Viral disease

A viral disease (or viral infection) occurs when an organism's body is invaded by pathogenic viruses, and infectious virus particles (virions) attach to and enter susceptible cells.

[1] Examples include the common cold, gastroenteritis, COVID-19, the flu, and rabies.

[2] Basic structural characteristics, such as genome type, virion shape and replication site, generally share the same features among virus species within the same family.

[citation needed] Human-infecting virus families offer rules that may assist physicians and medical microbiologists/virologists.

[citation needed] This group of analysts defined multiple categories of virus.

Virions of some of the most common human viruses with their relative size. Nucleic acids are not to scale. SARS stands for SARS-CoV-1 or COVID-19 , variola viruses for smallpox .