# Assessment of vector control strategies based on mass Aedes (Stegomyia) mosquito trapping (AGOs traps) pilot study in a US-Mexico border region of South Texas

## TL;DR

A pilot study in Texas found that AGO traps significantly reduced Aedes aegypti mosquitoes more effectively than conventional methods.

## Contribution

The study evaluates AGO traps as a novel alternative to chemical insecticides for mosquito control.

## Key findings

- AGO traps reduced Ae. aegypti females by 85%, outperforming conventional methods.
- Combined AGO and IVM treatments showed a 67.78% reduction in mosquito populations.
- Conventional IVM alone reduced mosquito populations by 33.7%.

## Abstract

Aedes (Stegomyia) aegypti and Ae. (Stegomyia) albopictus mosquitoes are major vectors of diseases including dengue, Zika, chikungunya, and yellow fever. The excessive use of chemical insecticides has caused resistance in mosquito populations, along with negative environmental impacts and harm to non-target organisms. In this regard, mosquito control strategies, such as passive mass trapping interventions with autocidal gravid ovitraps (AGO) offer a promising alternative. Here we report the results of a pilot study evaluating a passive mass trapping treatment using AGOs against Ae. aegypti in the city of Harlingen, Texas, USA, during the peak mosquito season.

Three treatments were assessed on Aedes populations: AGO mass trapping, integrated vector management (IVM) consisting of source reduction together with larvicides and adulticides, and AGO + IVM. The study design included a control area with no treatments. Four neighborhoods were selected to evaluate the impact of treatments on Ae. Aegypti comparing female abundance between pre-treatment (10 weeks) and post-treatment (9 weeks) periods.

All treatments were effective in significantly reducing Ae. aegypti females. IVM treatment reduced the number of females per trap per week from 3.29 ± 0.24 to 2.41 ± 0.20 (33.7% reduction), AGO from 1.58 ± 0.17 to 0.25 ± 0.05 (85.2% reduction), and AGO + IVM from 1.49 ± 0.17 to 0.53 ± 0.08 (67.78% reduction), based on Henderson’s formula. We observed a non-significant increase in the control area (no treatment provided) in the mosquito populations, increasing from 2.94 ± 0.24 in the pretreatment period to 3.25 ± 0.28 of the post treatment period.

Despite all treatments followed a reduction in mosquito populations, those that included AGO showed a greater decrease in post treatment populations than conventional control measures (IVM) alone. However, further studies with a larger number of replicates, conducted across different seasons and during peak abundance months are needed to fully assess their relative effectiveness for Ae. aegypti control. As this was a pilot study, these preliminary findings suggest that AGOs contribute to reducing Ae. aegypti populations and may serve as a complementary and useful tool in integrated vector management strategies. Nonetheless, further research is needed to verify and validate their effectiveness at larger operational scales.

Aedes aegypti mosquitoes are critically important vectors for global public health due to their primary role in the transmission of diseases such as dengue, Zika, chikungunya, and yellow fever, which affect millions of people worldwide, particularly in tropical and subtropical regions. Given the drawbacks of chemical insecticides used for vector mosquito control, including the development of insecticide-resistant mosquito populations, harm to non-target organisms, and environmental pollution, there has been increasing interest in evaluating alternative control strategies. We assessed the effectiveness of Autocidal Gravid Ovitraps (AGOs) in a passive mass trapping treatment to reduce Ae. aegypti populations. We compared this approach with conventional control measures (adulticides, larvicides and source reduction) as well as the combined effect of AGOs with conventional methods. All treatments successfully reduced mosquito densities; however, those that included AGOs were more effective than conventional control measures (IVM) alone. AGO treatment achieves the higher reduction with an 85% decrease in female Ae. aegypti mosquitoes. Our study aims to evaluate the potential of AGOs as a component of integrated vector management for reducing vector mosquitoes.