All are true about influenza viruses except: (AIIMS Nov 2010)
|A||Belong to orthomyxoviruses|
|B||Hemagglutination is an important characteristic|
|C||Hemagglunation occurs with the help of hemagglutinins|
|D||Mutation is responsible for antigenic shift|
Antigenic drift is due to point mutations.
a. Hemagglutination is brought about by peplomers (spikes) present on the envelop.
b. Hemagglutination is followed after a time by the detachment of the virus from the surface of RBCs, reversing the hemagglutination.
c. This process is called elution and is caused by the enzyme neuraminidase present on the viral surface as peplomers.