Viruses

Viruses (singular: the virus, outside the technical language also the virus; plural: viruses; from lat. virus, -i, n. "poison, juice, mucus") are particles, but not cells themselves.

Viruses contain the program (some viruses also contain further auxiliary components) for their multiplication and spread, but do not have their own metabolism and are therefore dependent on the metabolism of the host cell. They are thus intracellular parasites that reprogram the reproductive mechanism of the host cell in order to reproduce in it.

Viruses attack cells of eukaryotes (plants, animals, humans, fungi) and prokaryotes (bacteria and archaea). Viruses that use prokaryotes as hosts are called bacteriophages. The science that deals with viruses is virology.

https://de.wikipedia.org/wiki/Viren _{(Wikipedia CC-by-sa-3.0)}