ELI5 Bed Bugs - how did they make a comeback?

What are bed bugs? Can you see them? How long have they been around? We thought we had eradicated them at one point in the mid-20th century but why did they come back? Are there any health risks? How do I tell if I have them, and how does one get rid of bed bugs? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: jigmest, loimographia, animaanon and btrpiii To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Send us an e-mail: [email protected]