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travel / adventure / guides / summer 2005
| Travel & Adventure Guides |
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By David Smallwood
A love of camping, canoeing
and the outdoors played a major role in my decision
to move to northern Saskatchewan in 1988. The
region is renowned for its spectacular wilderness
and waterways, but as it happens, Saskatchewan
is also home to a whopping 47 of Canada's 74 mosquito
species. When camping in the north country, it
seems as though every one of them is in my tent.
A formidable little creature, the average mosquito
weighs a mere 2.5 milligrams. Highly mobile, it
can fly up, down, sideways and backward. Its wings
beat 250 to 500 times a second, which is the source
of that annoying buzz.
Only the female mosquito feeds on blood, which
is a vital source of protein for egg production.
The so-called mosquito bite is actually a puncture
by her proboscis. She then injects the site with
saliva that helps the blood flow.
Nature lovers and gardeners have long endured "mozzie
attacks" to do what they love best. With
heightened public awareness about the West Nile
virus, however, the question is simple: What is
the best protection against this relentless little
insect?
Natural protection | DEET | Clothing
Know
Thine Enemy
All mosquitoes are not created equal.
Some species are extremely aggressive
and annoying, others less so. Aedes
vexans, for example, is a small, in-your-face
mosquito that comes out a week after
a heavy rainfall, day or night. Other
species, such as Culex tarsalis,
are less aggressive. Sneaky but easily
disturbed when biting, C. tarsalis will
attack your ankles and the backs of
your arms when you're not looking. Other
species bite only later in the evening
and at night, and you don't notice you've
been bitten — until you wake up
scratching. |
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There are a number of natural insect repellents,
from Repel Lemon and Fite Bite with eucalyptus
oil to Natrapel (citronella oil) and Bite Blocker
(soybean oil). Natural repellents may provide
up to two hours of protection, but it's important
to know exactly what you are buying. In Canada,
a product can be registered as an insect repellent
only if it provides greater than 95% protection
for at least 30 minutes to an approximate area
of an average human forearm. If it meets this
standard, Health Canada issues it a Pest Control
Product number.
The word "natural" suggests a gentle,
toxic-free method of protection against nasty
skeeters, but the effectiveness of natural products
still relies on chemical action. Some plants are
toxic, and many used in repellents contain volatile
plant oils. Health Canada is currently re-evaluating
the safety and effectiveness of many natural products.
There are also several homestyle remedies: ingesting
foods high in sulphur, coating your skin with
petroleum jelly and eating garlic and onions.
It's safe to say that the amount of garlic you'd
have to eat would leave you friendless long before
you repelled any mosquitoes.
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Buzz
Off!
Entomologist Philip
Curry, Saskatchewan's West Nile Virus Coordinator,
offers a few self-defense strategies:
stay indoors during peak feeding times
(two hours before sunset until sunrise)
work outside when it is hot and sunny
or windy
avoid using fragrances and perfumes
wear light-coloured, loosefitting clothing,
socks, shoes and a hat
seal pant legs and socks using tape as
a barrier to shut out insects
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Jamie Heal, a biologist at the University of
Guelph, has studied hundreds of mosquito repellents
over the past 15 years. According to Heal, products
based on a synthetic chemical we know as DEET
(N,N-diethyl-m-toluamide) offer longer periods
of protection.
The mosquito works its devilry by honing in on
the carbon dioxide, heat and lactic acid that
we mammals produce. DEET works by blocking the
chemical receptors on the mosquito's antennae. "DEET
has been used for the past 40 years," says
Heal, "and it's proven to be the best protection
against mosquitoes." The statistics agree.
On the market since the mid-1950s, DEET has undergone
extensive testing and billions of applications.
As a result, it has a remarkable safety record.
DEET-based products are available in varying concentrations.
In a heavily infested area, a 30% DEET-based product,
which provides roughly six hours of protection,
may be the best choice for adults. An afternoon
spent gardening, on the other hand, may require
only a 5% concentration.
Regardless of the dose, however, sweat, rain,
swimming, sunscreen and evaporation from wind
or high temperatures all diminish a repellent's
effectiveness. In addition, most repellents are
applied in a spray formula that uses an alcohol
base to help disperse the DEET, speeding up the
evaporation. A DEET-based lotion or towelette
may prove more effective in certain circumstances.
As of December 31, 2004, insect repellents sold
in Canada cannot contain DEET concentrations higher
than 30%. Health Canada has introduced guidelines
for the use of insect repellents on children under
12. As a precaution, wash off insect repellent
when you come indoors - no matter what your age - and
do not use a DEET-based repellent on your pets.
Bug gear, such as a bug jacket, shirt or pants,
is constructed from tightly woven cottons or synthetic
fibres and should have elasticized or drawcord
waists, wrists and ankles and allow ample freedom
of movement. Head nets should offer good visibility.
Mesh-style garments impregnated with DEET or citronella
(derived from lenabatu grass from Southeast Asia)
also provide good protection, but they can be
easily damaged in heavy brush.
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