One idea is that HIV first got into humans in Africa when someone killed an infected chimpanzee and its blood went into an open wound on the hunter's body. It has also been linked to a Polio vaccine that was developed using chimpanzees. There are drugs that can delay HIV developing into Aids and there are others that can stop the virus passing from mothers to their children in breast milk. However, the companies in America and Europe that make these drugs charge a lot for them. Even when they reduce the price of their products they are still too costly for ordinary Africans.
Education is essential.
But safe-sex messages about using condoms have been slow to reach people in African countries, where some leaders have not done enough to fight ignorance and superstition about the disease. Traditional attitudes to sex do not help either - many men refuse to use condoms and African women often have little or no say in the matter. There have been many wars in Africa's recent history, and the armies fighting them may have spread Aids. The continent's poverty has also assisted the spread of Aids by forcing women into prostitution or weakening people through other illnesses and poor diet. Usually it is the young and the old who are at risk of disease, but Aids has been killing people in their 30s and 40s when they have families to support.