case_images: PMC10562539_01
case_images: Representative gross lesions of a 25-day-old bottle nose dolphin. (A) Multiple cutaneous ulcerations and underlying inflammation and granulation tissue on the dorsal and pectoral fins and rostrum. (B) Multiple nodules on the lungs (arrows). (C) Enlargement and congestion of mesenteric lymph nodes (asterisks) and stricture and serosal hyperemia of the intestines (inset, arrow). (D) Fibrinopurulent arthritis in the atlantooccipital joint and extension of the fibrin in the spinal canal (arrow).
case_images: fvets-10-1242599-g001.jpg
case_images: PMC10562539_01_fvets-10-1242599-g001.jpg
case_images: fig1
case_images: On gross examination, extensive cutaneous ulcerations were identified on the dorsal and pectoral fins and rostrum (Figure 1A). Marked consolidation, congestion, and edema were observed in the whole lung tissue, along with generalized multifocal round soft yellow nodules between 5 and 10 mm in diameter (Figure 1B). The serosa of the intestinal tract was edematous and hyperemic (Figure 1C). Enlargement and congestion of mesenteric lymph nodes were also observed (Figure 1C). Fibrinosuppurative arthritis in the atlantooccipital joint was observed (Figure 1D).
case_images: Representative photomicrographs of the hematoxylin and eosin (H&E) staining. (A) Trachea characterized by hemorrhage and necrosis of submucosal glands with infiltration of macrophages. 100x magnification, Inset: 800x magnification. (B) Lungs characterized by edema and congestion. Neutrophils and fibrin accumulation in the alveoli and larger airways. 100x magnification. (C) Intestines characterized by epithelial erosion, hemorrhages, detachement of epithelium and infiltration of the macrophages, lymphocytes, and neutrophils. 200x magnification, Inset: 800x magnification. (D) Brain characterized by meningeal vessel congestion. 200x magnification. (E) Intraparenchymal hemorrhages with neutrophils (black arrows) accompanied by neurodegeneration (white arrow). 400x magnification.
case_images: fvets-10-1242599-g002.jpg
case_images: PMC10562539_01_fvets-10-1242599-g002.jpg
case_images: fig2
case_images: Microscopic examination revealed tracheitis, characterized by hemorrhage and necrosis of the submucosal glands accompanied by infiltration of inflammatory cells, such as macrophages (Figure 2A). Within the nodules, and to a lesser extent affecting all pulmonary parenchyma, are numerous neutrophils and fibrin accumulation in the alveoli and larger airways (Figure 2B). Epithelial erosion with hemorrhages, karyorrhectic debris of the enterocytes, lymphocytes and plasma cells with neutrophil and macrophage infiltration, and progressive destruction of epithelium were observed in the intestines (Figure 2C). Meningeal vessel congestion was observed in the brain (Figure 2D). Intraparenchymal hemorrhage with neutrophils, neurodegeneration such as loss of nuclei were observed in the spinal cord at the site of fibrinosuppurative arthritis (Figure 2E).
case_images: Representative photomicrographs of gram staining. (A) Gram-negative bacterial colonies (arrows) in the lungs. 800x magnification. (B) Gram-negative bacterial colonies (arrows) in the crypts of the intestines. 1,500x magnification. (C) Gram-negative bacterial colonies (arrows) in the fibrinosuppurative arthritis observed in the atlantooccipital joint. 1,500x magnification.
case_images: fvets-10-1242599-g003.jpg
case_images: PMC10562539_01_fvets-10-1242599-g003.jpg
case_images: fig3
case_images: Rod-shaped Gram-negative bacteria were present in the lungs, especially in the nodules, Gram-negative bacterial colonies were found inside the blood vessels, alveolar spaces, and interalveolar septum (Figure 3A). Bacterial colonies were observed in the crypt and the lumen of the intestines (Figure 3B). Aggregates of rod-shaped Gram-negative bacterial colonies, which had a morphology identical to that in other organs, were also observed in the fibrinosuppurative arthritis lesion in the atlantooccipital joint and the fibrin extended into the spinal canal (Figure 3C), suggesting bacteremia.