Insect Repellent Use and Safety
 Insect Repellent Use
Q.
Why should I use insect repellent?
A. Insect repellents help
people reduce their exposure to mosquito bites that may carry
potentially serious viruses such as West Nile
virus, and allow them to continue to play and work outdoors.
Q. When
should I use mosquito repellent?
A. Apply repellent when you are
going to be outdoors and will be at risk for getting bitten by
mosquitoes.
Q. What time of
day should I wear mosquito repellent?
A. Many of the mosquitoes
that carry the West Nile virus are especially likely to bite
around dusk and dawn. If you are
outdoors around these
times of the day, it is important to apply repellent. In
many parts of the country, there are mosquitoes that also bite
during
the day,
and these mosquitoes have also been found to carry the West
Nile virus. The safest decision is to apply repellent whenever
you
are outdoors.
Q. How often should repellent be reapplied?
A. Follow the directions
on the product you are using in order to determine how frequently
you need to reapply repellent.
Sweating, perspiration or getting wet may mean that you
need to re-apply
repellent
more frequently. If you are not being bitten, it is not
necessary to re-apply repellent. Repellents containing a higher
concentration
of active ingredient (such as DEET) provide longer-lasting
protection.
Q. Should I wear repellent while I am indoors?
A. Probably not.
If mosquitoes are biting you while you are indoors, there are
probably better ways to prevent
these
bites instead
of wearing repellent all the time. Check window and
door screens for
holes that may be allowing mosquitoes inside. If your
house or apartment does not have screens, a quick solution
may
be to staple
or tack
screening (available from a hardware store) across
the windows. In some areas community programs can help older
citizens
or others who
need assistance.
Q. How does mosquito repellent work?
A. Female mosquitoes bite
people and animals because they need the protein found in blood
to help develop
their eggs.
Mosquitoes
are
attracted to people by skin odors and carbon dioxide
from breath. Many repellents contain a chemical,
N,N-diethyl-m-toluamide (DEET), which repels the mosquito,
making the person
unattractive
for
feeding. DEET does not kill mosquitoes; it just
makes them unable to locate
us. Repellents are effective only at short distances
from the
treated surface, so you may still see mosquitoes
flying nearby. As long as
you are not getting bitten, there is no reason
to apply more DEET.
Q. Which mosquito repellent works the best?
A. The most effective
repellents contain DEET (N,N-diethyl-m-toluamide), which is an
ingredient used to repel pests like
mosquitoes and ticks. DEET has been tested against a
variety of biting insects
and has
been shown to be very effective. The more DEET
a
repellent contains the longer time it can protect
you from mosquito
bites. A higher
percentage of DEET in a repellent does not
mean that your protection is better—just that it will
last longer. DEET concentrations higher than 50% do not
increase the length of protection.
Q. How does the percentage
of DEET in a product relate to the amount of protection it gives?
A.
Based on a recent study:
-
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
1 and a half
hour
of protection. Choose
a repellent that
provides protection for
the amount of time that you will
be outdoors. A higher
percentage of DEET should be used if
you will be outdoors
for several hours while
a lower percentage
of DEET can be used 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.
Q.
Why does CDC recommend using DEET?
A. DEET is the most effective
and best-studied insect repellent available. (Fradin, 1998).
Studies using
humans and mosquitoes
report that only
products containing DEET offer long-lasting
protection after a single application.(Fradin
and Day, 2002.
See Publications page.)
Q. Are non-DEET
repellents effective (e.g. Skin-So-Soft, plant-based repellents)?
A.
Some non-DEET repellent products which are intended to be applied
directly
to skin also
provide some
protection from
mosquito bites.
However, studies have suggested that
other products do not
offer the same level of protection,
or that protection does not last
as long as products containing DEET.
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.).
People
should choose a repellent that they will be likely to use consistently
and
that will provide
sufficient protection for the
amount of time that they will be spending
outdoors. Product
labels often indicate the length of
time that protection that
can be
expected from a product. Persons who
are concerned about using DEET may
wish to consult their 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
http://npic.orst.edu/
.
Q. I'm confused. None of the products
in the store says "DEET."
A.
Most insect repellents that are available
in stores are labeled with
the chemical
name for DEET.
Look
for N,N-diethyl-m-toluamide or, sometimes,
N,N-diethly-3-methylbenamide. Choose
a repellent that offers appropriate
protection for the
amount
of
time you will be
outdoors. A higher percentage of DEET
should
be used if you
will
be outdoors for several hours while
a lower percentage of DEET can be used
if time
outdoors will be
limited.
Q. Is DEET safe?
A. Yes, products containing DEET are
very safe when used according to the
directions.
Because
DEET is
so widely
used, a great
deal of testing has been done. When
manufacturers seek registration with
the U.S. Environmental Protection Agency
(EPA) for products such
as DEET, laboratory testing regarding
both short-term and long-term health
effects
must be carried
out. Over the
long history of
DEET use, very few confirmed incidents
of toxic reactions to DEET have
occurred when the product is used properly.
(From the National Pesticide Information
Center [NPIC],
EPA re-registration
eligibility decision.
See http://npic.orst.edu/factsheets/DEETgen.pdf
.)
Q. What are some general considerations
to remember in order to use products
containing DEET safely?
A. Always follow
the recommendations appearing on the product label.
-
Use enough
repellent to cover exposed skin or clothing. Don't apply
repellent to skin
that is
under clothing.
Heavy application
is not
necessary to achieve protection.
-
Do
not apply repellent to cuts, wounds, or irritated skin.
-
After
returning indoors, wash treated skin with soap and water.
-
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 mouth.
Use on Children
Q. How should products containing
DEET be used on children?
A. No definitive
studies exist in the scientific literature about what concentration
of
DEET is safe for children.
No serious illness
has arisen from use of DEET when used
according the manufacturer’s
recommendations. The American Academy
of Pediatrics has recommended that
a cautious approach is to use products
with a low concentration
of DEET, 10% or less, on children aged
2 - 12. Most guidelines cite that it
is acceptable to use repellents containing
DEET on
children
over 2 years of age. Other experts
suggest that it is acceptable to apply
repellent with low concentrations of
DEET to infants over
2 months old.
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 safer
for
use on children.
Parents should choose
the type and concentration of repellent to be used
by taking into
account the amount
of time
that a child will
be outdoors, exposure to mosquitoes,
and the risk of mosquito-transmitted
disease
in the
area. Persons
who
are concerned about using
DEET or other products on children
may wish to consult their 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 http://npic.orst.edu.
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 tend
to 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.
Using repellents on the skin
is not the only way to avoid
mosquito
bites.
Children
and
adults can
wear
clothing
with long pants
and long sleeves while outdoors.
DEET or other repellents
such as permethrin
can also be applied to clothing
(don’t
use permethrin on skin), as
mosquitoes may bite through
thin fabric. Mosquito
netting
can
be used over infant carriers.
Finally, it may be possible
to reduce the
number of mosquitoes in the
area by getting
rid of containers
with standing water that provide
breeding places for the mosquitoes.
Q. Is DEET
safe for pregnant or nursing women?
A.
There are no reported adverse events following use of repellents
containing
DEET in pregnant
or breastfeeding
women.
Q. Are there any risks due
to using repellents containing DEET?
A. 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.
Always follow the instructions
on the product label.
Source: Center
for Disease Control
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