Iratus bug retrovirus

Iratus bug retrovirus, an antidote developed by doctor Carson Beckett and his team on the Atlantis Expedition. They were trying to perfect methods in exterminating the DNA of the Iratus bug within the wraith, so that only the human parts withstands. In the experimental phase it was brought to Zaddik's planet. Ellia there, a female wraith, was positive to help them with the development, so that she would one day be human. The retrovirus at this point didn't have the affect that was wanted, but instead it neutralized the human DNA, leaving only iratus bug DNA. Ellia lost control over herself, and was soon forcibly killed by John Sheppard and Ronon Dex. (ATL: "Instinct")

During the fight with Ellia, Sheppard was infected by the retrovirus and this was life-threatening to him. With the help of stem-cells from live Iratus bug's eggs, Beckett's team managed to return him to normal appearence and life. (ATL: "Conversion")