Question

Question 5 0.25 pts What is the abrupt change in surface proteins that results from reassortment of genes in the influenza virus called? antigenic drift antigenic shift antigenic instability antigenic reassortment 0.25 pts D Question 6 MacBook Air

Answer 1

Answer :-

5)" Antigenic shift "

Explanation :- influenza strains are known to mutates constantly.

two main types of mutations are observed :-

I) antigenic drift - involve small changes to genetic make upit is a natural mutation occurs over a time.

Both influenza A and B undergoes genetic(antigenic) drift.

This type of mutation causes changes in surface proteins like heamagglutinin and neuraminidase.

We need new flu vaccine every is because of this type of mutation.

II) antigenic shift :- involve major changes in genetic make up.

This type of changes occurs when human influenza strain crosses with animal influenza strain (reassortment) and results in new subtype .

Only occur in influenza A.

Flu pandemic occured in recent year was due to this type of mutation.

Ans:-6)in herd immunity ,the

"Pool of susceptible people are vaccinated to prevent spread of disease."

Herd immunity :- when majority of community members (97-99%) are vaccinated then it prevents spread of disease among other non vaccinated susceptible members.