The terms used for the infectious jazz organism varies between the word "cell" and "virus". This shows a lack of medical knowledge although Howard and Naboo are not Doctors.
The two are not interchangeable terms for an illness.
Viruses contain no cells and
(cell based) bacteria would never referred to as a virus.
Vince: (about what makes him angry) Climate change.
Howard: Climate change?
Vince: It's getting hot, Howard. Didn't you notice?
Howard: That's making you angry why? Because it makes your hair a bit more difficult to straighten?
Vince: That, and it's a bit clammy.
Howard: Who are you?
Vince's brain: I'm the brain cell.
Howard: The brain cell?
Vince's brain: Yes.
Howard: Just you, yeah?
Vince's brain: Well, me and my secretary.