Immunofluorescence and confocal microscopy of PRV positive RBC. Fluorescent labeling of the PRV ơ1-protein in erythrocytes (green). Cell nucleus stained with propidium iodide (red). (A) Positive RBC detected by immunofluorescence (IF) microscopy. Labeled cells varied in morphology from elongated mature RBC (arrow) to more spherical cells resembling immature erythrocytes (arrowhead). (B) IF microscopy of a negative cell (i) and different staining pattern in the cytoplasm including a few smaller inclusions (ii), scattered granular staining (iii), and large cytoplasmic inclusions (iv). (C) Confocal microscopy images showing viral inclusions in the perinuclear region (i-iii) and a more scattered staining pattern (iv). (D) Cytoplasmic inclusion detected by phase contrast (i, iv) and IF (ii, v) microscopy, and co-localized by image overlay (iii, vi).