Modification of the Pathogenesis of Scrapie in Mice by Treatment of the Agent

Abstract

Two major areas in scrapie research depend on estimates of the concentration of the agent: investigation of the nature of the agent by the effect of various chemical or physical treatments and of the pathogenesis of the disease. Two methods have been used for these estimates. One is conventional serial dilution, with the end-point measured either by appearance of clinical disease^1–6 or by the occurrence of the brain lesions at a chosen time after injection⁷. The second methed relies on the finding that the incubation period is very closely related to dose if other variables are constant^8,9; when this relationship has been found for a given combination of strain of agent, tissue source, route and dose of injection and genotype of recipient, the concentration of agent can be estimated from the incubation period of a single dilution group.