The Starvia is a strange virus that was discovered upon the initial arrival on Li. The air itself is filled with the stuff and for many years it has been unknown what caused it and how it worked. It is the largest obstacle in making the planet hospitable.
How or why the Starvia was created is unknown. The creator is also unknown, but it has been discovered to be a new form of Shadow Bugs which means that Tabuu may have some kind of hand behind it. Whether or not he is alive is debatable.
The virus was originally found within the air of Li, making trips outside the Life Sphere dangerous as prolonged exposure to the air may corrupt and infect an individual. Even rapid short burst exposures to the air is extremely dangerous. The Life Sphere is the only known area on Li where the air is safe to breathe in.
At the moment the only known user and controller of the virus is Black Shadow, though he has eluded to the fact that there may be more.
Originally it was believed that the Starvia was merely a rage virus, something that would over power a person's mind with thoughts of rage and violence. While that still may seem true, recent studies have shown that it does not simply replace regular thought patterns with rage but instead it surrenders the infected person's mind to some sort of hive mind. It is unknown who or what controls the person once they become infected as Black Shadow seems to lack the ability to control them all at once.
Despite the infection totally consuming the host body's mind, it does have some perks in that it makes the individual even more powerful. The shadow bugs have been altered to clone the cells within an organic body and work harder and faster. In addition they imprint onto the brain and create a channel toward the hive mind itself, making all the infected have a linked mind. This means that whatever one infected discovers, the rest will learn or perhaps there is one source of knowledge that relays the newly found information to the other bodies.
While it may seem that machines would also become immune to this virus, that is not the case. Shadow bugs are not the same as simple bacteria, they can adapt to whoever or whatever the host body is so long as there is a mind to consume. Machines will be affected the same way as organic bodies.