The experiments repeatedly demonstrated the survival of vaccinia virus in the blood long after the disease process had stopped, including one case of smallpox. If one assumes that an infectious disease is an ecological process aimed not at the destruction of the two competing systems, but possibly at their survival and balanced coexistence, this result is not surprising. The survival of an infectious disease seems to indicate in most cases that the host has become unsuitable for further habitation by the parasite, i.e., that the parasite, while no longer able to propagate in the hosts body, does not perish all at once. Isolated pathogens may exist for extended periods in the hosts organism in a state of necrobiosis, i.e., they are able to reproduce, under special conditions, outside the host organism. This type of reservoir is more prevalent than previously assumed. It does not seem to be of great epidemiological importance, but does reinforce the immunity of the host, since daily disintegration of necrobiotic germs acts as a positive impulse on reinforcement of host immunity. In this perspective, the small number of germs present in 0.08 ml of blood must be evaluated correctly, as must be the observation that the number of increased little or not at all during the second transmission.
Partial trans. from Zeitschrift fuer Immunitaetsforschung, Allergie und Klinische Immunologie (West Germany) v117 p230-243 1959.