Lyme disease, or Lyme borreliosis, is a serious infection caused by bacteria. It's transmitted to humans through the bite of an infected black-legged tick and is therefore a vector-borne illness. It is a frequently reported condition, with doctors diagnosing and treating nearly 500,000 cases in the U.S. and more than 200,000 cases in western Europe each year.
The infection can cause a wide range of symptoms, ranging from mild to life-threatening. These include fever, fatigue, joint pain, and skin rashes, as well as more serious joint and nervous system complications. Without treatment, Lyme disease can cause long-term health problems.
What is Lyme disease?
Lyme disease is a potentially serious condition caused by the bacterium Borrelia burgdorferi. It's a tick borne illness meaning that the bite of an infected tick transmits the bacteria to humans. These black-legged ticks, also known as deer ticks, become infected after feeding on animals like deer or mice that carry the bacteria.
Once the tick bites someone, it must stay attached for 36 to 48 hours to transfer the infection to them. Often people are unaware they've been bitten because the immature ticks, called nymphs, are extremely difficult to see. Although adult ticks also carry the bacteria, they are usually noticed and removed before transmitting the disease.
Although Lyme disease can potentially cause serious health issues, a simple course of oral antibiotics cures the disease for most people.
Symptoms of Lyme disease
Lyme disease can cause a wide range of symptoms, depending on how long you've been infected. Doctors divide Lyme disease into three stages:
- Early localized
- Early disseminated
- Late disseminated
People may experience a rash at the tick bite site that resembles a red oval or 'bull's-eye' in the initial stages. This characteristic rash appears in up to 80% of infected people.
In the early localized stage, other common symptoms include fever, fatigue, achiness or joint pain, and headache. These symptoms appear 3 to 30 days following an infected tick bite.
Left untreated, Lyme disease can progress to the early disseminated stage. At this point, the infection spreads through the bloodstream to other parts of the body.
Symptoms may include:
- Muscle weakness
- Memory problems
- Skin rash
In the late disseminated stage, Lyme disease can cause more serious problems, including:
- Facial drooping
- Nervous system problems
- Heart palpitations
- Brain inflammation
Sometimes, a person can present in a later stage of the disease without having earlier symptoms.
Lyme disease diagnosis
A doctor diagnoses Lyme disease based on your symptoms and medical history. They'll perform a physical exam to check for a rash or other characteristic symptoms and consider the possibility of exposure to infected ticks.
Laboratory testing can be helpful, so the doctor may also order blood tests to look for antibodies to the B. burgdorferi bacterium or rule out other conditions with similar symptoms.
Lyme disease treatment
If Lyme disease is diagnosed in the early localized stage, it can usually be treated at home with a 10- to 14-day course of oral antibiotics – typically doxycycline or amoxicillin.
For later stages of Lyme disease, particularly with cardiac or central nervous system (CNS) involvement, doctors may prescribe intravenous (IV) antibiotics in a clinic or hospital. They'll also focus on relieving your symptoms to reduce discomfort.
If you have symptoms of Lyme arthritis, doctors can treat it with oral antibiotics for 28 days.
Is Lyme disease contagious?
No, Lyme disease is not contagious. It's only transmitted through the bite of an infected tick, not through physical contact, sneezing, coughing, or kissing.
Also, there are no reports of Lyme disease being transmitted to infants through breast milk.
What are the risk factors for Lyme disease?
People who live or spend time in areas where Lyme disease is common are at risk of infection. In the United States, these areas are mainly concentrated in the Northeast and upper Midwest. In Europe, the disease occurs mostly in Scandinavia, Germany, Austria, and Slovenia.
Anyone who works outdoors in farming, forestry, wildlife management, or landscaping has an increased risk of Lyme disease.
The time of year also affects Lyme disease risk as most tick bites happen in the summer months when ticks are active, and people spend more time outside. But, if the weather is unusually warm, people are also at risk of tick bites in fall or winter.
How can I prevent Lyme disease?
Lyme disease prevention centers around reducing the risk of tick bites. Here are some tips:
- Cover exposed skin. If you're visiting wooded or grassy areas, wear long trousers and long-sleeve shirts. You can also tuck your trousers into your socks to prevent ticks from crawling up your legs.
- Use insect repellents. Products with a 20% or higher concentration of DEET are most effective at repelling ticks. Protection lasts for a couple of hours, so you may need to reapply. Avoid using insect repellents on your hands, as it's easy to transfer the chemicals into your eyes. Also, be careful when applying insect repellent to young children and babies and look for child-safe options.
- Stick to the trails. When walking or hiking, stay on the trails and avoid walking through brush and long grass. If you have a dog, keep them on a leash.
- Tick proof your yard. Try to make your garden or yard unappealing to ticks by clearing wooded areas and underbrush and keeping any wood piles in sunny areas to discourage any rats and mice that may carry ticks.
- Check for ticks. When you return from the outdoors, check all clothing, children, and pets for ticks. If you find an attached tick, use tweezers, and grasp it firmly near the skin. Carefully and steadily remove it and then flush it down the toilet. Finally, apply antiseptic to the bite. Also, don't assume that you're safe from Lyme disease if you've already had an infection, as it's possible to get Lyme disease more than once.
- Shower as soon as you can. Many ticks remain on the skin before attaching themselves, and showering helps remove them.