Eperythrozoon coccoides and rodent malaria: Plasmodium chabaudi and Plasmodium berghei

Abstract

Interrelationships of dual infections of Eperythrozoon coccoides and Plasmodium chabaudi and E. coccoides and P. berghei were examined. In concurrent infections the E. coccoides patent period was lengthened. The P. chabaudi infection was less severe and as high as 100% survival was noted. In some cases the P. berghei infection was slower in developing but death invariably occurred. The diverse effect of E. coccoides on the two species of malaria parasites was correlated with a difference in extent of inhibition by the eperythrozoa and with the preference of P. berghei for reticulocytes as host cells. Both the dosage size of eperythrozoa and the time of eperythrozoan inoculation relative to the time of malaria inoculation were critical determinants of the outcome. The course of the E. coccoides infection alone was found to be influenced by the dosage of organisms injected. The time to patency, maximum parasitemia, maximum anemia, and reticulocytosis was delayed approximately 1 day with each 1000-fold reduction in inoculum size.