Lyme
Disease Prevention
Avoidance of Ticks. At present, the best way
to avoid Lyme disease is to avoid deer ticks. Although generally
only about one percent of all deer ticks are infected with the
Lyme disease bacterium, in some areas more than half of them
harbor the microbe.
Most people with Lyme disease become infected during the summer,
when immature ticks are most prevalent. Except in warm climates,
few people are bitten by deer ticks during winter months.
Deer ticks are most often found in wooded areas and nearby shady
grasslands, and are especially common where the two areas merge.
Because the adult ticks feed on deer, areas where deer are frequently
seen are likely to harbor sizable numbers of deer ticks.
To help prevent tick bites, people entering tick-infested areas
should walk in the center of trails to avoid picking up ticks
from overhanging grass and brush.
To minimize skin exposure to ticks, people outdoors in tick-infested
areas should wear long pants and long-sleeved shirts that fit
tightly at the ankles and wrists. As a further safeguard, people
should wear a hat, tuck pant legs into socks, and wear shoes
that leave no part of the feet exposed. To make it easy to detect
ticks, people should wear light-colored clothing.
To repel ticks, people can spray their clothing with the insecticide
permethrin, which is commonly found in lawn and garden stores.
Insect repellents that contain a chemical called DEET (N,N-diethyl-M-toluamide)
can also be applied to clothing or directly onto skin. Although
highly effective, these repellents can cause some serious side
effects, particularly when high concentrations are used repeatedly
on the skin. Infants and children may be especially at risk
for adverse reactions to DEET.
Pregnant women should be especially careful to avoid ticks in
Lyme disease areas because the infection can be transferred
to the unborn child. Although rare, such a prenatal infection
may make the woman more likely to miscarry or deliver a stillborn
baby.
Checking for Ticks. Once indoors, people should
check themselves and their children for ticks, particularly
in the hairy regions of the body. The immature deer ticks that
are most likely to cause Lyme disease are only about the size
of a poppy seed, so they are easily mistaken for a freckle or
a speck of dirt. All clothing should be washed. Pets should
be checked for ticks before entering the house, because they,
too, can develop symptoms of Lyme disease. In addition, a pet
can carry ticks into the house. These ticks could fall off without
biting the animal and subsequently attach to and bite people
inside the house.
If a tick is discovered attached to the skin, it should be pulled
out gently with tweezers, taking care not to squeeze the tick's
body. An antiseptic should then be applied to the bite. Studies
by NIH-supported researchers suggest that a tick must be attached
for at least 48 hours to transmit the Lyme disease bacterium,
so prompt tick removal could prevent the disease.
The risk of developing Lyme disease from a tick bite is small,
even in heavily infested areas, and most physicians prefer not
to treat patients bitten by ticks with antibiotics unless they
develop symptoms of Lyme disease.
Vaccine Development. Because Lyme disease is
difficult to diagnose and sometimes does not respond to treatment,
researchers are trying to create a vaccine that will protect
people from the disorder. Vaccines work in part by prompting
the body to generate antibodies. These custom-shaped molecules
lock onto specific proteins made by a virus or bacterium-often
those proteins lodged in the microbe's outer coat. Once antibodies
attach to an invading microbe, other immune defenses are evoked
to destroy it.
Development of an effective vaccine for Lyme disease has been
difficult for a number of reasons. Scientists need to find out
how the immune system protects against the bacterium. However,
a vaccine based on the outer surface protein A (OspA) of the
Lyme bacterium has been tested in people living in the northeastern
United States, and preliminary results are encouraging.
- Avoid tick-infested
areas, especially in May, June, and July.*
- Wear light-colored
clothing so that ticks can be easily spotted.
- Wear long-sleeved
shirts and closed shoes and socks.
- Tuck pant
legs into socks or boots and tuck shirt into pants.
- Apply insect
repellent containing permethrin to pants, socks, and
shoes, and compounds containing DEET on exposed skin.
Do not overuse these products.
- Walk in
the center of trails to avoid overgrown grass and brush.
- After being
outdoors in a tick-infested area, remove, wash, and
dry clothing.
- Inspect
the body thoroughly and remove carefully any attached
ticks.
- Check pets
for ticks.
* Local health
departments and park or agricultural extension services
may have information on the seasonal and geographic distribution
of ticks in your area.
- Tug gently
but firmly with blunt tweezers near the "head" of the
tick until it releases its hold on the skin.
- To lessen
the chance of contact with the bacterium, try not to
crush the tick's body or handle the tick with bare fingers.
- Swab the
bite area thoroughly with an antiseptic to prevent bacterial
infection.
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 Tick
Eradication. In the meantime, researchers are trying
to develop an effective strategy for ridding areas of deer ticks.
Studies show that spraying of pesticide in wooded areas in the
spring and fall can substantially reduce for more than a year
the number of adult deer ticks residing there. Spraying on a large
scale, however, may not be economically feasible and may prompt
environmental or health concerns.
Scientists are also pursuing biological control of deer ticks
by introducing tiny stingerless wasps, which feed on immature
ticks, into tick-infested areas. Researchers are currently assessing
the effectiveness of this technique.
Successful control of deer ticks will probably depend on a combination
of tactics. More studies are needed before wide-scale tick control
strategies can be implemented.
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Last Updated March 5, 1999 (kap)
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