Few can resist spending a warm afternoon in the backyard. However, even the most peaceful home refuge is not safe from hazards, including ticks. Black-legged ticks pose a particular threat, as they may carry the bacteria responsible for Lyme disease. Recognizing Lyme disease, its symptoms, and potential treatment plans are important.

According to the Centers for Disease Control and Prevention (CDC), Lyme disease is most often caused by Borrelia burgdorferi bacteria carried by black-legged ticks, sometimes referred to as “deer ticks,” however some cases are caused by the bacteria Borrellia mayonii. Named after the small town in Connecticut where the disease was first recognized nearly half a century ago, Lyme disease is the most common vector-borne disease in the United States, and is transmitted to humans through the bite of an infected black-legged tick. While there are many varieties of ticks, only the black-legged deer tick and Western black-legged tick transmit Lyme disease, according to Johns Hopkins Medicine.

The CDC notes that Lyme disease produces a wide range of symptoms, which vary depending on how long it’s been since a person was bitten by a tick. Early symptoms may appear anywhere from 3 to 30 days after a bite, and can include fever, chills, headaches, fatigue, muscle and joint aches, and swollen lymph nodes. Erythema migrans (EM) is a rash that occurs in approximately 70 to 80% of infected persons, and begins at the site of a tick bite after a delay of 3 to 30 days. The rash expands gradually over several days, reaching up to 12 inches or more (30 centimeters) across. EM may feel warm to the touch, but is not typically itchy or painful, and sometimes clears as it enlarges, resulting in a target or “bull’s-eye” appearance on any area of the body.

Some symptoms may appear days to months after a tick bite, and these may include severe headaches and neck stiffness; additional EM rashes that appear on other areas of the body; facial palsy characterized by a loss of muscle tone or droop on one or both sides of the face; arthritis with severe joint pain and swelling, particularly in the knees and other large joints; intermittent pain in tendons, muscles, joints, and bones; Lyme carditis, a condition characterized by heart palpitations or an irregular heartbeat; episodes of dizziness or shortness of breath; inflammation of the brain and spinal cord; nerve pain;shooting pains; and numbness or tingling in the hands or feet.

Many cases of Lyme disease are successfully treated after a few weeks of antibiotics. However, some people report persistent symptoms even after antibiotic treatments, and the CDC notes additional research is necessary to help people in such situations.

Lyme disease is something to keep in mind as warm weather returns. More information about Lyme disease is available at cdc.gov.