"Sunrise at Valley Forge, Valley Forge National Historical Park, 2015." by U.S. National Park Service , public domain
![]() | Valley ForgePreventing Lyme Disease |
Brochure about Preventing Lyme Disease at Valley Forge National Historical Park (NHP) in Pennsylvania. Published by the National Park Service (NPS).
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covered parks
Valley Forge National Historical Park
King of Prussia, Pa
National Park Service
U. S. Department of Interior
Preventing Lyme Disease
The More You Know The Easier It Is
What is Lyme Disease?
Lyme Disease is a bacterial infection which acquired its name from Lyme, Connecticut, where the
first cases were diagnosed in 1975. The Centers for Disease Control currently lists Lyme Disease as
the most common tick-borne illness. Although reported throughout the United States and Europe,
in the United States it is most prevalent in the Northeast and mid-Atlantic states.
Caused by the bacterium Borrelia burgdorferi, Lyme Disease is most commonly transmitted to
humans through the bite of the deer tick or black legged tick (Ixodes scapularis, formerly Ixodes
dammini). The tick becomes infected when it takes a first blood meal from the white-footed mouse,
its primary host.
Recognizing the Deer Tick
Deer ticks often go unobserved because of their small size compared to the
common dog tick (which also may transmit Lyme Disease). There are three
stages in the life cycle of the deer tick: larva, nymph, and adult. During the
larval stage it is the size of the head of a pin. The adult reaches the size of a
sesame seed unless it has just fed, then it may grow up to four times normal size.
Ixodes scapularis nymph
compared to a human thumb
These deer ticks are shown actual size:
larva nymph
adults
blood-engorged adult tick
How and Where the Tick Lives
In the Northeast, larval deer ticks hatch and take a first blood meal in August, often from the
white-footed mouse – the carrier of the Lyme Disease bacterium. This is usually when ticks become
infected with Lyme Disease. Fully engorged larvae drop to the ground then emerge as nymphs the
following Spring.
Nymphs (and in Fall the adult ticks), then transfer to a larger host. Lyme Disease can be
transmitted to humans if they encounter a tick at this time and become the secondary host. It is
common for nymphal and adult ticks to attach to dogs, cats, birds, squirrels, raccoons, foxes, mice,
deer, etc.
The primary role that deer and other wildlife such as birds play in the spread of Lyme Disease is in
the transport of potentially infected ticks into the home environment. Additionally, abundant hosts
may support a higher than normal tick population compared to areas with fewer host species.
Ticks spend most of their lives in moist, humid areas with abundant host species.
Although found in all natural environments at Valley Forge National Historical
Park, research indicates that the highest tick densities are in wooded areas. Ticks
can be found on shrubby vegetation less than 3 feet in height, the undersides of
leaves, logs, and in leaf litter. Structures such as stone walls, particularly when
located within wooded areas of the park, are also favored locations for ticks.
Student collecting ticks using
a drag cloth
Transmitting Lyme Disease to Humans
Although tick larvae do bite humans, they are unlikely to be a carrier of the Lyme Disease because
they have not yet been infected. The most dangerous period for transmission of Lyme Disease to
humans is during the nymphal stage because nymphs are most likely to feed on a person and are still
small enough to be difficult to detect.
The adult tick transmits the disease, but they are usually large enough to see and are often spotted
and removed quickly. Peak months for nymphal and adult deer ticks in this area are May, June,
July, and October.
If a tick is attached to your skin for less than 24 hours your chance of getting Lyme Disease is
very small. Prompt removal of ticks may substantially reduce the probability of acquiring Lyme
Disease from a tick bite.
How to Remove a Tick
The more quickly you remove a trick from your body, the better your
chances of avoiding infection. To safely remove a tick, grasp it firmly
with fine-point tweezers where the mouthparts enter the skin. Without
squeezing the body of the tick, tug gently until it releases its hold and then
wipe the bite area with antiseptic or wash with soap and water.
Lyme Disease Symptoms
The majority of Lyme Disease cases are reported in June, July, and August. Early symptoms usually
occur from a few days to a few weeks after infection, although it could be up to one a month. If
recognized early it is easily treated with antibiotics. A vaccine is also available. Ask you doctor
about this option.
Early Symptoms
The onset of Lyme Disease is usually accompanied by flu-like symptoms that include one or more
of the following: fatigue, chills and fever, headache, muscle and joint pain and/or stiffness, stiff
neck, discomfort in the jaw area, red eyes, and swollen glands.
As many as 50% of the people who are infected with Lyme Disease also develop a
RED RASH at the site of the initial bite. The rash is often round and may expand
up to 18 inches in diameter over a number of weeks. The center of the rash may
clear as it expands creating a “bulls-eye” effect. The rash can have several shapes
and multiple, secondary rashes may appear on other parts of the body. Shown
here is the most typical rash.
Swollen knee with
“bulls-eye” effect rash
Late Symptoms
If left untreated, Lyme Disease can cause serious problems and be difficult to treat. Late symptoms
may include: severe, chronic arthritis; meningitis; neurological disorders causing numbness,
tingling in the extremities, loss of concentration, and memory retention, lethargy, Bell’s Palsy (loss
of control on one side of the face), and cardiac symptoms such as heart palpitations or heart block.
The Best Treatment is PREVENTION
You can enjoy the natural beauty of the outdoors and the history and heritage of Valley Forge
National Historical Park by following these simple precautions:
1. Exercise caution about visiting heavily wooded areas with dense underbrush. Be especially
careful during the months of May, June, July, and October. If you hike through woodlands or
tall grass meadows, stay on designated trails and avoid vegetation along the path.
2. Avoid stone walls, logs, and other structures that may potentially harbor ticks and mice.
3. Dress appropriately. Cover your hair with a hat. Wear a long-sleeved shirt and long pants with
the bottoms tucked into your socks. Clothes should be a light color to make the ticks easier to
see. Protect your feet by wearing shoes and socks instead of sandals.
4. Use tick repellant containing Permethrin on the outside of your clothes and one containing no
more than 30% DEET on exposed skin.
5. Remove, wash, and dry clothing when you come in from the outdoors.
6. Check yourself, your family members, and your pet for ticks when you come in from outdoors
and remove ticks as soon as possible.
Additional Suggestions to Protect Yourself at Home
1. Cut back the brush and long grass bordering your home. Remove yard waste, brush piles, leaf
litter, and wood piles that are favorite spots for ticks and mice.
2. Place bird feeders away from heavily used areas and exclude or discourage animals such as deer
from entering the yard.
3. As a last resort you may research which pesticides are appropriate to use to reduce tick
populations and find the one that is safest for your pets, family, and the environment.
For Further Information Contact:
The PA Department of Health at 1-877-PA-HEALTH (1-877-724-3258)
Centers for Disease Control and Prevention, National Center for Zoonotic, Vector-borne and
Enteric Diseases (NCZVED), Division of Vector Borne Infectious Diseases, 3150 Rampart Road
Fort Collins, CO 80521 OR 1 (800) CDC-INFO (232-4636) OR visit their website at www.cdc.gov