Introduction

The human immunodeficiency virus (HIV) is a virus that infects humans and weakens the immune system. As a result, HIV-infected people are more prone to acquiring other infections and diseases that individuals who haven’t been infected with HIV are able to fight off easily. The collection of diseases that results from HIV infection is called Acquired Immunodeficiency Syndrome (AIDS).

In this study session, we will first briefly describe the status of the HIV epidemic, so you understand the magnitude of the problem and how it may affect your community. We will then describe some important functions of the immune system — the main target of HIV in the human body — so that you have a basic understanding of the biology of HIV infection, and how it eventually leads to AIDS. Finally, we will outline the different modes of HIV transmission between humans. This knowledge will help you in providing effective care and health education for your HIV-infected clients, and in the implementation of HIV prevention measures in your community. Care, health education and prevention in the context of HIV/AIDS will be discussed in greater detail in later study sessions.