Best biological method to control larva?

NORCET 2 -2021 (Shift-2)

Community Health Nursing

Easy

Appeared in: NORCET 2 -2021 (Shift-2)

Explanation

Gambusia, also known as mosquitofish, is a natural predator of mosquito larvae.
Introducing these fish into water bodies is a form of biological control, as it uses a living organism to reduce a pest population.
This method specifically targets the larval stage of the mosquito life cycle, preventing them from developing into adult mosquitoes.
It is an environmentally friendly alternative to chemical larvicides in certain settings.

Option A: DDT spray is a chemical method of vector control, not a biological one. It is also primarily an adulticide, used to kill adult mosquitoes, not larvae.
Option C: Using a chemical-treated mosquito net is a form of personal protection and a mechanical/chemical barrier. It protects individuals from bites by adult mosquitoes but does not control the larval population in their breeding sites.
Option D: Applying ointment (repellent) to the body is a personal protection measure. It repels adult mosquitoes to prevent bites but has no effect on the larval stage or the overall mosquito population.

Visual 1: Image - A picture of the Gambusia affinis (mosquitofish) to help learners identify this biological control agent.
Visual 2: Diagram - The life cycle of a mosquito (egg, larva, pupa, adult), highlighting the larval stage that Gambusia targets.
Visual 3: Infographic - A chart comparing the different types of mosquito control measures: biological, chemical, environmental, and personal protection.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Biological methods for vector control as background academic context rather than a clinical decision trigger.
Understanding different vector control methods is crucial for community health nurses to design and implement effective programs to prevent vector-borne diseases like malaria, dengue, chikungunya, and Japanese encephalitis.
Nurses educate communities on integrated vector management, which combines several methods for maximum effectiveness and sustainability.
Promoting biological control methods like using Gambusia fish can reduce reliance on chemical insecticides, minimizing environmental pollution and the development of insecticide resistance.

How to Approach the Question

First, dissect the question to identify the key requirements. The keywords are 'biological method' and 'control larva'.
Evaluate each option against these two criteria.
Option A, 'DDT spray', is a chemical, not biological. Eliminate it.
Option C, 'Use of chemical mosquito net', targets adult mosquitoes and is a personal protection method, not a larval control method. Eliminate it.
Option D, 'Use of ointment in body', also targets adult mosquitoes and is a personal protection method. Eliminate it.
Option B, 'Gambusia', refers to a fish that eats larvae. This fits both criteria: it's a living organism ('biological') and it targets larvae. This is the correct answer.

Concept Tested & Keywords

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