Nepedia
Back to Discover
Advanced Reader
🧬

Lyme disease

life science Maturity 11-13 Next article →

Lyme disease, also known as Lyme borreliosis, is a widespread infection in the Northern Hemisphere. It is caused by specific types of bacteria called Borrelia.

Borrelia burgdorferi-cropped
Borrelia burgdorferi-cropped

These bacteria are transmitted to humans through the bites of blood-feeding ticks. Specifically, the bacteria are carried by ticks in the genus Ixodes. Because it is the most common tick-borne disease in these regions, understanding how it spreads and how to treat it is very important. Most people can recover fully if they receive prompt medical care.

The infection process begins when an infected tick bites a person. The bacteria, which are spirochetes, enter the body from the tick.

Ixodes scapularis
Ixodes scapularis

These bacteria are part of a group known as Borrelia burgdorferi sensu lato. This group includes several different species. For example, B. burgdorferi sensu stricto is found in North America and Europe. Other species like B. afzelii and B. garinii are found in Eurasia. Once inside, the bacteria can move through the bloodstream or the lymphatic system. This allows the infection to travel from the bite site to other parts of the body.

Symptoms of Lyme disease often appear in distinct stages. The first stage is called early localized infection. About 70% to 80% of infected people develop a characteristic red rash called erythema migrans (EM).

Ixodes-ricinus-life-cycle
Ixodes-ricinus-life-cycle

This name means "migrating redness" because the rash expands over time. It typically appears 3 to 32 days after the bite. The rash can grow by 2 to 3 cm every day. It may reach a large diameter of up to 70 cm. In some parts of Europe, the rash clears in the center to look like a bull's eye. Other early signs include fever, headache, fatigue, and muscle aches.

If the infection is not treated, it can move into the early disseminated stage. This happens within days or weeks of the initial infection. During this stage, the Borrelia bacteria spread further through the body. Some people develop new rashes at sites far from the original bite. This stage can also cause neurological problems known as neuroborreliosis. This affects 10% to 15% of untreated cases. It can cause inflammation of the brain or spinal cord. This might lead to confusion, shaking, or difficulty with speech and movement.

Neuroborreliosis can also affect the nerves in the face or spine. Cranial neuritis is an inflammation of the cranial nerves. In North America, this often results in facial palsy. This makes it difficult to smile, blink, or chew on one side of the face. Lyme radiculopathy is another condition where spinal nerve roots become inflamed. This causes intense, migrating pain that is often worse at night. Some patients also experience Lyme carditis, which affects the heart. This occurs in about 4% to 10% of untreated cases in the United States. It can cause heart palpitations, dizziness, or fainting.

Later stages of the disease can involve the joints and skin. Lyme arthritis can affect up to 60% of untreated people. This usually begins about six months after the initial infection. It often causes swelling and pain in large joints, such as the knee or hip. In Europe, some people may develop a skin condition called acrodermatitis chronica atrophicans. This causes the skin to become thin, wrinkled, and hairless. Some patients may also experience post-treatment Lyme disease syndrome (PTLDS). This describes persistent symptoms that remain after the standard antibiotic treatment is finished.

Diagnosis is based on a patient's symptoms and their history of tick exposure. Doctors may also test the blood for specific antibodies.

Geographical distribution of reported Lyme Disease cases
Geographical distribution of reported Lyme Disease cases

If a diagnosis is made, antibiotics are used to fight the bacteria. Common treatments include doxycycline, amoxicillin, or cefuroxime. These treatments usually last for two to three weeks. Most patients experience a full recovery with these medicines.

Prevention is the best way to avoid the disease. Most infections occur between May and September because the nymphal stage of the tick is most active.

Deer Tick life cycle
Deer Tick life cycle

To stay safe, people can wear clothing that covers their arms and legs. Using insect repellents containing DEET or picaridin can also help. While there is currently no vaccine available for humans, vaccines do exist for dogs. Staying aware of your surroundings in tick-heavy areas is a key part of staying healthy.

700 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (8)
File:Right knee swelling caused by Lyme arthritis in a 3-year-old girl.jpg
Right knee swelling caused by Lyme...
File:Borrelia burgdorferi-cropped.jpg
Borrelia burgdorferi-cropped.jpg
File:Deer Tick life cycle.svg
Deer Tick life cycle.svg
File:Ixodes scapularis.png
Ixodes scapularis.png
File:Ixodes-ricinus-life-cycle.jpg
Ixodes-ricinus-life-cycle.jpg
File:Geographical distribution of reported Lyme Disease cases.png
Geographical distribution of reported...
File:Lyme Disease Risk Map.gif
Lyme Disease Risk Map.gif
File:Tickremoval.svg
Tickremoval.svg
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.