The cytopathic virus isolate Paplitz (cytopathic effect becomes apparent 3 to 5 days post infection) did not show a significant increase in CD46-MDBK cell infectivity after passaging based on the FACS results (from 1% positive cells with passage 0 virus to 4% with passage 15 virus, Figure 2a). The gene discussed is CD46; the disease is infection.