Adaptation of the Panama II strain of Plasmodium falciparum to Panamanian owl monkeys.

The Panama II strain of Plasmodium falciparum, acquired at the second passage level in splenectomized Colombian owl monkeys, was adapted to owl monkeys of Panamanian origin. Patent infections were induced in 22 of 27 unaltered and 20 of 21 splenectomized recipients during 19 serial passages. The infections were significantly more virulent in splenectomized than normal Panamanian owl monkeys, however recrudescences in seven normal monkeys achieved peak parasitemias 48 times greater than in the primary attack. These results describe the first reproducible infections of indigenous falciparum malaria in Panamanian owl monkeys.