Species prevalence of malaria in northern and southern Sudan, and control by mass chemoprophylaxis.

A survey in northern and southern Sudan showed that Plasmodium falciparum is the predominant species in malaria cases, occurring in 91% and 87%, respectively of the positive cases in these two regions. P. ovale was extremely rare in southern Sudan and was absent in the north. The survey, which was carried out during the transmission season in northern Sudan, showed that malaria is common, occurring in 62% of those tested in some villages. A trial of mass chemoprophylaxis resulted in a marked decline in prevalence after 1 year, demonstrating the importance of chloroquine and establishing that malarial parasites in Sudan are highly sensitive to the drug.