Fig. 1.

Schematic presentation of the proposed virus elimination program. The original herd was screened for the presence of a putative zoonotic virus (grey, positive animals; pink, negative animals). Negative animals (that may be actually positive, but below the detection limit) were selected and using Caesarean delivery, and treatment with antiviral drugs and/or vaccines, truly negative animals could be obtained and used for further breeding and xenotransplantation.