Reactions against the Megaloschizonts of Leucocytozoon Simondi Mathis and Leger in Ducks

Abstract

Study of duck tissues infected with megaloschizonts of L. simondi presented evidence of reactions against the parasites which included possible encapsulation, destruction by phagocytes, necrosis, combined phagocytosis and necrosis, and destruction by inflammatory cells. This suggested an explanation of the temporary resistance of ducks which had been sublethally infected and then protected against reinfection for an extended period. It is postulated that in the absence of continued stimulation by frequent reinfection, the number of phagocytes returns to a normal level and the host again becomes susceptible. Antibody production in these infections must be investigated before a complete understanding of the host-parasite relationships can be resolved.