Bed Bugs as opposed to bed or dust mites are nasty little creatures that bite humans and suck their blood!
In the days before white sheets they were actually known as wall lice as they actually lived in cracks and crevices in walls.
They tend to come out every third night for a feast. They will only feed on exposed parts of the body such as face, hands, feet – they don’t go under the bed clothes with you!
They tend to leave black marks as traces of their presence. Some people are not sensitised to their bites (or may take some time to become so) so they will not be aware of infestation other than by signs of these black marks.
Tend to be prevalent in low quality or multiple occupancy housing/hostels. Decoration is their enemy and a well maintained house: they need a bit of warmth as well. Can be brought into a house via old timbers –eg: firewood from derelict houses or even bargains from car boot sales! Normally they are found in low hundreds – but a serious infestation could amount to thousands!
They are quite tolerant to insecticides so you need a powerful one to get rid of them and will need to call in the experts.