Lyme disease, the tick-borne ailment once primarily a scourge of the Cape and Islands, is now rampant in swaths of Massachusetts where locally acquired cases were rare a decade ago.
In Middlesex, Norfolk, and Worcester counties, the number of patients diagnosed with the bacterial disease surged more than fourfold between 2000 and 2009, according to figures the state Department of Public Health provided to the Boston Globe.
The increase, which is fueling a statewide increase in reports of symptoms, is evident in the offices of infectious disease specialists and primary care doctors in places like Framingham and Natick, where Lyme disease diagnoses 10 or 15 years ago were largely restricted to people who had visited Cape Cod.
Correction: Because of a reporting error, a graphic accompanying this story in the Globe misstated in one reference the type of organism that causes the illness. It is caused by a bacterium.