What contributes to antigenic shift in influenza viruses?

influenza A viruses can trade genetic materials with the viruses of other species. Two different strains trade or merge material, a process known as an antigenic shift. read more

Some viruses, such as human herpesvirus 1, infect a cell without causeing symptoms; these are called Latent viruses Assume a patient had chickenpox (human (herpesvirus 3) as a child. read more

While influenza viruses are changing by antigenic drift all the time, antigenic shift happens only occasionally. Type A viruses undergo both kinds of changes; influenza type B viruses change only by the more gradual process of antigenic drift. read more