The virus that causes AIDS is called HIV which means Human Immunodeficiency Virus. HIV is a retrovirus, which is around 100-150 thousand millionths of a meter (4 millionths of an inch) wide. It is too small to see with an ordinary microscope, but can be clearly seen with an electron microscope.

In late 2007, an estimated 33 million people living with HIV, the virus that causes AIDS. This number includes men, women and children of all ethnic and social backgrounds. Virtually all countries in the world has been affected.

It is estimated that 15 million children have lost at least one parent to AIDS. Approximately 80% of these children live in sub-Saharan Africa hardest hit region in the world. Traditionally, these children have been supported by their extended family. However, the epidemic is now so serious in some countries where family structures are unable to cope, and many orphans are forced to live in households with children.