Incidence and Distribution of Lyme Disease in the United States

Lyme disease has a wide distribution in northern temperate regions of the world. In the United States, the highest incidence occurs in the Northeast, from Massachusetts to Maryland and the North-central states, especially Wisconsin and Minnesota.

In 2009, nearly 30,000 cases of Lyme disease were reported in the U.S., the highest number ever reported. This increase could be caused by an increase in human contact with infected ticks and enhanced reporting of cases.

Thirteen states have consistently reported an incidence of Lyme disease higher than the national average: Connecticut, Delaware, Maryland, Maine, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, and Wisconsin. During 2014, 25,359 Lyme disease cases were reported to CDC, of which 23,900 cases (94.2%) were reported from these 13 states. This data is representative of all years and is reflected in the CDC 2014 incidence map below. The highest incidence of Lyme Disease In the U.S. occurs in the Upper Midwest and in Pennsylvania northwards throughout the North East.