In malaria control under NVBDCP, indoor residual spraying (IRS) with DDT is still used in India. The primary mechanism by which IRS reduces malaria transmission is:

• A Killing Anopheles larvae in breeding sites indoors
• B Reducing humidity inside homes to prevent mosquito survival
• C Killing the Plasmodium parasite in the mosquito gut
• D Repelling and killing adult Anopheles mosquitoes resting indoors after blood meal ✓

Explanation

IRS deposits a residual insecticide on indoor walls and surfaces where endophilic Anopheles mosquitoes rest after taking a blood meal. Contact with the insecticide kills or repels the resting vector before it can complete sporogony and transmit malaria. IRS targets adult mosquitoes, not larvae, which are addressed by larval source management (anti-larval measures like oiling, flushing).

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.