· Virology: the study of virus. · Father of virology: Stanley · Link between living and non-living. · Simplest and smallest. · Non-cellular infectious entities. · Also called a super parasite. · Nucleo-proteinaceous entities (particle). · Tobacco mosaic was recognized to be caused by the virus. HISTORY · First detected by W. Meyer. · First discovered by D.J. Ivanosky (Russian scientist) and was TMV (Tobacco mosaic virus) · Term “virus” was given by Louis Pasteur. But some authors believe Beijernick gave the term virus but in fact, he used the term “Contagium vivum fluid” · Smallpox and polio are considered prehistoric diseases because they are known since 6th BC · Smallpox was discovered by E. Jenner and polio by sabin et al. Characteristics Feature of Virus (a) Living properties · Contain either DNA or RNA · Obligate intracellular parasite · Can multiply and mutate inside living host. · Controls the enzymatic system of the host when they enter into the li...