The cat virus's Genes Have now been decoded,making a more detailed comparison possible The cat and human viruses are “cousins” says John Elder,a molecular biologist at the Research Foundation of Scrips Clinic in La Jolla, who worked with Pederson on the study. But the evidence from stored blood samples suggests that the cat virus was present long before the human one arrived in this country .“The virus was always there” says Elder,“but it took the experience of the AIDS virus to bring it to light”