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A Clip-on Repellent Device Offers Protection Against Aedes aegypti Mosquitoes

Photo by Alexander Wild.

By Josh Lancette

With public concern about the Zika virus growing daily, people are looking for effective ways to prevent mosquito bites, and now there’s some good news for the concerned public. According to an article in the Journal of Medical Entomology, a product called the OFF!® Clip-On repellent device could be an effective tool for preventing bites from the Aedes aegypti mosquito, the primary vector of Zika, chikungunya, dengue, and yellow fever.

Josh Lancette

The OFF! Clip-On repels mosquitoes by releasing a vapor form of insecticide — a pyrethroid called metofluthrin — through a battery-powered fan, forming an insecticide “cloud” around the wearer of the device. In order to test the effectiveness of the device, Christopher Bibbs and Rui-De Xue of the Anastasia Mosquito Control District in Florida studied how the device performed against hungry Aedes aegypti mosquitoes. The study was done outdoors in order to replicate real-world conditions.

They found that the OFF! Clip-On caused high mosquito mortality and knockdown rates up to 0.3 meters from the device (“knockdown” is a term used to describe an acute paralysis that knocks the mosquitoes out of the air). While 0.3 meters is not a huge range, it’s enough to protect a single person wearing the device.

The effectiveness of the device came as a pleasant surprise to the researchers.

“In vector control, we see more often than not that tools available for consumers don’t work for the intended purpose,” said Bibbs. “Just look at all the bug zappers, repellent bracelets, sonic bug repellents, and other zany creations that wax and wane in popularity. Skepticism is inherent to the trade. But it was nice for a change of pace that one of these devices could actually do some good.”

However, Bibbs suggested that “repellent” might not be a sufficient term to describe the device because the insecticide cloud didn’t just repel mosquitoes, it actually knocked them down and/or killed them.

“I think “spatial repellent” is a misnomer,” said Bibbs. “In light of the recent evidence, I have taken more to thinking of such devices as ‘vapor active insecticides.’ Mosquitoes tend to be a delicate pest. What that means for us is that the low volume of vapor pushed by the OFF! Clip-On is enough to kill a mosquito that is determined to fly through the little protective cloud.”

Read more at:

OFF! Clip-on Repellent Device With Metofluthrin Tested on Aedes aegypti (Diptera: Culicidae) for Mortality at Different Time Intervals and Distances

Josh Lancette is Manager of Publications at the Entomological Society of America.


  1. I have not had the same result using this. I can clip it to my belt, turn it on, sit out on my deck and have mosquitoes bite my ankles…… I have a degree in entomology and was a mosquito biologist early in my career.

  2. 0.3 meters is about a foot. So, unless you are very short your ankles are further than 0.3 meters from the device on your belt.

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