Understanding Tick-borne Diseases
Did you know that ticks are responsible for more diseases in the United States than mosquitoes?
More than ¾ of all vector-borne diseases are spread through ticks. While you may have been worrying about West Nile virus and the Zika virus, you should be more concerned about the far more common tick-borne diseases, Lyme disease and Rocky Mountain Spotted fever.
Tick-borne diseases are on the rise in the United States. According to the Centers for Disease Control and Prevention (CDC), the reported incidence of tick-borne diseases more than doubled from 2004 to 2016.
There were only 22,527 reported cases of tick-borne illnesses in 2004. That number grew to 48,610 cases in 2016, and 50,865 cases in 2019. The actual rate of tick-borne diseases is thought to be significantly higher than the reported rate of infection.
What sort of tick-borne diseases do you need to worry about? Where are they most prevalent? What are tick disease symptoms? What does the tick bullseye bite mean? How can you prevent becoming the victim of a tick-borne disease? Keep reading for answers to these questions and more.
Where Do Ticks Live?
Various species of ticks can be found throughout the United States. Ticks are more commonly found in wooded areas and places with long grasses. They can’t jump or fly, so they wait until an unsuspecting host brushes against the plant they’re on to crawl over and attach themselves to the new host.
With that being said, tick-borne diseases appear to be more prevalent in the Northeast, upper Midwest, and southern parts of the country; however, they can also be found in certain wooded areas of the West too.
Tick-borne Diseases
There are a wide variety of tick-borne diseases across the United States right now. While each disease tends to be more common in certain areas of the country, no disease is limited strictly to one geographic area.
Lyme disease is the most common and well-known tick-borne disease in the United States. In fact, Lyme disease accounts for 82% of cases of tick-borne diseases in the United States. In the northeast and upper Midwest, it is transmitted by the black-legged tick (Ixodes scapularis), and along the Pacific coast, it is transmitted by the western black-legged tick (Ixodes pacificus).
Far less common causes of tick-borne disease include (listed alphabetically):
Anaplasmosis – This disease is transmitted mostly from bites to humans from black-legged ticks (Ixodes scapularis) in the northeast and upper midwest and bites from the western black-legged tick (Ixodes pacificus) along the Pacific coast.
Babesiosis – This disease is caused by a microscopic parasite transmitted by the bite of the black-legged tick (Ixodes scapularis). The Babesia microti parasite infects your red blood cells and is most common in the northeast and upper Midwest.
Borrelia mayonii – This is a newly-described tick-borne infection in the upper midwestern United States. It’s been found in black-legged ticks (Ixodes scapularis) in Minnesota and Wisconsin and can also cause Lyme disease.
Borrelia miyamotoi - This is another newly-described tick-borne illness spread by the black-legged tick (Ixodes scapularis) with a similar geographic range as Lyme disease.
Bourbon virus – This has also been discovered fairly recently in only a small handful of patients in the Midwest and south. It’s unknown if it can be found outside that range.
Colorado tick fever– This disease is spread by the Rocky Mountain wood tick (Dermacentor andersoni) and occurs in Rocky Mountain states at elevations ranging from 4,000 to 10,500 feet above sea level.
Ehrlichiosis – Found primarily in the south central and eastern United States, this disease is transmitted by the lone star tick (Ambylomma americanum).
Heartland virus – This is another little-studied tick-borne disease. It has been found in midwestern and southern states and is thought to be transmitted by the lone star tick (Ambylomma americanum).
Powassan disease – Reported mostly in the northeast and the Great Lakes region, Powassan disease is transmitted by the black-legged tick (Ixodes scapularis) and the groundhog tick (Ixodes cookei).
Rickettsia parkeri rickettsiosis – This disease is transmitted by the Gulf Coast tick (Amblyomma maculatum).
Rocky Mountain spotted fever (RMSF) – Several different species of tick are responsible for the transmission of this disease including the American dog tick (Dermacentor variabilis), Rocky Mountain wood tick (Dermacentor andersoni), and the brown dog tick (Rhipicephalus sangunineus).
STARI (Southern tick-associated rash illness) – More common in the east and southeast, STARI is transmitted by the lone star tick (Ambylomma americanum).
Tickborne relapsing fever (TBRF) – Found in 15 states so far, TBRF comes from soft ticks, and it is usually associated with sleeping in rustic cabins and vacation homes. The states where cases have been confirmed are Arizona, California, Colorado, Idaho, Kansas, Montana, Nevada, New Mexico, Ohio, Oklahoma, Oregon, Texas, Utah, Washington, and Wyoming.
Tularemia – Unlike most other tick-borne diseases, this one isn’t limited to any one geographic area; it is found throughout the United States. It is transmitted by the dog tick (Dermacentor variabilis), the wood tick (Dermacentor andersoni), and the lone star tick (Amblyomma americanum).
364D rickettsiosis (Rickettsia phillipi, proposed) – This new disease has been recently discovered in California and is transmitted by the Pacific Coast tick (Dermacentor occidentalis).
Tick Disease Symptoms
Tick disease symptoms will vary depending on the disease, but general tick disease symptoms may include any of the following:
Chills
Headache
Fatigue and malaise
Joint pain
Muscle pain
Stomach pain
Cough
Bullseye tick bite rash
Vomiting
Lack of appetite
Sweating
Body aches
Skin ulcer
Weakness
Confusion (rare)
Loss of coordination (rare)
Seizures (rare)
If you are experiencing any of these symptoms and have been bitten by a tick in the last few weeks, it’s important to speak to a physician. Some symptoms can take several weeks to show up after being bitten, which can make diagnosis difficult if you don’t think to mention a somewhat recent tick bite to your doctor.
Tick Bite Rash
The most classic symptom of Lyme disease is the tick bullseye bite rash. Anywhere from 3 to 30 days after being bitten by an infected tick, a growing, round, red rash may appear. It sometimes clears in the center, which creates the iconic bullseye pattern.
The rash is called erythema migrans and while it is usually small, it can spread to as much as 12 inches across. It is usually not itchy or painful. It may appear in more than one place on the body and won’t necessarily occur where the tick bite happened. Sometimes more than one bullseye bite rash will appear.
Because Lyme disease can become serious if left untreated, if you feel you may have a bullseye rash, you should talk to a doctor immediately. Serious side effects of Lyme disease can include chronic joint inflammation, neurological symptoms, cognitive defects, and heart rhythm abnormalities.
How to Remove a Tick
Using a pair of pointy tweezers, grasp the tick as close to the skin as possible and pull straight out. Be careful not to squish the tick’s body. It’s also important to make sure the entire head and all of the tick’s mouth parts are removed and not just the body.
Sealing the tick in a plastic bag can be helpful for diagnosis, since different tick species cause different diseases. Wash your hands and the area around the tick bite once you have removed the tick.
More About 6 Tick-borne Diseases on the Rise in the US
Lyme Disease
According to the CDC, Lyme disease is responsible for 82% of all tick-borne diseases. About 80% of people who contract Lyme disease will develop the iconic tick bullseye bite, which is a circular expanding rash that typically doesn’t itch or hurt. Since not everybody who contracts Lyme disease will suffer from the tick bite rash, it’s important to be familiar with the other symptoms of Lyme disease.
Aside from the tick bite rash, other common signs of Lyme disease include flu-like symptoms such as fever, chills, headache, fatigue, joint aches, and swollen lymph nodes. Less typically, symptoms can progress to shooting pains in the hands and feet, nerve pain, irregular heartbeat, facial palsy, or even inflammation of the brain and spinal cord.
Lyme disease is more common in the northeast and upper Midwest. Despite only 36,429 cases being officially recorded in 2016, the CDC estimates that around 300,000 Americans are actually infected every year.
Anaplasmosis and Ehrlichiosis
Anaplasmosis and Ehrlichiosis are the next most common after Lyme disease, but still quite rare: 5,750 cases were reported in 2016. These two diseases are caused by different ticks but have similar symptoms. The symptoms include fever, headache, muscle pain, malaise, chills, stomach pain, nausea, cough, and confusion. A rash may occur, but it won’t be the bullseye bite rash seen with Lyme disease.
Rocky Mountain Spotted Fever (RMSF)
4,269 cases of RMSF were recorded in 2016. It can occur throughout the United States but is the most common in North Carolina, Tennessee, Missouri, Arkansas, and Oklahoma – ironically, states that are not located in the Rocky Mountain region.
Symptoms of Rocky Mountain Spotted Fever include fever, headache, nausea, vomiting, stomach pain, muscle pain, and lack of appetite. The tick bite rash may be red and splotchy, or it may resemble pin prick dots.
RMSF can become fatal, so you should head to your doctor if you experience these symptoms after being bitten by a tick or having been in an area where ticks are known to live, such as wooded areas.
Babesiosis
This disease is still relatively uncommon, with only 1,910 cases reported in 2016, but it can become deadly in the elderly, people with compromised immune systems, and those battling cancer or kidney disease.
Babesiosis is the result of microscopic parasites invading and sometimes destroying your red blood cells, and many people don’t notice any symptoms, especially at the onset of the disease. Symptoms of infection may start weeks, months, or even years after being bitten by an infected tick and may include fever, chills, sweats, body aches, nausea, and fatigue.
Tularemia
230 cases of tularemia were reported in 2016. It can happen anywhere but seems to be more prevalent in central areas of the country.
There are two main types of tularemia. Ulceroglandular tularemia will cause a skin ulcer where the bacteria entered the body. Glandular tularemia does not cause an ulcer but shares the other symptoms with Ulceroglandular tularemia including a fever as high as 104° and swelling of glands, especially the ones located in your armpits or groin.
Powassan Virus
Powassan virus is quite rare – only 22 cases were reported in 2016 – but it can be very serious. Symptoms include fever, headache, vomiting, weakness, confusion, loss of coordination, difficulty speaking, and seizures. It can even cause swelling of the brain, and there is no specific cure. The only way to treat it is to handle each symptom and try to support the patient through recovery. Most cases have occurred in the northeast and the Great Lakes region.
How to Prevent Tick Bites
There are no vaccinations available for people against tick-borne diseases, so the only way to prevent acquiring a tick-borne disease is to avoid being bitten by ticks and remove any ticks immediately. Many of the above diseases require the tick to be attached for 36-48 hours before disease can occur in the host, so quick removal is key. Here are ways to prevent tick bites:
If you can, avoid areas of high grass, especially where the grass meets woodlands.
Stay on trails when hiking in the woods and try to avoid brushing up against any plants.
Treat your clothing with permethrin.
Use insect repellent that contains 20-30% DEET on all exposed skin.
Wear long pants tucked into enclosed shoes (avoid sandals), long sleeves, gloves, and a hat when you go to locations that are known to have ticks, like hiking in the woods.
Do a full-body check after going outside. Pay careful attention to areas like the groin, underarms, hairline, torso, and belly button. Ticks can be as small as the head of a pin, so you need to check every nook and cranny of your body thoroughly for any tiny ticks. And don’t forget to check any pets which may have been hiking with you, too!
Take a shower and use a washcloth as soon as possible after coming back inside to get rid of ticks that haven’t embedded themselves in your skin yet.
Wash your clothes in hot water or dry them on high heat to kill any hitchhiking ticks.
If you think you may have acquired a tick-borne disease, book an appointment with a physician as soon as possible to receive a diagnosis and treatment.
Read More About Tick-borne Diseases
Sources
Centers for Disease Control and Prevention. Lyme Disease. Accessed July 29, 2021 at https://www.cdc.gov/lyme/index.html
Centers for Disease Control and Prevention. Tickborne Disease Surveillance Data Summary. Accessed July 28, 2024 at https://www.cdc.gov/ticks/data-research/facts-stats/tickborne-disease-surveillance-data-summary.html?CDC_AAref_Val=https://www.cdc.gov/ticks/data-summary/index.html
The Washington Post. Ticks cause disease but you can avoid them. Accessed June 18, 2018 at https://www.washingtonpost.com/national/health-science/ticks-and-mosquitoes-are-ready-to-deliver-disease-in-a-bite-but-you-can-stop-them/2018/06/15/ff6c9f6c-602e-11e8-9ee3-49d6d4814c4c_story.html
