Lyme Disease Is Slowly Spreading Across the US East Coast

Lyme disease is the most common vector-borne disease in the United States, but it’s also mostly confined to a small swath of the country running down the eastern seaboard to the Mid Atlantic and along the Great Lakes. But while it was once thought that Lyme disease rarely occurred outside of the Northeast, a new report from the Centers for Disease Control confirms that Lyme is slowly expanding its geographic footprint. In 11 states that neighbor the 14 states where Lyme disease occurs frequently, the report found a significant increase in the number of confirmed Lyme cases.

“Although concentrated in historically high-incidence areas,” the report said, “the geographic distribution is expanding into neighboring states.”

Since 1991, when Lyme was first identified as a significant problem in the US, the number of annual cases has just about tripled. In recent history, somewhere between 30,000 and 40,000 cases have been reported to the CDC each year. 

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Between 2005 and 2015, the number of confirmed Lyme cases in what the CDC calls “neighboring states” increased by an average of six perecent. In some neighboring states, the rate at which it occurs doubled, due to changes in climate and the movement of Lyme-carrying animals.