Courtesy of CDC West Nile Virus Homepage
Why You Should Use Mosquito Repellent
Insect repellent helps reduce your exposure to mosquito bites that
may carry West Nile virus or other diseases, and allows you to continue
to play, work, and enjoy the outdoors with a lower risk of disease.
When You Should Use Mosquito Repellent
Use repellent when you go outdoors. You should use repellent even if
you're only going outside for a few minutes. Many of the mosquitoes that
carry the West Nile virus bite between dusk and dawn. If you're outside
during these hours pay special attention to using repellent.
Which Mosquito Repellents Work Best
The most effective repellents contain DEET (N,N-diethyl-m-toluamide)
or permethrin. You can use DEET directly on skin and on clothing. You
can use permethrin on clothing but not directly on skin. Both have
proved to be very effective against a variety of biting insects.
How Often You Should Re-apply Repellents
Follow the directions on the product you are using. Sweating or
getting wet may mean that you need to re-apply more frequently.
Repellents with a higher concentration of active ingredient (such as
DEET) provide longer-lasting protection.
How the Percentage of DEET in a Product Relates to Protection Time
A recent study indicates the following:
* A product containing 23.8% DEET provided an average of 5 hours of
protection from mosquito bites.
* A product containing 20% DEET provided almost 4 hours of protection.
* A product with 6.65% DEET provided almost 2 hours of protection.
* Products with 4.75% DEET and 2% soybean oil were both able to provide
roughly 90 minutes of protection.
Choose a repellent that provides protection for the amount of time that
you will be outdoors. You should use a higher percentage of DEET if you
will be outdoors for several hours. You can use a lower percentage of
DEET if time outdoors will be limited. You can also re-apply a product
if you are outdoors for a longer time than expected and start to be
bitten by mosquitoes.
Choose a repellent that you will be likely to use consistently. Also,
choose a product that will provide sufficient protection for the amount
of time that you will be spending outdoors. Product labels often
indicate the length of time that you can expect protection from a
product. If you are concerned about using DEET, you may wish to consult
your health care provider for advice.
The National Pesticide Information Center (NPIC) can also provide
information through a toll-free number, 1-800-858-7378 or
General Considerations for Using Products Containing DEET Safely
* Always follow the instructions on the product label.
* Cover exposed skin or clothing. Don't apply repellent under clothing.
* Do not apply repellent to cuts, wounds, or irritated skin.
* Wash treated skin with soap and water after returning indoors.
* Do not spray aerosol or pump products in enclosed areas.
* Do not apply aerosol or pump products directly to your face. Spray
your hands and then rub them carefully over the face, avoiding eyes and
Using Products Containing DEET Safely on Children
DEET products can be used safely on children. The American Academy of
Pediatrics (AAP) Committee on Environmental Health has recently cited:
"Insect repellents containing DEET with a concentration of 10% appear to
be as safe as products with a concentration of 30% when used according
to the directions on the product labels."
The AAP and other experts suggest using repellent with low
concentrations of DEET on infants over 2 months old. Other guidelines
suggest using repellents containing DEET after children are 2 years of
Repellent products that do not contain DEET are not likely to offer
the same degree of protection from mosquito bites as products containing
DEET. Non-DEET repellents have not necessarily been as thoroughly
studied as DEET, and may not be safe for use on children.
* Always follow the recommendations appearing on the product label
when using repellent.
* When using repellent on a child, apply it to your own hands and then
rub them on your child. Avoid children's eyes and mouth and use it
sparingly around their ears.
* Do not apply repellent to children's hands. (Children may put their
hands in their mouths.)
* Do not allow young children to apply insect repellent to themselves;
have an adult do it for them.
* Keep repellents out of reach of children.
* Do not apply repellent to skin under clothing. If repellent is applied
to clothing, wash treated clothing before wearing again.
In addition to wearing repellent, you can protect yourself and
your family by taking these precautions:
* Wear clothing with long pants and long sleeves while outdoors.
Apply DEET or other repellents such as permethrin to clothing, as
mosquitoes may bite through thin fabric. (Remember: don't use permethrin
* Use mosquito netting over infant carriers.
* Reduce the number of mosquitoes in your area by getting rid of
containers with standing water that provide breeding places for the
Using DEET Safely on Pregnant or Nursing Women
There are no reported adverse events following use of repellents
containing DEET in pregnant or breastfeeding women.
Risks of Using Repellents Containing DEET
Use of these products may cause skin reactions in rare cases. If you
suspect a reaction to this product, discontinue use, wash the treated
skin, and call your local poison control center. There is a new national
number to reach a Poison Control Center near you: 1-800-222-1222.
If you go to a doctor, take the product with you. Cases of serious
reactions to products containing DEET have been related to misuse of the
product, such as swallowing, using over broken skin, and using for
multiple days without washing skin in between use, for example.
Whenever possible, wash skin between applications of DEET. Always
follow the instructions on the product label.
Some non-DEET repellent products which are intended to be applied
directly to skin may also provide limited protection from mosquito
bites. However, because studies have suggested that other products do
not offer the same level of protection, or that protection does not last
as long as the protection provided by products containing DEET, you
should use DEET if possible.
A soybean-oil-based product has been shown to provide protection for a
period of time similar to a product with a low concentration of DEET
(4.75%) Fradin and Day, 2002: http://content.nejm.org/cgi/content/full/347/1/13.
Use this product instead of DEET if:
* You have had allergic skin reactions in the past to products
* If you have irritated, sunburned, bruised, or broken skin.
* If you have a skin condition such as skin cancer, dermatitis, acne,
eczema, or psoriasis.
If you are outdoors for periods longer than 90 minutes, or if you
start being bitten by mosquitoes, you will need to re-apply this product
to continue to provide protection against mosquito bites.
More Information about Repellents
For more information about using repellents safely please consult the
EPA Web site www.epa.gov/pesticides/factsheets/alpha_fs.htm
or consult the National Pesticide Information Center (NPIC),
which is cooperatively sponsored by Oregon State University and the U.S.
EPA. NPIC can be reached at
http://npic.orst.edu or 1-800-858-7378.
Five Common Myths about West Nile Virus
Avoid mosquito bites by applying insect repellent when spending time
outdoors. Use repellent safely. Always read and follow product
Myth #1: There's not much I can do about West Nile virus.
Truth: There is a lot that you, personally, can do to reduce your
chance of West Nile virus infection.
* Reduce the number of mosquito bites you get. Make a habit of using
insect repellent with DEET when outdoors. Spray repellent on exposed
skin and clothing. Get the details about safe repellent use.
* Prime mosquito-biting hours are usually dusk to dawn. Pay special
attention to protection during these hours, or avoid being outdoors.
* You can reduce the number of mosquitoes around your home. Mosquitoes
breed in standing water, so check your yard once a week: get rid of
containers that aren't being used, empty water from flower pots, change
water in bird baths and maintain clean gutters.
* Make sure window and door screens are in good condition. Have an older
neighbor or family member? See if they need help installing or
Myth #2: Kids are at the most danger of getting sick from West
Truth: People over 50 are at the highest risk for developing severe
West Nile disease.
* Relatively few children have been reported with severe West Nile Virus
disease. By contrast, most of the deaths due to WNV during 2002 were
among people over 50 years old. Half of those deaths were among people
over 77 years old.
* It is always a good idea for children to avoid mosquito bites, but
it's also important for adults - especially older adults - to take steps
to avoid mosquito bites. Click here for suggestions on how to avoid
Myth #3: It's only people who are already in poor health who have
to worry about West Nile virus.
Truth: Healthy, active older adults who spend time working and
exercising outdoors have been affected by severe West Nile virus
* Being over 50 is a risk factor for developing severe West Nile disease
if infected with the virus. There is a risk of getting mosquito bites
while leading an active life outdoors. This doesn't mean you have to
stay inside - it does mean that it's important to use repellent when you
Myth #4: Repellents containing DEET are not safe.
Truth: Repellents containing DEET are very safe when used according
* Because DEET is so widely used, a great deal of testing has been done.
When manufacturers seek registration with the US Environmental
Protection Agency (EPA) for products such as DEET, laboratory testing
regarding both short-term and long-term health effects must be carried
* There are products with different strengths (percentage of DEET)
available. The longer the protection you need the higher percent of DEET
* Repellent with DEET can be used for both adults and children,
according to directions
Myth #5: As long as my area has a mosquito control program, I
don't have to worry about using repellent.
Truth: Mosquito control activities don't eliminate every mosquito, so
personal protection is still important.
* Public activities, such as using products to kill mosquito larvae and
adult mosquitoes, are one part of control. Personal protection, such as
using repellent, keeping window screens in good condition, and control
of household breeding sites are other important steps.
* Collaboration between the community, the family and the individual is
needed to achieve the best prevention of West Nile virus infection.