Antigenic drift is a process of viral genetic code. DNA or RNA of virus mutate to other base. In point mutation protein base do not changes.
Antigenic shift occurs when in a major change occur in the genome of the virus. Hence, recombination or ressortment occured.
In most case of Influenza virus antigenic shift occurs that is a major cause of pandemic.
Virus is a microorganisms that is incapable to replicate independently, but capable to replicate in host cell.
The etymology of virus is that it originate from Latin neuter Virus which means as Poison and other noxious liquid. But, basically virus is not any liquid forms.
Latin word Virulent means Any agent that causes Infectious disease.
In 1892, Russian Biologist Dimitry Ivanovsky, observed tobaco is getting disease and sugested that infection is caused by a group of bacteria.
But, according to Germ theory of disease all infectious agent should retain and should grow up in nutrient. But, in that case it does not happened. Hence, 1898, Martinus Beijerinck again filltered and found a new format of infecrious agent.. He observed it only multiply only into living cell. He termed it as a soluble living germ.
But in latter, Windel Stanley termed virus as particles.
