Cyalax Virus

The Cyalax Virus was a specially engineered virus that replicated only in midichlorians and was quickly overwhelmed by a person's immune system if it could not locate midichlorians fast enough. This made it worthless as an intentional pandemic agent, but could be strategically used against Jedi and other Force-users.

Viral research began thanks to funding by Empress Shira in 20 ABY, but it was eight years before the virus was perfected. Many scientists, including Sarra Vall, worked on the project at Shira's command.

The first viral strain was a disaster; it rapidly mutated and began to seek out mitochondria as well as midichlorians and could survive in living tissue much longer than was desirable. This virus, called the Dantooine Virus after its complete destruction of Dantooine in 28 ABY, could strip an entire planet of all life, except perhaps for some sea and deep-underground life, in a matter of days. The Cyalax virus, named for the planet on which it was first tested, was gentler and did not directly kill anyone; its fatal effect came from weakening the Force powers of the Jedi so much that they could not use the Force to help them in combat or accelerate their healing.

After devastation from the virus, a normal human body took about two years to naturally replenish its own midichlorians, resulting in a return to full strength. In other species, the rate was slightly higher or lower.

Darth Inferna, who was inoculated, intentionally infected her two-year-old daughter Desa in order to easily spread the contagion on Coruscant. Only a handful of Jedi, those in remote locations, escaped the illness.