West Nile Virus Precautions
THEY'LL SOON be here, riding the warm currents of summer: MOSQUITOES armed with the latest bioweapon - the West Nile VIRUS. Short of building a concrete bunker or setting up an unhealthy fog of repellent spray, there are ways of safeguarding the pasty flesh of Canuckus winterus. Some suggestions:
ELIMINATE STANDING WATER
Mosquitoes lay eggs in stagnant water, where they take as little as five days to grow into adults. Empty rain barrels and dishes under flowerpots and change water in bird baths and pet bowls twice a week. Clean eavestroughs and get rid of anything that can hold a puddle - just 2.5 cm of water in a coffee can or a discarded tire may produce more than 1,000 mosquitoes a week. Drain pool covers and consider mosquito-eating fish for that ornamental pond.
BE SMART OUTSIDE
Use yellow bug lights to illuminate the porch or back door - they're less likely to attract insects. Limit time outside at dusk and dawn, when mosquito activity is at its feverish peak. Wear long pants and long-sleeved shirts in light colours. And to keep what's outside from getting in, make sure window and door screens are in good condition.
For fishing trips or other extended exposures, consider joining the many who would make the hooded, netted bug jacket this summer's equivalent of the SARS mask. Anxiety has been good for business. "Usually it doesn't start till about mid-April," says Annmarie Westerberg, whose company, Northern Bugwear, makes bug jackets and pants in the Northern Ontario town of Bear Valley, "but I've had people buying them for three or four months."
Health Canada has ordered bug repellents with more than 30 per cent N,N-diethyl-meta-toluamide, or DEET, to be phased out by next year because of concerns over toxicity. It considers repellents with 30 per cent or less concentration safe. It's a touchy subject. DEET has been in use since the U.S. Army patented it in 1946, more than 200 million people use it worldwide each year, and it works. However it can be a neurotoxin in very large doses, or after prolonged use. In 1998, the American College of Physicians counted 13 DEET-related cases of encephalopathy (brain disease) in children under eight; three of them died.
Health Canada offers these tips for protecting children:
• Under six months - don't use products with DEET
• Six months to two years - in high-risk situations, sparingly apply repellent containing 10 per cent or less DEET once a day, avoiding face and hands
• Two to 12 years - use DEET concentrations of 10 per cent or less, no more than three times a day, avoiding face and hands
• 12 years and over - use DEET concentrations of up to 30 per cent
Repellents containing citronella work, too, but they require frequent applications. Avon's Skin-So-Soft moisturizer, once touted as effective, is not, though the company now sells a repellent under the same name. Also debunked: fabric-softener sheets, bananas, garlic and vitamin B1.
Several expensive traps catch mosquitoes by spewing moist carbon dioxide to mimic a breathing human. Whether they substantially reduce the risk of being bitten is debatable. "When mosquitoes have a choice between a real person and the trap," says Health Canada entomologist Robbin Lindsay, "they'll fly to you." Ultra-violet bug zappers kill beneficial insects, and they even attract mosquitoes to the vicinity.
Take the all-natural route and create a habitat for fish, birds, bats or insects that eat mosquito as larvae or adults.
Maclean's May 19, 2003