The term "Prior Plague" was coined by Dr. Carolyn Lam to describe a rapidly-mutating virus given to human populations by a Prior of the Ori. Eventually, the SGC developed a cure to this plague, but not before several planets were completely wiped out and a little over three thousand people died on Earth.
The Plague That Killed Off the Ancients
When the SGC first encountered the Prior Plague on P8X-412, Dr. Lam said that the symptoms and rate of progression seemed "remarkably similar" to the virus to which SG-1 and the scientists at the Antarctic Research Station were exposed upon reviving the Ancient woman Ayiana who had been buried in the ice for millions of years. The virus nearly wiped out all of the Ancients who were living those millions of years ago in human form. Some of them ascended to a higher plane of existence as a form of energy (called Ascended Beings), but those who could not ascend died out. Ayiana was present in Antarctica when the city-ship Atlantis left for the Pegasus Galaxy some five to ten million years ago, so it was most likely five to ten million years ago that this virus spread across the galaxy. After this galactic devastation, a group of Ancients reseeded the galaxy with life which spawned the second evolution of humanity. (6.04 "Frozen", 6.22 "Full Circle", 8.18 "Threads", 9.05 "The Powers That Be"; Stargate Atlantis: 1.01 "Rising Part 1")
The virus started with a high fever, followed by organ shutdown, coma, and finally death. Antibiotics had no beneficial affect against it. The only cure for those stricken in the Antarctic was through the healing touch of Ayiana's hand. Ayiana herself was the carrier, but Dr. Janet Fraiser hypothesized that her physiology was different enough from current humans that she could have been successfully fighting off the disease within herself. But, after Ayiana healed several people over a short period of time, her immune system apparently could not fight off the disease and she eventually succumbed. Dr. Fraiser also hypothesized that the virus ultimately acted like cerebrospinal meningitis by attacking the brain and that Ayiana's brain chemistry was different enough from a current human's that it might have been possible for her to trigger an immune response in those she healed that she couldn't muster in herself once the disease reached an end stage. (6.04 "Frozen")
Col. Jack O'Neill wasn't cured by Ayiana, so his condition reached a critical stage. He entered a coma, but was pulled out of it so that he could give his permission to be implanted with a Tok'ra symbiote. According to the Tok'ra, diseases are more easily cured by a symbiote than physical injuries. O'Neill was cured by being implanted for a very short while with a symbiote. Additionally, Teal'c didn't develop symptoms of the virus and was most likely protected by the Goa'uld symbiote he was carrying at that time. (6.04 "Frozen", 6.06 "Abyss")
The Introduction of the Prior Plague
One of the most productive methods used by the Priors of the Ori in converting human populations into Ori worshippers was to introduce the Prior Plague and then heal the population en masse once their devotion was declared. This modus operandi was observed by SG-1 first-hand on P8X-412. (9.05 "The Powers That Be")
When the Prior felt that the people needed a demonstration of the Ori's power in order to be converted, he introduced the Plague by touching his victim as if giving a blessing. This person would either be a carrier of the disease or succumb and spread it to others, depending upon how the Prior wished to spread the virus. On P8X-412, the Prior touched Vachna and Vachna spread the disease quickly throughout his village. Vala Mal Doran, a former host to a Goa'uld symbiote, used the Goa'uld healing device on him, and he apparently recovered, but eventually those Vala treated would become reinfected and her ability to cure with the healing device became ineffectual. (9.05 "The Powers That Be")
The initial symptom of the disease appeared to be fatigue which eventually caused the victim to collapse. Lt. Col. Cameron Mitchell reported to the SGC that the symptoms were weakness, high fever, chest and stomach pains, and trouble breathing. Some of the extreme cases went into shock before Vala could get to them. Dr. Lam and her medical team went to the planet in hazmat suits and immediately put the victims on an anti-viral cocktail after having ruled out a bacterial infection. But, even with this treatment, the virus eventually mutated and caused the victim's internal organs to start to shut down, resulting in the body's inability to process toxins. Because of this organ failure, the victim's body was effectively poisoned to death. (9.05 "The Powers That Be")
The people of P8X-412 were cured en masse when the Prior used his orbed staff to emit an energy wave throughout the village and nearby pyramid temple. Mitchell was cured immediately after reaching the stage where his internal organs were failing and Azdak was revived after dying. The Prior successfully converted the people of the planet to Origin and let the SGC personnel go to spread the word. (9.05 "The Powers That Be")
Interesting enough, Teal'c, Vala, and Daniel Jackson did not become infected with the virus, although all of those around them were sick and dying. The members of the medical team were also not infected, but they were wearing hazmat suits. Although Dr. Lam ordered blood tests of the three, it was never revealed why they did not come down with the disease or even become carriers of it. (9.05 "The Powers That Be")
The Cure for the Prior Plague
SG-6 lived among the peasants of P2X-885 to observe the work of a Prior of the Ori and attempt to keep the people from converting to Origin. During one of the Prior's services, the Prior touched Lt. Fisher as if giving a blessing, but he actually infected him with the Prior Plague. The Prior knew that Fisher was from Earth and made him a carrier of the virus instead of an immediate victim. The people of the planet turned to Origin without having to be inflicted with the disease. (9.10 "The Fourth Horseman Part 1")
Upon SG-6's return, they went immediately to the infirmary to be checked by Dr. Lam. She cleared them and Fisher went to a ceremony at Peterson Air Force Base to hear Gen. George Hammond give a speech. He had made stops to a restaurant and gas station on his way to Peterson. People who attended the ceremony were infected, as well as those who touched the gas pump Fisher used. It appeared that the virus was spread through the air and through physical contact. Lt. Fisher himself didn't show symptoms, thus he became Patient Zero. His teammates, however, were infected, and although it was not stated outright, were possibly the first plague deaths of SGC personnel reported by Dr. Lam. (9.10 "The Fourth Horseman Part 1")
The Ascended Being Orlin observed the spread of the Plague on Earth and decided to retake human form to help develop a cure. He began developing a DNA sequencer program in order to track the virus's mutations. He determined that the Prior manipulated his own DNA to create the virus, so he requested that the SGC obtain a blood sample of the Prior who infected Fisher. Mitchell, Daniel, and SG-22 tracked this Prior down on the Sodan Jaffa's homeworld, P9G-844, and used a device on him which prevented him from using his mental powers. They obtained the blood sample, but Orlin wasn't immediately able to devise a cure. (9.10 "The Fourth Horseman Part 1", 9.11 "The Fourth Horseman Part 2")
The last piece of information that Orlin's program needed was the configuration of the antibodies generated by a body cured of this particular Prior's plague. This final part of the equation was provided when Gerak, the Free Jaffa leader who was converted into a Prior, used his powers and cured all of those infected at the SGC, including the base commander, Gen. Hank Landry. Using Orlin's formula, a cure for the Plague was developed, and from then on, the Priors had to resort to other means of converting the masses, since the SGC shared this cure with others, even with those stricken in an alternate reality. (9.11 "The Fourth Horseman Part 2", 9.13 "Ripple Effect")
- 6.04 "Frozen"
- 6.06 "Abyss"
- 6.22 "Full Circle"
- 8.18 "Threads"
- 9.05 "The Powers That Be"
- 9.10 "The Fourth Horseman Part 1"
- 9.11 "The Fourth Horseman Part 2"
- 9.13 "Ripple Effect"
- Col. Jack O'Neill
- Dr. Daniel Jackson
- Lt. Col. Samantha Carter
- Lt. Col. Cameron Mitchell
- Gen. George Hammond
- Gen. Hank Landry
- Lt. Fisher
- Dr. Janet Fraiser
- Dr. Carolyn Lam
- Vala Mal Doran
- Antarctic Research Station
- Anti-Prior Device
- Ascended Beings
- Free Jaffa Nation
- Healing Device
- Peterson Air Force Base
- Priors of the Ori
--DeeKayP 09:29, 2 May 2006 (PDT)