As I was driving across the state to Easter dinner with my family, I was surprised to see how many bugs were plastered to my
windshield. With the unseasonably warm weather we can see an early start to
mosquito season. In the southern states they are already beginning mosquito
control measures in preparation for a particularly nasty year. We should also
be prepared for a nasty year and protect ourselves and loved ones from mosquito
transmitted infection most notably West Nile virus. Some people infected will
show no symptoms, others can develop mild flu-like symptoms. The more severe
cases can result in swelling of the brain (encephalitis) and meningitis
(swelling around the brain and spinal cord) both of which can have deadly
results. Because this is a virus, our armament of antibiotics will not have any treatment value and currently
we have no antivirals to treat West Nile so only supportive measures are used.
When we can't treat an illness effectively, prevention is going to be the most
important measure. There were 33 reported cases in Michigan in 2011 which
resulted in 2 deaths. There were no reported cases in Washtenaw county
but were several in the surrounding counties.
A couple questions that come up each season are “ What is the most effective repellent?” and “which repellent is safe for
children?”.
The gold standard for repellent is DEET (N,N-diethyl-m-toluamide). This chemical can be found in many products and in
various concentrations. The higher the concentration the longer the product
will be effective though the effect will plateau near 50%. Based on a 2002
study 4.75% DEET would be effective for 1 & ½ hours and 20% would afford 4
hours of protection. This will help you select an appropriate product. If you
only plan to be outdoors for a couple hours 10% and lower would be a good
choice. For extended outdoor activity perhaps a 25% product. This chemical has
been used for over 50 years with very few adverse events reported even in
children. The American Academy of Pediatrics (AAP) recommends that DEET can be
used in children over 2 months old and that 30% seems to be as safe as 10% in
this group.
Picaridin (KBR 3023) is another chemical that has
demonstrated high degree of efficacy as a repellent. This chemical is similar
in concentrations to time of protection to that of DEET. This is sometimes
preferred by some because it is less greasy and less of an odor. The AAP does
not have an official opinion on the chemical at this time but there doesn't seem
to be any realistic danger to using these products in children.
Oil of Lemon of Eucalyptus is a good alternative
to the above as it has similar protective effects to DEET in low concentrations.
I would expect around 1 & ½ hours of protection so you may want to stick to
DEET for extended outdoor activities. Again AAP does not have an opinion on
this product however the labeling suggests not for use under 3 years old.
Permethrin is a good choice to spray on clothes
for additional protection but do not apply directly to skin.
Of course many other choices exist but how
effective are they? Many other products out there on the internet make claims
which are not supported by any peer-reviewed journal articles and are not
regulated by the EPA. I have seen various bracelets infused with citronella for
sale. The good news is the bracelet most likely will not be bitten by a
mosquito but I can't say the same thing about the people wearing them.
Citronella candles do not seem to be any more effective than regular candles
unless you are completely enveloped in the smoke. Citronella oil may be
effective but for very short periods of time probably around 20 to 30 minutes.
Other essential oils do not seem to be efficacious in most studies. Also don't
waste your money on sonic mosquito deterrents as this is just wishful thinking.
Eating cloves of garlic is sometimes recommended
but is not going to repel mosquitoes.
Additional tips:
-Apply repellent only to exposed areas of skin.
-Wear long sleeves and pants when possible to
minimize potential mosquito targets and use permethrin on clothing for
additional protection particularly on thin fabrics.
-Avoid combination sunscreen/repellent products
as you usually have to apply sunscreen more often. First apply sunscreen to
allow binding to skin then apply repellent if necessary.
-Young infants can be protected using proper
clothing and mosquito nets.
-Apply repellents to face by spraying on hands
and rubbing on. Seems sensible but I am sure someone out there has sprayed
repellent directly in their eyes.
-When returning indoors, you will want to wash
off the repellent with soap and water
I am hoping that the recent frosts will kill some
of the early mosquitoes so I can enjoy a nice Mojito in peace this summer but I
will be prepared for the mosquito apocalypse in any case.
Cheers