Fig. 5
A thin immunofluorescence blood smear showing three red blood cells which stain positive for the P. falciparum ring erythrocyte stage antigen. The two lower cells also contain ring stage parasites which stain with acridine orange, the upper cell has no intraerythrocytic parasite indicating that it has already been removed by “pitting”. This is the main mechanism of ring stage parasite clearance in non-immune patients following treatment with artemisinin derivatives [34, 82, 83]