Both Uses

virus
in
A Vampire's Assistant
(Auto-generated)

She'd picked up a virus, and Evra had to stay in to look after her.
Chpt 20 *

virus = a submicroscopic organism that causes disease
Evra had warned me not to sleep in his tent that night; his snake was in a foul mood because of the virus and might bite.†
Chpt 24

Definitions:

(1) (virus as in: Covid 19 virus)
a tiny infectious agent that causes disease by invading living cells and using them to make more copies of itself

Although viruses contain genetic material, they can only reproduce by hijacking the reproductive machinery of a cell they invade.
(2) (virus as in: computer virus)
a type of software that spreads without invitation between computers and causes damage to data and software

Computer viruses are so-named because like a biological virus, they contain instructions on how to reproduce, but require the infected computer to actually execute the instructions.
(3) (viral as in: it went viral)
spreading rapidly and widely -- especially through the internet or social media
(4) (meaning too rare to warrant focus)