Infections of ducklings by Plasmodium lophurae and controlled by quinine hydrochloride resulted in profound anemias and were marked by the radical reduction in the percentages of the polychromatophil erythroblasts. Infections in ducklings produced by P. relictum produced a transient anemia and an increase in the immature erythrocytes. In dual infections a blood picture identical to that seen in infections with P. lophurae alone were seen. Blood removal, production of lysed cells in ducklings and quinine treatment alone failed to evoke significant changes in the peripheral blood. Injection of lysed infected blood simulated somewhat the dyscrasia seen in infected birds while injection of lysed infected blood from birds treated with quinine failed to elicit significant anemia. Anemia and polychromatophil erythroblast elimination seem to be due to the loss of this cell in the bone marrow and may be due to a breakdown in some metabolic process or an autoimmune process.
Department of Zoology, University of Georgia, Athens, Georgia.