Studies on Plasmodium falciparum in continuous cultivation. I. The effect of chloroquine and pyrimethamine on parasite growth and viability.

Recent advances in the in vitro study of human malaria have provided the knowledge to maintain Plasmodium falciparum in continuous culture. Using relatively cheap and easily obtainable materials it is now possible to study many parameters including parasite chemotherapy. The activity of two standard antimalarials, chloroquine and pyrimethamine, has been examined in vitro. The effect on the parasite is easily observed and can be measured not only as a decrease in parasite density, but also as the viability of the remaining parasites after drug pressure. Both chloroquine and pyrimethine showed activity against P. falciparum in vitro in concentrations equivalent to those obtained in plasma levels in vivo. The technique is very reproducible and offers a most valuable tool to the research worker.