Last summer Felicia Keesing returned from a long trip and found that her home in upstate New York had been subjected to an invasion.
“There was evidence of mice everywhere. They had completely taken over,” says Keesing, an ecologist at Bard College.
It was a plague of mice. And it had landed right in Keesing’s kitchen.
“Not only were there mouse droppings on our countertops, but we also found dead mice on the kitchen floor,” says Keesing’s husband, Rick Ostfeld, an ecologist at the Cary Institute of Ecosystem Studies in Millbrook, N.Y.
The Hudson River Valley experienced a mouse plague during the summer of 2016. The critters were everywhere. For most people, it was just a nuisance. But for Keesing and Ostfeld, the mouse plague signaled something foreboding.
“We’re anticipating 2017 to be a particularly risky year for Lyme,” Ostfeld says.
Keesing and Ostfeld, who have studied Lyme for more than 20 years, have come up with an early warning system for the disease. They can predict how many cases there will be a year in advance by looking at one key measurement: Count the mice the year before.