Is Lyme Disease Contagious: How It Is Transmitted

Human-to-human transmission is highly unlikely

If you hear about rising cases in your community, you might wonder if Lyme disease is contagious.

Lyme disease is the most common illness caused by insect bites in the United States. It is caused by bacteria spread by a tick bite.

This article will go over how Lyme disease spreads. You'll learn whether Lyme is spread through saliva and blood; whether you can catch Lyme from someone else, and whether Lyme spreads from animals to humans.

Lyme Disease Transmission - Illustration by Katie Kerpel

Verywell / Katie Kerpel

How to Tell If You Have Lyme

One of the telltale signs that doctors look for when diagnosing Lyme disease is a bull’s-eye-shaped rash. This rash continues to expand over the next one to four weeks, starting at the red dot from the original bite.

Common Lyme disease symptoms include:

  • Body aches
  • Extreme fatigue
  • Fever
  • Headaches
  • Neck stiffness
  • Swollen lymph nodes

If left untreated, more serious conditions, like arthritis, Bell’s palsy, and neuropathy, can develop. The vast majority of people who are treated for Lyme disease make a full recovery.

Not all ticks carry Lyme disease. You’ll want to watch out for tiny black-legged ticks, called deer ticks. Deer ticks can be tricky to find since they may be as small as a poppy seed. The nymphs are less than two millimeters in size.

Lyme is not contagious. Lyme disease spreads from ticks to humans. Once you get it from a tick, your family and friends don't need to worry about catching Lyme disease from you through casual contact.

Human-to-human Lyme transmission is highly unlikely; however, there are a few potential exceptions.

Lyme Disease Transmission

For Lyme disease to spread from a tick to a human, the infected tick must bite you and remain attached for at least 24 to 36 hours. The ticks, who often live in tall grass and wooded areas, cling to humans in places that are hard to detect. Most of the ticks that transmit Lyme disease are young (nymphs). These smaller, immature ticks are even harder to discover on the body.

Tick bites can happen almost all year round but are most common in the spring and summer months. There is no concrete evidence that a person can transmit Lyme disease to another human, except for the possibility of a pregnant person with untreated Lyme disease transferring the infection to their unborn child.

Once a tick finds an attachment site on your skin, it makes an incision to place its feeding tube. It secretes substances to help it stay in place. Tick saliva has properties that numb your skin so you’re less likely to feel it. As the tick slowly sucks your blood, it can transmit bacteria that cause infections, like Lyme disease.

Is Lyme Disease Contagious Through Salvia or Blood?

Lyme disease cannot be passed from person to person through saliva. Kissing or sharing the same cup with an individual with Lyme disease is not cause for concern. Lyme disease cannot travel through saliva from one person to another.

Lyme disease is detectable in blood tests. Since it is present in the bloodstream, experts advise against donating blood until after completing the prescribed course of antibiotics. Delaying blood donation is a merely preventative measure, as there have been no reported cases of Lyme disease transmission through blood transfusions.

Can I Catch Lyme From My Pets?

Pet owners often worry about catching Lyme from a dog or cat.

While ticks can find their way onto you when you're outside, they often find it easier to hitch a ride on your dog or cat. If a person gets bitten by a tick that came in with their pet, it's possible for them to get Lyme.

Just as you should check yourself over when you've come in from being in the yard or going on a hike, thoroughly checking your pets for ticks is also key. Pets can take preventive medications that help kill ticks before they get a chance to transmit infections.

There are many preventive tick treatments and even a Lyme vaccine for animals. However, you should know that the products that are safe and effective for dogs and cats are not the same. In fact, some chemicals meant to kill ticks are extremely toxic to cats. Always talk to your vet before using any preventive on your pets or around your yard.

If your pet is bitten by a tick and gets Lyme, you might worry that you'll catch it from them. There is no evidence that Lyme can be transmitted from pets to owners. However, it is possible that you and your pet could be bitten by the same tick that is carrying Lyme.

Is Lyme Transmitted Through Sex?

Research on the possible sexual transmission of Lyme disease has left some questions unanswered. It's not clear if humans can pass Lyme disease to each other through sexual contact.

The molecular structure of Lyme disease is similar to a strain of syphilis, so scientists think it's possible that transmission via mucous membranes could happen.

One study identified the presence of Lyme disease in the genital secretions of those who were infected, suggesting possible transmission between sexually active partners.

Currently, the Centers for Disease Control and Prevention (CDC) states that there is not enough scientific evidence to support the theory that Lyme disease may be sexually transmitted. The CDC suggests that it is more likely for sexual partners to contract a similar strain of Lyme through tick bites occurring around the same time, even if one partner was bitten unknowingly.

Can I Give My Baby Lyme While I'm Pregnant?

If a pregnant person is infected and untreated, Lyme disease can pass to the fetus. With the proper use of antibiotics, people who are pregnant can avoid the adverse effects of Lyme for themselves and their babies.

There is no evidence of babies contracting Lyme through breast milk. If a breastfeeding person gets Lyme after pregnancy, there’s no reason to worry about transmission through breastfeeding.

If you get Lyme, let your healthcare provider know that you’re nursing, as they may prescribe you an antibiotic that’s safe for breastfeeding.

What to Do If You Get a Tick Bite

If you have a tick bite, remove the tick from your body as soon as possible. Use a pair of tweezers and remove the entire tick from your skin without crushing it. Once the tick is out, wash the site with soap and water.

Keep an eye on the area for a rash that slowly expands, leaving a target-shaped mark. Also, watch for fevers, chills, headaches, or muscle pains, which are all early signs of Lyme disease. If you experience any of these symptoms within 30 days of the bite, you should contact a doctor.

There are still some mysteries about Lyme disease, but fortunately, most cases can be treated with a two- to four-week course of oral antibiotics. If you’re worried about contracting Lyme disease, take precautions to avoid ticks in the first place:

  • Wear fully covering clothing when going outside (long pants, high socks, long sleeves).
  • Walk in the middle of trails instead of on the sides near trees and brush.
  • Avoid tall grass or areas with shrubs.

Summary

Lyme disease is not contagious like a cold or the flu. Lyme disease is transmitted by bacteria in the bite of black-legged ticks (deer ticks). They must remain attached for at least 24 hours to transmit the bacteria.

You can't catch Lyme from kissing someone with the infection. Scientists are not certain if Lyme can be passed through sex, but it seems to be extremely unlikely.

If a pregnant person gets Lyme they can pass it to the fetus if they don't get treatment. There is no evidence of Lyme being spread to babies through breastfeeding.

If you're worried that Lyme disease is contagious from animals to humans, know that there is no evidence that this can happen. While you can't catch Lyme from your pet, they can bring ticks into your home that might bite you.

A Word From Verywell

Don’t let a fear of Lyme disease prevent you from spending time in the great outdoors. If you love hiking, gardening, or eating dinner on your porch, there’s no reason to let ticks stop you from enjoying nature. Avoiding tick bites and checking your skin for signs of a bite will help you stay ahead of the dangers that can occur when Lyme disease goes untreated.

Frequently Asked Questions

  • How common is Lyme disease?

    According to data from the Centers for Disease Control and Prevention (CDC), about 30,000 cases of Lyme disease are reported in the U.S. each year. That said, those numbers might be underestimated.

    The CDC states that in reality, as many as 476,000 people may get Lyme disease each year in the U.S.

  • Is Lyme disease an autoimmune disease?

    Lyme disease is not considered an autoimmune disease. However, research shows that Lyme disease alters the immune system’s T-cells, prompting an attack on healthy cells instead of just foreign invaders. By disrupting normal immune cell communication, the bacteria from Lyme disease block important signals required for normal immune function.

    Because of these effects, Lyme disease presents itself similarly to some autoimmune diseases. It may affect the development of autoimmunity in someone who already has a genetic predisposition.

  • Is Lyme disease in dogs contagious?

    Although dogs can contract Lyme disease, no evidence suggests that dogs can spread their Lyme disease to humans. Dogs can, however, carry infected ticks in from outside. These ticks can then bite and transmit the disease to humans who encounter them.

  • Can Lyme be transmitted through saliva?

    Lyme disease cannot be spread through saliva. You can't catch Lyme by kissing someone who has it or sharing a cup with them.

  • Do mosquitos pass Lyme disease?

    Lyme disease is not known to be transmitted through other vector insects, including mosquitos, fleas, or lice.

  • How long does it take to get Lyme disease?

    Black-legged ticks must be attached for at least 24 hours before they can transmit Lyme disease. Always check yourself for ticks after spending time outdoors in the warm weather. If you can remove the tick properly within a day of being bitten, you’re unlikely to contract Lyme. The Lyme disease incubation period is between three to 30 days.

  • Does Lyme disease go away?

    Lyme disease is caused by bacteria and needs to be treated with antibiotics—and the sooner the better. Not only will the infection persist if it's not treated, but it can lead to more serious health problems over time.

  • What happens if Lyme disease goes untreated for years?

    If it's not treated, Lyme disease can lead to serious health problems in the joints, brain, and heart. In some cases, people have lasting Lyme symptoms even if they get treatment.

Was this page helpful?
11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Cleveland Clinic. Lyme disease.

  2. Centers for Disease Control and Prevention. Transmission.

  3. LaMorte WW. Boston University School of Public Health. Transmission of Lyme disease.

  4. Centers for Disease Control and Prevention (CDC). Preventing ticks on your pets.

  5. Middelveen MJ, Burke J, Sapi E, et al. Culture and identification of Borrelia spirochetes in human vaginal and seminal secretionsF1000Res. 2015;3:309. doi:10.12688/f1000research.5778.3

  6. Centers for Disease Control and Prevention. Lyme disease frequently asked questions (FAQs).

  7. John Hopkins Lyme Disease Research Center. Lyme disease frequently asked questions (FAQs).

  8. Centers for Disease Control and Prevention (CDC). Data and Surveillance.

  9. John Hopkins Medicine. Research story tip: Lyme disease bacteria alter immune system and may cause it to attack healthy cells.

  10. Mead PS. Centers for Disease Control and Prevention. Chapter 4 - Travel-related infectious diseases.

  11. Centers for Disease Control and Prevention. Signs of Untreated Lyme Disease.