Related Experiment Video
Updated: Apr 30, 2026
Visualizing Efficacy of Pesticides Against Disease Vector Mosquitoes in the Field
Published on: March 16, 2019
Effect of aerial insecticide spraying on West Nile virus disease--north-central Texas, 2012
Duke J Ruktanonchai1, Shelley Stonecipher1, Nicole Lindsey1
1Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, Georgia; Health Service Region 2/3, Texas Department of State Health Services, Arlington, Texas; Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Zoonosis Control Branch, Texas Department of State Health Services, Austin, Texas.
Abstract:
During 2012, four north-central Texas counties experienced high West Nile virus (WNV) disease incidence. Aerial insecticide spraying was conducted in two counties. To evaluate the effect of spraying on WNV disease, we calculated incidence rate ratios (IRRs) in treated and untreated areas by comparing incidence before and after spraying; for unsprayed areas, before and after periods were defined by using dates from a corresponding sprayed area. In treated areas, WNV neuroinvasive disease incidence before and after spraying was 7.31/100,000 persons and 0.28/100,000 persons, respectively; the IRR was 26.42 (95% confidence interval [CI]: 12.42-56.20). In untreated areas, the before and after incidence was 4.80/100,000 persons and 0.45/100,000 persons, respectively; the IRR was 10.57 (95% CI: 6.11-18.28). The ratio of IRRs was 2.50 (95% CI: 0.98-6.35). Disease incidence decreased in both areas, but the relative change was greater in aerial-sprayed areas.
