infective agent

(virology) ultramicroscopic infectious agent that replicates itself only within cells of living hosts; many are pathogenic; a piece of nucleic acid (DNA or RNA) wrapped in a thin coat of protein

any disease-producing agent (especially a virus or bacterium or other microorganism)

a large heterogeneous group of RNA viruses divisible into groups on the basis of the virions; they have been recovered from arthropods, bats, and rodents; most are borne by arthropods; they are linked by the epidemiologic concept of transmission between vertebrate hosts by arthropod vectors (mosquitoes, ticks, sandflies, midges, etc.) that feed on blood; they can cause mild fevers, hepatitis, hemorrhagic fever, and encephalitis

a virus that is parasitic (reproduces itself) in bacteria

a plant pathogen that is a virus consisting of a single strand of RNA

an animal pathogen that is a virus

a virus that remains dormant in the body for a long time before symptoms appear

a cell-free filtrate held to be a virus responsible for a specific neoplasm

(genetics) a virus or other agent that is used to deliver DNA to a cell