Which of the following is the most effective method for controlling mosquito larvae in water bodies?

NORCET 10 Mains

Community Health Nursing

Easy

Appeared in: NORCET 10 Mains

Explanation

Gambusia fish, also known as mosquitofish, are a form of biological control specifically used against mosquito larvae.
These fish are natural predators that feed voraciously on mosquito larvae and pupae present in water bodies.
By introducing these fish into stagnant water sources like ponds, ditches, and tanks, the mosquito population is controlled by breaking its life cycle at the larval stage.
This method is environmentally friendly and sustainable compared to widespread chemical use.

Option B: This term is too general. While chemical larvicides exist, 'chemical spray' often refers to fogging or space sprays that target adult mosquitoes (adulticides). These have no effect on larvae in water and can have negative environmental consequences.
Option C: Mosquito nets are a method of personal protection. They act as a physical barrier to prevent adult mosquitoes from biting people, primarily during sleep. They do not kill mosquitoes or affect the larval population in breeding sites.
Option D: Indoor Residual Spraying (IRS) is an anti-adult measure. It involves spraying insecticides on the inner walls of homes to kill adult mosquitoes that rest on these surfaces after taking a blood meal. It has no effect on larvae breeding in water bodies outside the home.

Visual 1: Image: A picture of 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 in water, which is the target for Gambusia fish.
Visual 3: Infographic: A chart comparing different mosquito control methods (biological, chemical, environmental, personal protection) and the mosquito life stage they target.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Methods of mosquito control, specifically targeting the larval stage as background academic context rather than a clinical decision trigger.
Controlling mosquito larvae is a fundamental public health measure to prevent vector-borne diseases like Dengue, Malaria, Chikungunya, and Zika.
Community health nurses play a crucial role in educating communities about identifying and eliminating mosquito breeding sites (source reduction) and the principles of integrated vector management.
What if? If the water body was a source of drinking water, using Gambusia fish would be a safer option than chemical larvicides, which could contaminate the water. This highlights the importance of selecting the appropriate control method for the specific context.

How to Approach the Question

First, identify the key terms in the question: 'controlling mosquito larvae' and 'in water bodies'. This specifies the target stage (larva) and location (water).
Next, evaluate each option based on this specific target.
Analyze Option C (Mosquito nets) and Option D (Indoor residual spraying). Recognize that both are methods to protect against or kill adult mosquitoes, not larvae. Eliminate them.
Compare the remaining options: Option A (Gambusia fish) and Option B (Chemical spray).
Recognize that Gambusia fish are a well-known biological control method specifically for larvae. 'Chemical spray' is a less specific term and can have environmental downsides.
Conclude that Gambusia fish is the most effective and specific method for larval control among the given choices.

Concept Tested & Keywords

Concept Tested: Methods of mosquito control, specifically targeting the larval stage.
Stem keywords: mosquito larvae, controlling, water bodies
Lead-in keywords: most effective

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