The initial infection by an organism in a host :

Appeared in: IGNOU PB. Bsc. Nsg. Entrance-2025

Explanation

Primary infection is the correct term for the initial or first-time infection of a host by a specific pathogen.
This initial encounter triggers the host's immune system to respond to the invading organism for the first time.
Primary infection matches the defining clue or classification criterion in the stem.
Supporting mechanism: The option aligns with the governing rule, pattern, sequence, classification, or exam logic being tested.
Key differentiator: It fits the one fact that separates the correct response from the closest distractor.

Option A: Auto-infection is incorrect because it describes an infection caused by an organism already present in the host's own body being transferred to a new site, not an initial encounter with a pathogen.
Option B: Re-infection is incorrect because it refers to a second infection with the same organism after the host has already recovered from the first one.
Option D: Secondary infection is incorrect because it describes a new infection by a different pathogen that takes advantage of a host's weakened immune system from a pre-existing (primary) infection.

Clinical Relevance

Nursing practice connection: Knowing Classification of Infections helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding the type of infection is crucial for nurses to anticipate the course of illness, implement appropriate isolation precautions, and select the correct treatment.
A primary viral infection, for instance, will not respond to antibiotics, but a secondary bacterial infection that follows it will require antibiotic therapy.
Nurses play a key role in preventing secondary infections in vulnerable patients by maintaining strict aseptic techniques and promoting immune health.

How to Approach the Question

This is a factual recall question testing your knowledge of fundamental medical terminology.
Focus on the key phrase in the question stem: 'initial infection'.
Analyze the prefixes and meanings of the options: 'Primary' means first, 'Secondary' means second, 'Re-' means again, and 'Auto-' means self.
Directly match the keyword 'initial' with the term 'Primary infection'.
Confirm your understanding by recalling that a secondary infection can only happen after a primary one, and re-infection is a repeat event.

Concept Tested & Keywords

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E6 Nursing Fundamentals Taylor pp. 163-165, 165-167

E6 Medicine Davidson Principles Practice 24e p. 120-122

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