Histological lesions of placenta and foetuses from infected ewes. a: Coronal section of a placentome from an acute case abortion. Several triangular areas of coagulative necrosis, involving both caruncular and cotyledonary villi (dotted line). HE. Bar = 2 mm. b: Thrombosis in the placenta of an acute abortion case. The thrombus is partially occluding the lumen of the vessel in the caruncular septa. HE. Bar = 100 μm. c: The presence of fibrin forming the thrombus is shown by the red staining in a serial section from the same placentome shown in b. MSB. Bar = 100 μm. d: Placentome from an acute abortion case. Detail from the margin of an infarct. The picture is divided in two areas by a caruncular villi showing congestion of the septal vessels (asterisk). At the left side there is abundant cellular debris between the denuded caruncular and foetal villi (white arrowhead). Caruncular villi in this area are necrotic, while cotyledonary villi show mesenchymal hyalinization. Note the relatively spare cotyledonary villus at the right side of the picture, with clear mesenchyme and intact trophoblasta layer (black arrowhead), and also the caruncular villus at the right superior corner with no evident lesions. HE. Bar = 200 μm. e: Area of leukomalacia (dotted line) in the white matter of a foetal brain from an acute phase abortion. Note numerous axonal spheroids (arrowhead) within the focus of malacia. HE. Bar = 100 μm. f: Necrotic in the placentome of an infected ewe culled at 21 dpi. The lesion affects both caruncular and cotyledonary villi. Bar = 25 μm. g: Focus of coagulative necrosis in the foetal white matter from an infected ewe culled at day 21 pi. Note the abundant infiltration of glial cells surrounding the necrotic focus. HE. Bar = 100 μm.