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What are the chances of Lyme disease after a tick bite?

Medically reviewed by Rosanna Sutherby, PharmD on August 11, 2020. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.


Lyme disease is a bacterial infection that’s transmitted through the bite of an infected deer tick. But what are the chances of Lyme disease after a tick bite? In this quick article, we’ll cover what Lyme disease is, factors that increase your risk of getting it after a bite, and helpful tick bite preventative measures you can use to help avoid it.

What is Lyme disease?

Lyme disease is caused by four different types of bacteria found in certain kinds of ticks (such as deer ticks, also known as blacklegged ticks). Borrelia burgdorferi and Borrelia mayonii are the Lyme bacteria that are commonly found in ticks in the United States, while Borrelia afzelii and Borrelia garinii are native to Europe and Asia.

Lyme disease occurs when an infected blacklegged tick (or other Lyme-carrying tick) bites someone and transmits Lyme bacteria into that person’s bloodstream. These ticks get the Lyme bacteria when they feed on animals such as deer, birds, and rodents.

If left untreated, Lyme disease can spread to the joints, heart, and nervous system—seriously hurting one’s health—so it’s a good idea to learn the symptoms, risk factors, and preventative measures you can take.

Chances of Lyme disease after a tick bite: what you need to know

When considering the chances of Lyme disease after a tick bite, there are two main factors to take into account: first, what kind of tick is responsible for the bite; and second, how long the tick was attached to the skin.

Type of tick

There are 700 species of hard ticks and 200 species of soft ticks found throughout the world, but there are only a small number of tick species that carry Lyme disease bacteria. In the United States, blacklegged or “deer ticks” (Ixodes scapularis) are the types of ticks that carry Lyme disease and can infect a human with the bacteria. This tick is known to have a reddish-orange body; black shield; and dark, black legs. For a full list of ticks along with their photos, pathogens they carry, and geographic distribution, take a look at this list of types of ticks from lymedisease.org.

How long the tick is attached

In general, it takes about 36 to 48 hours for Lyme bacteria to enter the bloodstream after a tick bite. So if you remove the tick within a day and a half, your risk of getting Lyme disease is substantially lowered. Using tweezers is thought to be the best approach for tick removal: carefully grab the tick near its head or mouth and do not squeeze or crush it, but instead pull gently and slowly in an upward direction.

Tick bite risk factors

Exposed skin

In both humans and pets, it’s easier for ticks to attach to bare flesh. If you’re entering an area where ticks are prevalent, make sure to protect yourself with long sleeve clothing, pants, a hat, and gloves. For extra protection, tuck your pants into your socks. Avoid walking through tall grasses, weeds, and low bushes.

Wooded and grassy areas

Ticks are commonly found in grassy, wooded areas. You have an increased risk if you have an outdoor occupation or have spent a lot of time in these areas (such as children who play outdoors).

Where you’ve traveled

Within the U.S., states in the Northeast and Midwest are known to have especially high populations of deer ticks. You’re at the greatest risk of being bitten in the spring, summer, and fall, though ticks may be searching for a host any time winter temperatures are above freezing. This map from the CDC is a good resource for seeing more precisely where you’ll find blacklegged tick populations in the U.S.

Central and Eastern European countries have the highest tick population in Europe (in terms of ticks that carry Lyme bacteria). This includes countries like Italy, Spain, Portugal, Greece, and central Russia. Lyme disease cases also occur in Asia; common regions that are at risk of this infectious disease include western Russia through Mongolia, northeastern China, and Japan.

How to prevent Lyme disease

If you’re a camper, hiker, or outdoor enthusiast, take these simple measures to help prevent tick bites and Lyme disease.

  • Use a tick repellent containing 20%-30% DEET or 20% Picaridin. Re-apply as needed.
  • Stay in the middle of trails when hiking and exploring.
  • Wear appropriate protective clothing.
  • Examine your clothes and pets after you’ve been outside.
  • Avoid tall grasses, shrubs, and leaf litter.
  • Use a tarp when sitting on the ground.

Everlywell at-home Lyme Disease Test

If you think you’ve been exposed to an infected tick, our at-home Lyme test is an easy way to find out if you’re positive for a Lyme infection. Just collect a small sample of blood via a simple finger prick, send the sample to the lab for testing (with the prepaid shipping label included with the kit), and get your results within days on our secure, online platform. If you receive a positive result, you’ll have the opportunity to connect with our independent physician network—and may be prescribed medication to treat the infection, if appropriate.


Can you get Lyme disease twice?

How accurate are Lyme disease tests?

Types of ticks that carry Lyme disease


References

1. Lyme Disease. Centers for Disease Control and Prevention. URL. Accessed August 11, 2020.

2. Lyme Disease. IAMAT. URL. Accessed August 11, 2020.

3. Regions where ticks live. Centers for Disease Control and Prevention. URL. Accessed August 11, 2020.

4. Tickborne Diseases Abroad. Centers for Disease Control and Prevention. URL. Accessed August 11, 2020.

5. Lyme disease. Mayo Clinic. URL. Accessed August 11, 2020.

6. Tick removal and testing. Centers for Disease Control and Prevention. URL. Accessed August 11, 2020.