This document discusses HIV and opportunistic infections. It begins by defining HIV as a retrovirus that infects and destroys CD4+ T cells, leading to AIDS. It then lists some common opportunistic infections seen in patients with HIV/AIDS like Pneumocystis jirovecii pneumonia, toxoplasmosis, mycobacterial infections, cryptococcosis, and viral infections caused by herpes simplex virus and varicella zoster virus. It provides details of pharmacological treatments for various opportunistic infections with drugs like trimethoprim-sulfamethoxazole, pentamidine, azithromycin, clarithromycin, fluconazole, acyclovir,