Freeze-preservation of Leucocytozoon simondi sporozoites in liquid nitrogen.

SYNOPSIS. Sporozoites of L. simondi were maintained in a viable state for 7 months in liquid nitrogen. Comparison of parasite development initiated with fresh and frozen sporozoites showed a delay in development of each stage studied. Comparisons of prepatency, first elongate gametocytes, peak density of round and elongate forms, anemia and disappearance of megaloschizonts were made. In each phase there was a delay of 2–3 days in ducks infected with frozen sporozoites.