This ability grants the user total control over any virus and bacteria close to them, this is achieved through mostly mental connection with said bacteria's and viruses. Most users seems to have a sort of domination type of communication rather than a both way type. This also means that the user have to concentrate to keep control.
This ability is limited by many factors, some which are more specific to the individual user than to the ability.
Because of the nature of this ability, it strains the body greatly to use certain aspects of it. Creating bacteria's and viruses are especially tiring for the body, not only because the body have to create organism that most often doesn't exists in the body, and secondly because if it is a lethal and very dangerous thing, then the body also have to keep it at bay, so it won't attack the host body.
This ability are also very tiring for the mind, though this depends more on the user. Different users have been shown to tire slower than others, it's theorised that the mind adapts to the strain and level of usage, so that one who uses this ability regularly, doesn't tire as fast as one who doesn't.
Level of practice Edit
Users have been shown to be able to create huge devastation with little effort, often because the ability is very uncontrolable, great attention is needed to keep a long lasting effect on going. though it has been shown that users with lots of practice has less need for focus and attention than newbies has. Some users have even shown that it can reach the state of being able to work on pure instinct.
Even though this ability can be used without no knowledge of medicine, and go onto become by pure instincts. Knowledge is needed if the user wants to go onto create more specific effects, like combined effects from totally different illnesses. Of course this does also depend on the users ability to use this power.
Even though most users have shown great control of their ability. Their ability have been shown to easily run rampage, when the user has extremely strong emotions. It is unknown why this ability easily runs rampage, but it is theorised that the strain placed on the mind of the user, easily becomes to much during times of heightened emotions, therefore allowing the power to play without the user controlling it.
This ability if known for being very volatile, any user of this can have a very hard time controlling it as it seemingly got a very mind of its own. This can be caused by the very fact that most of the times a user will control thousands of bacteria at once. The fact the brain is attempting to control so many things at once, is what makes it very volatile as it can easily forget about the single bacteria, and instead focus on the bigger group, thereby sometimes allowing single bacteria to escape control.
This ability have been shown to cause lots of different side effects, this depends on the individual of course, but of course some have been more regular than other side-effects. It aren't always bad side-effects, though most of the time it is more of a hindrance than a benefit for the user.
Dissociative Identity Disorder: Edit
Many users have been diagnosed with DID, this causes one or more different personalities to come forth in the individual. Most often this is cause by great strain from the ability under manifestation. Often the new personality are more dark and dominant if the old personality wasn't already that.
Strong Immune system: Edit
Not really a bad thing, but most individuals have been shown to have a natural strong immune system, this is theorised to come from the ability, though it has yet to be certain. Though through research, other more specialised types of this ability have been found, that specificly deals with granted total immunity.