Antimalarial Drug Susceptibility Testing of Plasmodium falciparum in Brazil Using a Radioisotope Method

Antimalarial Drug Susceptibility Testing of Plasmodium falciparum in Brazil Using a Radioisotope Method

From March 1996 to August 1997, a study was carried out in a malaria endemic area of the Brazilian Amazon region. In vivo sensitivity evaluation to antimalarial drugs was performed in 129 patients. Blood samples (0.5 ml) were drawn from each patient and cryopreserved to proceed to in vitro studies....

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Bibliographic Details
Published in:Memórias do Instituto Oswaldo Cruz Vol. 94; no. 6; pp. 803 - 809
Main Authors: Cerutti Junior, Crispim, Marques, Christiane, de Alencar, Filomena E.C, Durlacher, Rui Rafael, Alween, Anna, Segurado, Aluísio A.C, Pang, Lorrin W, Zalis, Mariano G
Format: Journal Article
Language:English
Published: Brazil Fundação Oswaldo Cruz, Fiocruz 01-11-1999
Instituto Oswaldo Cruz, Ministério da Saúde
Fundação Oswaldo Cruz (FIOCRUZ)
Subjects:
Animals
Antimalarials - pharmacology
arteether
atovaquone
Brazil
chloroquine
Drug Resistance
drug test
halofantrine
mefloquine
PARASITOLOGY
Parasitology - methods
Plasmodium falciparum
Plasmodium falciparum - drug effects
Plasmodium falciparum - drug resistance - drug test - chloroquine - quinine - mefloquine
quinine
Radioisotopes
TROPICAL MEDICINE
Brazil
chloroquine
Plasmodium falciparum
drug resistance
drug test
quinine
mefloquine
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Summary:From March 1996 to August 1997, a study was carried out in a malaria endemic area of the Brazilian Amazon region. In vivo sensitivity evaluation to antimalarial drugs was performed in 129 patients. Blood samples (0.5 ml) were drawn from each patient and cryopreserved to proceed to in vitro studies. In vitro sensitivity evaluation performed using a radioisotope method was carried out with the cryopreserved samples from September to December 1997. Thirty-one samples were tested for chloroquine, mefloquine, halofantrine, quinine, arteether and atovaquone. Resistance was evidenced in 96.6% (29/30) of the samples tested for chloroquine, 3.3% (1/30) for quinine, none (0/30) for mefloquine and none for halofantrine (0/30). Overall low sensitivity was evidenced in 10% of the samples tested for quinine, 22.5% tested for halofantrine and in 20% tested for mefloquine. Means of IC 50 values were 132.2 (SD: 46.5) ng/ml for chloroquine, 130.6 (SD: 49.6) ng/ml for quinine, 3.4 (SD: 1.3) ng/ml for mefloquine, 0.7 (SD: 0.3) ng/ml for halofantrine, 1 (SD: 0.6) ng/ml for arteether and 0.4 (SD: 0.2) ng/ml for atovaquone. Means of chloroquine IC 50 of the tested samples were comparable to that of the chloroquine-resistant strain W2 (137.57 ng/ml) and nearly nine times higher than that of the chloroquine-sensitive strain D6 (15.09 ng/ml). Means of quinine IC 50 of the tested samples were 1.7 times higher than that of the low sensitivity strain W2 (74.84 ng/ml) and nearly five times higher than that of the quinine-sensitive strain D6 (27.53 ng/ml). These results disclose in vitro high resistance levels to chloroquine, low sensitivity to quinine and evidence of decreasing sensitivity to mefloquine and halofantrine in the area under evaluation.
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ISSN:1678-8060
0074-0276
0074-0276
1678-8060
DOI:10.1590/S0074-02761999000600017