Frequency of relapse and primaquine resistance in Southeast Asian vivax malaria.

To the Editor: In the interval between January 1, 1979 and July 26, 1980, approximately 1871 cases of malaria in the United States were reported to the Center for Disease Control, 1 , 2 an incidence of about 98 per month. If the incidence in California (39 per cent of all U.S. cases) is used as an index, between 13 and 60 per cent of the reported cases of malaria occurred in Indochinese refugees3; all cases reported during this period were imported, i.e., contracted outside the United States.