What causes bed bugs?

Bed bugs are caused by an infestation of small, parasitic insects that feed on human blood. Bed bugs are not related to dirt or poor hygiene, and can infest even the cleanest of homes. They are primarily active at night and feed while people are sleeping, leaving itchy, red bites on the skin. Bed bugs can be transported from one place to another through luggage, furniture, or clothing, and can quickly spread throughout a home or building if not treated properly.