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The Female Changeling with the virus.

The morphogenic virus was a disease created by Section 31 that was designed to wipe out the Changeling race and deprive the Dominion of its leaders.


The virus made a Changeling's morphogenic matrix unstable, leading to them becoming desiccated and unable to hold humanoid forms. (DS9 episode: "Chimera")

A Changeling's use of their abilities also hastened the disease. (DS9 episode: "Tacking Into the Wind")

When the virus took hold, it left the Changeling unable to revert to their natural form or use their abilities at all. (DS9 episode: "What You Leave Behind")



In 2372, while on Earth helping Starfleet to find ways to detect Changelings, Odo was infected with the disease by Section 31, who hoped he would link with other members of his race and infect them all. (DS9 episode: "When It Rains...")

It was believed that Odo would not develop the virus and act only as a carrier. (DS9 episode: "The Dogs of War")

Taking effect

In 2374, Tomas Roeder discovered the existence of the virus. He attempted to smuggle classified data on Changeling morphology, the damage the virus was doing to it and the names of the designers and others involved to the Dominion. (DS9 novel: Hollow Men)

The Founders began suffering from the effects of the disease in 2375, with the entire Great Link being infected. The Female Changeling was also infected with the disease and her symptoms were noticed by Weyoun and Corat Damar. The Female Changeling informed Weyoun of the disease and the sixth clone of Weyoun informed Odo of it when he attempted to defect to the Federation. (DS9 episode: "Treachery, Faith, and the Great River")

The Vorta began research into a cure for the disease, but had no success. The Female Changeling had them document their findings before ordering Weyoun to execute them and activate their clones, hoping for a "fresh perspective". (DS9 episode: "Penumbra")

Late in 2375, Julian Bashir discovered Odo had become infected with the disease and began research into a cure. Despite his efforts, Bashir made little headway and he and Miles O'Brien sent a message to Starfleet Medical that stated that Bashir had found a cure. It was hoped Sloan or another 31 agent would come to Deep Space 9 to confirm it, giving Bashir and O'Brien an opportunity to find a cure from the agent or give them the name of someone who would have it. (DS9 episodes: "When It Rains...", "Tacking Into the Wind")


Towards the end of the war, after successfully luring Luther Sloan to Deep Space 9. Sloan attempted to commit suicide to prevent them from obtaining the cure from him. However, Bashir and O'Brien managed to keep him alive long enough to use a multitronic device to link their minds to Sloan's, and managed to find the cure before Sloan died. (DS9 episode: "Extreme Measures")

The Federation Council debated giving the Founders the cure, although they decided against it, as they felt it could strengthen the Dominion's hand and allow them to win the war. (DS9 episode: "The Dogs of War")

The Female Changeling had become terminally ill with the disease and had been unable to regenerate. Following the Battle of Cardassia, Odo linked with the Founder and cured her of the disease. In return for having the Female Changeling order her forces to stand down, Odo agreed to return home and cure the Great Link as well. Odo returned to the Gamma Quadrant several days later and cured the Link. (DS9 episode: "What You Leave Behind")


The Female Changeling learned that the virus had been created by Section 31, probably during her link with Odo. Odo himself was concerned how the Great Link would react to the information when he returned home. (DS9 short story: "Requital")

As Odo predicted, the disease and its creators cause discord in the Great Link, with some not accepting Odo's arguments that it was an extreme minority. (DS9 novel: Avatar, Book Two)

Laas was infected with the disease after linking with Odo, but was cured by the Great Link when he returned home. (DS9 novel: The Dominion: Olympus Descending)

In 2383, Benjamin Sisko wondered if the morphogenic virus had recurred when he found that there was no sign of the Great Link on their planet. (ST - Typhon Pact novel: Raise the Dawn)

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