Risk and risk management for xenotransplantation.

Transmission of an animal virus to man is probably a constant reality. Path ogenicity is is not inevitable. Some vaccines were contaminated by cell cul ture but remain safe. Haemorrhagic fevers, despite limited outbreaks, are o ften cited in the media. On the other hand, the influenza A virus has been responsible for a large mortality The cases of human infection with simian viruses (herpes virus B, cytomegalovirus, spumavirus, immunodeficiency viru s) were accidental and have always remained asymptomatic. Monkeypox virus e merges in only some outbreaks. No transmission of animal endogenous retrovi rus has been described. The precautionary principle, in the face of an unquantifiable risk, suppose s that preventive measures should be taken in advance to reduce the risk at each step: isolation of the animal source after hysterotomy, transport in a germ-free environment, procurement and transplantation in rigorous surgic al conditions, long-term follow-up surveillance of the patient, his or her family and healthcare workers. All the phases of the xenotransplantation pr ocedure should be taken to limit the number of places and persons coming in to contact with the recipient. Surveillance means regular clinical information. Various samples should be taken from the animal source, recipient, his or her family contacts, medica l staff and cryogenically preserved as 'biological memory'. A National Xeno transplantation Register should be set up to gather and share all informati on on incidents. (C) 2000 Editions scientifiques et medicales Elsevier SAS.