Antigenic Shift in Influenza Viruses

The video tutorial by Nikita explains antigenic shift, a genetic variation in influenza A virus. It details how antigenic shift allows the virus to jump between species, leading to new virus strains. The process involves reassortment of genes, resulting in a novel virus that can cause pandemics. The tutorial uses diagrams and analogies to clarify the concept.

Which type of influenza virus is associated with antigenic shift?

• Influenza B

• All of the above

• Influenza C

• Influenza A

What is the primary reason antigenic shift is observed only in influenza A virus?

• It has a limited range of hosts.

• It can infect a broad range of hosts.

• It mutates frequently.

• It only infects humans.

What are the two surface antigens involved in antigenic shift in influenza A virus?

• HC and NC

• HB and NB

• HA and NA

• HD and ND

How often does antigenic shift typically occur?

• Every year

• Once in many years

• Every decade

• Every month

Which of the following is NOT a way antigenic shift can occur?

• Direct jump from bird to human

• Mutation in a single host

• Co-infection of the same cell

• Infection of an intermediate host

What is the term used to describe the mixing of genes during antigenic shift?

• Mutation

• Recombination

• Reassortment

• Replication

In the reassortment process, what happens to the genomes of the viruses?

• They remain unchanged.

• They are destroyed.

• They mix and match.

• They duplicate.

What is the result of the reassortment process in terms of virus strains?

• Old virus strains are strengthened.

• New virus strains are formed.

• Virus strains disappear.

• Virus strains become weaker.

Why are previous antibodies ineffective against new strains formed by antigenic shift?

• The new strain is weaker.

• The new strain has a different identity.

• The old antibodies are too strong.

• The new strain is identical to the old one.

How frequently do influenza pandemics occur due to antigenic shift?

• Once every 100 years

• Once every 40 years

• Once every 20 years

• Once every 10 years