Morbidity from falciparum malaria in Natal/KwaZulu.

Plasmodium falciparum malaria is endemic in the northern KwaZulu areas of South Africa. The clinical morbidity produced by this parasite has not been studied since the institution of the present malaria control programme. Fifty-nine patients were prospectively studied at a peripheral clinic during the peak malaria season; symptoms and signs of the infection, parasite loads, haemoglobin values and leucocyte counts were recorded in all patients. Haemoglobin and leucocyte counts were also measured in 37 control subjects without malaria. The commonest symptoms were persistent headache (100%), rigors (98%) and myalgia (93%). None of the patients presented with coma, pulmonary oedema, hypoglycaemia or algid malaria. Splenomegaly was found in 49%, hepatomegaly in 20% and mental confusion in 5% of patients. Mean parasite load was 1.71% and 57% of patients had parasite loads of < 1%. Anaemia of < 10 g/dl was significantly more frequent (P < 0.0001) in the patient group than in the control group. Leucopenia (white cell count < 4.0 x 10(9)/l) was present in 12 of 50 patients in whom it was measured compared with 2 controls (P = 0.0175). The results show a wide range of morbidity, without severe complications as presenting manifestations. Symptomatic infection in the presence of low parasite loads suggests that there may be little or no immunity in this population.