Xenotransplantation is any transplantation, implantation, or infusion of either live cells, tissues, or organs from a nonhuman animal source, or human bodily fluids, cells, tissues, or organs that have had ex vivo contact with live nonhuman animal cells, tissues, or organs into a human recipient. Most scientists agree that clinical xenotransplantation should not be performed in the absence of accompanying public health safeguards The science upon which that consensus is based has been extensively described in the literature. By and large (...) the most compelling reason for public health safeguards is the possible introduction of new infectious agents into the human life cycle as a result of xenotransplantation.The most frequent source of new infectious diseases in human populations is the transfer of agents, such as viruses, bacteria, or prions, from animals to man. Human diseases and infectious agents that are thought to have originated from animals include influenza, rabies, malaria, lassa fever, lyme disease, AIDS, yellow fever, tuberculosis, the human t-cell lymphotropic virus, the herpes B virus, the hantavirus, and even the bubonic and pneumonic plagues. (shrink)