Von Magnus phenomenon -
a) Is a normal replicative cycle
b) Virus yield has low hemagglutination
c) Virus has high infectivity
d) Virus yields has high hemagglutination titre but low infectivity
Correct Answer - D
Ans. is ‘d’ i.e. virus yields has high hemagglutination titre but low
infectivity
Abnormal replicative cycles of viruses
. Von magnus phenomenon when cells are infected with a high dose
of influenza virus, there is defective assembly during replication and
the
produced virus has high hemagglutinin titre but low infectivity.
. Abortive infection Due to defective maturation or assembly, either
no release of virons occur or the progeny of virus is noninfectious.
. Defective viruses Some viruses are genetically defective and
require help of simultaneously infected helper virus for replication.
eg.
HDV, Rous sarcoma virus.