Orientia tsutsugamushi: Difference between revisions
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Orientia tsutsugamushi
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== Background == |
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* The entire life cycle is maintained within [[Is transmitted by::Leptotrombidium]] mites by vertical/transovarial transmission |
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* [[Leptotrombidium]] larvae (called '''chiggers''') normally feed on rodents, and occasionally humans, who are dead-end hosts |
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* Transmitted within mites (chiggers) transovarially |
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* Most common in rural Asia and western Australia, as well as other parts of eastern Asia, including Russia and India |
* Most common in rural Asia and western Australia, as well as other parts of eastern Asia, including Russia and India |
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== Clinical Manifestations == |
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* Fever, headache, myalgia, lymphadenopathy, and an eschar |
* Fever, headache, myalgia, lymphadenopathy, and an eschar |
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** Lymphadenopathy sometimes grouped near the eschar |
** Lymphadenopathy sometimes grouped near the eschar |
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== Diagnosis == |
== Diagnosis == |
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* Four-fold rise in immunofluorescence serology |
* Four-fold rise in immunofluorescence serology |
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* PCR on eschar, blood, or lymph node biopsy |
* PCR on eschar, blood, or lymph node biopsy |
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== Management == |
== Management == |
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* Alternative: [[azithromycin]] 500 mg p.o. daily for 1-3 days |
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* For severe disease, combination [[doxycycline]] and [[azithromycin]] for 7 days[[CiteRef::varghese2023in]] |
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** Dosing may be unusual: [[doxycycline]] 200 mg bid x2 followed by 100 mg bid; [[azithromycin]] 500 mg bid x2 followed by 500 mg daily |
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[[Category:Rickettsioses]] |
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Latest revision as of 17:13, 27 September 2024
- Chigger-borne rickettsial infection caused by the intracellular Gram-negative bacterium Orientia tsutsugamushi that causes scrub typhus
Background
Life Cycle
- The entire life cycle is maintained within Leptotrombidium mites by vertical/transovarial transmission
- Leptotrombidium larvae (called chiggers) normally feed on rodents, and occasionally humans, who are dead-end hosts
Epidemiology
- Most common in rural Asia and western Australia, as well as other parts of eastern Asia, including Russia and India
Clinical Manifestations
- Fever, headache, myalgia, lymphadenopathy, and an eschar
- Lymphadenopathy sometimes grouped near the eschar
- Should almost always be able to find the eschar if you look hard enough
- Transient pale macular rash
- May have cough
- May have mental status changes and hepatosplenomegaly
- In severe cases, may progress to multiorgan failure and hemorrhage
- After treatment, may relapse
- Infection also decreases HIV viral load and can lead to immune reconstitution
Diagnosis
- Four-fold rise in immunofluorescence serology
- PCR on eschar, blood, or lymph node biopsy
Management
- Doxycycline 100 mg po bid for 7 days
- Alternative: azithromycin 500 mg p.o. daily for 1-3 days
- For severe disease, combination doxycycline and azithromycin for 7 days1
- Dosing may be unusual: doxycycline 200 mg bid x2 followed by 100 mg bid; azithromycin 500 mg bid x2 followed by 500 mg daily
References
- ^ George M. Varghese, Divya Dayanand, Karthik Gunasekaran, Debasree Kundu, Mukta Wyawahare, Navneet Sharma, Dhruva Chaudhry, Sanjay K. Mahajan, Kavitha Saravu, Blessed W. Aruldhas, Binu S. Mathew, Roshini G. Nair, Nalini Newbigging, Aswathy Mathew, Kundavaram P.P. Abhilash, Manisha Biswal, Ann H. Prasad, Anand Zachariah, Ramya Iyadurai, Samuel G. Hansdak, Sowmya Sathyendra, Thambu D. Sudarsanam, John A.J. Prakash, Abi Manesh, Alladi Mohan, Joel Tarning, Stuart D. Blacksell, Pimnara Peerawaranun, Naomi Waithira, Mavuto Mukaka, Phaik Yeong Cheah, John V. Peter, Ooriapadickal C. Abraham, Nicholas P.J. Day. Intravenous Doxycycline, Azithromycin, or Both for Severe Scrub Typhus. New England Journal of Medicine. 2023;388(9):792-803. doi:10.1056/nejmoa2208449.
