Human immuno-deficiency virus (HIV) was first identified as the cause of acquired immuno-deficiency syndrome (AIDS) in 1981. The HIV virus compromises the body’s natural capacity to fight infection. AIDS is the final stage, when the body’s defences are so depleted as to expose the body to opportunistic infection such as tuberculosis, pneumonia and other diseases which kill the sufferer. But the transition from HIV to AIDS involves a number of stages that are not discrete but gradual. The virus is contracted through sexual intercourse, blood and blood product transfusions, use of contaminated needles, from mother to child through pregnancy, birth, and breast-feeding.

The pandemic of HIV/AIDS is a disease that has ramifications for the globe. It is estimated that the global HIV/AIDS figure at the end of 2003 was 40 million, 2.5 million of whom were children under 15. It is impossible to accurately determine the number of people who are at the end stage of the disease with AIDS because a blood test is required to determine white blood cell count, although there are certain diseases that are indicative of AIDS in different parts of the world, such as pneumonia in the developed world and tuberculosis in the developing world. Indeed, the disease takes the lives of 8,000 people every day.

But levels of infection are grossly uneven across the world, with developing countries suffering much higher rates. Moreover, developing countries are unable to afford the costly, life-saving anti-retroviral drugs to treat the virus and prevent the onset of full blown AIDS. Thus, they also incur much higher mortality rates than developed countries. Indeed, HIV/AIDS is ravaging many developing countries, particularly in sub-Saharan Africa (all countries in Africa except the five that border the Mediterranean Sea), where life-expectancy has been severely cut, and economic productivity slashed through the suffering wrought by the disease. At the start of this millennium over 23 million Africans, mostly from sub-Sahara, were estimated to have HIV/AIDS. This figure accounts for almost 70% of the world's total cases. However, Africa is home to only 10% of the world's population.

In the next four articles, we seek to look at the underlying questions that spring from this bleak picture, and in exploring them, draw on the experience of one developing country, Uganda, that has led the way in both fighting the disease and mitigating its impact. Uganda has one of the oldest HIV/AIDS epidemics in Africa, but has started to see declines in rates of new infections across most sectors of its population.

We'll look at the issues under the following themes:

- Why are rates of infection so high in the developing world?
- What is the impact of HIV AIDS on people, their communities and their nation?
- Faced with the scale of the challenges, how can development agencies help?
- What are the global responsibilities created by this crisis?