It is reported that the scientific circles known have two types at present HIV. And the HIV-1 HIV infection is strong, the dissemination scope is broadest; II infection is weak, infects the area to concentrate in the West Africa, the symptom development is relatively slow. HIV-1 HIV divides into three different groups, respectively is M group, N group and O group. M group is now most common HIV, is called the main group, O is called the secondary group or other groups, N is called the new group.
But recent discovery's variety virus is belonged to P group. It with causes monkey, primates and so on chimpanzee to have the immune system damage symptom the SIV virus to be extremely similar. But the scientific researchers indicated: “we did not know at present actually when has had the variation.”