Immune system is a system of biological structures and processes within an organism that protects against diseases by identifying and killing pathogens and tumor cells. The immune system is made up of organs that are involved in fighting invasion by foreign bodies.

HIV can’t grow or reproduce on its own. It requires cell of living organisms to infect & reproduce. HIV is specific to CD4+ cells in the human body i.e. cells with surface molecule called Cluster of Differentiation 4. Cells carrying this molecule are called CD4+ cells. Therefore HIV cant survive in the animal blood, because its only human blood that contains CD4+cells. HIV is a lentivirus. Like all viruses in this group it attacks the immune system. Lentiviruses are in turn part of a larger group of viruses called retroviruses. The term ”retrovirus” stems from the fact that these kinds of viruses are capable of copying RNA into DNA. The name lentivirus means slow virus. This is because they take such a longtime to produce any adverse effects in the body.

HIV infects cells of the immune system and the central nervous system. The main cell HIV infects is T helper cell which is a crucial part of the immune system, because it co-ordinates the actions of other cells of the immune system. A large reduction in the number of T helper cells seriously weakens the immune system.

General introduction: Public health and hygiene, human reproductive system, sex and sexuality. History of sexually transmitted diseases (STDs); History of Human Immunodeficiency virus/Acquired Immune deciency Syndrome (HIV/AIDS), Compara- tive information on trends, global and local distribution, Justification of importance of course. Biology of HIV/AIDS; Overview of immune system, natural immunity to HIV/AIDS. The AIDS virus and its life cycle, disease progression, transmission and diagnosis.

General introduction: Public health and hygiene, human reproductive system, sex and sexuality. History of sexually transmitted diseases (STDs); History of Human Immunodeficiency virus/Acquired Immune deficiency Syndrome (HIV/AIDS), Comparative information on trends, global and local distribution, Justification of importance of course. Biology of HIV/AIDS; Overview of immune system, natural immunity to HIV/AIDS. The AIDS virus and its life cycle, disease progression, transmission and diagnosis.

General introduction: Public health and hygiene, human reproductive system, sex and sexuality. History of sexually transmitted diseases (STDs); History of Human Immunodeficiency virus/Acquired Immune deficiency Syndrome (HIV/AIDS), Comparative information on trends, global and local distribution, Justification of importance of course. Biology of HIV/AIDS; Overview of immune system, natural immunity to HIV/AIDS. The AIDS virus and its life cycle, disease progression, transmission and diagnosis. Discordant couples.

General introduction: Public health and hygiene, human reproductive system, sex and sexuality. History of sexually transmitted diseases (STDs); History of Human Immunodeficiency virus/Acquired Immune deficiency Syndrome (HIV/AIDS), Comparative information on trends, global and local distribution, Justification of importance of course. Biology of HIV/AIDS; Overview of immune system, natural immunity to HIV/AIDS. The AIDS virus and its life cycle, disease progression, transmission and diagnosis.

General introduction: Public health and hygiene, human reproductive system, sex and sexuality. History of sexually transmitted diseases (STDs); History of Human Immunodeficiency virus/Acquired Immune deficiency Syndrome (HIV/AIDS), Compara- tive information on trends, global and local distribution, Justification of importance of course.

This unit aims at providing a good foundation in mathematics for students who plans to do more specialized work in the university, especially in the Computing, Medicine, Engineering, etc.

Upon completing this topic, you should be able to: Solve quadratic equations by factoring Learning outcomes Solve quadratic equations using the method of extraction of roots Determine the nature of the solutions to a quadratic equation Understand the logic underlying the method of completing Solve a quadratic equation using the method of completing