Fig. 2

Plasmodium berghei sporozoites escaping from oocysts. a P. berghei oocysts protruding among muscle fibers (Mfb) on the external surface of the midgut. The surfaces of the oocysts are partly smooth (white asterisks) and partly wrinkled (black asterisks), with the exception of a few flattened oocysts (F-ooc). Several oocysts have openings on their wrinkled surfaces, which appears as if the wall has peeled away, and sporozoites can be seen inside the hole (arrows). Muscle fibers = Mfb. Magnification = ×1000. b Small opening (arrowhead) in the oocyst (ooc) wall showing the orderly arrangement of several sporozoites (Spz) inside the oocyst. Note the wrinkled surface of the oocyst. Magnification = ×1900. c Oocyst (ooc) with a large opening, approximately half-size, showing a sponge-like part of the dissolving oocyst wall (D-wall). Note cluster of sporozoites (Spz) ready to escape from the oocyst. Magnification = ×1900. d A single oocyst (ooc) showing a large opening with a “cap” (asterisk) that appears to allow sporozoite escape. Note cluster of sporozoites (spz) attached to the internal side of the oocyst wall (arrows). Magnification = ×1700. e Magnified view of the dashed area from figure d, showing a large opening with several orderly arranged sporozoites (Spz) attached to the internal side of the oocyst wall (In-wall). Magnification = ×4300