Seminoma in an adult striped dolphin Stenella coeruleoalba: tomographic, macroscopical, histological and immunohistochemical study.

Testicular neoplasms have been extensively described and characterized in domestic animals, but reports in wildlife species, including marine mammals, are scarce. This case report describes a testicular seminoma in an adult striped dolphin Stenella coeruleoalba stranded along the coasts of the Canary Islands. Post-mortem computerized tomography (CT) showed a prominent enlargement of the cranial pole of the right testicle, displacing the intestinal loops. Necropsy gross findings confirmed the presence of a testicular mass, bulging at the cut surface, with multiple well-delimitated whitish nodular lesions. Histologically, intratubular and diffuse neoplastic germinative cell proliferation was described. Complementary immunohistochemical assessments for vimentin and CD117 antibodies were negative. To the authors' knowledge, this is the first seminoma described in a S. coeruleoalba. We suggest that post-mortem (PM) pre-necropsy CT in dolphins is a useful tool for anatomic-guided pathology in such cases.

Advances in research on the impacts of anti-submarine sonar on beaked whales.

Mass stranding events (MSEs) of beaked whales (BWs) were extremely rare prior to the 1960s but increased markedly after the development of naval mid-frequency active sonar (MFAS). The temporal and spatial associations between atypical BW MSEs and naval exercises were first observed in the Canary Islands, Spain, in the mid-1980s. Further research on BWs stranded in association with naval exercises demonstrated pathological findings consistent with decompression sickness (DCS). A 2004 ban on MFASs around the Canary Islands successfully prevented additional BW MSEs in the region, but atypical MSEs have continued in other places of the world, especially in the Mediterranean Sea, with examined individuals showing DCS. A workshop held in Fuerteventura, Canary Islands, in September 2017 reviewed current knowledge on BW atypical MSEs associated with MFAS. Our review suggests that the effects of MFAS on BWs vary among individuals or populations, and predisposing factors may contribute to individual outcomes. Spatial management specific to BW habitat, such as the MFAS ban in the Canary Islands, has proven to be an effective mitigation tool and mitigation measures should be established in other areas taking into consideration known population-level information.

Muscle Pathology in Free-Ranging Stranded Cetaceans.

Despite the profound impact that skeletal muscle disorders may pose for the daily activities of wild terrestrial and marine mammals, such conditions have been rarely described in cetaceans. In this study, the authors aimed to determine the nature and prevalence of skeletal muscle lesions in small and large odontocetes and mysticetes ( n = 153) from 19 different species. A macroscopic evaluation of the epaxial muscle mass and a histologic examination of the longissimus dorsi muscle were performed in all cases. The only macroscopically evident change was variable degrees of atrophy of the epaxial muscles ( longissimus dorsi, multifidus, spinalis) in emaciated specimens. The histopathological study revealed single or combined morphological changes in 91.5% of the cases. These changes included the following: degenerative lesions (75.2%), muscle atrophy (37.9%), chronic myopathic changes (25.5%), parasitic infestation (9.2%), and myositis (1.9%). The skeletal muscle is easily sampled during a necropsy and provides essential microscopic information that reflects both local and systemic conditions. Thus, skeletal muscle should be systematically sampled, processed, and examined in all stranded cetaceans.

Coinfection by Streptococcus phocae and cetacean morbillivirus in a short-beaked common dolphin Delphinus delphis.

We describe gross, histopathological, and immunohistochemical features of Streptococcus phocae and cetacean morbillivirus coinfection in a short-beaked common dolphin Delphinus delphis. Major gross findings were cutaneous purulent nodules in the tail fluke, vegetative mitral valve endocarditis, and presumed postpartum pyometra. Histologic examination revealed bacterial septicemia characterized by widespread intravascular coccoid bacterial emboli. These were associated with fibrinonecrotizing to pyogranulomatous dermatitis and panniculitis, embolic pneumonia, neutrophilic and lymphoplasmacytic meningochoroiditis, random neutrophilic hepatitis, lymphoplasmacytic myocarditis and epicarditis, necrotizing adrenalitis, suppurative endometritis, and multicentric reactive lymphadenopathy. Bacteriology and molecular analysis with sequencing of the 16S rRNA gene identified S. phocae from lung, brain, and adrenal gland tissue. Immunohistochemical analysis for morbillivirus detection revealed positive immunolabeling in the epithelium of the choroid plexus of the fourth ventricle. Published reports on S. phocae infection in cetaceans are rare, and pathological details are limited. The present case indicates that S. phocae has potential pathogenic capacity in common dolphins. The pathogenesis is proposed to have involved cutaneous penetration after a skin trauma, leading to initial cutaneous disease and eventual systemic infection.

Verminous Arteritis Due to Crassicauda sp. in Cuvier's Beaked Whales (Ziphius Cavirostris).

The vascular system of Cuvier's beaked whales (CBW) (Ziphius cavirostris; family Ziphiidae), an extremely deep, prolonged-diving cetacean, is increasingly receiving anatomic and physiologic study due to possible anthropogenic interactions; however, vascular pathology rarely has been reported in this species. Thirteen CBW stranded in the Canary Islands from June 2008 to June 2014 were autopsied. A careful dissection of the thoracic and abdominal vasculature was performed on these animals. All had moderate to severe and extensive chronic fibrosing arteritis with aneurysms, hemorrhages, and thrombosis primarily involving the mesenteric and gastroepiploic arteries and the thoracic and abdominal aorta. Microscopically, the lesions varied from subacute subintimal hemorrhages and severe neutrophilic, eosinophilic, and histiocytic dissecting arteritis with intralesional nematode larvae to marked, chronic, fibrosing arteritis with thickening and distortion of the vascular wall with calcification and occasional cartilage metaplasia. In addition, adult nematodes in renal arteries and veins, renal parenchyma and/or ureter were identified morphologically as Crassicauda sp. Nucleic acid sequenced from renal nematodes from 2 animals yielded closest nucleotide identity to C. magna The pathogenesis is proposed to involve a host response to larval migration from the intestine to the kidney through the mesenteric arteries, abdominal aorta, and renal arteries. Severe consequences for such lesions are possible and could vary from reduced vascular compliance to chronic renal disease and predisposition to the development of disseminated intravascular coagulation and multiorgan failure. Severe chronic arteritis in CBW is associated with renal parasitism by Crassicauda spp.

Fatal Erysipelothrix rhusiopathiae septicemia in two Atlantic dolphins (Stenella frontalis and Tursiops truncatus).

We describe gross, histopathologic, ultrastructural, immunohistochemical, and microbiologic features of acute septicemia by Erysipelothrix rhusiopathiae in an Atlantic spotted dolphin Stenella frontalis and an Atlantic bottlenose dolphin Tursiops truncatus. Generalized lymphadenomegaly and widespread hemorrhages were the most consistent macroscopic findings. Tricavitary effusion and icterus were noted in one individual. Histologically, all organs examined showed numerous variably sized bacillary bacterial emboli (Gram-positive; Ziehl-Neelsen-negative), typically associated with systemic congestion, edema, hemorrhages, and fibrinocellular thrombi. These bacteria were frequently intravascular, either extracellular or intramonocytic/macrophagic, and to a lesser extent, free within the interstitium of parenchymal organs. In both cases, microbiological analysis yielded E. rhusiopathiae. A primary anti-E. rhusiopathiae antibody created in mice from one of the strains isolated allowed positive immunohistochemical detection. Electron microscopy and dual immunohistochemistry with lysozyme and MAC387 antibodies confirmed the intramacrophagic location of the bacilli. E. rhusiopathiae, a known multispecies and zoonotic agent, should be considered as a potential etiologic agent in septicemia cases in free-ranging individuals of these dolphin species.

Decompression sickness ('the bends') in sea turtles.

Decompression sickness (DCS), as clinically diagnosed by reversal of symptoms with recompression, has never been reported in aquatic breath-hold diving vertebrates despite the occurrence of tissue gas tensions sufficient for bubble formation and injury in terrestrial animals. Similarly to diving mammals, sea turtles manage gas exchange and decompression through anatomical, physiological, and behavioral adaptations. In the former group, DCS-like lesions have been observed on necropsies following behavioral disturbance such as high-powered acoustic sources (e.g. active sonar) and in bycaught animals. In sea turtles, in spite of abundant literature on diving physiology and bycatch interference, this is the first report of DCS-like symptoms and lesions. We diagnosed a clinico-pathological condition consistent with DCS in 29 gas-embolized loggerhead sea turtles Caretta caretta from a sample of 67. Fifty-nine were recovered alive and 8 had recently died following bycatch in trawls and gillnets of local fisheries from the east coast of Spain. Gas embolization and distribution in vital organs were evaluated through conventional radiography, computed tomography, and ultrasound. Additionally, positive response following repressurization was clinically observed in 2 live affected turtles. Gas embolism was also observed postmortem in carcasses and tissues as described in cetaceans and human divers. Compositional gas analysis of intravascular bubbles was consistent with DCS. Definitive diagnosis of DCS in sea turtles opens a new era for research in sea turtle diving physiology, conservation, and bycatch impact mitigation, as well as for comparative studies in other air-breathing marine vertebrates and human divers.

Mixed testicular neoplasia in a short beaked common dolphin Delphinus delphis.

A diagnosis of mixed testicular neoplasia in a short beaked common dolphin Delphinus delphis involving a Sertoli cell tumor, an interstitial (Leydig) cell tumor and a seminoma is presented. Lymphatic spread of the Sertoli cell tumor to an adjacent retroperitoneal lymph node was observed. Testicular neoplasms have been infrequently reported in marine mammals. Demonstration of clinical signs and further health implications is extremely challenging when dealing with non accessible wildlife species, such as dolphins. However, metastatic potential for these neoplastic conditions should be considered.

Medical and surgical management of a dystocia because of foetopelvic disproportion in an African lioness (Panthera leo).

Medical and surgical management of a foetopelvic dystocia in an African lioness (Panthera leo) and the post-operative complications are reported. A caesarean section was performed to extract an oversize foetus blocked at the cervical canal; the lioness died 36 h after surgery. At necropsy, an abdominal effusion with sero-haemorrhagic fluid was observed, along with a fibrinopurulent exudate adhered to the serosal surfaces of the pelvic and abdominal cavities. In addition, the pelvic symphysis was not cartilaginous, but formed a firm and rigid joint between the pubis and ischium of each hip. The macroscopic and microscopic findings confirmed the presence of metritis, vaginitis and peritonitis. Dystocia may be caused by the premature ossification of the pelvic symphysis, reducing the dimensions of the pelvic cavity.

Retrospective study of foreign body-associated pathology in stranded cetaceans, Canary Islands (2000-2015).

Marine pollution, overrepresented by plastic, is a growing concern worldwide. However, there is little knowledge on occurrence and detrimental impacts of marine debris in cetaceans. To partially fill in this gap of knowledge, we aimed to investigate the occurrence and pathologies associated with foreign bodies (FBs) in a large cohort of cetaceans (n = 465) stranded in the Canary Islands. The Canary Islands shelter the greatest cetacean biodiversity in Europe, with up to 30 different species, of which nine are regularly present year around. We found at least one ingested FB in 36 out of 465 (7.74%) studied cetaceans, involving 15 different species, including eight out of the nine (80%) cetacean species present year-round in the Canary Islands. Risso's dolphin was the species most affected, followed by sperm whale, beaked whale and mysticetes. Plastic FB were the most common item found (80.56%). FB was directly associated with death in 13/36 (36.11%) animals. Poor body condition and deep diving behavior were found to be risk factors for FB ingestion, whereas the adult age was a protective factor. To the authors knowledge this is the first study that use statistical analysis to investigate risk and protective factors for FB ingestion. This study also provides insights of the potential impact caused by ingested FBs on the animal's health and mortality. This knowledge is critical to better understand and assess the impact of FB in cetaceans setting the scientific basis for prospective impact monitoring and future conservation policies.

Rhabdomyolysis and myoglobinuric nephrosis (capture myopathy) in a striped dolphin.

This report describes delayed myoglobinuric capture myopathy in a striped dolphin (Stenella coeruleoalba) found stranded alive on the coast of Fuerteventura (Canary Islands, Spain). The animal was transported to Gran Canaria where it died 48 hr after stranding. The main lesions consisted of acute rhabdomyolysis affecting both cardiac and skeletal muscles, and myoglobinuric nephrosis. Using immunohistochemistry, degenerate myofibers with depletion of myoglobin, and an intracytoplasmatic immunoreaction for fibrinogen were observed. Orange-red pigmented casts in renal tubular lumens were strongly immunolabeled for myoglobin. To our knowledge, this is the first pathologic description of capture myopathy with myoglobinuric nephrosis in stranded cetaceans. Stress, exertion, trauma, and crush injury caused during the stranding, restraint, and transportation were the main causes of rhabdomyolysis in this case.

Deadly acute Decompression Sickness in Risso's dolphins.

Diving air-breathing vertebrates have long been considered protected against decompression sickness (DCS) through anatomical, physiological, and behavioural adaptations. However, an acute systemic gas and fat embolic syndrome similar to DCS in human divers was described in beaked whales that stranded in temporal and spatial association with military exercises involving high-powered sonar. More recently, DCS has been diagnosed in bycaught sea turtles. Both cases were linked to human activities. Two Risso's dolphin (Grampus griseus) out of 493 necropsied cetaceans stranded in the Canary Islands in a 16-year period (2000-2015), had a severe acute decompression sickness supported by pathological findings and gas analysis. Deadly systemic, inflammatory, infectious, or neoplastic diseases, ship collision, military sonar, fisheries interaction or other type of lethal inducing associated trauma were ruled out. Struggling with a squid during hunting is discussed as the most likely cause of DCS.

Pathological and immunohistochemical study of gastrointestinal lesions in dolphins stranded in the Canary Islands.

This paper describes the gross, histopathological and immunohistochemical characteristics of gastrointestinal lesions and regional lymph nodes of six common dolphins (Delphinus delphis), 11 striped dolphins (Stenella coeruleoalba) and six Atlantic spotted dolphins (Stenella frontalis) found stranded along the coasts of the Canary Islands. The most common lesion was chronic granulomatous gastritis of the glandular stomach, associated with the parasite Pholeter gastrophilus, and characterised by the parasites, their eggs, or parasite debris in the mucosa, submucosa or tunica muscularis, surrounded by numerous lysozyme-positive macrophages and neutrophils, and more peripherally by abundant fibrous tissue containing variable numbers of immunoglobulin (Ig) G+ plasma cells, and small numbers of CD3+ T lymphocytes and IgM+ and IgA+ plasma cells. Anisakis simplex nematodes were found in two dolphins that were also parasitised by P gastrophilus and had parasitic granulomatous gastritis and multiple small chronic gastric ulcers. Lymphoplasmacytic enteritis was found in eight cases, three of them parasitised by Diphyllobothrium species; the lesion was characterised by moderate to severe infiltrations of CD3+ T lymphocytes and IgG+ plasma cells, with small numbers of IgM+ and IgA+ plasma cells in the lamina propria and submucosa, mainly of the small intestine. One dolphin had severe fibrinopurulent peritonitis, which may have been secondary to gastric perforation caused by the large mural granulomatous gastritis associated with P gastrophilus parasitism.

Multicentric Benign Epithelial Inclusions in a Free-ranging Risso's Dolphin (Grampus griseus).

This report describes the histological and immunohistochemical features of multicentric, benign, epithelial inclusions (BEIs) in a free-ranging, adult, female Risso's dolphin (Grampus griseus). The differential diagnoses included ectopic hamartomatous epithelial inclusions, non-Müllerian choristoma, Müllerian choristoma and low-grade metastatic carcinoma/mesothelioma. The most likely diagnosis of such BEIs was multicentric, embolic, reactive mesothelium, as suggested by cytomorphological and immunophenotypical features of the BEIs, the occurrence of focal pleural rupture and the immunophenotype of the pleural mesothelium. The former represents a pathological condition not previously reported in a marine mammal species, rarely described in animals, and relatively infrequently recognized in man.

Hepatosplenic large cell immunoblastic lymphoma in a bottlenose dolphin (Tursiops truncatus) with high levels of polychlorinated biphenyl congeners.

This report describes a large cell immunoblastic lymphoma in a bottlenose dolphin found stranded alive in Gran Canaria, Spain. Diffuse infiltration of round neoplastic cells was observed in the splenic cords and sinuses and in hepatic sinusoids, resulting in moderate organ enlargement. The tumour cells (immunophenotype IgG+ and CD3-) showed scant, lightly eosinophilic or basophilic cytoplasm, distinct cell boundaries and hyperchromatic nuclei, each with one or more nucleoli. Mitoses were common. On the basis of histopathological, immunohistochemical and ultrastructural features, the tumour was classified as an immunoblastic lymphoma. Eleven polychlorinated biphenyl (PCB) congeners, 23 organochlorine pesticides and 16 polycyclic aromatic hydrocarbons (PAHs) were detected in the blubber and liver. High concentrations of PCBs 153, 180, 138 and 187 found in the liver may have been associated with the hepatosplenic lymphoma.

Comparative histology of muscle in free ranging cetaceans: shallow versus deep diving species.

Different marine mammal species exhibit a wide range of diving behaviour based on their breath-hold diving capabilities. They are classically categorized as long duration, deep-diving and short duration, shallow-diving species. These abilities are likely to be related to the muscle characteristics of each species. Despite the increasing number of publications on muscle profile in different cetacean species, very little information is currently available concerning the characteristics of other muscle components in these species. In this study, we examined skeletal muscle fiber type, fiber size (cross sectional area and lesser diameter), intramuscular substrates, and perimysium-related structures, by retrospective study in 146 stranded cetaceans involving 15 different species. Additionally, we investigated diving profile-specific histological features. Our results suggest that deep diving species have higher amount of intramyocyte lipid droplets, and evidence higher percentage of intramuscular adipose tissue, and larger fibre sizes in this group of animals.

Immunohistochemical characterisation of parasitic pneumonias of dolphins stranded in the Canary Islands.

This is the first work that applies immunohistochemistry in the characterisation of the inflammatory infiltrate of verminous bronchopneumonia associated with lungworm parasites in stranded dolphins. Samples from three different species (Stenella coerulealba, Stenella frontalis and Delphinus delphis) stranded in the Canary Islands were used. The most common findings found in these animals varied from bronchitis to verminous bronchopneumonia with different degree of severity. The immunohistochemical study showed variable expressions of Lysozyme, MHC-II, iNOS and IgG. The main population presenting in the inflammatory infiltrates were CD3(+) lymphocytes. However, moderate number of Foxp3(+) lymphocytes was found in lymph nodes even though no Foxp3(+) cells were found in lung lesions in any of the samples analysed. This study revealed that lung lesions showed a chronic inflammatory infiltrate mainly composed by lymphocytes CD3(+). Deeper studies are needed in order to provide a more complete scope about the infiltrates involved in these types of lesions.

Uterine Leiomyoma and Prolapse in a Live-stranded Atlantic Spotted Dolphin (Stenella frontalis).

A uterine prolapse associated with a leiomyoma (fibroid) was observed in a live-stranded Atlantic spotted dolphin (Stenella frontalis). A 7 cm segment of the reproductive tract including the cervix, uterine neck and caudal uterine body had intussuscepted and prolapsed into the cranial vaginal vault. In the leading edge of the intussuscepted/prolapsed uterine wall was a 6 × 3 × 3.5 cm leiomyoma expanding the myometrium. The leiomyoma and prolapse were associated with necrotizing exposure endometritis. This is the first report of a uterine prolapse associated with a leiomyoma in a cetacean. This lesion was believed to be the underlying cause of the live stranding.

High-grade astrocytoma (Glioblastoma Multiforme) in an Atlantic spotted dolphin (Stenella frontalis).

This report describes the gross, microscopical and immunohistochemical features of a high-grade astrocytoma (glioblastoma multiforme) in an adult male Atlantic spotted dolphin (Stenella frontalis). On necropsy examination, a 5 × 2.5 × 2 cm, poorly demarcated, red, friable and locally expansile mass effaced the thalamus and the left periventricular region and extended to the left lateral ventricle of the brain. Microscopically, the mass consisted of haphazardly arranged bundles and rows of interweaving polygonal to spindle-shaped cells. These often palisaded along serpentine foci of necrosis and were surrounded by prominent vessels. Immunohistochemically, the neoplastic cells expressed glial fibrillary acidic protein, but not vimentin, S100 protein, neuron-specific enolase or neurofilament protein. A diagnosis of high-grade astrocytoma was made and this represents the first description of a glioma in a cetacean species.