Q. At which stage of HIV infection does one usually show symptoms of AIDS?
(a) When the infecting retrovirus enters host cell
(b) When viral DNA is produced by reverse transcriptase
(c) When HIV replicates rapidly in helper T-lymphocytes and damages larger number of these
(d) Within 15 days of sexual contact with an infected person
Solution : Correct option : C The causative HIV retrovirus enters helper T-Iymphocytes, replicates and produce progeny viruses, thus reducing the number of helper T- cells which stimulate antibody production by B- cells, thereby showing the primary symptoms like fever, swollen throat, muscle and joint aches.