For the U.S. Senator, see Fisher
Fischer and Airman Ryan attended morning Prostration two days before their departure. There, the Prior preached and went around blessing the people. He touched Fischer's head. Thinking nothing of it, he did not place it in his report. It is likely this is how the Prior made him a carrier for one of their plagues.
Fischer, back on Earth, soon left the base. He stopped at a restaurant and gas station, and sat in on a speech by Lieutenant General George Hammond. In that time he was able to ultimately infect the country with the Prior plague.
Because he was the carrier, Fischer himself never felt the effects of the plague.
The Fourth Horseman, Part 1 - Fischer and the rest of SG-6 return to Earth following a reconnaissance of P2X-885, unaware that the Lieutenant is the carrier for a deadly Prior plague.