A-H. Three-dimensional (3D) visualisations (A, D-H) and confocal images (B, C; green and red channel overlays) of the leech Zeylanicobdella arugamensis and developmental stages of Haemogregarina curvata within its salivary gland cells. A: Voltex 3D visualisation of bright field microscopy images of stacked haematoxylin and eosin (H&E) stained histological sections (n = 10), and B: a confocal image of a single H&E stained section, through the anterior end of Z. arugamensis, showing anterior sucker (as), proboscis (p), salivary glands (sg) and crop (c). Scale bars: A and B, 0.2 mm, Z axis in A not to scale. C: Non-infected (sgc) and infected (sgc*) leech salivary gland cells. Scale bar = 20 μm. D - F: Stacked orthoslice (D) and voltex (E-H) 3D visualisations of 10 stacked confocal images of infected salivary gland cells, showing haemogregarine stages at various angles of rotation (green and red channels displayed), with meront (m) and merozoite (mr) stages. G-H: 3D visualisation of 26 stacked confocal images of a marginally located meront (m) with prominent nucleus (n) and a tail-like connection (large arrows) to the salivary gland cell limiting membranes at different rotations. X-Y-Z axis dimensions for visualisations = 30 μm × 30 μm × 6 μm (D-F), 17 μm × 17 μm × 3 μm (G-H).