Lyme disease has tightened its grasp on the Northeast and Midwest, with a dramatic rise in the number of counties considered at high risk, a new government study finds.
The number of Northeast counties where the risk of Lyme disease is at least twice the national average skyrocketed from 43 in 1993-1997 to 182 in 2008-2012, according to the U.S. Centers for Disease Control and Prevention study. That’s an alarming jump of 323 percent.
In Maine, more than half of all counties are at high risk for the disease, spread by the bite of the eight-legged deer tick.
While the danger is highest in those counties, Lyme has marched northward in Maine, appearing in all 16 counties today.
So far this year, Maine has recorded 198 cases of Lyme disease, according to Maine CDC’s July public health update. That’s down from 246 cases at the same time last year. While the infection rate has slowed, we’re still in prime Lyme season and many more cases are sure to crop up before this winter.
2014 was a record year for Lyme in Maine, with more than 1,395 cases.
We continue to see other diseases carried by ticks as well, with 56 cases of anaplasmosis and four cases of babesiosis in 2015.
The CDC study also found that Lyme disease is increasingly creeping south and west, though as you can see from the first map, cases remain concentrated in areas already recognized as hotbeds for the infection.
Lyme’s expansion into new areas “may occur because of changes in conditions that favor tick survival or because of geographic dispersal of infected ticks by birds and deer to areas where other necessary components already exist to support ongoing transmission,” wrote lead author Kiersten J. Kugeler, a CDC epidemiologist.
Ticks like to hide out in wooded and grassy areas. Rodents carry the infection and spread it to ticks, who in turn infect deer and other mammals — including us.
“Our results show that geographic expansion of high-risk areas is ongoing, emphasizing the need to identify broadly implementable and effective public health interventions to prevent human Lyme disease,” Kugeler wrote.