Scrub typhus is a disease caused by?

Appeared in: CGHS SSC - 2018

Explanation

Scrub typhus is caused by the bacterium Orientia tsutsugamushi, an obligate intracellular parasite.
This infection is transmitted to humans through the bite of larval mites, commonly known as chiggers (Trombiculid mites).
A characteristic clinical sign of scrub typhus is the formation of a black, necrotic sore called an eschar at the site of the chigger bite, although it is not always present.
The disease is endemic in the 'tsutsugamushi triangle,' which includes Southeast Asia, India, Japan, and northern Australia.

Option A: Rickettsia typhi is the causative agent of endemic typhus, also known as murine typhus.
Option C: Clostridium is a genus of gram-positive, anaerobic bacteria. It is not a rickettsial organism and does not cause any form of typhus.
Option D: Rickettsia prowazekii is the causative agent of epidemic typhus, a severe disease transmitted by the human body louse.

Clinical Relevance

Nursing practice connection: Knowing Causative agent of Scrub Typhus helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses should advise individuals traveling to or living in endemic areas to use insect repellent (like DEET) and wear protective clothing to prevent mite bites.
In a patient presenting with fever, headache, and myalgia who has a history of travel to an endemic region, a thorough skin examination for a characteristic eschar is a critical nursing assessment.
Early administration of antibiotics is key. Doxycycline is the first-line treatment for scrub typhus in non-pregnant adults and children.

How to Approach the Question

This is a factual recall question that tests your knowledge of microbiology.
First, identify the specific disease mentioned in the stem: 'Scrub typhus'.
Recall the specific causative organism for this disease. Note that it belongs to the genus Orientia, which is related to Rickettsia.
Carefully evaluate the options. Notice that other options are also rickettsial organisms (R. typhi, R. prowazekii) that cause different types of typhus. Differentiate between them.
Eliminate the clearly incorrect option, Clostridium, which belongs to a completely different class of bacteria.
Select the option that correctly matches the causative agent to scrub typhus.

Concept Tested & Keywords

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E6 Medicine Davidson Principles Practice 24e p. 290-292

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1912-1914

Practise the full CGHS SSC - 2018

Attempt every question from this paper in a timed mock, then review the full solution for each one.