Rickettsiae produce which disease in humans?

Appeared in: MNS 2015

Explanation

Rickettsiae are a group of obligate intracellular Gram-negative bacteria.
This group of bacteria is known to cause several diseases in humans, which are collectively called rickettsial fevers.
Typhus fever is a prominent disease caused by species of Rickettsia, such as Rickettsia prowazekii (epidemic typhus) and Rickettsia typhi (endemic typhus).
Transmission to humans occurs through arthropod vectors like lice, fleas, and ticks.

Option B: Dengue fever is a viral infection, not a bacterial one. It is caused by the Dengue virus, a type of Flavivirus.
Option C: Enteric fever, or typhoid fever, is a bacterial disease, but it is caused by Salmonella typhi, not Rickettsiae. It is transmitted through the fecal-oral route.
Option D: Yellow fever is a viral disease caused by the Yellow fever virus, which is also a Flavivirus. It is not caused by bacteria.

Clinical Relevance

Nursing practice connection: Knowing Causative agents of infectious diseases helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Differentiating between febrile illnesses is crucial in clinical practice. While typhus, dengue, and enteric fever can present with similar initial symptoms like fever and headache, their causative agents are different, requiring distinct management.
Rickettsial diseases like typhus are treated with specific antibiotics (e.g., doxycycline), whereas viral infections like dengue and yellow fever require supportive care. Misdiagnosis can lead to delayed or incorrect treatment.
Identifying the correct disease and its vector is vital for public health interventions. For example, controlling lice and fleas is key for typhus prevention, while mosquito control is essential for dengue and yellow fever.

How to Approach the Question

First, identify the key term in the question stem: 'Rickettsiae'. This is a specific microbiological agent.
The question asks to identify the disease caused by this agent from the given options.
This is a factual recall question. Access your knowledge base about common pathogens and the diseases they cause.
Evaluate each option: Typhus fever is known to be caused by Rickettsia. Dengue and Yellow fever are viral. Enteric fever is caused by Salmonella.
Based on this direct association, select the option that correctly links the pathogen (Rickettsiae) to the disease (Typhus fever).

Concept Tested & Keywords

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E6 Microbiology Essentials Sastry 4e Part 1 p. 85-87

E6 Medicine Davidson Principles Practice 24e p. 291-293

E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart B (pp 202-403 of 604) p. 162-164

Practise the full MNS 2015

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