ovitraps info

facebook wrote:As Karnataka reported around 24,028 cases of dengue and five related deaths, the health department launched a new pilot project on 26 August to control the spread of dengue — installing Ovitrap baskets that attract mosquitoes.


The initiative was launched by Health Minister Dinesh Gundu Rao at Gopalapura in the Gandhinagar Assembly constituency.

“Ovitraps, used for monitoring, can detect Aedes mosquito populations, serving as an early warning system to preempt disease outbreaks. These baskets are installed 20 feet from houses, and a chemical sprayed inside attracts mosquitoes, luring them into the basket. This innovative experiment is expected to further help in controlling dengue mosquitoes,” said Dinesh Gundu Rao on X.


But, do ovitrap baskets work and how do they help control mosquitoes?

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What are Ovitrap baskets?
Ovitrap baskets are specialised devices designed to attract and trap mosquitoes, particularly species that breed in containers, such as Aedes aegypti and Aedes albopictus.

These traps consist of a dark container filled with water and a substrate for egg-laying, topped with a mesh that prevents adult mosquitoes from escaping once they enter.

The primary function of ovitraps is to monitor mosquito populations by collecting eggs, which fall into the water below after being laid.

This allows for the assessment of mosquito breeding hotspots and helps in planning vector control measures. Ovitraps can also be lethal; some designs incorporate insecticides that kill either the adult mosquitoes that enter or the larvae that develop within the trap, thus serving as a method of population control.

By regularly monitoring the Ovitraps, health officials can track the presence and abundance of Aedes mosquitoes in a given area. This helps in early detection of potential outbreaks and allows for timely interventions.

Recognised solutions
Ovitraps have long been recognised as effective surveillance tools for monitoring mosquito populations. Studies indicate that they can detect the presence of container-breeding mosquitoes and provide relative measures of adult abundance over time. This is crucial for identifying breeding hotspots and planning vector control efforts.

Recent advancements have led to the development of lethal ovitraps, which not only attract mosquitoes but also kill them using insecticides or sticky surfaces.

Trials have shown that these traps can significantly reduce adult mosquito populations. For instance, one study reported an 87 percent decrease in the number of Aedes aegypti females captured in sticky ovitraps following the introduction of lethal ovitraps combined with other control measures.

Field tests have demonstrated that ovitraps filled with larvicides, such as copper-based solutions, effectively eliminate mosquito larvae. In a study conducted in Indonesia, copper-treated ovitraps resulted in a significant number of dead larvae, confirming their potential as a practical and economical mosquito control method.

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Countries where it has been implemented
Several countries have implemented the use of ovitrap baskets for monitoring and controlling mosquito populations, particularly Aedes aegypti and Aedes albopictus, which are vectors of diseases like dengue, Zika, chikungunya, and yellow fever. Here are some examples:

Hong Kong, Singapore, Taiwan and Australia

These countries have been using ovitraps for routine surveillance of dengue vectors. Ovitrap surveying is preferred over larval surveys as it actively detects not only immature mosquitoes but also eggs laid by gravid mosquitoes.

Indonesia

In Indonesia, ovitraps filled with copper-based solutions have been used in field tests to effectively eliminate mosquito larvae. A study conducted in Painan City, West Sumatra, found that copper-filled ovitraps with a concentration of 10 ppm resulted in a large number of dead first and second-instar larvae of Aedes spp.

Taiwan

The extensive deployment of ovitraps in community settings in Taiwan has been part of a successful strategy to curb dengue outbreaks by mobilizing environmental clean-ups based on ovitrap surveillance data.

Philippines

The Philippines uses larvicidal ovitraps in their dengue prevention programs. Although these traps only kill the larvae, they have shown significant impacts in reducing dengue transmission levels, with one region reporting a 97 percent reduction in dengue cases.

United States

In the United States, lethal ovitraps have been developed by US military research scientists and are available under brand names like Trap-N-Kill and BG-GAT. These traps have been successfully used to reduce Asian tiger mosquito biting pressure in a neighbourhood project in University Park in Maryland.

In India

Ovitrap baskets have been implemented in India, specifically in the northeastern state of Assam. Research conducted in Sonitpur district utilised ovitrap surveillance to monitor the spatiotemporal distribution of dengue vectors, primarily Aedes aegypti and Aedes albopictus.

This study aimed to identify high-risk zones for dengue transmission by placing ovitraps in selected villages and collecting data on mosquito larvae throughout the year.

The findings from this research highlighted the effectiveness of ovitraps in assessing mosquito populations and their breeding patterns, which is essential for developing targeted vector control strategies in the region.

(Edited by Muhammed Fazil)