Among all infectious diseases, $\text{HIV}$ infection or $\text{AIDS}$ is the most dangerous and fatal disease. There is no treatment or cure for this disease, and prevention is the best option. HIV enters into helper T-lymphocytes (T_H), replicates and produces progeny viruses. The progeny viruses released in the blood attack other helper T-lymphocytes. This is repeated, leading to a progressive decrease in the number of helper T-lymphocytes
in the body of the infected person.