The Human Immunodeficiency Virus (HIV) is a single-stranded RNA virus which reproduces in human CD4-positive cells, which are primarily T-helper lymphocytes and macrophages. HIV is the causative pathogen of Acquired Immunodeficiency Syndrome (AIDS).
So, the HIV-1 jump to humans occurred as early as the 1920s, but the AIDS epidemic didn't start until the early 1980s.
Some things I don't understand about this:
Why the delay?
What is needed for a ...