Table 1.

Categories of potential pathogens resulting from xenotransplantation

1 ‘Traditional zoonosis’: Well characterized clinical syndromes of humans (e.g. T. gondii) – specific diagnostic assays generally available

2 ‘Species‐specific’: Organisms incapable of causing infection outside the xenograft (e.g. porcine CMV) – some tests available,few standardized assays available for humans

3 ‘Potential pathogens’: Organisms of broad ‘host range’ which may spread beyond the xenograft (e.g. adenovirus) – few specific diagnostic assays available

4 ‘Unknown’ pathogens: Organisms not known to be human pathogens and for which clinical syndromes and microbiologic assays are not available

• New virulence characteristics within a host; i.e. xenotropic organisms

• Viral recombinants resulting from intentional genetic modification of donor diseases resulting from multiple simultaneous infections (e.g. lymphosis of cattle resulting from Babesia and viral coinfection)