Alterations in the Development of Plasmodium gallinaceum Following Passage Through Tissue Culture

Abstract

Chicks infected with P. gallinaceum developed an exoerythrocytic infection which terminated fatally 10-17 days after inoculation with material from culture. No pigmented erythrocytic stages developed, although at death a low percentage of the erythrocytes were parasitized with minute, unpigmented, uninuclear forms. Except for a more rapid onset and a greater severity, the infection was almost identical with that seen in blood-infected, quinone-treated chicks. Parasites from chicks infected from culture were maintained by serial passages in other chicks. The nature of the exoerythrocytic infection remained unchanged in one expt. through 9 passages accomplished by intraperi-toneal inoculation of brain suspended in saline. Infection in birds 2-35 days old continues to be acute, with exoerythrocytic parasites in the capillary endothelium of the brain as early as 4 days after inoculation. Death occurred as early as 6 days with infected brain material. Passage by intraven. inoculation of blood from such birds produced a different picture. For example, blood from chicks of the previously mentioned series initiated a blood inoculation series. Parasitism in the 1st and 2d inoculations was almost exclusively exoerythrocytic. However, after the 3d blood passage, pigmented erythrocytic stages were found, and increased in number with continued passage. After 8 blood passages, however, infection was preponderantly exoerythrocytic.