The role of CD4 cells and HIV

The class is HIV and Epidemics.  In this module we are learning about the study of viruses. Viruses are very small particles that act as cellular parasites. Viruses are not life-forms themselves, because they can’t survive on their own. They must take over a host cell and commandeer it’s cellular machinery in order to survive. 

Find a unique approach to write about this topic. I’m not looking for a vague description or a generalized summary of the topic.