acquired immunodeficiency syndrome (AIDS) is caused by either HIV-1 or HIV-2 or by both. They are mainly transmitted by unprotected sexual contact, exposure to infected blood through a syringe, needle, and blood transfusion or from mother to fetus and through breast feeding. Belonging to the retrovirus class, both HIV1 and HIV 2 share many similarities including their basic gene arrangement, modes of transmission, intracellular replication pathways and clinical consequences: both result in AIDS. However, HIV-2 is characterized by lower transmissibility and reduced likelihood of progression to AIDS. In terms of epidemiology, HIV-2 remains largely confined to West Africa, whereas HIV-1 extends worldwide
