Question

Compare and contrast the antigenic shift and antigenic drift that type A influenza viruses undergo. State the functions of the hemagglutinin and neuraminidase spikes present in the influenza viral envelope. List the factors that contribute to the formation of a wholly new antigenic strain of Type A influenza.

Answer 1

Antigenic shift	Antigenic Drift
Major antigenic change	Minor antigenic change
Involves one or two viruses	Invilves only one virus
Occurs once	Occurs frequently
Large and sudden mutation	Random and spontaneous

Function of hemagglutinin- It is a surface glycoprotein found in the viruses, It helps in binding the viruses to the surface of cells wwhich has sialic cid on its membrane(respirtory tract)

Function of neuraminidase- These are enzymes that are involved with virus replication. These cleave sialic acid from glycoproteins.

The factors that contribute to the formation of a wholly new antigenic strain of Type A Influenza-

• Antigenic shift
• Antigenic drift
• Mutations
• Adaptations