Trudy joins the the TWiVlords to discuss new tests for detecting prions in the blood, and evidence showing that foamy retroviruses originated in the seas with their jawed vertebrate hosts at least 450 million years ago.

Vincent and Dickson continue virology 101 with a discussion of information flow from RNA to DNA, a process known as reverse transcription, which occurs in cells infected with retroviruses, hepatitis B virus, cauliflower mosaic virus, foamy viruses, and even in uninfected cells.