Tuberculosis is predominantly spread by:?

SGPGI Nursing Officer-2022

Applied Microbiology & Infection control

Easy

Appeared in: SGPGI Nursing Officer-2022

Explanation

Tuberculosis is primarily an airborne disease, spread through microscopic particles known as droplet nuclei.
When a person with active pulmonary TB coughs, speaks, or sneezes, they release respiratory droplets containing Mycobacterium tuberculosis.
These droplets evaporate into smaller, lighter droplet nuclei (1-5 microns) that can remain suspended in the air for extended periods.
Infection occurs when a susceptible individual inhales these airborne nuclei, which travel deep into the alveoli of the lungs.

Option A: Vector-borne transmission involves living carriers, typically arthropods like mosquitoes or ticks. Tuberculosis is a bacterial infection and is not spread by insects or animals in this manner.
Option C: Fomites are contaminated inanimate objects. While tubercle bacilli can survive in dust for some time, transmission via contact with objects is extremely rare and is not the predominant route of infection.
Option D: While a type of tuberculosis (caused by Mycobacterium bovis) can be transmitted through the ingestion of unpasteurized milk from infected cattle, this is not the predominant mode of transmission for the common human form of TB (Mycobacterium tuberculosis).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Mode of transmission for Tuberculosis as background academic context rather than a clinical decision trigger.
Understanding that TB is airborne is fundamental to nursing infection control. It mandates the use of 'Airborne Precautions,' which are stricter than 'Droplet Precautions.'.
Nurses must ensure patients with suspected or confirmed TB are placed in a negative-pressure isolation room to prevent the spread of infectious particles to other areas of the hospital.
Healthcare workers entering the room of a TB patient must wear a fit-tested N95 respirator mask, not a standard surgical mask, to protect themselves from inhaling droplet nuclei.

How to Approach the Question

First, identify the key terms in the question: 'Tuberculosis' and 'predominantly spread'. This directs you to recall the primary mode of transmission for this specific disease.
Recall that Tuberculosis is a major respiratory illness. This strongly suggests a transmission route involving the air or breathing.
Evaluate the given options in the context of a respiratory disease. 'Droplet' is directly related to respiratory secretions.
Systematically eliminate the other options. 'Vector' involves insects, 'Food' involves ingestion, and 'Fomites' involves surfaces. While some of these can be routes for other diseases, they are not the main route for TB.
Confirm that droplet/airborne transmission is the most common and clinically significant route for TB, making 'Droplet' the best answer.

Concept Tested & Keywords

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