Lyme disease is a bacterial infection caused by bites from Ixodes scapularis (also known as "deer" ticks or "black-legged" ticks). It is the most common tickborne disease in the United States and West Virginia. Symptoms generally begin 3 to 30 days after the tick bite and include fever, headache, chills, and rash (erythema migrans). If an infected person is not treated early with antibiotics, Lyme disease can progress over weeks to years to cause recurrent arthritis, pain and swelling at joints, facial palsy, and neurological complications.
Most cases of Lyme disease are concentrated in the northeastern and midwestern regions of the United States. In 2013, 95% of cases were reported in 14 states (which include neighboring Maryland, Pennsylvania, and Virginia). As of 2016, there are eleven counties in West Virginia that are considered "endemic" for Lyme disease: Berkeley, Hampshire, Hancock, Jefferson, Kanawha, Marshall, Mineral, Morgan, Roane, Wetzel, and Wood Counties.