Pathological findings in cetaceans with brucellosis. (A) Striped dolphin S. coeruleoalba fetus within placental presenting multiple necrotic foci diffusely distributed (arrow points a prominent focus); and, B. ceti detected by IF in impressions of placenta tissues (insert). (B) From (A) severe necrotizing placentitis showing detached placental cells (arrow) and marked necrosis of trophoblastic epithelial cells lining with infiltration of neutrophils into the fetal placental villi (HE stain 10×); and, I-HRP labeling of Brucella antigen within inflammatory cells invading the placental villi (insert). (C) Harbor porpoise P. phocoena right enlarged testicle (twofold) demonstrating an abscess and multi-locular lesions in the proximal area (arrow). From Dagleish et al., 2008, with permission, license N° 2756120153946). (D) From (C) HE histological section of the affected testis showing necrosis (asterisk), thick fibrous capsule of the abscess (black arrows) and the foci of mononuclear inflammatory cells (blue arrows); and I-HRP labeling of Brucella inside macrophage like cells (arrows) in the testicular lesion (insert). From Dagleish et al., 2008, with permission, license N° 2756120153946). (E) Vegetative nodule in the mitral valve (white arrow) of striped dolphin heart. (F) From (E) HE 10× histological section of the mitral valve showing bacterial colonies (arrow) intermixed within abundant fibrin deposits over the valve surface, focal areas of dystrophic calcification and severe suppurative inflammatory infiltrate surrounding this area. Insert shows positive I-HRP Brucella staining in inflammatory cells and bacterial aggregates (G) Hyperemic meningeal blood vessels in cerebral hemispheres and cerebellum from striped dolphin, showing cloudy and hemorrhagic cerebrospinal fluid in syringes. (H) Wright–Giemsa stained cells in cerebrospinal fluid from (G) composed of ependymal cells and mononuclear leukocytes. (I) IF of B. ceti and bacterial debris within phagocytic cells infiltrating cerebrospinal fluid shown in (H). (J) From (G) severe mononuclear inflammatory infiltrate in the meninges (black arrow) surrounding the spinal cord and hyperemic blood vessel (white arrow). (K) I-HRP labeling of Brucella antigens in cells that seem to be perivascular macrophages or pericytes laying below the endothelium of a vessel of the brain of striped dolphin (arrow), with no inflammatory response (courtesy of M. Barberán, Servicio de Investigación Agraria-DGA, Zaragoza, Spain). (L) I-HRP labeling of Brucella antigens in cells that seem to be macrophages or glial cells in the parenchyma of the brain of striped dolphin (courtesy of M. Barberán, Servicio de Investigación Agraria-DGA, Zaragoza, Spain). (M) Skulls (caudal view) and atlas bones (cranial surface view) of the affected Atlantic white-sided dolphin L. acutus (left) and the normal counterpart (right). The occipital condyles are completely absent in the affected animal (arrows), and only a roughened surface remains, which extends beyond the normal margins where these structures should be. There is also a lack of dorsal and lateral vertebral processes and normal smooth bone architecture, as well as a large amount of remodeling, present in the atlas bone. From Dagleish et al., 2007, with permission, license N° 2756130134008).