The Ori plague outbreak on Earth was a publicity incident which occurred in late 2005, where an outbreak of the Ori plague took place on the planet Earth. The outbreak started when SG-6 went undercover to P2X-885, a poverty stricken planet converted to Origin. By the time Stargate Command realized they were infected, it was too late. Despite their best efforts to contain the outbreak, there were several severe breaches in quarantine, resulting in the isolation in the United States of America from the rest of the planet. However, cases were later reported in Canada and Mexico, followed by more confirmed cases growing in Europe and Africa. Despite efforts to help contain the plague, their creation of a cure did not end well. Fortunately, the plague was eradicated after a Prior-converted Gerak of the Free Jaffa Nation cured the planet, though this resulted in his death.
SG-6 members Colonel Barnes and Lt. Fischer was sent to go undercover to P2X-885, a poverty stricken world in the Milky Way. They went there to pose as simple villagers, to confirm that the planet was converted to Origin. When the Prior Damaris arrived on the planet, he touched the villagers on the head supposedly as a sign of benediction. Fischer was touched also, but he did not realise that Damaris infected them with the Ori plague. They returned to Stargate Command for a briefing. Afterwards, Fischer left the base, while Barnes stayed behind. Barnes reported to Dr. Carolyn Lam, complaining of fatigue. An hour later, he showed more signs of his illness; he could barely stand, followed by high fever, chest pain and respiratory failure, definite signs of the plague from P8X-412 a few months previous. Realizing the high possibility that Fischer would follow with the same symptoms, the SGC needed to find him quickly to prevent a possible outbreak on Earth. (SG1: "The Powers That Be")
Stargate Command later found Fischer at Peterson Air Force Base in Colorado, which was where Lt. General George S. Hammond gave a speech to certain members of the public. Fischer was about to approach and shake hands with him, inadvertently infecting him too, but a team in Hazmat suits quickly arrived at the scene; Hammond was escorted off the base, the attendees were checked up on, and Fischer was escorted back to Stargate Command. Meanwhile, other members of SG-6 began showing symptoms as well. Furthermore, hours after Fischer was brought in, a few people who attended Hammond's speech started showing signs as well. Major General Henry Landry decided to initiate a cover story that a new influenza outbreak started in St. Francis Medical Center two days previously. Fischer was able to detail his moves since leaving Stargate Command, and told the team what he touched. Lt. Colonel Cameron Mitchell was ordered to go out and follow up on Fischer's activities, as well as monitor all hospitals to see if any other civilians started showing symptoms. (SG1: "The Fourth Horseman, Part 1")
Breaches of containment
Working with the Centers for Disease Control and Prevention, Mitchell found that the gas station Fischer used was self-serviced, but twenty-two people have used it since Fischer did, but tracking all but six were easy, since they used their credit cards. As a security measure, the United States National Guard was dispatched to possibly close down Colorado if the outbreak would get out of control. Mitchell later visited the restaurant Fischer ate at, and quarantined everyone there; some have been tested positive, but there were still fourteen people unaccounted for; Stargate Command decided to launch bulletins to help track them down. Unfortunately, it seemed too late to close down the borders of Colorado, as civilians were reported showing signs of the plague in the surrounding states, particularly in Utah, Kansas and New Mexico. All airports, bus and train stations have been closed down to prevent the wide spreading of the plague.
Among the civilian population, the outbreak attracted media attention; several news stations update the outbreak, not realizing the culprit was from another planet. There were also signs of panicking civilians who were demanding answers. Several hospitals and medical centers were reportedly full of people with the plague. Later on, Mitchell reported some distressing news; before the airports could close down, one of the gas station attendants boarded a flight to New York City, via Denver and Chicago. Soon enough, 13 states were confirmed to have cases of the plague, and 8,000 people were confirmed to have been infected. With this news, President Henry Hayes gave an announcement to quarantine the United States of America from the rest of world, closing all borders, shipping and air routes to the country. (SG1: "The Fourth Horseman, Part 1")
Outbreak outside the United States
Unfortunately, putting the entire country under quarantine did not work out; cases were soon reported in Canada and Mexico. In a meeting between Landry and Hammond; Hammond was not tested positive, they hear that the outbreak had reached Europe; a flight from Salt Lake City landed on Charles de Gaulle Airport, Paris before air routes were shut down. Despite the French authorities best efforts to put the passengers into quarantine, cases were reported outside the city, and France. Cases of the plague were particularly found in Bonn, Germany; Amsterdam, The Netherlands; Rome, Italy and Madrid, Spain, as well as suspected cases in London, England and Athens, Greece. Suspected cases were also reported in Africa, and in response, some of the African nations declared a state of martial law. Since the plague reached Europe, Hammond hypothesized that the outbreak would reach the Middle East within three days, and China within six. Meanwhile, because of the state of panic among the Tau'ri population, Earth's economy started showing signs of recession. (SG1: "The Fourth Horseman, Part 2")
Efforts to find the cure
While the outbreak affected Earth, SG-1 were attempting to find a cure. After Orlin returned to Lt. Colonel Samantha Carter since their last encounter in 2001, they discovered that the key is to retrieve a sample of blood from the Prior responsible; the Prior also happened to be the same one visiting the Sodan, a group of Jaffa Mitchell encountered previously. Mitchell and Dr. Daniel Jackson returned to P9G-844 to capture him. With the help of Carter's invention of a Prior disruptor, and through trial and error, the team were successful in capturing Damaris. After taking a sample of his blood, it was taken to Earth in the hope of creating a cure. Unfortunately, through the stresses of the Ancient knowledge within Orlin's adolescent human body, he showed signs of degradation, and dropped the blood sample through fatigue. After retrieving it again, they find that the blood took no effect in stopping the plague. Furthermore, the Prior disruptor no longer took any effect on Damaris, and he was forcibly shot and killed by Mitchell, though he infected Landry before he was killed. (SG1: "Ascension", "Babylon", "The Fourth Horseman, Part 2")
Ending the plague
Gerak of the Free Jaffa Nation was converted to a Prior to convince the Nation to convert to Origin. With some resistance on Teal'c and Bra'tac's part, Gerak drew a lot of influence and before a battle would start over Chulak, Teal'c was able to convince Gerak that being a Prior would mean that the Jaffa would no longer be free, after reminding him of a chapter in Jaffa history about a rebellion at the Battle of Tazek'sur, Gerak decided to help the Tau'ri. With Landry infected after contact with Damaris, Gerak arrived in Stargate Command and used his Prior powers to cure those infected in the SGC. This action, resulted in him being burned to death, after he knowingly betrayed the Ori.
With Landry and the SGC personnel cured, the team was able to use their blood and mass-produce the cure, where everyone on Earth would be inoculated as soon as possible, thus resulting in the end of the outbreak. After it was over, the media reported that just over 3,000 people on Earth died from it. However, they were confused about the origin of the plague. The outbreak would never happen on Earth again, since the antibodies rendered a possible other plague useless. (SG1: "The Fourth Horseman, Part 1", "The Fourth Horseman, Part 2")
- In an alternate reality in which Dr. Janet Fraiser and Martouf were members of SG-1, another Ori plague was caused under similar circumstances. However, they could not find the cure; millions on Earth were infected. After that team, among at least 20 others accidentally traveled to Earth of this reality, Fraiser realized that our Earth went through a plague and found a cure for it, and it could potentially save her reality's Earth. Initially Major General Henry Landry refused to wait for the scientists to find a way to send the alternate SG-1s back to their own realities, instead opting to seal the cause for the incident and strand the teams to this reality. However, our SG-1 later found a way to send the teams back and gave this Frasier the cure for the plague on their Earth. (SG1: "Ripple Effect")