It is generally accepted that human immunodeficiency virus (HIV) is the etiological agent of acquired immune deficiency syndrome. According to this claim, HIV was transferred to humans from contact with monkeys around 35-50 years ago. However, this claim has not been sufficiently confirmed statistically and epidemiologically. The spread and incubation period and other symptoms of the plague epidemic have led to the theory that Black Death may have been caused by hemorrhagic viruses. Having examined detailed historical data, we have concluded that the bacterium Yersenia pestis was an infectious agent in the epidemic, together with another agent which we suggest was HIV. Our considerations are strongly supported by the CCR5 delta 32 mutation, which protects against HIV infection and has been present in the Caucasian population for over 2000 years. The combination of two infectious agents led to the devastation of the Black Death, the removal of HIV carriers, and an increase in the number of CCR5D32 mutations in the Caucasian population. In sub- Saharan Africa, this epidemic and subsequent sanitation process did not occur, resulting in a much higher level of HIV genetic information in this population.
