Tick Awareness in the U.S.
Tick Overview
Warmer temperatures means more ticks are finding host to bite and latch onto. Tick exposure can occur year-round, but ticks are most active during warmer months (April-September). According to Centers for Disease Control and Prevention (CDC) data, the prevalence of tickborne diseases has been generally been increasing since 2004. Of the many different tick species found throughout the world, only a select few bite and transmit disease to people. Ticks are generally found near the ground, in brushy or wooded areas. They can’t jump or fly. Instead, they climb tall grasses or shrubs and wait for a potential host to brush against them. When this happens, they climb onto the host and seek a site for attachment.
Of the ticks that bite people, different species of ticks transmit different diseases. In the United States, some ticks carry pathogens that can cause human disease, including:
Anaplasmosis is transmitted to humans by tick bites primarily from the blacklegged tick (Ixodes scapularis) in the northeastern and upper midwestern U.S. and the western blacklegged tick (Ixodes pacificus) along the Pacific coast.
Babesiosis is caused by microscopic parasites that infect red blood cells. Most human cases of babesiosis in the U.S. are caused by Babesia microti. Babesia microti is transmitted by the blacklegged tick (Ixodes scapularis) and is found primarily in the northeast and upper midwest.
Borrelia mayonii infection has recently been described as a cause of illness in the upper midwestern United States. It has been found in blacklegged ticks (Ixodes scapularis) in Minnesota and Wisconsin. Borrelia mayonii is a new species and is the only species besides B. burgdorferi known to cause Lyme disease in North America.
Borrelia miyamotoi infection has recently been described as a cause of illness in the U.S. It is transmitted by the blacklegged tick (Ixodes scapularis) and has a range similar to that of Lyme disease.
Bourbon virus infection has been identified in a limited number patients in the Midwest and southern United States. At this time, we do not know if the virus might be found in other areas of the United States.
Colorado tick fever is caused by a virus transmitted by the Rocky Mountain wood tick (Dermacentor andersoni). It occurs in the the Rocky Mountain states at elevations of 4,000 to 10,500 feet.
Ehrlichiosis is transmitted to humans by the lone star tick (Ambylomma americanum), found primarily in the southcentral and eastern U.S.
Heartland virus cases have been identified in the Midwestern and southern United States. Studies suggest that Lone Star ticks can transmit the virus. It is unknown if the virus may be found in other areas of the U.S.
Lyme disease is transmitted by the blacklegged tick (Ixodes scapularis) in the northeastern U.S. and upper midwestern U.S. and the western blacklegged tick (Ixodes pacificus) along the Pacific coast.
Powassan disease is transmitted by the blacklegged tick (Ixodes scapularis) and the groundhog tick (Ixodes cookei). Cases have been reported primarily from northeastern states and the Great Lakes region.
Rickettsia parkeri rickettsiosis is transmitted to humans by the Gulf Coast tick (Amblyomma maculatum).
Rocky Mountain spotted fever (RMSF) is transmitted by the American dog tick (Dermacentor variabilis), Rocky Mountain wood tick (Dermacentor andersoni), and the brown dog tick (Rhipicephalus sangunineus) in the U.S. The brown dog tick and other tick species are associated with RMSF in Central and South America.
STARI (Southern tick-associated rash illness) is transmitted via bites from the lone star tick (Ambylomma americanum), found in the southeastern and eastern U.S.
Tickborne relapsing fever (TBRF) is transmitted to humans through the bite of infected soft ticks. TBRF has been reported in 15 states: Arizona, California, Colorado, Idaho, Kansas, Montana, Nevada, New Mexico, Ohio, Oklahoma, Oregon, Texas, Utah, Washington, and Wyoming and is associated with sleeping in rustic cabins and vacation homes.
Tularemia is transmitted to humans by the dog tick (Dermacentor variabilis), the wood tick (Dermacentor andersoni), and the lone star tick (Amblyomma americanum). Tularemia occurs throughout the U.S.
364D rickettsiosis (Rickettsia phillipi, proposed) is transmitted to humans by the Pacific Coast tick (Dermacentor occidentalis ticks). This is a new disease that has been found in California.
Regions Where Ticks Live
Centers for Diseases Control and Prevention Data Map
American Dog Tick-Dermacentor Variabilis
Where found: Widely distributed east of the Rocky Mountains. Also occurs in limited areas on the Pacific Coast.
Transmits: Tularemia and Rocky Mountain spotted fever.
Comments: The highest risk of being bitten occurs during spring and summer. Dog ticks are sometimes called wood ticks. Adult females are most likely to bite humans.
Blacklegged Tick-Ixodes Scapularis
Where found: Widely distributed across the eastern United States.
Transmits: Borrelia burgdorferi and B. mayonii (which cause Lyme disease), Anaplasma phagocytophilum (anaplasmosis), B. miyamotoi disease (a form of relapsing fever), Ehrlichia muris eauclairensis (ehrlichiosis), Babesia microti (babesiosis), and Powassan virus (Powassan virus disease).
Comments: The greatest risk of being bitten exists in the spring, summer, and fall. However, adults may be out searching for a host any time winter temperatures are above freezing. Stages most likely to bite humans are nymphs and adult females.
Brown Dog Tick-Rhipicephalus Sanguineus
Where found: Worldwide.
Transmits: Rocky Mountain spotted fever (in the southwestern U.S. and along the U.S.-Mexico border).
Comments: Dogs are the primary host for the brown dog tick in each of its life stages, but the tick may also bite humans or other mammals.
Gulf Coast Tick-Amblyomma Maculatum
Where found: Coastal areas of the U.S. along the Atlantic coast and the Gulf of Mexico.
Transmits: Rickettsia parkeri rickettsiosis, a form of spotted fever.
Comments: Larvae and nymphs feed on birds and small rodents, while adult ticks feed on deer and other wildlife. Adult ticks have been associated with transmission of R. parkeri to humans.
Lone Star Tick-Amblyomma Americanum
Where found: Widely distributed in the southeastern and eastern United States.
Transmits: Ehrlichia chaffeensis and Ehrlichia ewingii (which cause human ehrlichiosis), Heartland virus, tularemia, and STARI.
Comments: A very aggressive tick that bites humans. The adult female is distinguished by a white dot or “lone star” on her back. Lone star tick saliva can be irritating; redness and discomfort at a bite site does not necessarily indicate an infection. The nymph and adult females most frequently bite humans and transmit disease.
Rocky Mountain Wood Tick-Dermacentor Andersoni
Where found: Rocky Mountain states and southwestern Canada from elevations of 4,000 to 10,500 feet.
Transmits: Rocky Mountain spotted fever, Colorado tick fever, and tularemia.
Comments: Adult ticks feed primarily on large mammals. Larvae and nymphs feed on small rodents. Adult ticks are primarily associated with pathogen transmission to humans.
Western Blacklegged Tick-Ixodes Pacificus
Where found: Along the Pacific coast of the U.S., particularly northern California.
Transmits: Anaplasmosis and Lyme disease.
Comments: Nymphs often feed on lizards, as well as other small animals. As a result, rates of infection are usually low (~1%) in adults. Stages most likely to bite humans are nymphs and adult females.
Preventing Tick Bites
Before You Go Outdoors
Know where to expect ticks. Ticks live in grassy, brushy, or wooded areas, or even on animals. Spending time outside walking your dog, camping, gardening, or hunting could bring you in close contact with ticks. Many people get ticks in their own yard or neighborhood.
Treat clothing and gear with products containing 0.5% permethrin. Permethrin can be used to treat boots, clothing and camping gear and remain protective through several washings. Alternatively, you can buy permethrin-treated clothing and gear.
Use Environmental Protection Agency (EPA)-registered insect repellents containing DEET, picaridin, IR3535, Oil of Lemon Eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. EPA’s helpful search tool can help you find the product that best suits your needs. Always follow product instructions. Do not use products containing OLE or PMD on children under 3 years old.
Avoid Contact with Ticks
Avoid wooded and brushy areas with high grass and leaf litter.
Walk in the center of trails.
After You Come Indoors
Check your clothing for ticks. Ticks may be carried into the house on clothing. Any ticks that are found should be removed. Tumble dry clothes in a dryer on high heat for 10 minutes to kill ticks on dry clothing after you come indoors. If the clothes are damp, additional time may be needed. If the clothes require washing first, hot water is recommended. Cold and medium temperature water will not kill ticks.
Examine gear and pets. Ticks can ride into the home on clothing and pets, then attach to a person later, so carefully examine pets, coats, and daypacks.
Shower soon after being outdoors. Showering within two hours of coming indoors has been shown to reduce your risk of getting Lyme disease and may be effective in reducing the risk of other tickborne diseases. Showering may help wash off unattached ticks and it is a good opportunity to do a tick check.
Check your body for ticks after being outdoors. Conduct a full body check upon return from potentially tick-infested areas, including your own backyard. Use a hand-held or full-length mirror to view all parts of your body. Check these parts of your body and your child’s body for ticks:
Under the arms
In and around the ears
Inside belly button
Back of the knees
In and around the hair
Between the legs
Around the waist
Before You Go Outdoors
Know where to expect ticks. Ticks live in grassy, brushy, or wooded areas, or even on animals. Spending time outside walking your dog, camping, gardening, or hunting could bring you in close contact with ticks. Many people get ticks in their own yard or neighborhood.
Treat clothing and gear with products containing 0.5% permethrin. Permethrin can be used to treat boots, clothing and camping gear and remain protective through several washings. Alternatively, you can buy permethrin-treated clothing and gear.
Use Environmental Protection Agency (EPA)-registered insect repellents containing DEET, picaridin, IR3535, Oil of Lemon Eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. EPA’s helpful search tool can help you find the product that best suits your needs. Always follow product instructions. Do not use products containing OLE or PMD on children under 3 years old.
Avoid Contact with Ticks
Avoid wooded and brushy areas with high grass and leaf litter.
Walk in the center of trails.
Preventing ticks on your pets
Tick bites on dogs may be hard to detect. Signs of tickborne disease may not appear for 7-21 days or longer after a tick bite, so watch your dog closely for changes in behavior or appetite if you suspect that your pet has been bitten by a tick.
Talk to your veterinarian about:
The best tick prevention products for your dog
Tickborne diseases in your area
To further reduce the chances that a tick bite will make your dog sick:
Check your pets for ticks daily, especially after they spend time outdoors.
If you find a tick on your pet, remove it right away.
Reduce tick habitat in your yard.
Tick Removal
If you find a tick attached to your skin, simply remove the tick as soon as possible. There are several tick removal devices on the market, but a plain set of fine-tipped tweezers works very well.
Use clean, fine-tipped tweezers to grasp the tick as close to the skin’s surface as possible.
Pull upward with steady, even pressure. Don’t twist or jerk the tick; this can cause the mouth-parts to break off and remain in the skin. If this happens, remove the mouth-parts with tweezers. If you cannot remove the mouth easily with tweezers, leave it alone and let the skin heal.
After removing the tick, thoroughly clean the bite area and your hands with rubbing alcohol or soap and water.
Never crush a tick with your fingers. Dispose of a live tick by
Putting it in alcohol,
Placing it in a sealed bag/container,
Wrapping it tightly in tape, or
Flushing it down the toilet.
If you develop a rash or fever within several weeks of removing a tick, see your doctor:
Tell the doctor about your recent tick bite,
When the bite occurred, and
Where you most likely acquired the tick.
Tick Resources
CDC offers free tick and tickborne disease resources. Order here.
For more detailed data about each disease, including state totals, see the Notifiable Infectious Diseases and Conditions Annual Data Tables.
Radio PSA for Healthcare Providers: Preventing Tick Bites and Tickborne Diseases (2:40) [mp3 – 160sec]
Go here for the latest CDC tick surveillance
Go here for the CDC’s tick bite data tracker
Learn more at Tick paralysis: MedlinePlus Medical Encyclopedia
Find disease-specific resources for Lyme disease, Rocky Mountain spotted fever, and babesiosis.