| 1. | sexual contact with the infected person |
| 2. | by transfusion of contaminated blood and blood products |
| 3. | from infected mother to her child through placenta |
| 4. | mosquito bite |
| I: | the person suffers from bouts of fever, diarrhoea and weight loss. |
| II: | the person starts suffering from infections that could have been otherwise overcome |
| 1. | The heart and blood vessels |
| 2. | The brain and nervous system |
| 3. | The liver and kidney cells |
| 4. | Helper T cells and macrophages of the immune system |