[The immunodeficiency retrovirus in man and primates].

Human immunodeficiency viruses, HIV-1 and HIV-2, are similar, by genome structure, nucleotide sequences and pathogenicity, to retroviruses existing in various primates, SIVs. The possibility is discussed that the human viruses have their origin in accidental transmission of some monkey viruses to man. Studies of SIVs also suggest that the pathogenic effect not only depends on the virus strain, but also on the host species.