Gerrit J. Schuurkamp, Paul E. Spicer, Richard K. Kereu, Peter K. Bulungol, Karl H. Rieckmann; Chloroquine-resistant Plasmodium vivax in Papua New Guinea. Trans R Soc Trop Med Hyg 1992; 86 (2): 121-122. doi: 10.1016/0035-9203(92)90531-G
An Australian expatriate on regular weekly antimalarial prophylaxis with chloroquine base and Maloprim® developed symptomatic Plasmodium vivax infection which failed to respond adequately to 600 mg of chloroquine base. More ominously, a resident of the Highlands region of Papua New Guinea contracted vivax malaria which failed to be cleared by 2400 mg chloroquine base administered over 4 d. Both patients had achieved appropriate blood and plasma concentrations of chloroquine after treatment. Chloroquine-resistant P. vivax is now a clinical fact in Papua New Guinea.