Targeted indoor spraying reduces community risk of mosquito-borne viruses

Spraying insecticide on the household surfaces where mosquitoes that carry chikungunya, dengue and Zika rest after feeding led to a 24% reduction of those illnesses among community members, according to a new study published in the New England Journal of Medicine.

The randomized trial was conducted by an international group of infectious disease experts including Ira Longini, Ph.D., a professor in the Department of Biostatistics in the University of Florida College of Public Health and Health Professions. Researchers tracked households in Mérida in Mexico’s Yucatán Peninsula, from 2021 to 2023, a period which also coincided with a dengue outbreak in that city.

Applying a mosquito insecticide once a season indoors on surfaces such as lower walls and under furniture resulted in a 60% reduction of mosquitoes in treated households compared to untreated households, and one-quarter fewer cases of chikungunya, dengue and Zika at the community level.