Lyme disease is a bacterial infection that is transmitted to humans by ticks that usually live on mice or deer. Most infections are acquired in three distinct sections of the United States, particularly along the northeast coast, in areas of Wisconsin and Minnesota, and to a lesser extent in northern California. People who hike, camp, or live in or near wooded areas in these locations during summer months are most at risk for Lyme disease. If a deer tick bites them, they may get a red bump at the site of the bite. If the tick is infected, a larger area of redness may form around the bite days later and expand slowly. Symptoms such as chills, fever, fatigue, headache, and joint pains may accompany the rash. The classic description of the rash is an enlarging area of redness with partial central clearing. However, it may take a number of days before the lesion expands enough to have the classic appearance.