Preventing Tick Borne Diseases in Virginia- VDH Brochure
Spring and summer bring warm temperatures, just right for
walking in the woods or other outdoor activities. Warm
weather also means that ticks become more active and this
can increase the risk of a tick-borne disease.
The tick-borne diseases that occur most often in Virginia are
Lyme disease, Rocky Mountain spotted fever, and ehrlichiosis.
Lyme Disease
Lyme disease is caused by infection with a spiral-shaped
bacterium called Borrelia burgdorferi. Although Lyme dis-
ease most often occurs in the Northeastern and upper
Midwestern states, people can get Lyme disease in Virginia.
The number of cases reported in Virginia has increased sub-
stantially in recent years.
The Tick
The blacklegged tick (Ixodes scapularis), formerly known
as the deer tick, is the only carrier of Lyme disease in the
Eastern U.S. The blacklegged tick's name comes from it
being the only tick in the Eastern U.S. that bites humans and
has legs that are black (or dark chocolate brown) in color.
Lyme disease transmission to humans usually occurs during
the late spring and early summer when young (nymph
stage) ticks are active and feeding. Tick nymphs normally
feed on small and medium sized animals, but will also feed on
people. Tick nymphs typically become infected with the
Lyme disease agent by feeding on certain rodent species
while in thier larval stage.
In the fall, the nymphs become adults and infected nymphs
will become infected adults. Adult blacklegged ticks prefer to
feed on deer. However, adult ticks will occasionally bite
people on warm days of the fall and winter and can transmit
Lyme disease at that time.
Transmission of Lyme disease by the nymph or adult ticks
usually does not occur until the tick has been attached and
feeding on a human or animal host for at least 36 hours.
The Symptoms
Between three days to several weeks after being bitten by an
infected tick, 70-90% of people develop a circular or oval
rash, called erythema migrans (or EM), at the site of the bite.
To qualify as an EM, the rash must be at least two inches in
diameter. That is because bites by some tick species can cause
local inflammation and redness around the bite that could be
mistaken for an EM. Unlike localized inflamation, an EM
rash will increase in size and may become more than 12 inch-
es across. As it enlarges, the area around the center of the rash
clears giving it a “bull's eye” appearance. The EM rash does
not itch or hurt so if it is not seen, it may not be noticed.
In addition to an EM rash, Lyme disease may cause
headache, fever, muscle and joint aches, and a feeling of
tiredness. If left untreated, Lyme disease may progress to
affect the joints, nervous system, or heart several weeks to
months after the tick bite. In a small percentage of infected
people, late symptoms may occur months to years later and
cause long-term nervous system problems or arthritis.
Unfortunately, blacklegged tick nymphs are small (about
the size of a pinhead), difficult to see, and cause no itch or
irritation at the site of the bite, so many people are not aware
they have been bitten. If you have been in an area that might
contain ticks and you experience any symptoms of Lyme
disease, contact your doctor.
The Treatment
When Lyme disease is detected early, its effects can be mild
and it is easily treated with antibiotics. In the late stages,
Lyme disease can be treated successfully with antibiotics,
but the treatment lasts longer and is more involved.
Rocky Mountain Spotted Fever
Rocky Mountain spotted fever (RMSF) is caused by infec-
tion with a bacterium called Rickettsia rickettsii. The dis-
ease is characterized by a sudden onset of symptoms and
can be fatal if not treated. Nearly all cases occur in the
spring and summer months.
The Tick
In Virginia, the American dog tick (Dermacentor variabilis)
is the species known to carry the agent of Rocky Mountain
spotted fever. The tick needs to feed on a host/person for
only about four hours to transmit the bacteria. Fortunately,
less than 1% of American dog ticks carry the agent of RMSF.
The Symptoms
Symptoms of Rocky Mountain spotted fever begin 2-14 days
after the tick bite, and may include fever, deep muscle pain,
severe headache, chills, and upset stomach or vomiting.
From the third to fifth day of illness a red, spotted rash may
appear, beginning on the wrists and ankles. The rash spreads
quickly to the palms of the hands and soles of the feet and
then to the rest of the body. However, only about half of
RMSF patients develop a rash.
The Treatment
Antibiotic treatment for RMSF is effective, and suspected
RMSF should be treated as soon as possible based on symp-
toms and a history of tick exposure. The risk of death from
RMSF increases by the fifth day of illness - but the rash often
does not occur until that time. Therefore, do not wait for
RMSF blood test results, or the appearance of a rash, before
starting treatment. Treatment is important; almost one-third
of those who do not get treated die from this disease.
Ehrlichiosis and Anaplasmosis
Although several diseases can be caused by bacteria in the
Ehrlichia and Anaplasma genera, the most common in
Virginia are human monocytic ehrlichiosis (HME) and
human granulocytic anaplasmosis (HGA). HME is transmit-
ted only by the lone star tick (Amblyomma americanum).
Disease transmission occurs most commonly by bites from
the adult ticks. Lone star ticks are very common and are the
species causing the most tick bites to people in Virginia.
HGA is transmitted only by the blacklegged tick (most com-
monly by bites from nymphal stage ticks). The bacteria caus-
ing HME or HGA will not be transmitted unless the infected
tick has been attached and feeding for at least 24 hours.
The Symptoms
Symptoms for both HME and HGA can include fever, head-
ache, muscle pain, vomiting, and general discomfort. Illness
can be severe - up to 3% of patients may die if not treated.
The Treatment
HME and HGA respond rapidly to treatment with antibi-
otics. Treatment should be based on symptoms (including
platelet and liver enzyme tests) and history of tick exposure -
treatment should not be delayed while waiting for ehrli-
chiosis or anaplasmosis-specific test results.
Other Diseases
Ticks can transmit other diseases, such as tularemia (rabbit
fever) and babesiosis. Neither of these illnesses is common in
Virginia. Tularemia is a bacterial disease that has a sudden onset
of fever and chills. Typically, an ulcer develops at the site of
the tick bite and surrounding lymph nodes become enlarged.
Tularemia can be transmitted by the American dog tick, the
lone star tick and the blacklegged tick.
Babesiosis is caused by a parasite that infects red blood
cells. The babesiosis agent is transmitted only by infected
blacklegged ticks. Symptoms include fever, chills, muscle
aches, fatigue, and jaundice.
Tick Identification Chart
Prevention
Ticks do not jump or fly; they wait on the forest floor, leaf
litter, or low vegetation and attach to the feet, shoes or legs
of people and animals that pass by. The ticks then crawl
upward. The following steps can reduce your risk of tick-
borne diseases:
• Avoid potential tick-infested areas such as tall grass and
dense vegetation in shaded areas and along forest edges.
• Walk in the center of mowed trails to avoid brushing
against vegetation.
• Keep grass cut and underbrush thinned in yards. If chem-
icals are used for tick control, follow directions carefully
or hire a professional to apply the chemicals.
• Eliminate the living places of small rodents around your
home.
• Wear light-colored clothing so that ticks are easier to see
and remove.
• Tuck pant legs into socks and boots. Wear long-sleeved
shirts buttoned at the wrist.
• Conduct tick checks on yourself, your children, and your
pets every four to six hours while in tick habitat.
• Apply tick repellent to areas of the body and clothing that
may come in contact with grass and brush. Repellents
include those containing up to 50% DEET for adults or
less than 30% for children. An aerosol repellent/insecti-
cide containing 0.5% permethrin may be applied to shoes,
socks, and other clothing, but should not be used on skin.
Follow directions carefully and do not overuse. Some tick
repellents can cause toxic or allergic reactions.
• Ask your veterinarian to recommend tick control meth-
ods for your pets. Animals can get Lyme disease, Rocky
Mountain spotted fever, and ehrlichiosis, but they do not
transmit these diseases to humans.
Tick Removal
Because ticks do not transmit disease until they have been
attached to the host for several hours to several days, it is
very important to remove ticks as soon as they are found.
The following is the best way to remove a tick:
• Grasp the tick with tweezers as close to the skin as possi-
ble and gently, but firmly, pull it straight out. Avoid any
twisting or jerking motion that may break off the mouth
parts in the skin. Mouth parts left in the wound will not
transmit the disease, but may cause irritation or infection
similar to a reaction from a splinter.
• If tweezers are not available, protect your fingers with
gloves, tissue, or a paper towel; do not touch the tick
with bare fingers. Do not squeeze or rupture the tick's
swollen abdomen. This may cause an infectious agent to be
injected into the skin and cause disease.
• After the tick has been removed, wash hands with soap
and water. Apply a topical antiseptic to the bite site.
• You can dispose of the tick by drowning it in alcohol or
flushing it down a drain or toilet. However, it may be
useful to save the tick in alcohol for several weeks and
have it identified by an expert in case you become ill.
Knowing what kind of tick bit you might help your doc-
tor diagnose the illness.
• Tick removal using nail polish, petroleum jelly, alcohol
or a hot match is not safe. These methods could cause
the tick to regurgitate an infectious agent into the site of
the bite.
If you get sick, and you have been exposed to ticks, be sure to tell your doctor about your tick exposure.
For more information, visit our website at:
www.vdh.virginia.gov/epidemiology/DEE/Vectorborne/index.htm
www.vdh.virginia.gov
August 2008