Quantifying the Epidemiological Impact of Targeted Indoor Residual Spraying on Aedes-borne Diseases

Quantifying the Epidemiological Impact of Targeted Indoor Residual Spraying on Aedes-borne Diseases

The objective of this trial is evaluate the efficacy of Targeted Indoor Residual Spraying (TIRS) in preventing symptomatic disease caused by Aedes-borne diseases (ABDs) in children 2 to 15 years of age in the city of Merida, Yucatan State, Mexico.

Contemporaneous urban vector control (truck-mounted ultra-low volume spraying, thermal fogging, larviciding) has failed to contain dengue epidemics and to prevent the global range expansion of Aedes-borne diseases (ABDs: dengue, chikungunya, zika). Part of the challenge in sustaining effective ABD control emerges from the remarkable paucity of evidence about the epidemiological impact of any vector control method. Furthermore, the classic deployment of interventions in response to clinical cases fails to account for the important contribution of out-of-home human mobility and asymptomatic infections.

The trial will be conducted in the city of Merida extending ongoing longitudinal cohort to follow a population of 4,600 children 2-15 years old randomly allocated to receive either TIRS treatment or not. If efficacious, TIRS will drive a paradigm shift in Aedes control by: considering Ae. aegypti behavior to rationally guide insecticide applications; the change to preventive control (pre- ABD transmission season rather than in response to symptomatic cases); the use of third generation insecticides to which Ae. Aegypti is susceptible.

Inclusion Criteria:

Household Level Inclusion Criteria:

• Household is located within the bounds of a study cluster (5x5 city-block clusters)
• City block has at least 60% premises that are residential

Individual Level Inclusion Criteria:

• 2 or more and up to 15 years of age at the time of initial enrollment
• Living in a house that consented to TIRS (for children in TIRS cluster)

Exclusion Criteria:

Household Level Exclusion Criteria:

• Households where study personnel identify a security risk (i.e., site where drugs are sold, residents are always drunk or hostile)
• Sites where no residents spend time during the day (i.e. work 7days a week outside the home)
• Inability for a resident to provide informed consent
• Non-residential places (e.g., businesses, schools, markets, etc.)

Individual Level Exclusion Criteria:

• Less than 2 years of age or more than 15 years of age at the time of enrollment
• Not living in a house that consented to TIRS (for children in TIRS cluster)
• Having a medical condition that prevents implementation of study procedures
• Temporary visitor to household
• Plans to leave study area within next 12 months