Human Immunodeficiency Virus
Human Immunodeficiency Virus falls into a retrovirus group known as lentivirus. It alters genomes in RNA and DNA. In addition to this, HIV turns cells into a form in which they are easily susceptible to viruses and diseases. Adding further to its misery, HIV leads to acquired immune deficiency syndrome or AIDS. AIDS is the condition in which human immune system fails and eventually leads to life-threatening ailments.
HIV is easily transferable to each other. It is transferred by contact between blood, pre-ejaculate or vaginal fluid, semen and breast milk. Remember that virus operates as free particles and the main method of transmission is sharing needles, unprotected sex, through a mother to a child in birth and ingestion of breast milk. Blood screening has minimized this problem and proper precaution has eliminated the transmission.
HIV attacks the helper T cells of the immune system. It not only handles minimum function of the immune system but also attacks macrophages and dendritic cells which operate as immune system cells of tissues. Cells are destroyed over a period of time with the formation of unfavourable biochemical conditions. AIDS is eventually developed when the number of helper T cells and other cells fall.