A person is infected with a pathogenic organism but shows no discernible clinical signs or symptoms of the disease. This individual, who can still transmit the pathogen to others, is best described as a:

Appeared in: NORCET 9 Prelims-2025

Explanation

A carrier is defined as an infected person who harbors a specific infectious agent without showing any discernible clinical signs of the disease.
Despite being asymptomatic, a carrier serves as a potential source of infection for others by shedding the pathogen.
This term precisely matches the description in the question stem of an infected, asymptomatic, but transmissible individual.

Option A: A 'case' refers to an individual who is identified as having the disease, which typically involves the presence of clinical signs and symptoms.
Option C: A 'host' is a very general term for any person or animal in which an infectious agent lives and multiplies. While a carrier is a type of host, the term 'carrier' is more specific and accurate for the scenario described.
Option D: A 'vector' is an organism, usually an arthropod like a mosquito, tick, or fly, that transmits an infectious agent from an infected animal or person to another. The question describes a person, not an insect or other animal vector.

Clinical Relevance

Nursing practice connection: Use the key finding related to Epidemiological terminology related to disease transmission to guide bedside assessment, documentation, and the next nursing action.
Understanding the concept of carriers is fundamental to infection control. Nurses must use standard precautions with all patients because anyone could be an asymptomatic carrier of a pathogen.
Public health strategies, such as screening food handlers for diseases like typhoid fever or healthcare workers for MRSA, are based on identifying and managing carriers to prevent outbreaks.
What if the person later develops symptoms? If the asymptomatic carrier begins to show signs of the disease, their classification would change from a 'carrier' to a 'case'.

How to Approach the Question

This is a definition-based recall question common in community health nursing and microbiology.
First, break down the question stem into its core components: 1) person is infected, 2) person has no symptoms, and 3) person can transmit the infection.
Next, evaluate each option against these three components.
A 'case' fails because they have symptoms. A 'vector' fails because it's typically not a person. A 'host' is too general.
The term 'carrier' is the only option that perfectly matches all three components of the definition provided in the question.

Concept Tested & Keywords

Concept Tested: Epidemiological terminology related to disease transmission.
Stem keywords: pathogenic organism, no clinical signs or symptoms, transmit the pathogen
Lead-in keywords: best described as

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E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart A (pp 26-201 of 604) p. 88-90

Practise the full NORCET 9 Prelims-2025

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