Most efficient antilarval measure to prevent urban malaria is
**Core Concept**
In urban malaria prevention, the most efficient anti-larval measure involves targeting the Anopheles mosquito's life cycle, focusing on the larval stage to prevent adult mosquito emergence.
**Why the Correct Answer is Right**
The World Health Organization recommends larval control measures, such as larval source management (LSM), as a key strategy for preventing urban malaria. LSM involves identifying and eliminating or modifying mosquito breeding sites, which typically include standing water in containers, such as flowerpots, buckets, and clogged drains. This approach is particularly effective because it targets the larval stage, when the mosquito is most vulnerable, and prevents the development of adult mosquitoes that can transmit malaria.
**Why Each Wrong Option is Incorrect**
**Option A:** Insecticide-treated bed nets (ITNs) are an important tool for preventing malaria, but they are most effective when used by individuals to prevent bites from adult mosquitoes, not to control the larval stage. ITNs do not address the root cause of urban malaria, which is the presence of breeding sites.
**Option B:** Indoor residual spraying (IRS) involves applying insecticides to indoor surfaces to kill adult mosquitoes. While IRS can be an effective tool for reducing malaria transmission, it does not address the larval stage and may not be feasible in urban areas where residents may object to the use of insecticides.
**Option C:** Mosquito coils or vaporizers are available for personal use to repel adult mosquitoes, but they are not an effective anti-larval measure and may not provide consistent protection against mosquito bites.
**Clinical Pearl / High-Yield Fact**
To prevent urban malaria, residents should eliminate standing water around their homes, including clogged drains, flowerpots, and other containers that can collect water. Regular inspections and maintenance of these areas can significantly reduce the risk of mosquito breeding and malaria transmission.
**Correct Answer:** C. Insect growth regulators (IGRs) are a type of larval control measure that can be used to prevent mosquito development. They work by disrupting the normal development of mosquitoes, preventing them from reaching adulthood.