Common Ticks
Although ticks are
commonly thought of as insects, they are actually arachnids; like scorpions,
spiders and mites. All members of this group have four pairs of legs as adults
and have no antennae. Adult insects have three pairs of legs and one pair of
antennae. Ticks are among the most efficient carriers of disease because they
attach firmly when sucking blood, feed slowly and may go unnoticed for a
considerable time while feeding. Ticks usually take several days to complete
feeding.
Ticks have four life
stages: egg, six-legged larva, eight-legged nymph and adult. After the egg
hatches, the tiny larva (sometimes called a “seed tick”) feeds on an
appropriate host. The larva then develops (molts) into the larger nymph. The
nymph feeds on a host and then molts into an even larger adult. Both male and
female adults find and feed on a host, and then the females lay eggs sometime
after feeding.
Ticks wait for host
animals from the tips of grasses and shrubs (not from trees). When brushed by a moving animal or person,
they quickly let go of the vegetation and climb onto the host. Ticks can only
crawl; they cannot fly or jump. Ticks found on the scalp have usually crawled
there from lower parts of the body. Some species of ticks will crawl several feet
toward a host. Ticks can be active on winter days when the ground temperatures
are about 45 degrees Fahrenheit.
There are two groups
of ticks, sometimes referred to as “hard” ticks and “soft” ticks. Hard ticks,
like the common dog tick, have a hard shield just behind the mouthparts
(sometimes incorrectly called the “head”); unfed hard ticks are shaped like a
flat seed. Soft ticks do not have the hard shield and they are shaped like a
large raisin. Soft ticks prefer to feed on birds or bats and are seldom encountered
unless these animals are nesting or roosting in an occupied building.
American
Dog Tick
(Dermacentor variabilis)
 |
| American Dog Tick |
One of the most
frequently encountered ticks is the American dog tick, also sometimes known as
the wood tick. The larvae and nymphs feed on small warm-blooded animals such as
mice and birds. The adult American dog tick will feed on humans and medium to
large mammals such as raccoons and dogs.
Unfed males and
females are reddish-brown and about 3/16-inch long. Females have a large silver-colored
spot behind the head and will become ½-inch long after feeding or about the
size of a small grape. Males have fine silver lines on the back and do not get
much larger after feeding. Males are sometimes mistaken for other species of
ticks because they appear so different from the female.
In Illinois, the adults are most active in
April, May and June. By September, the adults are inactive and are rarely
observed. The American dog tick can transmit Rocky Mountain spotted fever,
tularemia and possibly ehrlichiosis to humans.
Lone Star Tick
(Amblyomma americanum)
 |
| Lone Star Tick |
The lone star tick is
primarily found in the southern half of Illinois,
although it can occasionally be found further north. Larvae, nymphs and adults
will feed on a variety of warm-blooded hosts, including people. The larva is
very tiny, only a little larger than the period at the end of this sentence.
The nymph, the most common stage found on people, is about pinhead-sized.
Adults are about 1/8-inch long and brown. The adult female has a white spot in
the middle of her back. Because they are so similar in size, the lone star tick
is sometimes misidentified by laypersons as the blacklegged / deer tick (see
below).
The lone star tick is
most active from April through the end of July. Although it can transmit Rocky
Mountain spotted fever, the lone star tick is not as likely to transmit the
disease as the American dog tick. This tick also may transmit tularemia and
ehrlichiosis to humans. The lone star tick is not believed to transmit the
bacteria that causes Lyme disease (Borrelia burgdorferi), but may be associated
with a related bacteria species that has not been completely identified.
Blacklegged Tick,
also known as the Deer Tick
(Ixodes
scapularis)
 |
| Blacklegged (Deer) Tick |
All three active
stages of the blacklegged / deer tick will feed on a variety of hosts including
people. After the eggs hatch in the spring, the very tiny larvae feed primarily
on white-footed mice or other small mammals. The following spring, the larvae
molt into pinhead-sized, brown nymphs that will feed on mice, larger
warm-blooded animals and people. In the fall, they molt into adults that feed
primarily on deer, with the females laying eggs the following spring. Adults
are reddish-brown and about 1/8-inch long (or about one-half the size of the more
familiar female American dog tick).
These ticks are found
in wooded areas along trails. The larvae and nymphs are active in the spring
and early summer; adults may be active in both the spring and fall. The
blacklegged / deer tick can transmit Lyme disease and possibly ehrlichiosis to
humans.
The deer tick has
been found sporadically in many Illinois
counties. However, in recent years it has been common only in limited areas,
mostly in northern Illinois
(Geographic distribution by county). Additionally, Illinois
residents may encounter the deer tick during trips to Michigan,
Indiana, Minnesota,
Wisconsin or the northeastern United States
where it is very common in some areas.
Brown Dog Tick
(Rhipicephalus sanguineus)
 |
| Brown Dog Tick |
The brown dog tick
(also known as the kennel tick) is found through most of the United States This tick feeds on dogs, but rarely
bites people. Unlike the other species of ticks, its life cycle allows it to
survive and develop indoors. The brown dog tick is found primarily in kennels
or homes with dogs where it may be found hiding in cracks, behind radiators,
under rugs and furniture, and on draperies and walls.
The adult is
reddish-brown and about 1/8-inch long, and usually attaches around the ears or
between the toes of a dog to feed. After feeding, a female may engorge to
½-inch long. She then drops off the dog and crawls into a hiding place where
she may lay as many as 3,000 eggs. This tick is tropical in origin and does not
survive Illinois winters outdoors. The
brown dog tick is not an important carrier of human disease.
Winter Tick
(Dermacentor albipictus)
 |
| Winter Tick |
The winter tick is a
species that feeds on large mammals like deer, cattle and horses. Unlike the
hard ticks mentioned above, the winter tick attaches to the host as a larva and
remains attached throughout its life. Consequently, this tick is rarely
encountered by campers or hikers. However, hunters may find the winter tick in
large numbers on deer carcasses. Although the winter tick may carry diseases of
large wild mammals, it is not known to transmit disease to humans.
Preventing Tick
Bites and Disease
The best way to
protect yourself against tickborne illness is to avoid tick bites. This
includes avoiding known tick- infested areas. However, if you live in or visit
wooded areas or areas with tall grass and weeds, follow these precautions to
help prevent tick bites and decrease the risk of disease:
- Wear protective clothing such as
long-sleeved shirts, long trousers, boots or sturdy shoes and a head covering.
(Ticks are easier to detect on light-colored clothing.) Tuck trouser cuffs in
socks. Tape the area where pants and socks meet so ticks cannot crawl under
clothing.
- Apply insect repellent containing
10 percent to 30 percent DEET primarily to clothes. Apply sparingly to exposed skin.
Do not spray directly to the face; spray the repellent onto hands and then
apply to face. Avoid sensitive areas like the eyes, mouth and nasal membranes.
Be sure to wash treated skin after coming indoors. Use repellents containing
permethrin to treat clothes (especially pants, socks and shoes) but not skin.
Always follow label directions; do not misuse or overuse repellents. Always
supervise children in the use of repellents.
- Walk in the center of trails so
weeds do not brush against you. In camping areas, individuals who sit on the
ground or disturb leaf litter on the forest floor may encounter ticks.
- Check yourself, children and other
family members every two to three hours for ticks. Most ticks seldom attach
quickly and rarely transmit disease organisms until they have been attached
four or more hours. If your pets spend time outdoors, check them for ticks,
too.
- If ticks are crawling on the
outside of clothes, they can be removed with masking tape or cellophane tape. A
ring of tape can be made around the hand by leaving the sticky side out and
attaching the two ends. Ticks will stick to the tape which can then be folded
over and then placed in the trash.
- Remove any tick promptly. The
mouthparts of a tick are barbed and may remain embedded and lead to infection
at the bite site if not removed promptly. Do not burn the tick with a match or
cover it with petroleum jelly or nail polish. Do not use bare hands to remove
the tick because tick secretions may carry disease. The best way to remove a
tick is to grasp it firmly with tweezers as close to the skin as possible and
gently, but firmly, pull it straight out. Do not twist or jerk the tick. If
tweezers are not available, grasp the tick with a piece of tissue or cloth or
whatever can be used as a barrier between your fingers and the tick. Ticks can
be safely disposed of by placing them in a container of soapy water or alcohol,
sticking them to tape or flushing them down the toilet. If you want to have the
tick identified, put it in a small vial of alcohol.
- Wash the bite area and your hands
thoroughly with soap and water and apply an antiseptic to the bite site.
- If you have an unexplained illness
with fever, contact a physician. Be sure to tell the physician if you have been
outdoors in areas where ticks were present or traveled to areas where tickborne
diseases are common.
Prevention and
Control of Ticks Around the Home
Make sure the
property around your home is unattractive to ticks. Because ticks are sensitive
to dry conditions and do not thrive in short vegetation, they are seldom a
problem in well-maintained lawns. Keep your grass mowed and keep weeds cut. Clean
up items that attract rodents which can carry ticks, such as spilled birdseed,
and hiding places like old wood piles. If ticks are present in vegetation along
the edge of the property, insecticides labeled for control of ticks can be
applied to small areas of high weeds that cannot be mowed. Often, one or two
applications per season will be adequate to control ticks in these areas.
Free-roaming dogs and
cats are much more likely to encounter ticks than those that are confined to
the home or yard. If ticks are found on pets, contact your veterinarian for
information about an appropriate tick treatment. Remove the occasional tick
found indoors by vacuuming, seal the vacuum bag and place it in the trash.
Owners of kennels or homes infested with the brown dog tick may wish to contact
a professional pest control company for assistance.
Identification of
Ticks
During the last
several years, about 75 percent of the ticks submitted to Department staff have
been identified either as the American dog tick or as the lone star tick. Many
people are familiar with the female American dog tick. However, the adults of
several species and immature stages must be identified by an entomologist or
other professional familiar with ticks. To submit a tick for identification,
put it into a leak-proof container with rubbing alcohol along with the date and
location where the tick was encountered and contact your local health
department for assistance.
This publication is
for information and is intended as a guide only. Always read and follow all
current label instructions for repellents and pesticides. If any information in
these recommendations disagrees with the pesticide label, the label
instructions must be followed. Prepared with the assistance of the University of Illinois
Extension, University of Illinois Department of Veterinary Pathology and
Illinois Natural History Survey. Edited and Condensed by Scott Glaze February 19, 2012.
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