In vivo and in vitro chloroquine-resistant falciparum malaria in Venda. A case report.

A Venda child with Plasmodium falciparum malaria had a recurrence of illness 3 weeks after an adequate course of chloroquine. She was treated again with chloroquine and improved clinically but had persistent asexual parasitaemia during the 9 days after completion of the second course of treatment. At this stage chloroquine-resistant malaria was suspected but she was treated again with chloroquine in higher dosage, as alternative antimalarial drugs were not available locally. The patient recovered clinically, her parasitaemia cleared, and she showed no side-effects. Although not routinely recommended, a higher dose of chloroquine may be a useful option when alternative antimalarial drugs are not readily available. Chloroquine resistance was confirmed by Rieckmann's in vitro method, which showed complete inhibition of schizont development in the presence of 16 pmol chloroquine base per well instead of 6 pmol or less as seen with sensitive strains. This case is the first reported of proven chloroquine-resistant malaria acquired in the RSA. This single case does not indicate the existence of a drug-resistant malaria problem in the RSA but points to a need for clinical vigilance and for appropriate surveillance.