How to avoid becoming a mosquito’s dinner
dr Ben Matthews
Summer is almost over, but that doesn’t mean mosquitoes aren’t still looking for their next meal – and the next one could be you.
A new study led by Dr. Co-authored by UBC’s Ben Matthews, suggests humans may be the pesky insects’ most coveted delicacy. A common mosquito species that is invasive worldwide Aedes aegypti, literally sniffs out humans and drives them to even bite us over other animals.
In these questions and answers, Dr. Matthews, a professor at UBC’s Department of Zoology, on how to avoid being on the menu for mosquitoes and why the future of bite prevention could include odor-reducing skin creams.
Why do we smell so good for mosquitoes?
The female mosquitoes are the ones that bite. With their eyesight and other senses, they can tell between animals and humans, the carbon dioxide in our breath and the body odor of our skin, as well as body heat and moisture. Every time you exhale, the female mosquitoes stimulate all of their senses trying to figure out where the carbon dioxide might be coming from.
In the past hundred years Aedes aegypti Mosquitoes have evolved to feed on humans specifically, and we know that smell is one of the ways they find us when other animals are around. In our recent work with colleagues from Princeton University, we found that a specific compound in human scent actually activates a specific area of the mosquito brain, while animal scent does not, meaning that this type of mosquito actually bites a human, itself when man is standing next to another mammal. And it’s a pretty good bet that the same type of cues are used by other mosquito species as well.
What mosquito species is most common in Canada?
Aedes aegypti is one of the most common mosquitoes that transmits human diseases, but they are not found here (although they have been found in southern Ontario and a related species in the summer, Aedes albopictus has already taken up residence there). Canada has 84 known mosquito species. Although you never want to be bitten, we’re lucky in Canada that we don’t have to worry too much about disease if we’re bitten.
They’re so highly evolved to find and bite humans, it’s like an arms race between us and the mosquitoes: we use chemicals, and now there are many strains that are resistant to those chemicals; Some species evolved to bite during the day because humans used mosquito nets at night. Some use human structures to survive in places they otherwise could not live, including living in parking garages during the winter.
What can people do to avoid being bitten?
- Avoid standing water around your home as this is a perfect mosquito breeding ground including tires that collect rainwater, puddles, clogged gutters, bird baths, even a soda bottle or bottle cap with some water in it.
- Use insect repellents that contain DEET. It’s still our go-to mosquito repellent to date, and while some of the natural repellents sound great, including citronella candles, they tend not to be particularly effective.
- Avoid exposed skin – so wear long sleeves and trousers.
- Avoid going to mosquito areas. This depends on the species, but generally avoid locations with stagnant water, including wooded areas or lakes. There’s even a mosquito that breeds in rock pools at Lighthouse Park in West Vancouver.
- When traveling to places where mosquito-borne diseases are endemic, have mosquito screens on the windows, don’t leave doors and windows wide open, and sleep under a mosquito net.
What does the future of mosquito bite prevention look like?
We believe that the microbiome, or the bacteria that live on our skin and break down sebum, attracts mosquitoes. There are people thinking about probiotic creams that we could develop to boost or replace bacteria on your skin to create repulsive odors, or to reduce the bacteria that create the mosquito-attractive odors. And a one-time use can last months or years. That will be something to watch.
Images: Dropbox
Interview language(s): English