Effect of Eperythrozoon Coccoides upon Lymphocytic Choriomeningitis in Mice

Abstract

The pathogenicity of lymphocytic choriomeningitis virus inoculated subcutaneously and intraperitoneally was much greater in mice which had been recently infected with Eperythrozoon coccoides than in normal mice. This enhancement of pathogenicity was observed with two strains of virus and a tissue cultured subline of one of them. With the more virulent strain of virus which was able to kill normal mice by the intraperitoneal route, the mean survival time of the E. coccoides treated mice was shorter than that of the normal mice. The enhancing effect of E. coccoides, given as a 10-6 dilution of infected mouse blood, was maximal when the parasite was inoculated from 4 days before to 2 days after the inoculation of virus. The similarity of these results to those reported earlier with mouse hepatitis virus is discussed.