1.In view of the absence of malaria transmission in the study area, no direct information was obtained as to the efficacy of chloroquine in suppressing malaria.
2.Indirect evidence indicates that chloroquine (0.3 gram free base once weekly) is at least as effective in suppressing relapses of vivax malaria as a daily 0.1-gram dose of quinacrine.
3.Approximately 350 men took chloroquine (0.3 gram free base once weekly) for varying lengths of time up to 20 weeks. Three men were forced to discontinue the drug because of gastro-intestinal reactions. Four men had mild gastrointestinal reactions which did not necessitate stopping the drug. Twelve men had headaches attributed to the drug. No occular symptoms were noted.
Formerly Major, M.C., A.U.S., on leave of absence from the International Health Division of The Rockefeller Foundation.