Insecticide resistance spreads across South American disease vectors

Insecticide resistance is emerging as a growing threat to the control of arboviral and malaria vectors across South America, according to findings presented at a regional workshop held in Bogotá, Colombia, in March 2026. The meeting, organized by the Worldwide Insecticide Resistance Network—South America (WINSA), brought together experts from 13 South American countries and territories representing academia, public health institutions, and international organizations to assess the current status of resistance and chart priorities for regional collaboration.

Vector-borne diseases remain a major and evolving public health challenge in the region, where dengue, chikungunya, Zika, and malaria continue to expand in both incidence and geographic distribution. Insecticides remain central to vector control programs, but the rapid emergence and spread of resistance across multiple vector species increasingly threatens the effectiveness and sustainability of these interventions, the workshop participants reported.

Sixteen presentations at the meeting addressed the current status of insecticide resistance in major disease vectors, including mosquitoes and triatomines. Discussions covered surveillance systems, resistance mechanisms, molecular and genomic tools, operational challenges, and innovative vector control strategies, providing a broad technical overview of the state of resistance science in the region.

A central finding was widespread resistance to pyrethroids and organophosphates across multiple vector species in South America. High frequencies of knockdown resistance mutations, known as kdr mutations, and evidence of metabolic resistance mechanisms were reported in several countries, particularly in Aedes aegypti, the principal dengue vector. These mechanisms reduce the ability of standard insecticide treatments to kill or knock down susceptible insects, undermining interventions that rely on those chemical classes.

Participants also identified emerging resistance to novel insecticide formulations, a development with direct operational implications for programs that have turned to newer products as older chemistries lose effectiveness. The reports suggest that resistance is not confined to long-established insecticide classes but is appearing even against recently introduced tools.

Beyond the biological findings, the workshop highlighted major disparities in surveillance capacity across the region, insufficient standardization of methodologies, and uneven geographical coverage. These gaps complicate efforts to compare resistance data between countries and to build a coherent regional picture of where resistance is developing and how quickly it is spreading.

In response, participants proposed an Integrated Vector Resistance management framework that integrates biological, molecular, genomic, and spatial surveillance approaches. The framework is intended to support evidence-based decision-making in vector control by combining multiple lines of resistance evidence rather than relying on single methods, and to help programs target interventions where resistance data indicate they are most needed.

Innovative approaches presented at the workshop included insecticide combinations, spatial repellents, and insecticidal paints, which were described as promising complementary tools for integrated vector management. Such strategies aim to diversify the chemical and behavioral tools available to control programs, potentially reducing the selection pressure that accelerates resistance when a single insecticide class is used intensively.

The participants concluded that strengthening harmonized surveillance systems, integrating molecular and genomic tools, and improving regional coordination are critical priorities for the continent. WINSA is positioned as a strategic scientific and technical platform to support collaborative research, capacity building, harmonized resistance surveillance, and the translation of resistance evidence into information that can support vector-control decision-making across the region.

Subject of Research: Insecticide resistance in South American disease vectors and regional surveillance priorities

Article Title: Challenges and opportunities for strengthening South American responses to insecticide resistance in disease vectors: Lessons from the WINSA workshop in Bogotá, Colombia

Article References: Martins, A. J., Ahumada, M., Bowman, T. S., Cabrera, O. L., Doerdjan-Ramoutar, K., dos Santos Dias, L., Duchemin, J.-B., Duchon, S., Figueroa, L., Flores, A. E., González, C. R., González-Brítez, N., Harburguer, L., Lenhart, A., Lima, J. B. P., Lopez, R., Morales, D., Quinones, M. L., Salcedo, M. P., … Corbel, V. (2026). Challenges and opportunities for strengthening South American responses to insecticide resistance in disease vectors: Lessons from the WINSA workshop in Bogotá, Colombia. PLOS Neglected Tropical Diseases, 20(10), e0014809. https://doi.org/10.1371/journal.pntd.0014809

Image Credits: AI Generated

DOI: 10.1371/journal.pntd.0014809

Keywords: insecticide resistance, South America, WINSA, Aedes aegypti, kdr mutations, pyrethroids, organophosphates, vector control, dengue, malaria, surveillance, Bogotá workshop