Surveillance of Insecticide Resistance and Operational Research with Aedes aegypti in Mexico

Gabriela González Olvera, PhD, works within the Collaborative Unit for Entomological Bioassays, University of Yucatan, Mexico; and is part of an ongoing effort that involves the country’s Federal Ministry of Health, the State of Yucatan Ministry of Health, and the US-based Centers for Disease Control and Prevention (CDC). As a featured speaker at the Global Mosquito Resistance Management Summit (March 2022), Olvera detailed how the collaboration is an extension of a state-of-the-art surveillance platform established by the national Ministry of Health.

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The platform is designed to facilitate the capture and management of entomological and epidemiological information, which then provides online decision support for vector control professionals in Mexico. The system has four main modules which include a country-wide network of 230,000 ovid traps for surveillance of Aedes aegypti, routine resistance monitoring for A. aegypti, detection of dengue, chikungunya and zika from among field collected mosquitoes, and the surveillance of other vector species such as kissing bugs and ticks.

Central to Olvera’s presentation was an investigation of the persistence of pyrethroid resistance in Mexico (with an emphasis on the Yucatan peninsula) despite the fact that Mexico began phasing out the use of pyrethroids in Public Health – due to declining efficacy – beginning in 2016. The study revealed that the presence of resistance causing mutations among individuals varied widely at the local level – ranging from 0% to 80% of populations collected within less than 500 meters of each other.

“Household insecticides may be critically relevant in explaining the lack of restoration of susceptibility years after [pyrethroids] were phased out of vector control programs.”

The team has hypothesized that despite the absence of their use by the Ministry, household aerosolized products containing a mixture of pyrethroids may be the cause. Such insecticides are often used by homeowners daily.