The Activity of Primaquine‐Pyrimethamine (Daraprim®) Combinations Against Plasmodium relictum in Pigeons

SUMMARY. As part of an extended series of experiments, various combinations of primaquine‐pyrimethamine were tested against pigeons infected with Plasmodium relictum. (a) Rapid clearance of blood forms was observed, although each component had been reduced to one‐half of its previously established MED (minimal effective dose) for such clearance when administered alone. (b) Primaquine‐pyrimethamine was followed by unprecedented delays in relapse after drug withdrawal. Such delays had not been elicited in any previous experiments in the series, employing each component alone, or chloroquine alone, or primaquine‐chloroquine combinations, or pamaquine‐plasmocid‐chloroquine (Premaline N).