- This article is about biological viruses. There are also computer viruses.
A virus is a submicroscopic parasite that can cause disease. They are a core of DNA or RNA surrounded by protein. Viruses are not considered lifeforms.
During a scan of Aldean DNA, Doctor Beverly Crusher was able to confirm that viral contaminants were not responsible for the Aldeans' sterility. (TNG: "When The Bough Breaks")
Dejaren, a Serosian HD25 Isomorphic Projection, claimed to B'Elanna Torres and The Doctor that a virus killed his crewmates, when in fact he murdered them. (VOY: "Revulsion")
Tools of treatment