Lyme disease is caused by a type of bacteria called borrelia burgdorferi, when it is transferred to a human bloodstream through the bite of a tick who carries it. The bacteria also finds hosts in deer and rodents, which are the source of the bacteria to a feeding tick.
A bite from a contaminated tick can then pass the disease to humans and other animals. Lyme disease is most common in the Northeast U.S. from Maryland to Maine due to seasonally high tick populations, but can also be seen more rarely in the Midwest, California, Oregon and Europe.
Approximately 3 days after being bitten, a large, red, bullseye-shaped rash can appear. The rash produces round, red lesions that appear to have rings around the bite area. Often these lesions can become quite large, or the rash may appear to resolve on its own. Not all patients who have contracted Lyme disease will get this rash, so it can be an unreliable indication.
Independent of the appearance of a rash, patients will experience flu symptoms such as fever, chills, muscle aches, joint pain, and headaches. Most commonly patients experience severe fatigue alongside any other symptoms, and symptoms often seem to resolve on their own.
Not every tick bite will cause Lyme disease, mainly because not every tick carries the bacteria that causes Lyme disease. Complications are possible, with a small number of patients developing nerve damage, symptoms of meningitis (head and neck pain, light sensitivity, headache), or other nerve pain. If left untreated, patients can develop arthritis or painful swelling of the joints.
Tests available to detect Lyme disease are not extremely reliable, and can take weeks for the tests to become positive, while not all patients with the hallmark bullseye rash will display positive test results.
Prevention mainly includes finding ticks before they have bitten into the skin. If you find a tick bitten into your skin or the skin of children and pets, be sure to remove the tick properly to ensure you remove the entire tick and lessen the chance of contracting Lyme disease from the tick.
Prevention methods include avoiding wooded areas or tall grass where ticks live, using insect repellent, covering exposed skin when outdoors with tall socks and long sleeves, and routinely checking your body and clothing when coming into your house from outside. Pets and small children who are consistently close to the ground are more likely to pick up ticks on their bodies, so it is important to prevent a Lyme-positive tick from hiding in your house by removing it before entering.