Orientia tsutsugamushi: Difference between revisions

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Orientia tsutsugamushi
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* Chigger-borne rickettsial infection caused by the intracellular Gram-negative bacterium ''Orientia tsutsugamushi'' that causes '''scrub typhus'''
* Chigger-borne [[Ricketssioses|rickettsial infection]] caused by the intracellular [[Has Gram stain::Gram-negative]] bacterium ''Orientia tsutsugamushi'' that causes '''scrub typhus'''


== Life Cycle ==
== Background ==
=== Life Cycle ===

* The entire life cycle is maintained within [[Is transmitted by::Leptotrombidium]] mites by vertical/transovarial transmission
* Transmitted within mites (chiggers) transovarially
* [[Leptotrombidium]] larvae (called '''chiggers''') normally feed on rodents, and occasionally humans, who are dead-end hosts

== Epidemiology ==


=== Epidemiology ===
* 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


== Clinical Presentation ==
== Clinical Presentation ==

* Fever, headache, myalgia, lymphadenopathy, and an eschar
* Fever, headache, myalgia, lymphadenopathy, and an eschar
** Lymphadenopathy sometimes grouped near the eschar
** Lymphadenopathy sometimes grouped near the eschar
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== Diagnosis ==
== Diagnosis ==

* Four-fold rise in immunofluorescence serology
* Four-fold rise in immunofluorescence serology
* PCR on eschar, blood, or lymph node biopsy
* PCR on eschar, blood, or lymph node biopsy


== Management ==
== Management ==

* [[Doxycycline]] 100 mg po bid for 7 days
* [[Doxycycline]] 100 mg po bid for 7 days



Revision as of 17:10, 20 November 2019

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 Presentation

  • 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

References

  1. ^  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.