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August 28, 1981

Failure of Chloroquine Prophylaxis in Plasmodium falciparum From East Africa

Author Affiliations

From the Vector Biology and Control Division, Center for Infectious Diseases, Centers for Disease Control, Atlanta (Ms Gardner); and the Division of Infectious Diseases, Department of Medicine, Michael Reese Hospital and Medical Center, Chicago (Dr Weinstein). Dr Lincoln is in private practice in Tucson, Ariz.

JAMA. 1981;246(9):979-980. doi:10.1001/jama.1981.03320090041026

IN 1979, four cases of chloroquineresistant Plasmodium falciparum infections were reported from Kenya and Tanzania.1-4 All four cases were characterized by RI type of resistance5 (RI in vivo resistance indicates that, following a 1.5-g [base] dose of chloroquine, the parasitemia clears within seven days but recrudesces from persisting blood forms within 28 days of initiation of therapy). These cases represent the only documented evidence of chloroquine-resistant falciparum malaria in East Africa. We report evidence of another manifestation of chloroquine resistance in East Africa, the development of falciparum malaria in two persons despite adequate chloroquine prophylaxis.

Report of Cases 

Case 1.—  A 27-year-old white American woman traveled in rural northeast Tanzania from June 15 to July 6, 1980. One week before her departure, she began and reportedly took 500 mg of chloroquine phosphate (300-mg base) weekly. She continued to follow this same regimen after her return to the United