Is Lyme Disease Contagious?

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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.

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.

Other 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 disease spreads from ticks to humans. Once you get it, your family and friends generally don’t need to worry about catching Lyme disease from you through casual contact. Human-to-human transmission is highly unlikely in most cases, although there are a few potential exceptions worth noting.

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.

Bodily Fluids

Lyme disease is detectable in blood tests, but it 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.

Since Lyme disease 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.

Sexual Transmission

Scientists aren’t as clear about whether humans can pass Lyme disease to each other through sexual contact. The molecular structure of Lyme disease is similar to a strain of syphilis, prompting healthcare professionals to suspect 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.


If a pregnant person is infected with Lyme disease and is untreated, Lyme disease can pass to the unborn baby. With the proper use of antibiotics, the pregnant person can avoid adverse effects on the fetus.

There has been no link to babies contracting Lyme through breast milk. If the disease is contracted after pregnancy, there’s no reason to worry about transmission from breastfeeding.

You should still seek Lyme disease treatment for yourself. Let your healthcare professional know that you’re nursing so you may be prescribed an antibiotic that’s safe for breastfeeding.

Frequently Asked Questions About Lyme Disease

Here’s some more information to clarify common misconceptions about Lyme disease.

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.

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.

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.

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.


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. It cannot be transmitted in saliva, and there is no evidence of sexual transmission. It can be transmitted by a pregnant person to their unborn child if it is not treated.

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.

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