Disseminated panniculitis in a bottlenose dolphin (Tursiops truncatus) due to Mycobacterium chelonae infection

A 14-year-old female bottlenose dolphin was diagnosed with mycobacterial panniculitis based on punch biopsy specimens. The necropsy revealed numerous pyogranulomas in the blubber, as well as marked acute multifocal necrosuppurative pneumonia and lymphadenitis. In addition, the animal had marked scoliosis, which had first been noted clinically in the dolphin at about 1 mo of age. The animal had been treated with low-dose dexamethasone for approximately the last 19 mo to reduce perceived discomfort from spondyloarthritis and with the progestational agent altrogenest for approximately 8 yr to prevent pregnancy. Acid-fast positive bacilli were detected in the dermis but not in lung or lymph nodes. Mycobacterium chelonae was isolated from pooled skin, lung, and peripheral lymph-node tissue. Mycobacterial infection may be considered as a differential diagnosis in bottlenose dolphins with generalized cutaneous inflammation, particularly if chronic steroid and progesterone treatments were administered, both of which may have an immunomodulatory effect.     

Disseminated histoplasmosis in an Atlantic bottlenose dolphin (Tursiops truncatus).

An approximately 37-yr-old female Atlantic bottlenose dolphin (Tursiops truncatus) died after a 4-mo illness characterized by intermittent anorexia, lethargy, mild neutrophilic leukocytosis, and mild nonregenerative anemia. At necropsy, the lungs were diffusely consolidated, and histopathology of the lungs revealed severe pneumonia with macrophages containing clusters of numerous yeast cells. Inflammatory lesions and yeast also were found in pulmonary, mediastinal, prescapular, and duodenal lymph nodes, spleen, liver, kidneys, urinary bladder, pancreas, right adrenal gland, and the pyloric stomach. Histomorphology, fungal culture, and polymerase chain reaction analysis indicated that the fungus was Histoplasma capsulatum var. capsulatum. This is the first report of histoplasmosis in a cetacean.     

Hepatitis B-like infection in a Pacific white-sided dolphin (Lagenorhynchus obliquidens)

A Pacific white-sided dolphin (Lagenorhynchus obliquidens) developed clinical signs, serum biochemical values, and serologic viral markers consistent with chronic persistent hepatitis caused by a hepatitis B-like virus. The hepatitis had a sporadic cyclical pattern of lethargy, inappetance, and icterus, with leukocytosis and increased serum activities of alanine transaminase, aspartate transaminase, and gamma-glutamyltransferase. The serum from this dolphin contained hepatitis B virus core antibodies, hepatitis B surface antibodies, and hepatitis B viral DNA. Supportive treatment consisted of administration of antibiotics, cimetidine, menadiol sodium diphosphate, and vitamin/dextrose supplementation. A clinically normal killer whale (Orcinus orca) housed in the same pool had serum hepatitis B surface antibodies, suggesting immunologic responsiveness and that this disease was not species-specific.     

Stimulation of lymphocytes from a dolphin (Tursiops truncatus) by phytomitogens

Activation of dolphin peripheral blood lymphocytes by the phytomitogens, concanavalin A, phytohemagglutinin, and pokeweed mitogen, was evaluated. Whole blood culture technique was employed, which eliminated the necessity of lymphocyte isolation or purification procedures. Dolphin lymphocytes responded (by increased [14C]thymidine incorporation) to all 3 mitogens, but concanavalin A consistently produced the highest degree of stimulation.     

Characterization of a parainfluenza virus isolated from a bottlenose dolphin (Tursiops truncatus)

A novel member of the parainfluenza virus family was identified in a bottlenose dolphin with respiratory disease. The case animal was a 19-year old male Atlantic bottlenose dolphin (Tursiops truncatus) that presented with signs of respiratory illness, including raspy, foul-odored breaths and cream-colored exudate from the blowhole. Focally extensive pyogranulomatous bronchointerstitial pneumonia with moderate numbers of intralesional yeast organisms was identified on histopathological examination. Other significant microscopic findings included multifocal erosive and ulcerative tracheitis and laryngitis consisting of active laryngeal lymphatic tissue and dilated glands with eosinophilic fluid. The cause of death was attributed to respiratory disease of unknown etiology. In addition to the postmortem isolation of Candida glabrata and mixed bacteria from lung tissue, a virus was isolated from two antemortem affected lung aspirates collected over a 2-month period and two postmortem samples (mediastinal lymph node and left lung tissue homogenate). The morphology of the virions on negative staining and transmission electron microscopy was consistent with that of paramyxoviruses. Two genomic fragments, comprising 532 and 419 nucleotides from the open reading frames that code for the viral polymerase and fusion protein, respectively, were amplified by polymerase chain reaction using degenerate primers. Phylogenetic analyses of the two viral RNA segments showed that the isolate comprised a novel virus strain, tentatively named T. truncatus parainfluenza virus type 1 (TtPIV-1). The virus is monophyletic with, but genetically distinct from, the various bovine parainfluenza virus type 3 strains.     

Pulmonary vascular proliferation and lungworm (Stenurus ovatus) in a bottlenose dolphin (Tursiops turncatus)

A female adult bottlenose dolphin suddenly died at 17 days after the capture. Macroscopically, severe pulmonary congestive edema was found. Histopathology revealed many lungworms in the bronchioli and the worms were identified as Stenurus ovatus. Variously sized vessels proliferated around the lesioned bronchioli. Based on these findings, chronic bronchopneumonia due to the lungworm was diagnosed and vascular proliferation was similar to angiomatosis recently reported in Atlantic bottlenose dolphin.     

Bronchoscopic and serologic diagnosis of Aspergillus fumigatus pulmonary infection in a bottlenose dolphin (Tursiops truncatus).

A 4-yr-old male bottlenose dolphin (Tursiops truncatus) developed an Aspergillus fumigatus pneumonia. Fungal elements were identified by cytology and microbiology from endoscopic bronchoalveolar lavage and brushings of a raised yellow endobronchial lesion. The results of qualitative immunodiffusion serology, a technique that identifies specific circulating antibodies to Aspergillus fumigatus, were suggestive of an active infection. The dolphin was treated with itraconazole for over 2 yr, which resulted in remission of clinical signs. Pneumonia caused by Aspergillus sp. accounts for the large majority of pulmonary mycoses in marine mammals. Bronchoscopy facilitated an early definitive diagnosis, accurate treatment, and remission.     

Dermal-epidermal relationships in the skin of the bottlenose dolphin (Tursiops truncatus)

Using a variety of methods the outer surface of the dolphin dermis presents as a rather regularly arranged series of mainly longitudinal and approximately parallel ridges which are surmounted by laterally flattened, regularly distributed dermal papillae. At variable intervals groups of dermal ridges are supported by shallow elevations referred to here as basal dermal elevations. These tend to contain vessels and/or nerves for distribution to two or more dermal ridges. The opposing epidermal surface reveals an irregularly edged series of nearly parallel epidermal ridges alternating with the grooves which in the living state contain the dermal ridges. In the depths of these grooves are the crypts which in the intact skin contain the dermal papillae. Nothing is observable which could correspond to the epidermal pegs referred to in the literature. Small irregular epidermal projections (knobs) appear along the free edge of the epidermal ridge. Topographical variations in density and height of dermal ridges, height of basal dermal elevation plus dermal ridge and papillae as well as total epidermal thickness are illustrated by means of skin maps. Inconsistencies in the literature on Cetacean skin are discussed.     

Non-purulent meningoencephalomyelitis of a Pacific striped dolphin (Lagenorhynchus obliquidens). The first evidence of morbillivirus infection in a dolphin at the Pacific Ocean around Japan

On March 22, 1998, a mature, male, hyposthenic Pacific striped dolphin (Lagenorhynchus obliquidens) was stranded at Aoshima Beach in Miyazaki prefecture, Japan. A necropsy performed 14 hr after death revealed mild diffuse congestion and edema of the leptomeninges and mild pulmonary atelectasis. Histopathologically, non-purulent inflammatory were observed throughout the cerebrum, thalamus, midbrain, pons, medulla oblongata, and spinal cord. Hematoxylin and eosin stain revealed no viral inclusion bodies. Immunohistochemistry using a monoclonal antibody against nucleoprotein of canine distemper virus (CDV-NP) revealed a number of CDV-NP-positive granular deposits in the cytoplasm and cell processes of the degenerating or intact neurons. The present paper is a first report of spontaneously occurred morbillivirus infection in a dolphin at the Pacific Ocean around Japan.     

Morphology of the lymph nodes in bottlenose dolphin (Tursiops truncatus) and striped dolphin (Stenella coeruleoalba) from the Adriatic Sea

Morphology of the lymph nodes was examined in six bottlenose dolphins (Tursiops truncatus) and three striped dolphins (Stenella coeruleoalba) from the Adriatic Sea. All animals had been found dead in nature. One group of the nodes was taken from the tracheal branching area and was marked as bifurcational lymph node, and the other group was taken from the mesenteric root and was marked as mesenteric lymph node. Microscopic analysis showed that the lymph nodes in both dolphin species were surrounded by a connective tissue capsule comprising smooth muscle cells. The parenchyma of the mesenteric and bifurcational lymph nodes in bottlenose dolphin was divided into the peripherally situated cortex with the lymphatic nodules and diffuse lymphatic tissue, and the centrally situated medulla structured of the medullary cords separated by the medullary sinuses. These lymph nodes structurally correspond to the lymph nodes in the majority of terrestrial mammals. The mesenteric lymph node of striped dolphin also had a peripherally situated cortex and a centrally positioned medulla as the majority of terrestrial mammals. In the bifurcational lymph nodes of striped dolphin, there was a central dense lymphatic tissue with the lymphatic nodules and a peripheral less dense lymphatic tissue structured of the cell cords and sinuses. The bifurcational lymph node in striped dolphin resembled porcine lymph nodes and belonged to the inverse lymph nodes.     

Feeding and growth in a captive-born bottlenose dolphin Tursiops truncatus

The feeding and growth of a captive-born bottlenose dolphin Tursiops trunÄtus calf were studied for 30 months post partum. Changes in the behaviours associated with suckling were monitored and suggested that the mammary glands need tactile stimulation before the calf can feed. The calf exhibited no teat preference and mean duration of each suckling bout (4 s) remained constant throughout the suckling period. Suckling frequency declined rapidly during the first two months and continued decreasing steadily for the remainder of the study. A reduced growth rate from seven months suggests that nutrition obtained only from milk is insufficient; however, growth rate increased from 11 months, after the calf started feeding on fish. Solid food intake increased rapidly until completion of the study, by which time the calf was eating 16 kg of fish daily. Short-term reductions in food intake after weaning resulted in corresponding reductions in weight, but appeared to have no effect on linear growth.