- malaria diagnosis: a thick and thin smear of fingerprick blood will be prepared from each subject. Thin films will be fixed with methanol and stained with Giemsa in phosphate buffer (pH 7.2) for 30 min. and examined with a 100X oil immersion objective. The parasite species will be determined on the thin film and the parasites densities evaluated on the thick film by counting the number of asexual P.falciparum parasites against 200 leukocytes and expressed as number of parasites by microliter (µl) of blood assuming a standard leukocyte count of 8000/µl. At least 100 thick film fields will be examined to declare a slide negative.