In vivo imaging of gametocytes within erythroblasts. (A) Immunofluorescence analysis of gametocyte-infected erythroblasts on methanol-fixed bone marrow smears from a P falciparum–infected patient. Gametocytes were stained with anti–Pf11-1 antibody (green), and erythroblasts were stained with anti-GPA labeling the erythroid membrane (red). DNA is stained with Hoechst 33342 (blue). (i-ii) Stage I-II gametocyte inside erythroblast. (iii-iv) Stage III-IV gametocyte inside erythroblast. (v) Stage I-II gametocyte inside reticulocyte or erythrocyte. (vi) Stage III-IV gametocyte inside reticulocyte or erythrocyte. (vii) Stage V gametocyte inside reticulocyte or erythrocyte. Gametocyte stages were evaluated based on the size and the shape of P11-1⁺ cells. Scale bars, 5 μm. (B) Quantification of P11-1⁺ cells in 3 bone marrow smears from the same patient. The absolute numbers of observed cells are indicated, with the percentages in parentheses.