Mosquito Deterrents: The Good, the Bad and the Potentially Effective

Typical civic mosquito control involves spraying clouds of insecticides around buildings. But this spraying (or “fogging,” as it’s called in parts of Southeast Asia) must be repeated regularly. What if the insecticide could actually be embedded in house paint? That’s the idea behind a newly invented anti-mosquito paint from Malaysia. The product involves mixing paint with deltamethrin, a common insecticide, which disrupts mosquitoes’ nervous systems. Trials have been promising—the company claims the paint repels mosquitoes for up to two years—and the final formulation of the paint is set to hit the market soon. 

In recent years, a number of companies have begun hawking mosquito-repellent bracelets and bands. Rather than spraying yourself all over with smelly bug spray, you can simply slip on a bracelet or anklet permeated with anti-mosquito compounds, they say. Some of the bracelets involve traditional insecticides, such as DEET. Others opt for a more “natural” approach: Para Kito is a colorful neoprene band with a pellet of essential oils, while MosquitNo bracelets contain citronella. Results have been mixed, with experts saying traditional spray is still more effective. 

Mosquitoes are attracted to humans by the smell of the carbon dioxide we exhale. This is the principle behind carbon-dioxide-releasing mosquito traps, which emit carbon dioxide and sometimes other compounds found in human breath to draw in mosquitoes, then kill them with electricity or trap them in a chamber. The traps are designed to be placed in yards, with the claim they’ll rid the area of mosquitoes. But how effective they are is still unclear. Though the traps do catch some mosquitoes, they do not necessarily reduce the number of bites received by people in the vicinity.

We know that female mosquitoes find their mates by listening for wing beat frequency. Once a female mosquito has mated, she wants to eat, and she is not interested in being near male mosquitoes. This has led some to conclude that replicating the frequency of mosquito wing beats might deter female mosquitoes (the only ones that bite). A plethora of ultrasonic devices, from phone apps to stroller clip-ons to key chains claim to keep the bugs from biting. The only problem? They don’t work. Research has roundly dismissed the idea that ultrasonic devices influence mosquito behavior at all. You’re better off using your cell phone to smash mozzies instead. 

Researchers have long been looking into the possibility of genetically modifying mosquitoes to prevent the spread of disease. Some models involve releasing mosquitoes that can spread genetic infertility, thus causing populations to die out. Others involve editing the mosquito genome to prevent it from carrying specific diseases. A University of California experiment showed that releasing mosquitoes incapable of carrying malaria could eventually make 99.5 percent of their surrounding population resistant as well through interbreeding. A recent World Health Organization report suggested using genetically modified mosquitoes could be an important tool in fighting Zika.