Devices that claim to repel mosquitoes through the emission of high-pitched high-frequency sound waves have been widely available for some time. They base their claim of repellency on the basis that the sound replicates the frequency of the wings of a Dragonfly (a natural predator of mosquitoes). This range of sound is also available through mobile phone apps that claim to protect the user from mosquitoes.
So, do they work? The short answer is – no they don’t.
10 studies from across the world on this particular issue have been studied and analyzed, taking into account variations based on locality and climate, time of day, and species of mosquito. There was no evidence in these field studies to support the repellency claims of these ultrasound devices.
Bart Knols, a Netherlands based entomologist and nobel prize winner claims that “there is no scientific evidence whatsoever” that ultrasound devices and similar phone apps repel mosquitoes. He argues that people need to protect themselves from mosquitoes with repellent sprays and lotions, mosquito nets and anti-malarial drugs.
With mobile phone apps there is an even greater potential for let-down. It is possible that many mobile phones just do not have the capacity to issue the high frequency sound at a volume, or with a consistency, that is reliable. Even if ultrasound worked, mobile phones may not be able to produce this.
Many people will claim that their device or phone app has worked wonderfully for them, but this sort of anecdotal evidence can be very misleading as there can be all sorts of reasons (unrelated to the ultrasound) as to why they may have escaped mosquito attention (or they may not even realise that they have been bitten). We urge people not to rely upon anecdotal evidence, but to trust the findings of properly calibrated scientific experiment.
These devices and apps are still widely available here in the UK and across Europe and range in price from being free to costing two or three times the cost of a mosquito net. Our advice is to make sure that you are safe – rely upon mosquito repellents and nets, not ultrasound.
Enayata, A., Hemmingway, J. & Garner, P. ‘Electronic mosquito repellents for preventing mosquito bites and malaria infection (review)’ 2010. Accessed at http://www.thecochranelibrary.com/userfiles/ccoch/file/CD005434.pdf
BBC ‘Ultrasound mosquito repellents : zapping the myth’ 2012 Accessed at http://www.bbc.co.uk/news/magazine-20669080