Michaeleen Doucleff

It all started in the shower. Tucker Lane looked down, and there they were.

"Two ticks, on my right hip, directly next to each other," he says.

At the time, Lane didn't think much about it. He grew up on Cape Cod. Ticks are everywhere there in the summer. "Just another tick bite. Not a big deal," he thought.

That was June. In September, everything changed.

"I was working outside, and I just had a pounding headache," says Lane, 24, who works as a plumber and at a pizza restaurant.

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.