values of eucalyptus oil and DEET were 0.025 and 0.018 $mg/cm^2$, respectively while that of permethrin was higher than 0.2 $mg/cm^2$. In the repellency test of these materials at 6.14 $mg/cm^2$, eucalyptus oil gave complete repellency, and the larvae crossed the treated zone killed. But permethrin showed 60% repellency at 9.20 $mg/cm^2$ and the mites croosed the zone were not killed. The percent repellency of DEET at 0.53 $mg/cm^2$ was 8.3 and 2.8 times higher than that of permethrin and eucalyptus oil, respectively. The acaricidal activities of emulsifiable concentrates-pump sprayers containing the eucalyptus oil as an active ingredient were assayed. The emulsifiable concentrates containing 1% and 3% eucalyptus oil showed weak mortality at 1 hour after treatment, while all ones containing more than 6% oil produced 100% activity against L. pallidum larvae. The mortality also increased as exposure time to the concentrates increase. These results suggest that the potential of eucalyptus oil highly expected to be used as a control or repellent agent against L. pallidum larvae may be very high.

• Korean Journal of Veterinary Service
• /
• v.26 no.3
• /
• pp.203-214
• /
• 2003

Scrub typhus and murine typhus are common endemic febrile illness in the fall in Korea. Scrub typhus is caused by Orientia tsutsugomushi, murine typhus is caused by Rickettsia typhi. Trombiculid mites are known as both the vector and the reservoir host of O tsutsugamushi, the mites which transmit O tsutsugomushi have been reported to be Leptotrombidium pallidum and L scutellare. The author carried out an epidemiological study of scrub typhus and murine typhus in Kyodong-Myeon, Kanghwa-Gun, Incheon in relation to the residents and the host rodents, such as their distribution, seroepidemiology, and population density of chigger mites. 1. Out of 900 residents, 33(3.7%) showed positive reaction to O tsutsugamushi, 24(2.7%) to R typhi. 2. In the seropositives to O tsutsugamushi or R typhi, between the sixties and the seventies of the age were dominant. 3. In the seropositives to O tsutsugamushi serotypically Gilliam was dominant. 4. Among the total 42 field rodents trapped by the sherman traps, 18 rodents were Apodemus agrarius(42.9%), 13 rodents were Crocidura lasiura(31.0%), 5 rodents were Musmusculus(11.9%), 2 rodents(4.8%) were Crocidura suaveolens, Rattus norvegicus, Tscherskia triton, respectively. 5. Out of 42 field rodents, 25 were parasitized by 4,419 chigger mites, showing 59.5% of the infestation rate and 98.8 of the chigger index. L pallidum parasitized in A agrarius, C lasiura, M musculus, R norvegicus and T triton, and L scutellare parasitized only C lasiura. 6. Antibodies in the sera of field rodents against O tsutsugamushi and R typhi were investigated by indirect immunofluorescent antibody technique. Positive rate of antibody against O tsutsugamushi were 11.9(5 of 42) and all of the positive is A agrarius. Antibody against R typhi was not detected. These results might provide the basic information for the management of scrub typhus and murine typhus in Kyodong-myeon, where the epidemiological studies on scrub typhus and murine typhus was not carried out enough.

• Parasites, Hosts and Diseases
• /
• v.33 no.1
• /
• pp.27-36
• /
• 1995

Comparative epidemiological studies on vector reservoir animals of tsutsugamushi disease were carried out in between south coast (the highest endemic) areas and east coast flow endemicl areas in October 1993. Fauna of field rodents and their population densities were not different between two areas. Antibody positive rate of Apodemus agrarius sera was higher in east coast (43.2% in south coast and 63.6% in east coast). High correlation (r = 0.87) was shown between antibody positive rate of A. osrwiur sera and population density of the vector mites (Leptotrombidium scutellare and 1. pnllidunl). L. scutellare was predominant in south coast, showing 110.6 chigger index (74.9% of the total chiggersl , whereas L. pcllidum was predominant in east coast, showing 126.3 chigger index (60.4% of the total). As higher population density of 1. scutellare was found in south coast where the prevalence rate of tsutsugamushi disease is the highest, it is believed that L. scutellare is more important vector species than L. pallidum which may result from more frequent vector-human contact.

• The Korean Journal of Nuclear Medicine
• /
• v.30 no.1
• /
• pp.118-125
• /
• 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 agricultural medicine and community health
• /
• v.46 no.3
• /
• pp.162-170
• /
• 2021

Objectives: This study was carried out to understand the seroprevalence and risk factors for severe fever with thrombocytopenia syndrome (SFTS) among the Korea National Park Service (KNPS) workers. Methods: We used the stored serum samples (763) and survey results collected from the previous investigation on scrub typhus and Lyme disease among the KNPS workers during 2016-2017. The serum samples were analyzed by double-antigen sandwich enzyme-linked immunosorbent assay, which was used to test the total antibody including IgG and IgM. Results: The SFTS seroprevalence among the KNPS worrkers was 1.4%. In multivariate logistic analysis, the national park exploration programs (odds ratio, 3.48; 95% confidence interval, 1.01-12.01) was significantly associated with the seroprevalence of SFTS. Conclusion: This study was the first serological study of SFTS among forestry workers in South Korea. Although the KNPS workers are at a high-risk group of SFTS, the prevention activities related to the working environment and habit was insufficient. Thus, systematic prevention education and training for the KNPS workers need to be strengthened.