Study summary
Field evaluation of the efficacy and persistence of insect repellents DEET, IR3535, and KBR 3023 against Anopheles gambiae complex and other Afrotropical vector mosquitoes
Costantini C, Badolo A, Ilboudo-Sanogo E
Read the original paper- Study type
- Field Trial
- Year
- 2004
- Species tested
- Anopheles gambiae complex (Burkina Faso field)
- Published in
- Transactions of the Royal Society of Tropical Medicine and Hygiene 98(11):644-652
- Evidence strength
- Definitive evidence
How it was tested
Volunteers wore each repellent on skin while collecting every mosquito that landed over a 10-hour window. The team fitted dose-response models to estimate the dose needed for 95% protection and a decay rate for how fast each repellent wore off.
Summary
A large field trial in Burkina Faso that benchmarked two newer skin repellents, IR3535 and picaridin (KBR 3023), against the reference standard DEET using wild-biting malaria mosquitoes rather than caged ones. More than 49,000 mosquitoes were collected, about 95% of them the Anopheles gambiae complex that carries most African malaria.
Key findings
Picaridin came out ahead on both counts. It was the most potent, needing the lowest dose for 95% protection (81.8 µg/cm², versus 94.3 for DEET and 212.4 for IR3535), and the longest-lasting, with a protection half-life near 4.1 hours against roughly 2.9 hours for DEET and IR3535. In plain terms, picaridin matched or beat DEET while fading more slowly, and IR3535 needed more than twice the dose to reach the same protection. A check of 842 mosquitoes for malaria sporozoites found infective ones equally common on treated and untreated volunteers, consistent with repellents cutting the number of infective bites rather than changing which mosquitoes carry the parasite.
Limitations
The results are model-derived dose and decay estimates rather than a directly measured protection time in minutes, and they reflect Afrotropical vectors under Burkina Faso field conditions. The infection sub-analysis rested on a relatively small sample of 842 mosquitoes.