Lyme disease comes from the bite of an infected tick, usually one so small you won't notice it
Lyme disease is spread through the bite of a tick carrying the bacterium Borrelia burgdorferi. The tick must be infected, must bite you, and must stay attached long enough to transmit the bacteria—usually at least 24 to 48 hours. Most people get Lyme disease outdoors during spring, summer, and early fall, when ticks are most active and people spend more time in grassy, wooded, or brushy areas where ticks live.
You cannot catch Lyme disease from another person, from pets, or from touching an infected tick. The bacteria live in the tick's gut and saliva, not on its body. You also cannot get it from eating contaminated food or drinking contaminated water.
Key Takeaways
- Lyme disease spreads only through bites from infected ticks, most commonly the deer tick (also called the black-legged tick) in the northeastern and midwestern United States.
- The tick must remain attached to your skin for roughly 24 to 48 hours before it can transmit the bacteria that causes Lyme disease.
- Ticks are most active from April through October, and they hide in tall grass, leaf litter, and low brush rather than on tree branches.
- Removing a tick within the first 24 hours significantly reduces your risk of infection, even if you were bitten by an infected tick.
- Lyme disease cannot spread from person to person, from pets, or from handling a tick with your bare hands.
Which ticks carry Lyme disease
In the United States, Lyme disease is spread almost entirely by the deer tick, also called the black-legged tick. This tick is found across the northeastern states, down through the mid-Atlantic, and into parts of the Midwest and upper Great Lakes region. The same tick species also carries Lyme disease in parts of Europe and Asia.
Deer ticks are much smaller than the common wood tick or dog tick. An adult deer tick is about the size of a sesame seed. The nymph—the younger stage—is even tinier, roughly the size of a poppy seed. Because of their small size, many people never see the tick that bites them. Nymphs are responsible for most human Lyme disease cases because they are so easy to miss.
Other tick species in North America do not carry Lyme disease, though they may carry other illnesses. If you live outside the geographic range where deer ticks are found, your risk of Lyme disease from a local tick bite is very low.
Where ticks hide and when they bite
Ticks do not jump or fly. They wait on vegetation—tall grass, shrubs, leaf litter, and low branches—and grab onto you as you brush past. They are most active in spring and summer, with a smaller peak in fall. Winter cold slows them down, though in milder climates they may remain active year-round.
You are at higher risk if you spend time in wooded areas, brush, or tall grass, especially in regions where Lyme disease is common. Hiking, camping, gardening, and yard work in these environments increase exposure. Ticks can also attach to pets, which may then bring them into your home.
Once a tick attaches, it typically feeds for several days. The longer it stays attached, the more likely it is to transmit bacteria. This is why removing a tick promptly—ideally within 24 hours—is one of the most effective ways to prevent infection.
How the bacteria enters your body during a tick bite
When a tick bites, it does not inject bacteria immediately. Instead, the tick's saliva contains substances that numb the area and prevent blood from clotting, allowing it to feed. As the tick remains attached and feeds, bacteria from its gut can gradually enter your bloodstream through the bite wound.
This is why timing matters so much. A tick that is removed within 24 hours is far less likely to have transmitted enough bacteria to cause infection. After 48 hours of attachment, the risk rises significantly. However, infection is not certain even after a long attachment—it depends on whether the tick was actually infected and how many bacteria it carried.
Geographic areas with higher Lyme disease risk
Lyme disease is not evenly distributed across the United States. The highest concentration of cases occurs in the Northeast, particularly in New England and the Mid-Atlantic states. Significant numbers of cases also occur in parts of the upper Midwest, especially around the Great Lakes, and in parts of the Pacific Northwest.
If you live in or travel to these regions, your risk is higher during the warm months. If you live in the South, Southwest, or in areas where deer ticks are not established, your risk from a local tick bite is much lower. However, you could still contract Lyme disease while traveling to a high-risk area.
What happens after a tick bite
Most tick bites do not result in Lyme disease, even in high-risk areas. Many ticks are not infected, and many bites are discovered and removed before 24 hours have passed. If you are bitten by an infected tick and bacteria do enter your body, symptoms typically appear 3 to 30 days later, though some people develop symptoms weeks or months after infection.
The first sign is often a rash called erythema migrans, which expands outward from the bite site and may resemble a bull's-eye. Not everyone develops this rash, and some people have no symptoms at all in the early stage. If left untreated, Lyme disease can progress to affect the joints, heart, and nervous system.
Reducing your risk of tick bites
If you spend time outdoors in tick-prone areas, several steps can lower your risk. Wear long sleeves and long pants, tuck pants into socks, and wear light-colored clothing so ticks are easier to spot. Use an insect repellent containing DEET or picaridin on exposed skin and clothing. Some people treat clothing and gear with permethrin, an insecticide that kills ticks on contact.
After being outdoors, check your entire body for ticks, paying special attention to warm, moist areas like the groin, armpits, and behind the ears. Shower within a few hours of coming indoors. Wash clothes in hot water and dry them on high heat, which kills any ticks that may be hiding in fabric.
If you find a tick attached to your skin, remove it promptly by grasping it as close to the skin as possible with tweezers and pulling straight out. Do not twist, squeeze, or use petroleum jelly or heat—these methods may cause the tick to release more bacteria. After removal, clean the bite area with soap and water or rubbing alcohol.
Frequently Asked Questions
Can you get Lyme disease from a tick that is not attached to your skin?
No. A tick must bite and remain attached to transmit the bacteria. Simply touching a tick or having one crawl on your skin does not spread Lyme disease. The bacteria live inside the tick and are transmitted through the bite wound as the tick feeds.
How long does a tick have to be attached before it can give you Lyme disease?
Most experts agree that a tick needs to be attached for roughly 24 to 48 hours to transmit the bacteria. However, this is not a hard cutoff—transmission can occasionally occur sooner, and it is not may provide even after 48 hours. Removing a tick within the first 24 hours significantly reduces your risk.
If I remove a tick right away, am I safe from Lyme disease?
Removing a tick within 24 hours greatly lowers your risk, but it does not may provide you will not develop Lyme disease. A small number of infections occur even after prompt removal. However, the sooner you remove a tick, the better your chances of avoiding infection.
Can pets give you Lyme disease?
No. Pets cannot transmit Lyme disease to you directly. However, ticks can attach to pets and then move to you, so it is worth checking both yourself and your pets for ticks after time outdoors. Treating pets with tick prevention medication can reduce the number of ticks in your home.
What should I do if I find a tick on my body?
Use tweezers to grasp the tick as close to your skin as possible and pull straight out. Do not twist, squeeze, or apply heat. After removal, wash the area with soap and water. If you develop a rash or symptoms in the following weeks, contact your doctor and mention the tick bite.