Response of Plasmodium falciparum in Sudan to oral chloroquine

The chloroquine sensitivity of Plasmodium falciparum was studied in two areas of Sudan. In the Gezira, 99.2% of the patients tested responded completely to the drug. Two patients (0.4%) and one patient (0.2%) showed, respectively, RI and RII responses. However, in those showing RI response reinfection could not be excluded. In an area of southern Sudan patients could only be followed-up for 7 days; nevertheless, this was sufficient to exclude the presence of RII and RIII responses there. This study also showed that malaria is a common cause of fever in Sudan, as over 90% of fever cases tested in the Gezira were positive for malaria and P. falciparum was the predominant species in these cases.