Figure 3.

Megalomeronts of Haemoproteus pastoris (lineage hLAMPUR01) in the cerebellum of the brain (A–D) and esophagus (E–P) of naturally infected Common starlings Sturnus vulgaris. Note the prominent capsular-like wall covering each megalomeront (B–P). The megalomeront in the brain was mature and overfilled with completely developed merozoites (C,D). Images E–L show two different histological sections of the same megalomeront, which was cut at different depths; as this megalomeront likely was a roundish body in 3D, the parasite in image I was bigger than in image E due to the location of the former section being closer to the center of the parasite. Note that developing cytomeres were present in section I (located closer to the center of the parasite) but not in section E (located closer to the periphery of the parasite), indicating uneven cytomere location during their development within the same megalomeront. It is possible that nuclear division started first at the center of the roundish megalomeronts (section I), and while the parasite grew, megalomeront division continued until the merozoites reached the extremities of the megalomeronts (section E). Images M–P show a mature ruptured megalomeront containing mature merozoites and infiltration of blood cells inside the megalomeront. Each megalomeront was shown at four different magnifications: A, E, I, M ×100; B, F, J, N ×200; C, G, K, O ×400, and D, H, L, P ×1000. Simple arrows ()—megalomeronts. Filled-black triangle arrows ()—capsular-like wall. Contoured-black triangle arrows ()—rupture of the capsular-like wall. Flat triangle arrows ()—red blood cells inside or outside the megalomeront. Triangle arrowheads ()—deformed adjacent tissue cells suppressed by the megalomeront. Simple arrowheads ()—merozoites. All scale bars = 20 μm.