Scrub typhus
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: Bush typhus
Overview
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Scrub typhus or Bush typhus is a form of typhus caused by the intracellular parasite Orientia tsutsugamushi, a Gram-negative α-proteobacterium of family Rickettsiaceae first isolated and identified in 1930 in Japan.[1][2]
Although the disease is similar in presentation to other forms of typhus, its pathogen is not anymore included in genus Rickettsia with the typhus bacteria proper, but in Orientia. The disease is thus frequently classified separately from the other typhi.
Diagnosis
Physical Examination
Maculopapular rash, eschar, splenomegaly and lymphadenopathies are typical signs.
Laboratory Findings
In endemic areas, diagnosis is generally made on clinical grounds alone. Where there is doubt, the diagnosis may be confirmed by a laboratory test such as serology.
References
- â Tseng BY, Yang HH, Liou JH, Chen LK, Hsu YH (2008). “Immunohistochemical study of scrub typhus: a report of two cases”. Kaohsiung J. Med. Sci. 24 (2): 92â8. doi:10.1016/S1607-551X(08)70103-7. PMIDÂ 18281226. Unknown parameter
|month=ignored (help) - â Pediatric Scrub Typhus, accessdate: 16 October 2011
Historical Perspective
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Historical Perspective
Severe epidemics of the disease occurred among troops in Burma and Ceylon during World War II (WWII).[1] Several members of the U.S. Army’s 5307th Composite Unit (Merrill’s Marauders) died of the disease; and before 1944, there were no effective antibiotics or vaccines available.[2][3]
World war II provides some indicators that the disease is endemic to undeveloped areas in all of Oceania in the Pacific Theater, although war records frequently lack assured diagnoses to desired by epidemiological staticsâand many records of “high fever” evacuations were also likely to be other tropical illnesses. In the chapter entitled “The Green War”, General MacArthur‘s biographer William Manchester identifies that the disease was one of a number debilitating afflictions affecting both sides on New Guinea[4] in the running bloody Kokoda battles over unbelievably harsh terrains under incredible hardshipsâ fought during a six month span[5] all along the Kokoda Track in 1942-43, and mentions that to be hospital evacuated, Allied soldiers (who cycled forces) had to run a fever of 102°Fâand that sickness casualties outnumbered weapons inflicted casualties 5:1.[4] Similarly, the illness was a casualty producer in all the jungle fighting of the land battles of New Guinea campaign and Guadalcanal campaign. Where the allies had bases, they could remove and cut back vegetation or use DDT as a prophylaxis area barrier treatment, so tick induced sickness rates in forces off the front lines was diminished.
The disease was also a problem for US troops stationed in Japan after WWII, and was variously known as “ShichitĆ fever” (by troops stationed in the Izu Seven Islands) or “Hatsuka fever” (Chiba prefecture).[6]
References
- â Audy JR (1968). Red mites and typhus. London: University of London, Athlone Press. ISBNÂ 0-485-26318-1.
- â Kearny CH (1997). Jungle Snafus…And Remedies. Cave Junction, Oregon: Oregon Institute of Science & Medicine. p. 309. ISBN 1-884067-10-7.
- â Smallman-Raynor M, Cliff AD (2004). War epidemics: an historical geography of infectious diseases in military conflict and civil strife, 1850â2000. Oxford: Oxford University Press. pp. 489â91. ISBN 0-19-823364-7. More than one of
|isbn13=and|isbn=specified (help) - â 4.0 4.1 William Manchester (1978). “The Green War”. American Caesar. Little Brown Company. pp. 297â298. ISBN 0-316-54498-1.
- â Manchester, p. Six months to recapture Buna and Gona from July 21â22, 1942
- â Ogawa M; Hagiwara T; Kishimoto T; et al. (1 August 2002). “Scrub typhus in Japan: Epidemiology and clinical features of cases reported in 1998”. Am J Trop Med Hyg. 67 (2): 162â5. PMIDÂ 12389941. Unknown parameter
|author-separator=ignored (help)
Pathophysiology
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References
Causes
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Causes
Scrub typhus or Bush typhus is a form of typhus caused by the intracellular parasite Orientia tsutsugamushi, a Gram-negative α-proteobacterium of family Rickettsiaceae first isolated and identified in 1930 in Japan.[1][2]
Scrub typhus is transmitted by some species of trombiculid mites (“chiggers“, particularly Leptotrombidium deliense),[3] which are found in areas of heavy scrub vegetation. The bite of this mite leaves a characteristic black eschar that is useful to the doctor for making the diagnosis.
References
- â Tseng BY, Yang HH, Liou JH, Chen LK, Hsu YH (2008). “Immunohistochemical study of scrub typhus: a report of two cases”. Kaohsiung J. Med. Sci. 24 (2): 92â8. doi:10.1016/S1607-551X(08)70103-7. PMIDÂ 18281226. Unknown parameter
|month=ignored (help) - â Pediatric Scrub Typhus, accessdate: 16 October 2011
- â Pham XD, Otsuka Y, Suzuki H, Takaoka H (2001). “Detection of Orientia tsutsugamushi (Rickettsiales: Rickettsiaceae) in unengorged chiggers (Acari: Trombiculidae) from Oita Prefecture, Japan, by nested polymerase chain reaction”. J Med Entomol. 38 (2): 308â311. doi:10.1603/0022-2585-38.2.308. PMIDÂ 11296840.
Differentiating Scrub typhus from other Diseases
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References
Epidemiology and Demographics
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Epidemiology and Demographics
Scrub typhus is endemic to a part of the world known as the tsutsugamushi triangle (after O. tsutsugamushi). This extends from northern Japan and far-eastern Russia in the north, to the territories around the Solomon Sea into northern Australia in the south, and to Pakistan and Afghanistan in the west.[1]
The precise incidence of the disease is unknown, as diagnostic facilities are not available in much of its large native range which spans vast regions of equatorial jungle to the sub-tropics. In rural Thailand and in Laos, murine and scrub typhus accounts for around a quarter of all adults presenting to hospital with fever and negative blood cultures[2] [3] The incidence in Japan has fallen over the past few decades, probably due to land development driven decreasing exposure, and many prefectures report fewer than 50 cases per year.[4] [5] It affects females more than males in Korea, but not in Japan,[6] and this is conjectured to be because sex-differentiated cultural roles have women tending garden plots more often, thus being exposed to plant tissues inhabited by chiggers. The incidence is increasing day-by-day in southern part of Indian Peninsula.
References
- â Seong S, Choi M & Kim I (2001). “Orientia tsutsugamushi infection: overview and immune responses”. Microbes and Infection. 3 (1): 11â21. doi:10.1016/S1286-4579(00)01352-6. PMIDÂ 11226850.
- â Phongmany S; Rolain JM; Phetsouvanh R; et al. (2006). “Rickettsial infections and fever, Vientiane, Laos”. Emerging Infect. Dis. 12 (2): 256â62. doi:10.3201/eid1202.050900. PMCÂ 3373100. PMIDÂ 16494751. Unknown parameter
|month=ignored (help); Unknown parameter|author-separator=ignored (help) - â Suttinont C; Losuwanaluk K; Niwatayakul K; et al. (2006). “Causes of acute, undifferentiated, febrile illness in rural Thailand: results of a prospective observational study”. Ann Trop Med Parasitol. 100 (4): 363â70. doi:10.1197/136485906X112158. PMIDÂ 16762116. Unknown parameter
|month=ignored (help); Unknown parameter|doi_brokendate=ignored (help); Unknown parameter|author-separator=ignored (help) - â Katayama T, Hara M, Furuya Y, Nikkawa T, Ogasawara H (2006). “Scrub typhus (tsutsugamushi disease) in Kanagawa Prefecture in 2001â2005”. Jpn J Infect Dis. 59 (3): 207â8. PMIDÂ 16785710. Unknown parameter
|month=ignored (help) - â Yamamoto S, Ganmyo H, Iwakiri A, Suzuki S (2006). “Annual incidence of tsutsugamushi disease in Miyazaki prefecture, Japan in 2001-2005”. Jpn J Infect Dis. 59 (6): 404â5. PMIDÂ 17186964. Unknown parameter
|month=ignored (help) - â Bang HA, Lee MJ, Lee WC (2008). “Comparative research on epidemiological aspects of tsutsugamushi disease (scrub typhus) between Korea and Japan”. Jpn J Infect Dis. 61 (2): 148â50. PMIDÂ 18362409.
Risk Factors
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References
Screening
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References
Natural History, Complications and Prognosis
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References
Diagnosis
Diagnosis
History and Symptoms | Physical Examination | Laboratory Findings | Imaging Findings | Other Diagnostic Studies
Treatment
Treatment
Medical Therapy | Primary Prevention | Secondary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies
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