By Dr. Carol Fenton
There are about 3,500 different species of mosquitoes around the world.Most of these mosquito species bite animals to drink their blood – but only the female mosquitoes do, since the reason they bite animals for blood is to get the nutrients to make eggs. Female mosquitoes lay eggs on the surface of standing water, which then hatch into larvae that eat algae and other things in the water in order to grow into pupa and then adult mosquitoes. A mosquito egg can grow into an adult mosquito in as little as a week.
When mosquitoes bite animals to drink their blood, they inject a bit of their saliva so the blood flows well. The proteins in the saliva is what causes the itch from the mosquito bite. This transfer of saliva can also transmit disease. Some diseases around the world that are transmitted by mosquitoes include malaria, yellow fever, Chikungunya, dengue fever, Zika virus and West Nile virus. Luckily, most of those are not found in B.C.
One mosquito-borne virus that has been found in B.C., although rare, is West Nile virus. West Nile virus can be found in many species of birds. Humans can get infected by West Nile virus if they get bitten by a mosquito who has also bitten a bird that has the virus. You can learn more about the detection of West Nile virus at the BC Centre for Disease Control (BCCDC).
Whether you want to prevent infection from West Nile virus, or just avoid pesky itchy mosquito bites, there are two main ways to reduce your risk. The first way is to reduce the number of mosquitoes around you. The second way is to reduce the chance of being bitten by mosquitoes.
To reduce mosquitoes around your home, remove any places where a mosquito might like to lay their eggs. Look around for items that could collect water, like old tires, flower pots, wheelbarrows, barrels, tin cans, or even small containers like bottle tops that are outdoors. You can drill holes in the bottom of used containers so water can’t collect. Empty wading pools after use. If you have water in your yard you’d like to keep, like a bird bath, change the water at least once a week to remove any mosquito eggs or larvae before they become adult mosquitoes. For ponds and pools, prevent female mosquitoes from landing on the surface by making sure the water is moving, by using a pump or fountain, or having fish in your pond that can eat the mosquitoes, eggs, and larvae. Don’t forget to check eaves troughs, gutters, flat roofs, drains, and ditches for collected water.
In addition, you can stop mosquitoes from getting in your home. Use window and door screens to block their entry, and check that they fit properly and don’t have any holes.
If you’re venturing outside and want to prevent being bitten by mosquitoes, you can wear long pants and shirts. Light coloured clothing is better than darker colours for mosquito bite prevention. Use mosquito netting over cribs and strollers. Finally, you can use an approved insect repellent. Check to make sure any insect repellent you buy is recommended by Health Canada – the most common and effective will contain DEET. Apply the repellent on exposed skin as well as the outside of clothing, because some mosquitoes can bite through clothes. Do not spray insect repellent or insecticide into the air or on the ground. Mosquitoes can easily avoid these sprays, while they can kill friendly bugs (including those that eat mosquitoes), and you don’t want to accidentally inhale the spray. If you or your child has many itchy mosquito bites, try not to scratch: if you damage your skin from scratching, you can get an infection. And, the more you scratch, the more it will itch! To reduce the itch, try washing the bite with cool water and soap, apply an alcohol-based hand sanitizer, apply an anti-itch cream, use a cool compress like an ice pack, or take an over-the-counter antihistamine. If you’re not sure which is for you, talk to your doctor.
Dr. Carol Fenton, is an Interior Health Medical Health Officer.