If you live in a big city like New York, you're probably familiar — a little too familiar, perhaps — with bed bugs.
As their name suggests, they start by infesting the places we sleep.
Within weeks, the blood-sucking creatures have turned an entire apartment into an itchy nightmare.
And their numbers are on the rise.
Since the early 2000s, bed bug infestations have grown more common in the US, UK, Canada, and Europe, according to the US Centers for Disease Control and Prevention.
Part of the reason? They've evolved resistance to our defenses against them. The bed bugs of today, for example, have thicker, waxier exoskeletons (to shield them from insecticides) and faster metabolisms (to beef-up their natural chemical defenses).
They're also being transported with increasing frequency by people traveling internationally, according to the British health agency NHS. As they follow us across the globe, the pests get tougher. "In a way, we created the modern bed bug: it evolved to live on us and to follow us," science writer Brooke Borel explained in her recent book "Infested."
msn / lifestyle