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.

“Gas and Fat Embolic Syndrome” Involving a Mass Stranding of Beaked Whales (Family Ziphiidae) Exposed to Anthropogenic Sonar Signals

A study of the lesions of beaked whales (BWs) in a recent mass stranding in the Canary Islands following naval exercises provides a possible explanation of the relationship between anthropogenic, acoustic (sonar) activities and the stranding and death of marine mammals. Fourteen BWs were stranded in the Canary Islands close to the site of an international naval exercise (Neo-Tapon 2002) held on 24 September 2002. Strandings began about 4 hours after the onset of midfrequency sonar activity. Eight Cuvier's BWs (Ziphius cavirostris), one Blainville's BW (Mesoplodon densirostris), and one Gervais' BW (Mesoplodon europaeus) were examined postmortem and studied histopathologically. No inflammatory or neoplastic processes were noted, and no pathogens were identified. Macroscopically, whales had severe, diffuse congestion and hemorrhage, especially around the acoustic jaw fat, ears, brain, and kidneys. Gas bubble-associated lesions and fat embolism were observed in the vessels and parenchyma of vital organs. In vivo bubble formation associated with sonar exposure that may have been exacerbated by modified diving behavior caused nitrogen supersaturation above a threshold value normally tolerated by the tissues (as occurs in decompression sickness). Alternatively, the effect that sonar has on tissues that have been supersaturated with nitrogen gas could be such that it lowers the threshold for the expansion of in vivo bubble precursors (gas nuclei). Exclusively or in combination, these mechanisms may enhance and maintain bubble growth or initiate embolism. Severely injured whales died or became stranded and died due to cardiovascular collapse during beaching. The present study demonstrates a new pathologic entity in cetaceans. The syndrome is apparently induced by exposure to mid-frequency sonar signals and particularly affects deep, long-duration, repetitive-diving species like BWs.

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.

Primary central nervous system T-cell lymphoma in a common dolphin (Delphinus delphis)

This report describes the pathological findings in an adult female short-beaked common dolphin (Delphinus delphis) stranded alive in the Canary Islands. Necropsy examination revealed the presence of a nodular neoplastic growth in the central nervous system (CNS) at the level of the thalamus. Microscopical examination revealed the mass to be a lymphoma and immunohistochemical labelling demonstrated a T-cell origin. No significant lesions were observed in other organs, including lymphoid organs. This is the first report of a primary T-cell lymphoma in the CNS in cetaceans.

Biliary cirrhosis caused by Campula spp. in a dolphin and four porpoises

Biliary cirrhosis produced by Campula spp. is described in 1 striped dolphin Stenella coeruleoalba and 4 harbour porpoises Phocoena phocoena. The hepatic lesions consisted of severe proliferation of fibrous connective tissue with loss of the lobular pattern, nodular regeneration of the hepatic tissue, bile duct hyperplasia and severe inflammatory infiltrate composed of eosinophils, macrophages, lymphocytes and plasma cells. These lesions were associated with severe infestation by Campula spp. Although inflammatory and degenerative hepatic lesions are frequently found in stranded dolphins, biliary cirrhosis has not been previously reported in cetaceans. Massive infestation by these parasites should be included as a cause of hepatic failure resulting in stranding of marine mammals.

Use of CD10 as a marker of canine mammary myoepithelial cells

CD10 is an important cell marker in the diagnosis of acute lymphoblastic leukaemia and of breast myoepithelial (ME) cells in humans. The objective of this study was to assess the value of CD10 as a marker of canine ME cells using immunohistochemistry on routinely processed normal, dysplastic and neoplastic mammary tissue. Five different CD10 positive cell types were identified on the basis of cell morphology, pattern of immunoreactivity, and on the co-expression of additional cell lineage-specific markers. Type 1 cells were typical fusiform cells with a ME cell phenotype (calponin- and cytokeratin [CK] 14-positive, CK8/18-negative). Type 2 cells were typical or atypical polyhedral cells with a luminal epithelial (LE) cell phenotype (calponin- and CK14-negative, CK8/18-positive). Type 3 cells had a type 1 phenotype with variable morphology, and type 4 were atypical neoplastic cells with a mixed ME/LE phenotype. Type 5 cells were typical fusiform cells with a stromal phenotype. Type 1 cells were considered normal ME cells and were found in all sample types; type 2 cells were considered normal or neoplastic LE cells and were also found in all sample types; types 3 and 4 cells were restricted to tumour samples and to malignant tumours, respectively, and type 5 cells were found in all sample types, although predominantly in neoplastic tissue. The findings indicate that the CD10 antigen is a sensitive (although not specific) marker of canine ME cells in normal, dysplastic and neoplastic mammary tissue. Differences in the distribution and staining intensity of CD10-positive cells suggest a number of potential roles for this protein in the pathogenesis of canine mammary neoplasia.

Capture myopathy in live-stranded cetaceans

A group of 51 cetaceans that had been stranded alive on the coasts of the Canary Islands, experienced human capture/rescue interactions and then died, were necropsied over a 12-year period. Of these cetaceans, 25 had haemodynamic lesions indicative of multiorganic vascular shock, degenerative muscle lesions affecting both skeletal and cardiac muscles and myoglobinuric nephrosis typical of capture myopathy (CM). Because macroscopic lesions in muscles and kidneys were not always obvious, a standard protocol was developed where the longissimus dorsi muscle was examined histologically for segmental hypercontraction, contraction band necrosis and segmental muscular degeneration and cardiomyocytes studied for hypereosinophilic wavy fibres, sarcolemmal and perinuclear vacuolation and contraction band necrosis. Light microscopic skeletal and cardiac muscle lesions in all CM animals were confirmed as ante mortem by immunohistochemical assay for myoglobin loss from and fibrinogen entry into affected myofibres. All animals had tubular nephrosis with casts and tubular myoglobin. The oxidative stress-related marker HSP70 was demonstrated immunohistochemically in tubular epithelium. Although the syndrome related to death of live-stranded cetaceans is multifactorial, this study documents that a clinicopathological syndrome comparable to CM of terrestrial wildlife has a role in stranding outcomes.

Exuberant mucometra associated with atresia of the cervix in a queen

This short communication reports the clinical, ultrasonographic and histopathological findings in a cat with atresia of the uterine cervix and mucometra. After 6 months of continuous oestrous behaviour, a remarkable abdominal enlargement was observed in a 14-year-old queen. A presumptive diagnosis of mucometra was concluded after the ultrasound evaluation and based on clinical signs and blood analyses. Ovariohysterectomy revealed a notable symmetrical distension (4-5 cm in diameter) of both uterine horns that were filled with fluid (690 ml); microbiological analyses confirmed the aseptic nature of the uterine fluid. Ovarian follicular cysts and cystic subsurface epithelial structures, >1.5 cm in diameter, were present in both ovaries and no corpora lutea were observed. Gross and microscopic evaluation of the uterus confirmed the development of cystic endometrial hyperplasia and the absence of an internal cervical os. The endometrial hyperplasia and mucometra could have developed as a consequence of repeated oestrogenic stimulation.

Weissella ceti sp. nov., isolated from beaked whales (Mesoplodon bidens)

During an investigation into the microbiota of beaked whales (Mesoplodon bidens), nine isolates were obtained from different organs of four animals. The isolates were Gram-positive-staining, catalase-negative, short rod-shaped or coccoid organisms. A phylogenetic analysis based on 16S rRNA gene sequences of these isolates allocated them to the genus Weissella, showing 96.3 % and 96.0 % 16S rRNA gene sequence similarity with Weissella viridescens NRIC 1536Tand Weissella minor NRIC 1625T, respectively. On the basis of phenotypic, physiological and phylogenetic evidence, it is proposed that the new isolates from whales represent a novel species of the genus Weissella, Weissella ceti sp. nov. The type strain of Weissella ceti is 1119-1A-09T ( = CECT 7719T = CCUG 59653T).

Congenital biventricular cardiac diverticula in a dog

Multiple diverticula of the right and left cardiac ventricular walls were incidental findings at necropsy in a juvenile, male, mixed-breed dog with no clinical history of heart disease. Each saccular diverticulum had a narrow communication into the corresponding ventricular chamber. Histologically, the diverticular walls consisted mainly of collagen without elastin fibers and atrophic cardiomyocytes. No inflammation or other lesions were associated with the diverticula or the rest of the myocardium. Based on the history and pathologic findings, a diagnosis of congenital biventricular fibrous diverticula was made.

Morphological and Immunohistochemical Characterization of Spontaneous Mammary Gland Tumors in the Guinea Pig (Cavia porcellus)

Ten spontaneous mammary gland tumors affecting guinea pigs (GP) were analyzed histologically and immunohistochemically. Histologically, 3 were benign (2 simple adenomas and 1 benign mixed tumor) and 7 were malignant (1 simple solid carcinoma and 6 simple tubulopapillary carcinomas). Immunohistochemical data revealed the glandular immunoprofile of all the tumors and suggested their ductal origin on the basis of cytokeratin 20 expression. Interestingly, cytokeratin 7 was detected in basal/myoepithelial cells. Further, all tumors were positive for type α estrogen and progesterone receptors, suggesting a role for steroid hormones in the development of these neoplasias in GP. This article describes the morphological and immunohistochemical features of the normal mammary gland and spontaneous mammary gland tumors in GP.

Malignant peripheral nerve sheath tumour (malignant schwannoma) in the diaphragm of a goat

This report describes a malignant schwannoma in the diaphragm of a 2-year-old goat. The immunohistochemical and histological features indicated a diagnosis of malignant schwannoma rather than neurofibrosarcoma. The diaphragm represents an unusual location for neoplasia in both domestic animals and human beings. A possible anatomical origin from the phrenic nerve is discussed.

Mucor ramosissimus associated with feather loss in canaries (Serinus canarius)

Three canaries showing feather loss on legs, dorsum, neck, and head, and hyperkeratosis on the feet were sacrificed because of their poor corporal condition and submitted to the Unit of Histology and Anatomic Pathology at the Veterinary School of Las Palmas de Gran Canaria. Histologically, skin revealed pronounced epidermal and follicular infundibular hyperplasia associated with orthokeratotic hyperkeratosis. Numerous fungal spores were observed on the stratum corneum of the epidermis and within feather follicles, associated with destruction of the feathers. This fungus was identified as Mucor ramosissimus. To the best of authors' knowledge, this is the first report of dermatitis and feather loss associated with Mucor ramosissimus, not only in canaries but also in birds.

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.

Fibrino-necrotic typhlitis caused by Escherichia fergusonii in ostriches (Struthio camelus)

Two adult ostriches developed anorexia, prostration, and severe hemorrhagic diarrhea, dying 24 hr after the onset of clinical signs. On postmortem examination, the cecal mucosa showed locally extensive areas of hemorrhages and fibrino-necrotic typhlitis with a white-yellowish material covering the mucosal surface. Multiple serosal petequial hemorrhages and fibrinous peritonitis were present. Histologic examination revealed an intense mononuclear infiltration in the lamina propria and submucosa of the cecum and extensive superficial necrosis associated with fibrin and serocellular deposits. Several gram-negative bacterial colonies were observed within the necrotic areas. Samples from intestinal lesions were collected, and pure growth of Escherichia fergusonii was obtained. Escherichia fergusonii is a member of Enterobacteriaceae, closely related to Escherichia coli and Shigella sp., established as a new species of the genus Escherichia in 1985. In veterinary medicine, E. fergusonii has been reported in calves and sheep from dinical cases suggestive of salmonellosis. To our knowledge, this report represents the first description of E. fergusonii associated with enteritis in ostrich.

Lipid-rich carcinomas of the mammary gland in seven dogs: clinicopathologic and immunohistochemical features

Lipid-rich carcinomas occurred in seven female dogs. Affected dogs were purebred (all but one), intact (all but one), and between 4 and 13 years of age. Five of them had a history of parity, one had pseudopregnancy, and none had received contraceptive steroids. The tumors were single (five cases) or multiple (two cases) well-circumscribed masses of different sizes (varying from 1 to 6 cm in diameter), composed of solid nests and cords of tumor cells separated by a moderate amount of stroma. The tumor cells contained either multiple and small or large and solitary vacuoles that pushed the nucleus to the periphery of the cell (signet-ring cell). A glandular epithelial immunophenotype (cytokeratins 5 and 8 and 8 and 18) was observed in the majority of tumor cells. All tumors lacked both estrogen and progesterone receptors, and five out of seven tumors gave rise to local recurrence and proximal or distant metastases or both.

Cross-reactivity of human and bovine antibodies in striped dolphin paraffin wax-embedded tissues

This study evaluates the cross-reactivity of seven anti-human and one anti-bovine antibodies in formalin-fixed, paraffin-embedded tissue samples of liver and mesenteric lymph nodes of 13 striped dolphins (Stenella coeruleoalba). Four antibodies (CD3, IgG, lysozyme and S100 protein) reacted with striped dolphin lymph nodes in a similar pattern to that observed in the species of origin. The anti-human MHC class II mAb reacted strongly with macrophages and dendritic-like cells of striped dolphins, whereas a small number of lymphocytes were labelled with this antibody. These antibodies were used to study the immunophenotype of the inflammatory infiltrated in non-specific chronic reactive hepatitis (eight cases) and chronic parasite cholangitis (two cases) and normal liver (three cases) of striped dolphins. Non-specific chronic reactive hepatitis was composed of inflammatory infiltration of CD3+ T lymphocytes and IgG+ plasma cells in portal spaces and hepatic sinusoids. Lymphonodular aggregates observed in chronic parasitic cholangitis showed a cellular distribution similar to that found in lymph node cortex, including the presence of S100+ and MHC class II+ dendritic-like cells in lymphoid follicles and interfollicular areas. This result suggests that those inflammatory infiltrates are highly organised to enhance antigen presentation to B and T cells.

Left ventricular outflow tract-right atrial communication (Gerbode type defect) associated with bacterial endocarditis in a dog

Left ventricular (LV) outflow tract-right atrial (RA) communication associated with bacterial endocarditis is described in a 6-year-old intact male Great Pyrenees dog with a 4- to 5-day history of fever, lethargy, weight loss, severe regenerative anemia, and asplenia. Typical vegetative mural endocardial lesions were observed grossly. Histologic evaluation revealed small gram-negative coccobacilli that were consistent with Bordetella avium-like organisms. These bacteria were associated with severe endocardial inflammation characterized by neutrophilic infiltration, extensive necrosis of endocardium, and fibrin deposition. LV-RA shunt (Gerbode defect) is a rare cardiac defect in humans that can be either congenital or, more rarely, secondary to septic endocarditis, valve replacement procedures, or thoracic trauma. B. avium-like organisms causing septicemia and endocarditis in immunocompromised and asplenic human patients have been described. To our knowledge, no previous descriptions of Gerbode defect associated with bacterial endocarditis in domestic animals have been reported in veterinary literature.

Immunophenotypic characterization of hepatic inflammatory cell infiltrates in common dolphins (Delphinus delphis)

Of 14 common dolphins, 12 showed non-specific reactive hepatitis and three chronic parasitic cholangitis with lymphoid proliferation. Non-specific reactive hepatitis was shown immunohistochemically to be associated with small clusters of CD3(+) cells in portal areas and hepatic sinusoids. Polyclonal antibody against S100 protein reacted with a variable number of lymphocytes from portal areas and hepatic sinusoids, as well as with Kupffer cells and epithelial cells of the bile ducts. The majority of plasma cells observed in portal areas and hepatic sinusoids were IgG(+). In lymphonodular lesions of chronic parasitic cholangitis, the distribution of immunoreactive cells was similar to that found in the cortex of lymph nodes. The presence of stellate cells similar to follicular dendritic and interdigitating cells expressing S-100 protein and MHC class II antigen in lymphonodular lesions suggested that these were highly organized structures developed to enhance antigen presentation to B and T cells.

A morphologic and immunohistochemical study of the bronchus-associated lymphoid tissue of pigs naturally infected with Mycoplasma hyopneumoniae

Porcine enzootic pneumonia (PEN), caused by Mycoplasma hyopneumoniae (Mh), has been described in pigs in all geographic areas. The disease is characterized by high morbidity and low mortality rates in intensive swine production systems. A morphologic and immunohistochemical study was done to determine the cellular populations present in lung parenchyma of infected pigs, with special attention to the bronchus-associated lymphoid tissue (BALT). Polyclonal and monoclonal antibodies were used for the detection of antigens of Mh, T lymphocytes (CD3+, CD4+, and CD8+), IgG+ or IgA+ lymphocytes, and cells containing lysozyme, S-100 protein, major histocompatibility complex class II antigen or myeloid-histiocyte antigen. Findings in lung tissues associated with Mh infection were catarrhal bronchointerstitial pneumonia, with infiltration of inflammatory cells in the lamina propria of bronchi and bronchioles and alveolar septa. Hyperplasia of mononuclear cells in the BALT areas was the most significant histologic change. The BALT showed a high morphologic and cellular organization. Macrophages and B lymphocytes were the main cellular components of germinal centers. T lymphocytes were primarily located in perifollicular areas of the BALT, lamina propria and within the airway epithelium, and plasma cells containing IgG or IgA at the periphery of the BALT, in the lamina propria of bronchi and bronchioles, in alveolar septa, and around bronchial submucosal glands. The hyperplastic BALT in PEN cases consisted of macrophages, dendritic cells, T and B lymphocytes, and IgG+ and IgA+ plasma cells. CD4+ cells predominated over CD8+ cells. Local humoral immunity appears to play an important role in the infection.

Cutaneous lesions in experimental acute and subacute African swine fever: an immunohistopathological and ultrastructural study

Histopathological, immunohistochemical and ultrastructural cutaneous changes are described in acute and subacute forms of experimental African Swine Fever (ASF). Fourteen 3-month-old Large White cross pigs were infected intramuscularly with the Dominican Republic 78 (DR78) ASF virus isolate and euthanized in pairs on alternatives days (3 to 17) post-inoculation (dpi). Three pigs were found dead at 8, 10 and 13 dpi, respectively. Antibodies against viral antigen Vp73, human fibrinogen, glycoprotein IIIa and Factor VIII-ra were used to evaluate viral antigen distribution, fibrin microthrombi and platelets in dermal vessels, respectively. Cutaneous lesions were characterised by vascular changes ranging from hyperaemia, mild oedema, scarce fibrin microthrombi and microhaemorrhages in euthanized animals, to generalized fibrin microthrombosis and microhaemorrhages in dead pigs. Secondary pustules and superficial folliculitis were observed in two animals dead at 10 and 13 dpi. Diffuse cytoplasmic Vp73 labelling was found in numerous intravascular monocytes and dermal macrophages. Ultrastructural studies showed mature viral particles in the lumen of dermal vessels but viral replication was not observed; nonetheless, microtubuloreticular structures were observed in the cytoplasm of some endothelial cells and macrophages which showed cytopathic effects, signs of cell activation or degeneration. Morphological and immunohistochemical evidences of platelet activation, degranulation and consumption were observed from 5 dpi onward.

Collateral circulation in experimental coarctation of the aorta in minipigs: a possible association with hypertrophied vasa vasorum

Experimental coarctation of the thoracic aorta was produced in 13 adult Yucatan minipigs by placing a gradually expanding "C-shaped" occluder around the aorta. The aortic constriction was standardized by measuring the blood pressure above the coarctation, with a mean arterial pressure of 165-170mmHg as the target. The pigs were humanely killed after 8 weeks of hypertension. No deaths were associated with constriction of the aorta, and neither rear limb weakness nor neurological dysfunction was noted. The lack of clinical signs in these animals suggested the development of an extensive collateral circulation. Collateral vessels, which were verified angiographically, included intercostal arteries, muscular intercostal arteries, and the internal thoracic artery. In two of the animals in which the thoracic aorta was completely occluded, revascularization also occurred via small arterial channels. Histologically, there was a marked increase in the number of vessels as well as significant hyperplasia and hypertrophy of smooth muscle of adventitial vasa vasorum. These findings support the hypothesis that collateralization of occluded thoracic aortas may be aided by hypertrophy of the vasa vasorum. To our knowledge, these vessels have not previously been shown convincingly by histopathological methods to revascularize occluded large arteries such as the aorta.

Invasive phaeohyphomycosis caused by Curvularia species in a dog

A 2-year-old female Boxer dog was presented with a history of skin lesions that started 1 month after being given oral glucocorticoids for a neurologic problem. Clinically, the animal had focal areas of alopecia with papules and nodules often with ulceration overlain by crusts. Lesions were most common on the dorsum and the lateral aspects of the trunk and extremities. Histologic evaluation revealed pigmented fungal organisms within the lumina of hair follicles and throughout the dermis and subcutis. These organisms were associated with a multinodular, pyogranulomatous luminal folliculitis/furunculosis, dermatitis, and panniculitis. Curvularia sp. was isolated from the cutaneous lesions. The histologic identification of dematiaceous fungal organisms in the hair follicles may explain how phaeohyphomycosis can occur without history of a penetrating injury.

Coordinate expression of cytokeratins 7 and 20 in feline and canine carcinomas

Forty-seven feline and 60 canine epithelial tumors were studied to test the coordinate expression of cytokeratin 7 (CK 7) and cytokeratin 20 (CK 20) using commercially available monoclonal antibodies and an avidin-biotin immunoperoxidase staining technique. Previously, the distribution of both cytokeratins was examined in normal tissues from 4 cats and 4 dogs. The pattern of distribution of CK 7 in normal tissues was similar, with minor differences, to that described in humans, whereas the reactivity pattern of CK 20 in cats and dogs was wider than that in humans. The subset of tumors strongly expressing CK 7 and CK 20 included pancreatic adenocarcinomas (100%), transitional cell carcinomas (75%), and endometrial carcinomas (67%) in the cat. None of the canine tumors had this immunophenotype. Feline (50%) and canine (56%) mammary gland carcinomas and canine cholangiocarcinomas (67%) were the only tumors presenting the CK 7 +/CK 20- immunophenotype, whereas the CK 7-/CK 20+ immunophenotype included thyroid carcinomas (100%), intestinal adenocarcinomas (60%), bronchioloalveolar carcinomas (50%), and renal carcinomas (50%) in the cat and intestinal adenocarcinomas (56%), gastric adenocarcinomas (50%), and ovarian carcinomas (50%) in the dog. The CK 7-/CK 20- immunophenotype included the rest of the analyzed tumors. The immunohistochemical evaluation of coordinate expression of both CK 7 and CK 20 in feline and canine carcinomas using monoclonal antibodies provides important information that can help to discriminate among carcinomas from different primary sites and could be particularly helpful in the determination of the primary site of origin of carcinomas presenting as metastatic disease.

Simultaneous occurrence of Salmonella arizonae in a sulfur crested cockatoo (Cacatua galerita galerita) and iguanas

A case of fatal hepatitis in a captive sulfur crested cockatoo (Cacatua galerita galerita) in which Salmonella arizonae was microbiologically and immunohistochemically detected is described. The death of the cockatoo was closely related to the arrival of a group of 10 green iguanas (Iguana iguana) at a pet shop, and no previous clinical signs were observed in the cockatoo. The most important lesion observed at necropsy of the cockatoo was a multifocal necrotic hepatitis. Salmonella arizonae was isolated from the liver of the cockatoo and was detected immunohistochemically mainly around the edges of necrotic foci. Four iguanas died 3 days later showing a severe enteritis, and Salmonella arizonae was isolated from these lesions. The importance of quarantine and, because of pathogens such as Salmonella, the need to house reptiles at a distance from avian species, mainly psittacids, are reinforced. This is the first report of Salmonella arizonae infection in a cockatoo.

Serological and immunohistochemical study of African swine fever in wild boar in Spain

A serological and immunohistochemical study of African swine fever was carried out in wild boar killed in seven municipalities in the north of the province of Córdoba during two hunting seasons (1991-92 and 1992-93), when the area was affected by the disease. Fourteen of 147 wild boar analysed by ELISA and immunoblotting had antibodies to African swine fever virus. The immunohistochemical study revealed that four cases (two seropositive and two seronegative) showed immunoreactivity to the anti-VP73 monoclonal antibody. Two of the VP73+ wild boar had severe generalised haemorrhages consistent with the acute from of the disease, and another had lesions consistent with subacute African swine fever, but none of the remaining 144 animals had gross or microscopic changes suggestive of the disease. These results indicate that wild boar can suffer from African swine fever without showing clinical signs. The disease in wild boar was associated with the disease in domestic pigs. Thus, no African swine fever-positive boar were found either in one municipality with no out-breaks in domestic pigs or in three municipalities with only one outbreak in pigs during the hunting seasons and during the previous year. These results suggest that European wild boar do not play an important role as carriers of the virus of African swine fever.

Ovine cutaneous squamous cell carcinoma: immunohistochemical expression of CD3, CD4, CD8 and MHC class II antigens in the associated inflammatory infiltrate

The immunohistochemical expression of CD3, CD4, CD8 and MHC class II antigens in the cellular inflammatory infiltrate associated with early and advanced ovine squamous cell carcinomas (OSCC), as well as actinic keratosis was analyzed. The majority of the peritumoral and intratumoral lymphocytes reacted with the anti-human CD3 polyclonal antibody. The number of CD8+ T lymphocytes increased in advanced OSCC compared with that of actinic keratosis and early OSCC, whereas the number of CD4+ lymphocytes was similar in early and advanced OSCC. Tumor cells were unreactive with the anti-MHC class II antibody, but the majority of the mononuclear cellular infiltrate expressed this antigen in early and advanced tumors.

Tracheal malformation in a bicephalic Honduran milk snake (Lampropeltis hondurensis) and subsequent fatal Salmonella arizonae infection

A bicephalic Honduran milk snake (Lampropeltis hondurensis) with tracheal duplication and malformation and Salmonella arizonae infection is described. There were atypically wide collapsed tracheal rings with necrotizing tracheitis and abundant necrotic epithelial debris and inflammatory cells obstructing the lumen in one of the duplicate tracheae. Salmonella arizonae was cultured from the malformed duplicate trachea and was considered to be the etiologic agent causing necrosis.

Collagen dysplasia in a litter of Garafiano shepherd dogs

A connective tissue disease resembling the human Ehlers-Danlos syndrome is reported in three Garafiano shepherd dogs from the same litter. The clinical signs included skin hyperextensibility and fragility, joint laxity, and ocular lesions. Microscopical studies showed abnormalities in the packing of collagen in fibrils and fibres in the skin. Systemic connective tissue defects were demonstrated in one necropsied puppy.

Respiratory and digestive lesions caused by Salmonella arizonae in two snakes

Cases of diphtheritic necrotizing gastritis in a Rosy Boa (Lichanura trivirgata) and of necrotizing tracheitis in a double-headed Kingsnake (Lampropeltis hondurensis), both associated with Salmonella arizonae, are described. An immunoperoxidase technique indicated that S. arizonae played a role in the causation of the lesions. In addition, the study showed the value of the technique for the detection of S. arizonae in the tissues of infected snakes.