Virus ... A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. [1]

When a virus infects a cell, the virus forces it to make thousands more viruses. It does this by making the cell copy the virus's DNA or RNA, making viral proteins, which all assemble to form …

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.

After the Dutch Erasmus Medical Centre sequenced the virus, the virus was given a new name, Human Coronavirus–Erasmus Medical Centre (HCoV-EMC). The final name for the virus is …

For a list of virus families and subfamilies, see List of virus families and subfamilies. For a list of virus realms, subrealms, kingdoms, subkingdoms, phyla, subphyla, classes, subclasses, …

However, the number of named viruses considerably exceeds the number of named virus species since, by contrast to the classification systems used elsewhere in biology, a virus "species" is …

The genetic material within virus particles, and the method by which the material is replicated, varies considerably between different types of viruses. This false-coloured transmission …

A virus is a small piece of genetic information in a “carrying case” — a protective coating called a capsid. Viruses aren’t made up of cells, so they don’t have all the equipment that cells do to …

Oct 13, 2025 · Virus, infectious agent of small size and simple composition that can multiply only in living cells of animals, plants, or bacteria. Viruses possess unique infective properties and …

The average virus is about 1/100 the size of the average bacterium, and most are too small to be seen directly with an optical microscope. The origins of viruses are unclear: some may have …