A virus is an infectious microorganism made up of a nucleic acid segment (either DNA or RNA) wrapped by a protein coat.
Viruses cannot multiply on their own and must thus seek for a host cell to proliferate.
They are small, simple infectious agents that can reproduce solely in live cells of animals, plants, or microorganisms.
The goal of the virus:
As a result, the only purpose of a virus (pathogenically) is to infect a host and replicate itself.
As a result, viruses infect host cells by one of several possible transmission channels, which include direct contact, indirect, common vehicle, and airborne transmission.
Viruses frequently end up destroying host cells, causing harm to the host body.
AIDS, COVID-19, measles, and smallpox are examples of viruses that cause human illness.