A pregnant Japanese woman returning from Africa with recurrent fevers.

Certain clinical aspects of vivax malaria are no longer defined as benign. We present a case of vivax malaria with three relapses in a pregnant Japanese woman who had returned to Japan from the Comoros Islands in East Africa. Data on the successful delivery, examination of Duffy-blood group antigen, and microscopic findings of growing stages of Plasmodium vivax are thought to be of considerable interest.