Study summary
OFF! Clip-on Repellent Device With Metofluthrin Tested on Aedes aegypti for Mortality at Different Time Intervals and Distances
Bibbs CS, Xue RD
Read the original paper- Study type
- Lab
- Year
- 2016
- Published in
- Journal of Medical Entomology (2016), 53(2):480
- Evidence strength
- Limited evidence
Summary
This was a controlled laboratory study, not a backyard trial, designed to map exactly how far the OFF! Clip-On's metofluthrin actually reaches. The researchers exposed caged Aedes aegypti mosquitoes, the yellow fever and dengue vector, at set distances from the running device and at different time intervals, then recorded knockdown and death. The point was to test the intuitive question every buyer has: does one of these clip-on emanators really protect a whole area around you, or only the air right next to it?
Key findings
The device did knock down and kill mosquitoes, but only very close in. Meaningful, sustained mortality happened at about 0.3 meters, roughly a foot, from the device, and this effect was not sustained at distances greater than 0.3 meters. In plain terms, the lethal reach of a single clip-on is small, on the order of the space right around your torso, and it falls off quickly as you move away. This is the honest counterweight to the impressive landing-reduction percentages from other studies: an emanator can create a genuine protective pocket, but that pocket is small, so a device clipped to one person does little for someone sitting a few feet away.
Limitations
This was a caged-mosquito lab study on a single species under still-air conditions, which is close to a best case for a device that relies on holding active ingredient in the air, so real outdoor reach in any breeze would be similar or smaller, not larger. The endpoint here was knockdown and death of confined mosquitoes rather than how many bites a free-moving person avoids, and lethality at very close range is not the same thing as area-wide repellency. Results could differ for other mosquito species and for fan-driven versus purely passive emanators.