In-vivo and in-vitro sensitivity of Plasmodium falciparum to chloroquine in Chennai (Tamil Nadu) , India
Dua, V.K.; Kar, P.K.; Gupta, N.C.; Kar, I.; Sharma, V.P.
Indian Journal of Malariology 34(1): 1-7
1997
ISSN/ISBN: 0367-8326 PMID: 9291668 Document Number: 475430
The in vitro and in vivo susceptibility of Plasmodium falciparum to chloroquine was investigated in 67 patients aged between 15 and 50 years in Chennai city, India. Of 30 samples examined for chloroquine resistance by the in vitro test, 18 (60%) showed resistance; the EC50 of resistant and sensitive cases was 0.40 and 0.24 micro mol chloroquine/litre blood, respectively; the EC90 was 2.64 and 0.84 micro mol chloroquine/litre blood, respectively. 60 patients who received 1500 mg chloroquine base and underwent the in vivo WHO 28-day extended test were successfully followed up. Of these cases, 24 (40%) were classed as resistant (23 RI and one RII) and 36 (60%) as sensitive. A total of 8 isolates which were classed as resistant by the in vitro test showed sensitivity to chloroquine when assessed by in vivo studies.