Table of Contents
Introduction
When my son was a small boy at age 7, he asked me, “Why
did God create mosquitoes?” A difficult question, my
only response was to say “They help feed the birds,
in fact we probably wouldn’t have dragonflies since
that is their main source of food.” There are more mosquito
related deaths than AIDS. 1 out of 17 people die from a mosquito
related death. (Taubes G., “A Mosquito Bites Back”,
The New York Times, 1997).
Mosquito Facts
Mosquitoes are found all over the world except for Antarctica.
Malaria which is transmitted via the mosquito is responsible
for 300 to 500 million deaths per year. Only the female mosquito
bites, the male feeds on plant juices. The female feeds every
3 to 4 days eating their own body weight each time. Mosquitoes
find their host by visual, thermal, and olfactory stimuli
i.e. By sight, heat, and recognition of carbon dioxide excreted
from our skin.
Dark colored clothing is an attractant as opposed to light
colored clothing. Carbon dioxide can be recognized by a mosquito
up to 155 feet away. Soaps, cologne, and lotions can also
attract mosquitoes.
It appears when reviewing the data that men are bitten more
than women. This could be due to men being in the outdoors
more and/or men have large body mass and excrete more carbon
dioxide. We do know that heavier individuals are bitten more
than thin.
Mosquitoes are more active early in the morning and at dusk.
They will also bite throughout the night. They need a very
small amount of water to breed, in fact a soda bottle cap
turned upside down is enough to breed many mosquito larvae.
Pathophysiology
When the mosquitoes sword like mouth pierces our skin we
rarely feel pain. The mosquito uses an anesthetic in its saliva
that is injected in the tissue. This can cause a local reaction
usually of redness, and a wheel with intense itching.
Rarely do mosquito bite reactions occur in children less
than 1 year old due to their levels of antibodies. The bite
itself is our bodies response to antibody complexes and histamine.
The bite will go away in a few days. In rare situations it
may last for a couple of months.
Mosquito Bite Symptoms
Symptoms are usually the typical redness and wheel with associated
itching. There are situations that arise where an individual
has an intense local allergic reaction. These individuals
are usually fair skinned, and also could have a history of
allergies such as allergic asthma, and many have a history
of psoriasis or eczema. These reactions are sudden and progressive.
This author has seen mosquito bites as large as the top of
a coffee cup with redness measuring 8 to 10 inches in diameter.
In these situations if the mosquito bite is on the face, eyes
can actually swell shut. Although these symptoms are dramatic
and rare, they do occur. They are easily treated and resolve
in 1 to 2 days.
Mosquito Bite Treatment and Prevention
Avoiding the outdoors is the obvious prevention, however
this is not practical and not the mission of Survive Outdoors.
One can avoid early morning outings and evening treks.
Prevention Tips:
- Light colored are helpful as opposed to dark.
- Avoid cologne, perfume, scented soaps and lotion.
- Use mosquito repellents such as products with DEET and
the new product PICARIDIN. (Please see our section on Mosquito
Repellents)
- Skin so Soft by Avon is NOT very effective. Survive Outdoors
has tried this product in very infected areas and we cannot
recommend it.
- Citronelle products do work but are very short lived.
- Permethrin is very effective to treat clothing and tents.
Products Permethrin need to be sprayed on clothing or fabric
for 30 seconds and allowed to dry for up to 2 hours before
wearing them.
- At your campsite or home, it is helpful after a rain
to walk around and empty such items as hollow logs, empty
pots, and attempt to drain all standing water. Each step
can be helpful to not only you and your family, but the
neighborhood as well. A conscious effort needs to be implemented
for this to work.
Healthcare Provider - Medical Treatment
For the vast majority of mosquito bites,
a topical steroid is effective to reduce itching and redness.
A very small amount can be applied 2 times a day will usually
resolve the bite in 2 to 3 days.
It is advised to educate the patient on what
to look for in case of a secondary infection. A wound care
sheet should be given to the patient to show them what to
look for in case the bite worsens.
- Increasing redness moving up an extremity.
- Fever
- Pain
- Drainage of pus
- Tender lymph nodes
Antihistamines are helpful with local itching
and oral steroids are rarely needed, only in severe reactions
would they be necessary.
Mosquito Repellent
Over the years repellents have been experimented with to
come up with an effective and safe product. Repellents are
big business and caution needs to be used as a consumer in
terms of safety as well as price. Companies will not always
have a consumer’s safety in mind with their primary
goal being to sell the most product compared to competitors.
We must remember, with the increase in West Nile Virus, and
the panic associated with it, companies are scrambling to
do whatever it takes to satisfy consumer demands - from mosquito
foggers to Mosquito Deleto TM machines, to new formulations
that may irritate our skin. Survive Outdoors will attempt
to educate you on what is safe, and what is effective.
DEET (N1 N - diethyl-3-methylbenzamide)
DEET is the most actively used ingredient in today’s
repellents. However, Survive Outdoors predicts it will shortly
become the no. 2 player in repellents. DEET was approved for
the general public in 1957.
DEET should be applied directly to the skin. It is not as
effective when applied on clothing, and is worthless when
applied to tents. DEET can damage plastic, erode tents, and
rain gear, as well as eye-glass frames.
The concentration of DEET in repellents ranges from 5% to
99%. Survive Outdoors recommends NO MORE than 30% DEET, and
it should be reapplied to the skin every 4 to 6 hours depending
on temperature, perspiration, and activity. We do not recommend
spraying or applying DEET before sleeping, and we strongly
encourage mesh shelters or tents when in the outdoors. So
why does Survive Outdoors recommend no DEET at bedtime? A
good but old research study in 1969 had 77 volunteers applying
75% DEET to the antecubital fossa at bedtime on their arms.
It was found that 50% of the volunteers developed blisters
and scaring at the application site. It is speculated that
while sleeping, the arm was bent occluded. The area could
not be exposed to air. The DEET could not evaporate and caused
a severe reaction.
Another report reconfirms this in an Israeli study. One day
after the same application with 50% DEET, 50% of the Israeli
soldiers had ulcerations and scaring.
The American Academy of Pediatricians recommends DEET applied
to children should be no more than 10%. There have been rare
situations of neurotoxicity in children. In 1989, 2 deaths
of children were reported to be contributed by DEET. These
cases were due to prolonged use and high concentrations. It
boggles this author’s mind that some companies can still
promote their product with 99% DEET.
So how does DEET work? It basically masks the carbon dioxide
being excreted from your body, making us invisible to the
pests. Survive Outdoors still uses DEET products, but never
anything over 30% for adults, and not over 10% for children.
Lemon Eucalyptus Oil (p-menthane-3, 8-diol) or PMD
In reviewing the literature, it is interesting how little
is discussed about a natural product as eucalyptus oil. It
lacks the unpleasant odor of DEET and appears to be effective
and safe, however it needs to be applied frequently. The application
the should be about every 2 hours. In field trials, it should
good comparison to 50% DEET.
Skin-So-Soft TM (by Avon)
Survive Outdoors has personally used Skin-So-Soft with less
than adequate results. It appears to be effective against
no-see-ums, which are biting midges which are very common
in northern climates. We feel it is not effective against
mosquitoes and cannot be recommended.
Citronella
Oil of citronella approved by the EPA in 1948 has been tested
as a good repellent. It appears to be effective for the first
hour, then decreases over time. In one study, citronella candles
resulted in 42% fewer bites than the control group. Interesting
though, another group that used non-scented candles resulted
in 24% fewer bites. It appears that candles act as a decoy
and mosquitoes will seek out the warmth and carbon dioxide
emitted by the candles.
Picaridin
Well here it is, the newest attack against mosquitoes. Picaridin
has been used in Australia commercially since 2000. It does
not dissolve plastic, it is dramatically less irritating than
DEET, and the odor is almost non existent. In head to head
studies with DEET, it lasted 2 hours longer and a more favorable
response from participants.
The CDC endorses Picaridin, and in May, 2005, a press release
was issued that stated Picaridin was approved by the CDC as
a repellent for the West Nile mosquito.
Picaridin formulations are available by the company Cutter.
You cannot miss their blue bottle with an orange cap, and
it clearly states “Cutter Advanced”. It has 7%
Picaridin, and comes in an environmentally safe pump spray.
Summary
As with most interventions, it is best to use a combination
approach. Survive Outdoors recommends Cutter Advanced, with
7% Picaridin, light-colored clothes, and avoiding extended
time in the dawn and dusk hours. Candles around the campsite,
and mesh or netting over hammocks and tents are also recommended.
It is also advisable to tuck pants into socks. With all these
precautions, one can still enjoy the outdoors and minimize
the risk of the all to familiar mosquito.
References
1. Paul S. Auerbach, Wilderness Medicine
2. Judith Tintanelli, Emergency Medicine: A Comprehensive
Study Guide
3. Kettle, DS. Medical and Veterinary Entomology, New
York, 1982.
4. Keystone JS: Of Bites and Body Odor, Lancet, 347:1423,
1996
5. Foster WA, Hancock RF: Nectar-related Olfactory and
Visual Attractants for Mosquitoes. Journal of American
Mosquito Control Associations. 10:288 1994.
6. Lamberg SI, Mulrennan Jr. JA. Bullous reaction to diethyl
toluamide (deet) resembling a blistering insect eruption.
Arch Dermatol 1969; 100:582-586
7. Reuveni H, Yagupsky P. Diethyltoluamide-containing
insect repellent. Adverse effects in worldwide use. Arch
Dermatol 1982; 118: 582-583
8. Maibach HI, Johnson HL. Contact urticaria syndrome.
Arch Dermatol 1975; 111: 726-730.
9. ADF Health: Personal protection measures against mosquitoes.
http://Defense.gov.au
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