Published: 2016-12-19

Chiggerosis: an emerging disease

Meenu Meena, Shivraj Meena


Scrub typhus is a zoonotic disease caused by orientia tsutsugamushi,is a very less known cause of fever of unknown origin (FUO). It was first observed in Japan where it was found to be transmitted by mites. The disease was called as tsutsugamushi (tsutsu means dangerous and mushi means insect or mite. This disease is endemic to a geographically distinct region, so called tsutsugamushi triangle, which includes northern Japan and eastern Russia in the North to northern Australia in the South and to Pakistan and Afghanistan in the West. Clinical picture consist of high grade fever, severe headache, myalgia, lymphadenopathy and maculopapular rash on the trunk and then on extremities. A necrotic eschar at the inoculating site of the mite is pathognomic of scrub typhus. Incubation period is 1-3 week. Patients may develop complication like interstitial pneumonia, meningoencephalitis and myocarditis. Diagnosis is often missed because clinical manifestations are similar with other febrile tropical is diagnosed clinically based on sign and symptoms, serologically molecular methods can be used for their rapid identification as well as for epidemiological purposes. However public health importance of this disease is underestimated because of difficulty in clinical diagnosis and lack of laboratory methods in many geographical areas. Drugs like chloromphenicol and tetracycline effectively treat scrub typhus. No vaccine is available for Scrub typhus but many vaccines using Sta47 and Sta56 antigens are under trial as a recombinant vaccine.


Eschar, Mite islands, Scrub triangle, Scrub vegetation, Zoonotic tetrad

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Rodrigo C, Fernando D. Scrub typhus: Pathophyisology, clinical manifestation and prognosis. Asian Pacific J Trop Med. 2011;261-4.

Watt G, Walker DH. Scrub typhus Tropical infectious Disease Principles, Pathogen and Practice. 2nd ed. Philadelphia, PA: Elsevier Churchill Livingstone, 2006;52(1).

Kelly DJ, Fuerst PA, Ching WM, Richards AL. Scrub typhus: The Geographic Distribution of Phenotypic and Genotypic variants of Orientia tsutsugamushi. Clin Infect Dis. 2009;48(Suppl- 3):S203-30.

Blacksell SD, Luksameetanasan R, Kalambaheti T, Aukkanit N, Paris DH, McGready R, et al. Genetic typing of the 56 kDa type specific antigen gene of contempory Orientia tsutsugamushi isolates causing human scrub typhus at two sites in North-eastern and Western Thailand. FEMS Immunol Med Microbiol. 2008;52(3):335-42.

Sharma P, Kakkar R, Kaore SN, Yadav VK, Sharma R. Geographical Distribution and Effect of Season and life cycle of Scrub typhus. JK Science. 2010;12(2):63-4.

Mahajan SK, Rolain JM, Kashyap R, Bakshi D, Sharma V, Prasher BS, et al. Scrub typhus in Himalayas. Emerg infect DIS. 2006:12(10);1590-2.

Bithu R, Kanodia V, Maheshwari RK. Possibility of scrub typhus in fever of unknown origin (FUO) cases: An experience from rajasthan. Indian J Med Microbiol. 2014;32(4):387-90.

Sastry AS. Essentials of medical microbiology, first edition. 2016:392.

Mahajan SK. Scrub typhus: Review article. JAPI. 2005;53:954-6.

Sinha P, Gupta S, Dawra R, Rijhawan P. Recent outbreak of scrub typhus in North Western part of India. Indian J Medical Microbiology. 2014;32(3):247-50.

Watt G, Jongsakul K, Chouriyagune C, Paris R. Differentiating dengue virus infection from scrub typhus in Thai adults with Fever. Am J Trop Med. 2012;5(4):261-4.

Wang CC, Liu SF, Liu JW, Chung YH, Su MC, Lin MC. Acute respiratory Distress Syndrome in scrub typhus. Am J Trop Med Hyg. 2007;76(6):1148-5.

Hendershot EF, Sexton DJ. Scrub typhus and rickettsial diseases in international travelers: a review. Curr Infect Dis Rep. 2009;11(1):66-72.

Chauhan M, Mahajan S, Manish S, Abrol RK. Scrub typhus: An emerging scourge. Indian J Basic and Applied Med Res. 2015;4(4):394-401.

Singh P. Scrub typhus a case report: Military and regional significance. Med J armed forces India. 2004;60:89-90.

Sharma A, Mahajan S, Gupta ML, Kanga A, Sharma V. Investigation of an outbreak of scrub typhus in the Himalayan region of India. Jpn J Infect Dis. 2005;58(4):208-10.

Olson JG, Bourgeois AL, Fang RC, Coolbaugh JC, Dennis DT. Preventation of scrub typhus. Prophylactic administration of doxycycline in a randomized double blind trial. Am J Trop Med Hyg. 1980;29(5):989-97.

DHR-ICMR, Guideline for diagnosis and management of rickettsial disease in India. 2015.

Chogle AR. Diagnosis and treatment of scrub typhus –the Indian scenario. J Assoc physicians India. 2010:58:11-2.