You can't reason with a mosquito

This microscopic portrait of a mosquito is one of the displays in a new exhibition at the Smithsonian Institution in Washington, " Exploring Microspace." The mosquito is viewed through the scanning electron microscope. (AP PHOTO)

People, it seems, will go to great lengths to keep from getting bitten by mosquitoes.

On June 16, 2005, the RCMP in New Brunswick warned people to start locking up their mosquito zappers. Several of the $400 propane-powered gadgets, were stolen from stores and backyards in the Fredericton area.

The devices work by enticing mosquitoes, sending out a message that there's a meal of blood in the area. They do that by mimicking human breath. The propane gas emits a warm, moist carbon dioxide plume, which attracts the blood-seeking insects.

As the unsuspecting bug approaches the source, it's sucked into a net where – instead of feasting on a nice plump, juicy human – it dehydrates and dies.

The devices may also combine certain chemicals with the carbon dioxide, to attract a broader range of mosquitoes.

"They're a pretty hot commodity right now, and especially at this time of year," RCMP Cpl. Kevin Jackson told CBC News. "People want to get rid of the hordes of mosquitoes that are in their backyard, and I do believe that there is an underground market for these things."

One brand of mosquito zapper – the Mosquito Magnet – claims it will rid your yard of mosquitoes within 6-8 weeks, as it wipes out the population of female mosquitoes in the area. But you have to keep the device on until the temperature consistently drops back down below 10 C.

There are other – low tech – methods to keep the mosquitoes from biting that some people swear by. Among them:

• Vitamin B-1.
• Fabric softener sheets.
• Clear real – not artificial – vanilla.
• Electronic (ultrasonic) devices.
• Wristbands, neckbands and ankle bands impregnated with repellents.
• Electrocuting devices ("bug zappers").
• Odour-baited mosquito traps.
• Citrosa plant (geranium houseplant).
• Marigolds.
• Skin moisturizers that do not contain an approved repellent active ingredient.

Trouble is they don't work, according to Health Canada. The agency says there are basically two ways to protect yourself from mosquitoes and other biting bugs: physical barriers and chemical barriers.

You can put a layer between you and the bug. Wear long-sleeved shirts (sleeves down, buttoned or zipped, tucked into pants) and long pants (tucked into socks or footwear). You can also wear light-coloured clothing, which wards off some bugs

You can use a mosquito net. But keep in mind that mosquitoes can still bite you if your skin is against the mesh.

Two types of chemical barriers reduce the risk of bug bites: repellents and insecticides. Repellents won't kill that lone mosquito buzzing around your tent. Instead, they will trick that bug into believing you're no tasty meal. Insecticides don't beat around the bush. They kill bugs on contact, or shortly afterwards.

'Natural-based' repellents

According to Health Canada, most repellents containing "naturally derived," or synthetic analogues of "naturally-derived," materials aren't your best protection against a swarm of hungry mosquitoes.

Some do repel mosquitoes, but not for very long. Products made from oil of citronella will generally buy you between 30 minutes and an hour of mosquito-free time. Health Canada also recommends that you don't rub the stuff on your skin. There are concerns that citronella repellents on skin may be a risk to your health.

Lemon eucalyptus plant extract is registered in Canada for use as an insect repellent. It may protect you for up to two hours, but is not recommended for use on children under the age of three.

Soybean oil two per cent "Blocker" products may keep you mosquito-free from one to four hours. Soybean oil has low toxicity, has no age-associated use restrictions, and is non-irritating. Consequently, it may also be considered an alternative to DEET, albeit one with a substantially shorter protection time and without a long history of use.

Despite some controversy Health Canada maintains that the best protection against biting mosquitoes continues to be repellents that contain DEET as their active ingredient. The higher the concentration, the better the protection.

A mosquito repellent with a 20 - 35 per cent concentration of DEET will keep the bugs away for six to 12 hours. DEET concentrations of less than 10 per cent will protect you for one to three hours.

For years, the labels on products containing DEET said clearly: "Do not use on infants or toddlers." Those guidelines have been amended to allow spray with 10 per cent or less DEET to be used on children as young as six months – but not for daily use.

Here are some guidelines on using products containing DEET:

• Don't use a stronger product than you need. If you're going out for an hour stroll in the evening, you don't need a product that keeps mosquitoes away for 13 hours.
• Follow the application instructions. Using more than the specified amount won't give you extra protection but may increase your risk.
• Don't apply DEET near eyes or mouth, or on broken skin. If using a spray, don't spray your face directly or breathe in the spray mist. Spray it on your hands and then rub it on your face.
• Don't apply DEET under clothing. Your skin may absorb it more quickly. Spray it over your clothes, and be sure to wash them before wearing again. DEET generally doesn't harm cotton, nylon or wool, but it can damage some synthetics.
• When you come back inside, wash the repellent off your skin.

Prevention remains the best defence against mosquito bites. Take a walk around your yard and check all flowerpots, garbage cans and eavestroughs for standing water. That's where mosquitoes love to frolic and make zillions more mosquitoes. And it doesn't take much. The insects can breed in as little as one centimetre of standing water.