- ultramicroscopic, virulent organism composed of a nucleoprotein core and a protein shell, which causes certain plant or animal diseases
Source: Noland, George B. 1983. General Biology, 11th Edition. St. Louis, MO. C. V. Mosby
- An infectious particle composed of a protein capsule and a nucleic acid core, which is dependent on a host organism for replication. A double-stranded DNA copy of an RNA virus genome that is integrated into the host chromosome during lysogenic infection.