ASSESSING DRUG SENSITIVITY OF PLASMODIUM VIVAX TO HALOFANTRINE OR CHOROQUINE IN SOUTHERN, CENTRAL VIETNAM USING AN EXTENDED 28-DAY IN VIVO TEST AND POLYMERASE CHAIN REACTION GENOTYPING

Authors

W. R.J. Taylor, Department of Tropical Medicine, Tulane University School of Public Health, Canal Street, New Orleans
Doan Hanh Nhan, Institute of Malariology, Parasitology, and Entomology, Hanoi, Vietnam
Nguyen Dieu Thuong, Institute of Malariology, Parasitology, and Entomology, Hanoi, Vietnam
Tran Thi Uyen, Institute of Malariology, Parasitology, and Entomology, Hanoi, Vietnam
D. J. Fryauff, US NAMRU-2, Box 3, Unit 8132, APO, AP 96520-8132Follow
E. Gomez-Saladin, US NAMRU-2, Box 3, Unit 8132, APO, AP 96520-8132
K. C. Kain, Tropical Disease Unit, The Toronto Hospital and the University of Toronto, Canada
Le Dinh Cong, Institute of Malariology, Parasitology, and Entomology, Hanoi, Vietnam
J. Kevin Baird, US NAMRU-2, Box 3, Unit 8132, APO, AP 96520-8132Follow

Date of this Version

2000

Citation

Am. J. Trop. Med. Hyg., 62(6), 2000, pp. 693–697

Comments

U.S. Government Work

Abstract

Chloroquine-resistant Plasmodium vivax malaria is emerging in Oceania, Asia, and Latin America. We assessed the drug sensitivity of P. vivax to chloroquine or halofantrine in two villages in southern, central Vietnam. This area has chloroquine-resistant Plasmodium falciparum but no documented chloroquine-resistant P. vivax. Standard dose chloroquine (25 mg/kg, over 48 hours) or halofantrine (8 mg/kg, 3 doses) was administered to 29 and 25 patients, respectively. End points were parasite sensitivity or resistance determined at 28 days. Of the evaluable patients, 23/23 100% (95% confidence interval [CI] 85.1–100) chloroquine and 21/24 (87.5%) (95% CI 67.6–97.3) halofantrine-treated patients were sensitive. Three halofantrine recipients had initial clearance but subsequent recurrence of their parasitemias. Genotyping of the recurrent and Day 0 parasitemias diiumffered, suggesting either new infections or relapses of liver hypnozoites from antecedent infections. Among these Vietnamese patients, P. vivax was sensitive to chloroquine and halofantrine. Genotyping was useful for differentiating the recurrent vivax parasitemias.