"They're just the size of my little fingernail," says Dr. Dean Sienko from the Ingham County Health Department.

They're hard to detect, and even harder to get rid of.

"They can live for a long time without a human bite," Sienko says.

Bed bugs --- the common household pest --- is becoming more of a problem, Sienko says. They're not just crawling around in mattresses.

"There are all sorts of ways for these bed bugs to get into your possession and for you to bring them home."

Sienko says bed bugs have hitched rides into movie theatres, shopping centers and bedrooms across the country.

"Anytime you have a lot of people coming to live in an area or a lot international travel seem to be a place for bed bugs to find people."

That's why MSU senior Katrina Dehart, along with students returning to campus this weekend, is taking every precaution.

"I sprayed everything with Lysol and rinsed it down," Dehart says.

She's moving into an apartment that comes fully-furnished, used mattress and all.

"I do have protective covers for mattresses," Dehart says.

But Dr. Sienko says covering mattresses, even using pesticides, may not be enough to keep the critters out.

"Vacuum, vacuum, vacuum. And after you vacuum, throw the bag out. Wash your clothes on a high heat."

It takes careful cleaning, Sienko says, or the bed bugs will bite.