Table 1.
Species studied and pathologic categories in stranded cetaceans from the Canary Islands (2006–2012).
Table 2.
Pathologic categories and etiologic diagnoses for cetaceans studied that stranded in the Canary Islands (2006–2012).
Fig 1.
Panel of ‘natural pathologies associated with good nutritional status’ in cetaceans stranded in the Canary Islands (2006–2012).
A) Cetacean morbillivirus infection (animal no. 202; Stenella coeruleoalba). There is severe mononuclear inflammation at the cerebellar foliar grey and white matter interface with rarefaction at the Purkinje cell layer (asterisks). Hematoxylin and eosin (H&E). Right upper inset: focal neuronal degeneration and neuronophagia. H&E. Right middle inset: Swollen and chromatolytic cortical neuron with intranuclear eosinophilic inclusion body (arrowhead). Right lower inset: Degenerating neuron shows strong intranuclear and intracytoplasmic granular morbilliviral immunolabeling. Immunohistochemistry (IHC) for CDV. B) Aspergillus fumigatus encephalitis (animal no. 63; S. coeruleoalba). Multifocal to coalescing necrohemorrhagic encephalitis in the left cerebral hemisphere (asterisk). C) Aspergillus fumigatus encephalitis (animal no. 63; S. coeruleoalba). Severe pleocellular and necrohemorrhagic cerebral inflammation. H&E. Right upper inset: focal necrotizing vasculitis with hemorrhage and perivascular cuffing. H&E. Right lower inset: Necrotizing vasculitis with intralesional hyphae. Gomori Methenamine-Silver nitrate (GMS). D) Systemic toxoplasmosis (animal no. 46; S. frontalis). Severe lymphohistiocytic to granulomatous white matter inflammation with neuroparenchyma necrosis and rarefaction and rare T. gondii protozoal cysts (asterisk). H&E. Right upper inset: some protozoal cysts had no evident inflammation (asterisks). Right middle inset: T. gondii cysts within sarcoplasm of cardiomyocytes (asterisk). H&E. Right lower inset: cerebral protozoal cyst is strongly positive for anti-T. gondii antibody. IHC for T. gondii. E) Middle and inner ear nasitremiasis (animal no. 220; Tursiops truncatus). Lateral window (removed) of tympanic bulla (middle ear) after fixation and decalcification. There is marked proliferative otitis media with numerous intralesional adult Nasitrema sp. (asterisks). Inset: longitudinal section through the cochlea (inner ear). The cochlear nerve is swollen, dark and fragmented (arrowhead). F) Rhombencephalic nasitremiasis (animal no. 220; T. truncatus). Ventral surface of brainstem shows locally extensive necrotizing and hemorrhagic meningoencephalitis with intralesional adult Nasitrema sp. (arrowhead). Inset: detail of adult Nasitrema sp. G) Cerebellar nasitremiasis (animal no. 157; T. truncatus). Pyogranulomatous and necrotizing encephalitis with intralesional Nasitrema sp. eggs. H&E. Inset: Detail of pleocellular pyogranulomatous inflammation and Nasitrema sp. eggs. Periodic acid–Schiff (PAS). H) Inner ear nasitremiasis (animal no. 220; T. truncatus). Pyogranulomatous and necrotizing cochlear neuritis with intralesional Nasitrema sp. eggs (asterisks). H&E. Inset: endoneural lymphoplasmacytic inflammatory infiltrate in proximal cochlear nerve. H&E. I) Gastrohepatic abscess (animal no. 208; S. coeruleoalba). Severe transmural pyogranulomatous gastritis and hepatitis leading to large right hepatic lobe abscess.
Fig 2.
Panel of natural pathologies associated with loss of nutritional status in cetaceans stranded in the Canary Islands (2006–2012).
A) Cerebral herpesvirus infection (animal no. 165; S. coeruleoalba). Lymphocytic encephalitis with perivascular cuffing and gliosis. H&E. Inset: Focal eosinophilic intranuclear inclusion body (arrowhead). H&E. B) Atlanto-occipital osteoarthritis (animal no. 165; S. coeruleoalba). Marked, chronic osteoarthritis and synovitis with cartilage loss at the cranial articular facets of atlas vertebra. C) Nephrolithiasis (animal no. 127; Delphinus delphis). Severe nephrolithiasis with hydronephrosis, proximal hydroureter and chronic renicular disease with atrophy and hypertrophy. D) Ciliate protozoal lymphadenitis (animal no. 94; S. bredanensis). Pyogranulomatous and necrotizing prescapular lymphadenitis with numerous intralesional ciliate protozoan. H&E. Inset: Detail of ciliate protozoon surrounded by neutrophils and necrotic cell debris, and lymphocytes. H&E.
Fig 3.
Panel of neonatal/perinatal pathologies in cetaceans stranded in the Canary Islands (2006–2012).
A) Pulmonary edema (animal no. 132; Balaenoptera acutorostrata). The trachea, mainstem bronchi and primary bronchi are filled with abundant frothy fluid. B) Pulmonary edema (animal no. 21; Stenella frontalis). The bronchioles and alveoli are diffusely filled by abundant proteinaceous fluid. Inset: numerous keratin squames (arrows) fill in the alveoli. H&E. C) Omphaloarteritis (animal no. 213; Kogia breviceps). The umbilical margin is infiltrated by abundant pleocellular suppurative inflammatory cells and fibrin. H&E. Inset: Numerous viable and degenerate neutrophils with macrophages, edema, fibrin and necrotic cell debris. H&E.
Fig 4.
Panel of pathologies associated with fatal intra- and interspecific interactions in cetaceans stranded in the Canary Islands (2006–2012).
A) Subcutaneous hemorrhage (animal no. 221; Mesoplodon mirus). The subcutis and suprascapular musculature is focally expanded by hemorrhage. B) Traumatic glossitis (animal no. 64; Pseudorca crassidens). Full-thickness perforating traumatic glossitis with intralesional stingray spine (asterisks).
Fig 5.
Panel of pathologies associated with fatal interaction with fishing activities in cetaceans stranded in the Canary Islands (2006–2012).
A) Fishing net markings (animal no. 57; Globicephala macrorhynchus). The left mouth commissure and adjacent mandibular skin has multiple, linear, parallel erosions and lacerations due to net entanglement (asterisks). B) Anthropogenic fishing-related incisive wounds (animal no. 199; S. frontalis). There are two deep incised skin cuts on the right suprascapular region. C) Thoracic wall perforation (animal no. 66; S. frontalis). There is a focal mid-diaphyseal rib fracture with muscle tearing and hemorrhage (arrowhead) on the left thoracic wall. D) Lung perforation (animal no. 66; S. frontalis). The left lung is focally perforated and lacerated and there is abundant hemothorax (asterisks) (there is some freezing artifact).
Fig 6.
Panel of foreign body-associated pathologies in cetaceans stranded in the Canary Islands (2006–2012).
A) Gastric impaction (animal no. 27; Stenella frontalis). The keratinized stomach is filled with abundant plastics. Inset: detail of plastic mass mixed melena. B) Chronic entanglement (animal no. 42; Balaenoptera acutorostrata). The fishing net had lodged deeply around the maxilla leading to soft tissue constrictive necrosis, periostitis and osteomyelitis (not visible in the image) and exuberant granulation tissue.
Fig 7.
Panel of vessel collision-associated pathologic findings in cetaceans stranded in the Canary Islands (2006–2012).
A) Cervico-occipital fracture (animal no. 142; Physeter macrocephalus). There is a single, well-demarcated, deep incisive cut through the dorsal occipital region and the atlas vertebra. B) Cervico-occipital fracture (animal no. 142; P. macrocephalus). Multiple bone fracture surfaces are stained with blue antifouling paint from the vessel cutting edges (presumably the keel). C) Fat embolism (animal no. 86; Kogia breviceps). The microvasculature of the lung parenchyma, mainly alveolar capillaries, contains multiple osmium-tetroxyde-positive (black) fat emboli. OsO₄ (postfixation technique) and H&E. Inset (animal no. 86; K. breviceps): fat embolus obliterates and expands the vascular lumen. OsO₄ (postfixation technique) and H&E. D) Pulmonary bone emboli (animal no. 60; K. breviceps). There are multiple osseous emboli in the pulmonary microvasculature. H&E. Inset: Embolic osseous fragments consists of lamellar (mature) bone with multiple presumably viable osteocytes in lacunae. H&E.
Fig 8.
Panel of pathologic findings associated with active stranding in cetaceans stranded in the Canary Islands (2006–2012).
A) Cutaneous erosions, lacerations and abrasions (animal no. 56; Kogia breviceps). There are multiple, longitudinal and somewhat parallel skin erosions, lacerations and abrasions with hemorrhage linked to live-stranding in a mildly abrupt substrate. B) Myodegeneration (animal no. 9; Mesoplodon europaeus). There are multifocal acutely degenerating myofibers showing variable patterns of segmental sarcoplasmic loss and edema. H&E. C) Cardiomyocyte degeneration (animal no. 56; K. breviceps). Multifocally, cardiomyocytes are swollen, hypercontracted and hypereosinophilic or pale and vacuolated. Inset: cardiomyocyte contraction band necrosis. H&E. D) Hepatocytic globules (animal no. 24; Globicephala macrorhynchus). Hepatocytes are multifocally expanded by intracytoplasmic, lightly eosinophilic single vacuoles with occasional pink points or strands. H&E. E) Tubulonephrosis (animal no. 138; Grampus griseus). Multifocally, the renal cortex has foci of pallor and tubular disruption. H&E. Inset: Multiple proximal convoluted tubules have degenerating, necrotic and sloughed epithelial cells and there is marked congestion. H&E.