Therapeutic efficacy of chloroquine against uncomplicated, Plasmodium falciparum malaria in south-western Saudi Arabia.

The results of annual random screening indicated that Plasmodium falciparum strains showing chloroquine (CQ) resistance in vitro became increasingly common in the Jazan region of south-western Saudi Arabia between 1986 and 1998 (chi(2) for trend = 50.027; P < 0.001).

Chloroquine-resistant Plasmodium falciparum cerebral malaria in a chloroquine-susceptible area.

Chloroquine-resistant Plasmodium falciparum is endemic in many areas. Saudi Arabia was considered to have chloroquine-susceptible P. falciparum.

Longitudinal study on the in vitro immune response to Plasmodium falciparum in Sudan.

Inhibition of Plasmodium falciparum in vitro by human immune serum provides needed information in understanding antimalarial immune mechanisms. Longitudinal, dry season-to-wet season changes in antimalarial activities were studied in sera isolated from 62 individuals living in an area of hyperendemic but unstable malaria. Highly synchronous cultures of P.

Comparison of immunity to malaria in Sudan and Indonesia: crisis-form versus merozoite-invasion inhibition.

Immunity to falciparum malaria was compared in two populations from malarious areas of southern Sudan and Flores, Indonesia. In Sudan, splenomegaly in adults was rare and anti-plasmodium indirect fluorescent antibody (IFA) titers were low to moderate, 1:1,280 being the modal titer. Sudanese serum was profoundly inhibitory to cultured Plasmodium falciparum, reducing incorporation of radiolabeled hypoxanthine by 63-93% and severely retarding intraerythrocytic parasite development, resulting in moribund crisis-form parasites and virtually no healthy schizonts.

African serum interference in the determination of chloroquine sensitivity in Plasmodium falciparum.

Isolates of Plasmodium falciparum from villagers in central Sudan were tested for chloroquine and mefloquine sensitivity using the WHO microtechnique procedure and a modified 48-h in vitro test for drug resistance. No drug-resistant strains were noted. In the WHO procedure, in which parasites were cultivated in the presence of the patient's plasma, 72% of the isolates failed to mature to the schizont stage, but when infected erythrocytes were washed free of the patient's plasma and cultivated in pooled nonimmune serum only 28.