What Are Ticks?
Ticks are parasites, which means they live off a host. They feed on the blood of people and animals. Ticks might look like insects, but they’re arachnids, such as spiders. There are many types of ticks, and they live in different parts of the U.S.
What Do Ticks Look Like?
Ticks are related to spiders, so they have eight legs. They have flat, oval bodies that swell when they eat. They range in color from light brown to dark brown or brownish-red, depending on the species. All types are very small. The largest tick may swell to the size of an apple seed after it feeds, but many ticks are much smaller than that.
Types of Ticks
Ticks can be hard or soft. Each type has a different type of body and life cycle.
Hard ticks (Ixodidae). This type has a hard outer shell called a scutum. Hard ticks come in 700 species. Their life cycle has four stages:
- An adult female lays eggs.
- The eggs hatch and very young ticks called larvae come out.
- After the larvae feed on animal or human hosts, they turn into nymphs.
- Once the nymphs feed on a host, they change into adults.
Hard ticks carry the germs that cause Lyme disease, Rocky Mountain spotted fever, and other diseases. Their bite doesn’t hurt. It can take them hours, days, or weeks to feed.
Soft ticks (Argasidae). This type has a soft body and comes in 200 species. A soft tick’s life cycle also has four phases:
- An adult female lays eggs.
- The eggs hatch into larvae.
- Larvae feed and change into nymphs.
- Nymphs go through up to seven phases before they turn into adults. They must feed on a host during each phase.
Soft ticks can live for months to years. They mainly bite rodents such as rats and mice. Less often, they bite humans. Their bite is painless and they feed for just 15 to 30 minutes.
Only a small number of ticks bite and spread diseases to humans. How many ticks actually cause disease depends on the number of infected ticks in a certain area. For example, between 1% and 50% of ticks may be infected with the bacteria that cause Lyme disease. The actual risk of getting Lyme disease from a single tick bite is about 2%.
Where Do Ticks Live?
Ticks prefer to live in warm, humid climates. Many of them die when it’s cold outside. Warming temperatures from climate change help ticks live longer, and allow them to move into more northern areas that were once too cold for them.
The most common types of ticks live in different parts of the U.S.:
- American dog tick: East of the Rocky Mountains, in the Central and Eastern U.S.
- Blacklegged tick: Eastern U.S.
- Brown dog tick: Southwestern U.S.
- Gulf coast tick: Southeastern U.S.
- Lone star tick: Southern and Eastern U.S.
- Rocky Mountain wood tick: Rocky Mountain states (Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, and Wyoming)
- Western black-legged tick: Pacific Coast
When are ticks most active?
Ticks can be active at any time of the year, but they’re most active in the spring and summer months, from April to September. That’s when you’re most likely to get a tick bite.
Who’s Likely to Be Bitten?
It’s not just the outdoorsy types who get exposed to ticks. You may get bitten while playing, gardening, or doing yard work right outside your house, especially if you live in an area where there are a lot of ticks. Ticks can also hitch a ride on animals, such as pets, and get into your home that way.
Symptoms of a Tick Bite
It's common for a red bump to form in the area of the tick bite. This is a reaction to the tick’s saliva. The bite may or may not itch.
Infections from a tick bite cause symptoms such as:
- Fever
- Chills
- Headache
- Extreme tiredness
- Joint stiffness
- Achy or painful muscles
- Swollen glands
- Nausea or vomiting
Rashes are another common symptom. Infections such as Rocky Mountain spotted fever and Lyme disease cause a rash that looks like:
- Small red or purple spots
- Red or dark-colored blotches
- A red bull's-eye
What Diseases Do Ticks Spread?
Ticks spread disease by passing along bacteria, viruses, and parasites. Most of these illnesses cause typical flu-like symptoms, such as chills, fever, headache, and muscle aches.
Lyme disease
Lyme disease is a bacterial disease that spreads through the bite of infected blacklegged ticks in the upper Midwest, mid-Atlantic, and Northeast. The western blacklegged tick spreads Lyme disease along the Pacific Coast. In the U.S., Borrelia burgdorferi bacteria transmit Lyme disease. In other countries, other Borrelia species spread Lyme disease.
Soon after a tick bites, you may see the telltale bull’s-eye rash. Lyme disease also causes flu-like symptoms, such as:
- Fever
- Headache
- Joint and muscle aches
- Extreme tiredness
- Swollen glands
If you don’t treat Lyme disease, it can get more serious and cause:
- Brain and nervous system problems such as numbness and weakness
- Joint pain that doesn’t go away
- Heart problems such as an irregular heart rhythm
- Problems with memory and thinking
Doctors usually treat Lyme disease with antibiotics. The sooner you start taking these medicines, the better.
Other illnesses caused by ticks
Anaplasmosis. This bacterial illness spreads through the bite of the blacklegged tick and western blacklegged tick. In the first 5 days after infection, symptoms such as fever, chills, muscle, aches, and nausea are common. The illness can become serious if you don’t treat it. Quick treatment with antibiotics usually clears up the infection.
Babesiosis.The blacklegged tick spreads this parasitic infection. The parasites infect red blood cells and cause symptoms such as fever, chills, headache, and body aches. Eventually, the parasites can destroy more red blood cells than your body can produce. Babesiosis can be life-threatening, especially if you’re 50 or older, you had your spleen removed, or you have a weak immune system.
Hard tick relapsing fever (HTRF). This infection is caused by Borrelia miyamotoi bacteria. It's spread by blacklegged ticks in the upper midwestern, northeastern, and mid-Atlantic states, as well as in Pacific coastal states. Although its name indicates otherwise, research shows that people with HTRF usually only have one episode of fever. This comes along with flu-like symptoms such as chills, headache, fatigue, and achy muscles and joints. Taking antibiotics for about 2 weeks can clear up the infection.
Colorado tick fever.This rare viral disease spreads through bites from the Rocky Mountain wood tick. The tick lives in Rocky Mountain states at heights of 4,000 to 10,000 feet above sea level. If you get this infection, you may have a fever for several days, then feel fine for a while, and then have a fever again for a few more days. Chills, headache, and body aches are other symptoms. Most people who get Colorado tick fever have a mild illness that goes away within a few weeks.
Ehrlichiosis. This flu-like bacterial illness spreads through the bite of lone star and blacklegged ticks in the midwestern, south-central, and eastern U.S. Typical symptoms include fever, chills, headache, and muscle soreness. A few days later, some people get a cough, nausea, stomach pain, and a rash. A 5- to 7-day course of antibiotics should get rid of the infection.
Heartland virus. This is a viral illness that spreads in the eastern, southeastern, and south-central U.S. Lone star ticks spread the virus. Like other tick-borne illnesses, the Heartland virus causes flu-like symptoms such as tiredness, fever, nausea, and muscle or joint pain. It may also damage blood cells that help your body fight infections and stop you from bleeding.
Powassan virus.This virus used to be rare, but it has become more common in recent years. Backlegged ticks and groundhog ticks spread the virus in the Great Lakes and Northeast regions. Early symptoms include fever, headache, weakness, and vomiting. Sometimes, the virus can cause more serious problems such as memory loss, trouble speaking, and seizures.
Red meat allergy.This serious allergic condition happens after a bite from the lone star tick. Another name for the allergy is alpha-gal syndrome (AGS). The bite causes you to develop a meat allergy. When you’re exposed to meat or other foods made from mammals (pork, lamb, venison), you may get symptoms such as hives, belly pain, shortness of breath, or even a severe, life-threatening reaction called anaphylaxis.
Rickettsia parkeri rickettsiosis. This is a bacterial infection spread by the Gulf Coast tick. After the bite, a dark scab forms on the skin, followed by a fever, muscle pain, headache, and rash. Some people have swollen glands. Antibiotics treat the infection.
Rocky Mountain spotted fever (RMSF). RMSF is a bacterial infection that spreads through the bite of the American dog tick, Rocky Mountain wood tick, and brown dog tick. Despite the name, it’s most common in the southeastern and south-central U.S. Most people get a pink spotted rash on their hands, feet, arms, and legs. Other symptoms include a fever, headache, appetite loss, and stomach pain.
RMSF damages small blood vessels, which can cause swelling in the brain, heart, and lungs. Untreated, it can lead to amputation, hearing loss, and mental changes. Treating the bacteria with antibiotics can prevent complications, especially if you start the medicine within 5 days after your symptoms first appear.
Southern tick-associated rash illness (STARI). STARI is a disease with symptoms that are similar to those of Lyme disease, including a bull's-eye-like rash and joint pain. Bacteria cause Lyme disease, but experts don’t know what type of germ causes STARI. The illness starts after a bite from the lone star tick. Other symptoms include tiredness, fever, headache, and muscle pain.
Tick-borne relapsing fever. This bacterial illness spreads through bites from the soft-bodied tick. People get it in mountainous areas from California to Ohio, usually after sleeping in rustic cabins infested with mice or rats. The illness causes a high fever, headache, muscle and joint aches, and chills. Fevers come in episodes with shaking chills and drenching sweats. This infection can be life-threatening without antibiotic treatment.
Tularemia.Also called “rabbit fever,” tularemia is an infection with the bacteria Francisella tularensis. It spreads from the bite of a dog tick, wood tick, or lone star tick in many parts of the country. The most common symptoms are a high fever, swollen glands, sore throat, and an open, painful sore where you were bitten. Tularemia can be life-threatening, but it’s treatable with antibiotics.
364D rickettsiosis. Also called Pacific Coast tick fever, it spreads along the coasts of California, Oregon, and Washington through the bite of the Pacific Coast tick. Rickettsia bacteria also cause this infection. 364D rickettsiosis causes fever, headache, muscle aches, and a dark scab in the bite area.
When to See a Doctor for a Tick Bite
If you see a tick on your skin, try to remove it. Use fine-tipped tweezers to grab the tick as close as possible to your skin. Then, pull up with even pressure. Save the tick in a bag, in case you need to bring it to your doctor’s office with you.
Contact a doctor if:
- You can’t fully remove the tick.
- You get a rash, fever, or other flu-like symptoms within 2 weeks after the tick bite.
- You think a deer tick bit you.
- The bite looks red or oozes, which are signs of infection.
Takeaways
Ticks are parasites that feed on the blood of humans and animals and spread disease when they bite. Fever, chills, headache, and rash are common symptoms of an infection after a tick bite. If you see a tick on your skin, try to remove it with tweezers. See a doctor if you can’t fully remove the tick, you have symptoms of a tick bite, or the bite looks infected.
Ticks FAQs
What do ticks do?
Ticks are parasites that feed on the blood of humans and animals. They can spread disease when they bite.
What ticks carry Lyme disease?
Blacklegged ticks carry the bacteria that cause Lyme disease. These ticks live in the northeastern, mid-Atlantic, and north-central U.S.
How do you know if a tick has Lyme disease?
You can’t tell if a tick has Lyme disease just by looking at it. But you’ll know that you have the infection by symptoms such as a growing red bull's-eye rash, fever, chills, headache, and swollen glands.
