Guess how much bacteria is lurking in your bed...

There's a lot more under your covers than bed bugs, so you may want to wash those sheets pretty soon.

See also: How to prevent bed bugs

A new study says there are billions of bacteria hiding under your covers.

And your pillowcase is one of the worst offenders.

See also: Are you doing your laundry all wrong?

Left unwashed for four weeks, a pillowcase can accumulate 39 times more bacteria than your pet's food bowl.

Using the same pillow for a week straight can build up 17,442 times more bacteria than a toilet seat.

If left unwashed for four weeks,

Washing your sheets regularly banish the bacteria.