Select the correct odd one?

Appeared in: NIMHANS Nursing Officer - 2021

Explanation

The question requires identifying the disease that does not fit the pattern of the other three.
The key differentiating factor among the listed diseases is their mode of transmission.
Plague (flea-borne), Malaria (mosquito-borne), and Dengue (mosquito-borne) are all vector-borne diseases.
Measles is the exception, as it is transmitted directly from person-to-person via respiratory droplets and is not vector-borne.
Therefore, Measles is the odd one out in this group.

Option A: Plague is not the odd one out because, like Malaria and Dengue, it is a vector-borne disease, transmitted by fleas.
Option B: Malaria is not the odd one out because, like Plague and Dengue, it is a vector-borne disease, transmitted by mosquitoes.
Option C: Dengue is not the odd one out because, like Plague and Malaria, it is a vector-borne disease, transmitted by mosquitoes.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of infectious diseases based on their mode of transmission as background academic context rather than a clinical decision trigger.
Understanding the mode of transmission is fundamental for nurses in implementing appropriate infection prevention and control measures.
For vector-borne diseases like Plague, Malaria, and Dengue, nursing interventions and public health strategies focus on vector control (e.g., insecticide-treated nets, eliminating mosquito breeding sites, flea control on rodents).
For droplet-transmitted diseases like Measles, interventions include patient isolation, use of masks, promoting hand hygiene, and ensuring high vaccination coverage (MMR vaccine).

How to Approach the Question

First, identify the four items being compared: the diseases Plague, Malaria, Dengue, and Measles.
Next, look for a common characteristic or classification that applies to three of the diseases but not the fourth.
Consider various ways to classify these diseases: causative agent (bacterium, virus, protozoan), reservoir (zoonotic vs. anthroponotic), or mode of transmission.
Evaluate the mode of transmission for each. You'll find that Plague, Malaria, and Dengue are all transmitted by vectors (insects).
Recognize that Measles is transmitted directly between people via respiratory droplets, not by a vector.
Conclude that Measles is the 'odd one out' based on this clear distinction in transmission mode. The phrase 'is zoonotic' in the options is a distractor from the main classification principle.

Concept Tested & Keywords

Concept Tested: Classification of infectious diseases based on their mode of transmission.
Stem keywords: odd one, Plague, Malaria, Dengue, Measles
Lead-in keywords: Select, correct

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E6 Medicine Harrison 22e Part 1 p. 1383-1385

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 2079-2081

Practise the full NIMHANS Nursing Officer - 2021

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