Spirocerca lupi esophageal granulomas in 7 dogs: resolution after treatment with doramectin

Seven dogs with Spirocerca lupi esophageal granulomas were identified based on the site of involvement (ie, distal esophagus) and characteristic endoscopic appearance. Six dogs presented with signs of esophageal disease and 1 dog was asymptomatic. Ova were only identified in the feces of 2 dogs. On thoracic radiographs, 4 dogs had evidence of a caudodorsal mediastinal mass, and 2 of these dogs had spondylitis of midthoracic vertebrae. On endoscopy, single esophageal nodules were observed in 5 dogs, 1 dog had 3 nodules, and 1 dog had 6 nodules. All 7 dogs were treated with doramectin at a dosage of 200 microg/kg SC at 14-day intervals for 3 treatments. Dogs had physical and endoscopic examinations at 2, 4, and 6 weeks after treatment. By 6 weeks, clinical signs had resolved in 6 dogs (1 dog was asymptomatic), and the esophageal nodules had completely resolved in 4 dogs, and incompletely resolved in 3 dogs. Two dogs with incomplete resolution were treated again with doramectin at 500 microg/kg PO daily for an additional 6 weeks. Complete resolution of the esophageal nodules was confirmed by endoscopy in all dogs. Nodules had resolved in 4 dogs by 6 weeks, in 2 dogs by 12 weeks (after 6 weeks additional daily oral therapy), and in 1 dog 22 months after the initial 200 microg/kg treatment regimen. No dog experienced adverse effects to the drug, and all symptomatic dogs have been free of disease for periods ranging from 3 to 4 years.     

Establishment and characterization of the growth and pulmonary metastasis of a highly lung metastasizing cell line from canine osteosarcoma in nude mice.

Highly lung metastasizing model of canine osteosarcoma in nude mice was established from five subcutaneous implantation cycles of lung tumor deposits. The selection of cells with increased metastatic properties from the parent POS canine osteosarcoma cell line recovered medium sized and polygonal Highly Metastasizing POS cells (HMPOS). The doubling time of HMPOS and POS in culture averaged 30 +/- 1.2 hr and 32 +/- 1.3 hr respectively, and their cell growth patterns in vitro were comparable to their in vivo growth patterns. HMPOS cells produced more tumor deposits (> 20 nodules, > 1 -mm in diameter) of various sizes with replacement of lung tissues at 12 weeks after implantation. POS cells produced fewer and smaller lung deposits (< 10 nodules, 1-mm in diameter). Tumor size and number of metastatic tumor deposits showed a regular association. HMPOS cells developed an osteoblastic type of cellular differentiation subcutaneously and in the lungs. HMPOS micrometastasis along the alveolar walls and blood vessels at 4 weeks averaged 6-7 small tumor locus. Each micrometastatic locus contained an average of 5-7 tumor cells, and developed a pleomorphic osteoblastic type of cellular differentiation. An average of 4 macrometastatic nodules could be seen at 6 weeks, composed of an average of 23 tumor cells, 10 nodules at 8 weeks, 12 nodules at 10 weeks and 20 nodules at 12 weeks. These model provides an opportunity for the evaluation of new treatments against canine lung metastatic osteosarcoma in a nude mice model.     

Histologic evaluation of lung and bronchus-associated lymphoid tissue in young turkeys infected with Bordetella avium

One-day-old turkeys were inoculated intranasally with Bordetella avium. Noninoculated hatchmates were housed separately. At postinoculation weeks 1, 2, 3, 4, and 5, B avium-infected (BA+) and B avium-free (BA-) turkeys were necropsied; specimens of tracheas, intrapulmonary primary bronchi, and lung adjacent to primary bronchi were bacteriologically cultured. Lung tissue was collected for histologic examination. Lungs perfused with acetic acid were collected for evaluation to determine the size, number, and distribution of lymphoid nodules associated with primary bronchi. Bordetella avium was isolated from trachea and primary bronchi of all BA+ turkeys, but was never isolated from lung parenchyma. Acute purulent bronchitis was associated with colonization of the primary bronchi by B avium from postinoculation weeks 1 to 3. Macrophages and lymphocytes persisted in the peribronchial connective tissue for 5 weeks after inoculation. Bronchus-associated lymphoid tissue consisted of discrete lymphoid nodules protruding into the lumens of primary bronchi. Lymphoid nodules, morphologically similar in BA+ and BA- turkeys, were composed of nonciliated, cuboidal epithelium covering a zone of loosely arranged lymphocytes and macrophages and a deeper, sharply demarcated lymphoid follicle. Compared with bronchus-associated lymphoid tissue of BA- turkeys, lymphoid nodules of bronchus-associated lymphoid tissue in BA+ turkeys were more numerous and widely distributed along primary bronchi. In both BA- and BA+ turkeys, the mean diameter of lymphoid nodules doubled between 1 and 5 weeks of age.     

THORACIC COMPUTED TOMOGRAPHY FINDINGS IN DOGS EXPERIMENTALLY INFECTED WITH ANGIOSTRONGYLUS VASORUM

To characterize the computed tomography (CT) features of thoracic lesions caused by infection with Angiostrongylus vasorum, pre‐ and postcontrast CT was performed in six experimentally infected Beagles 13 weeks postinoculation and in four of these 9 weeks postchemotherapy. Findings were compared with survey radiographs and necropsy findings. A multicentric bronchoalveolar pattern more pronounced at the lung periphery was present radiographically. On CT, the predominant abnormality underlying this alveolar pattern was multiple large nodules merging to areas of consolidation, and containing air bronchograms of varying extent. These nodular changes corresponded to histopathologic granulomata, consisting mainly of macrophages, multinucleated giant cells, and lymphocytes that had accumulated around larvae and eggs. Morphologically, no bronchial changes were observed on CT or histologically. Quantitatively, however, on CT there was evidence of bronchial thickening at 13 weeks postinoculation and mild very peripheral bronchiectasia 9 weeks postchemotherapy. Regional lymph nodes were enlarged after infection, and smaller after treatment. On postcontrast CT, several suspicious intraluminal filling defects suggestive of thrombosis were found; however, the tortuosity of some pulmonary arteries seen radiographically was not present in CT images. After treatment, the consolidations and large nodules had almost completely disappeared. A remaining radiographic interstitial pattern was characterized on CT as ground‐glass opacifications, subpleural interstitial thickening, subpleural lines, and interface signs. These interstitial changes reflected fibrosis as documented histopathologically. CT allowed very detailed and accurate characterization of pulmonary parenchymal lesions, bronchi, and lymphnodes and closely reflected histopathological changes.     

Use of percutaneous ethanol injection for treatment of bilateral hyperplastic thyroid nodules in cats

OBJECTIVE: To determine the efficacy and safety of percutaneous ethanol injection (PEI) for the treatment of hyperthyroidism caused by bilateral hyperplastic thyroid nodules in cats. DESIGN; Prospective study. ANIMALS: 7 cats. PROCEDURE: Hyperthyroidism was diagnosed on the basis of clinical signs and increased serum total thyroxine (TT4) concentrations. The presence of 2 cervical thyroid nodules was confirmed by use of ultrasonography and technetium Tc 99m albumin thyroid scans. After the death of 1 cat that received PEI in both thyroid nodules at the same time, the protocol was changed to injecting ethanol into 1 nodule at a time, with at least 1 month between injections. Clinical signs, serum TT4 concentrations, serum ionized calcium concentrations, laryngeal function, findings on ultrasonographic examinations of the ventral cervical region, and results of thyroid scans were monitored. RESULTS: Serum TT4 concentrations transiently decreased in all 6 cats (into the reference range in 5 of 6 cats) within 4 days of the first staged ethanol injection. Each subsequent injection resulted in a transient decrease in serum TT4 concentration. The longest period of euthyroidism was 27 weeks. Adverse effects included Horner's syndrome, dysphonia, and laryngeal paralysis. One cat died of unrelated causes. One cat underwent bilateral thyroidectomy, 2 cats were treated with methimazole, and 2 cats that had increased serum TT4 concentrations were not treated further, because they remained clinically normal. CONCLUSIONS AND CLINICAL RELEVANCE: Percutaneous ethanol ablation of bilateral thyroid nodules as a treatment for cats with hyperthyroidism is not recommended. This treatment is not as efficacious as the medical and surgical treatments presently used.     

Skin pustules and nodules caused by Actinomyces viscosus in a horse

A 12-year-old Arabian stallion was evaluated for a refractory skin problem of 2 years' duration. Skin nodules and pustules, which would rupture, had developed over the right lumbar muscles. Anaerobic culturing from the pustules yielded Actinomyces viscosus, and histologic examination of biopsy specimens revealed globular eosinophilic structures. Concomitant treatment with isoniazid (8 mg/kg of body weight, q 24 h for 8 weeks), trimethoprim-sulfadiazine (30 mg/kg, q 24 h for 8 weeks), and sodium iodide solution (66 mg/kg, every 1, 2, or 4 weeks, for 32 weeks) resolved the condition.     

Cutaneous collagen nodules in a dog

A 16-month-old German short-haired pointer was examined because of the development of multiple nodules (0.5-3 cm diameter) in the skin of the head, back, sternum and limbs. The nodules were first noticed when the dog was 8 weeks of age. At no time did the animal show clinical signs of a systemic disease. Histology and electron microscopy revealed that the nodules were composed of irregular bundles of dense collagen fibres and the constituent fibrils had a distribution of diameters similar to that expected in normal skin. Immunofluorescence tests for immunoglobulin (IgG) and complement (C3) showed no deposits of these in the skin and the serum antinuclear antibody test was negative. It was concluded that the nodules were collagenous naevi.     

Ocular metastasis of a vaccine-associated fibrosarcoma in a cat

A 6‐year‐old, neutered male domestic shorthair cat was evaluated for a recurrent vaccine‐associated fibrosarcoma. The cat had three excisions of the tumour prior to presentation and was referred for radiation therapy. Ten months following treatment with radiation therapy, the cat was presented again for a cloudy appearance to the eye. An exenteration was performed, and biopsy revealed fibrosarcoma. At the same time, two discrete pulmonary nodules were identified on thoracic radiographs. Two doses of doxorubicin (20 mg/m²) and cyclophosphamide (100 mg/m²) were administered intravenously 3 weeks apart. Despite treatment, the pulmonary nodule doubled in size. This case represents the first antemortem report of ocular metastasis of a vaccine‐associated sarcoma and supports the highly aggressive nature of these tumours.     

Demodicosis in a Toggenburg goat

This report describes the findings in a four-year-old Toggenburg goat with demodicosis. The skin had multifocal nodules, which were approximately 5 mm in diameter and contained thick yellow exsudate. Microscopic examination of the exsudate revealed numerous Demodex caprae. The goat was clipped and treated topically every five to seven days for a total of 12 treatments with a 1:100 dilution of amitraz (Ectodex, Hoechst Roussel Vet). The treatment resulted in a marked decrease in the number of skin nodules. However, new nodules appeared after treatment was discontinued and complete clinical cure was not achieved.     

A case of feline gastrointestinal eosinophilic sclerosing fibroplasia limited to the mesentery

An entire, female, mixed-breed cat of unknown age was presented with a 6-week history of lethargy, anorexia and vomiting. There was an increase in the number of white blood cells in the blood, including neutrophils and eosinophils; moderate anaemia; ascites; and possible mesenteric peritonitis. Exploratory laparotomy revealed firm, multifocal small nodules in the mesentery. As the nodules were surgically unresectable, they were biopsied. Histologically, the nodules were composed of thin trabeculae of dense collagen fibres mixed with plump fibroblasts and numerous eosinophils, consistent with feline gastrointestinal eosinophilic sclerosing fibroplasia. Bacteria were not detected on histological examination of the nodules and cytology of the ascites. Remission of disease occurred following treatment with prednisolone and ciclosporin A for 22 days and antibiotics for 40 days. After remission, ciclosporin A was administered for 236 days and then discontinued. Eosinophilia also resolved after treatment with ciclosporin A. The cat is still alive and in good condition on day 689. This report describes what may be an atypical case of feline gastrointestinal eosinophilic sclerosing fibroplasia, lacking involvement of the gastrointestinal tract, and was apparently cured by treatment that involved ciclosporin A.     

Transplantable mononuclear cell leukemia in F344 rat with particular reference to nodular tumor developing at the transplant site.

A transplantable mononuclear cell leukemia (MCL) was established from spontaneous MCL in an F344 rat. In this work, we paid special attention to a nodular tumor, named MCL-YSK, developed at the subcutaneous transplant site. MCL-YSK was serially passaged in subcutaneous tissue of syngeneic rats up to the 19th generation. Transplants from MCL-YSK grew into nodules 3 cm in diameter and 11.3 g in weight 9 weeks after subcutaneous implantation. Neoplastic cells forming the nodules had azurophilic cytoplasmic granules, which ultrastructurally appeared to be lysosomes. The cells reacted positively for acid phosphatase and nonspecific esterase, but not for alkaline phosphatase, alpha-1 antitrypsin and lysozyme, nor reacted with anti-rat monocyte/macrophage monoclonal antibody and anti-rat CD-8 monoclonal antibody. They possessed Fc-receptor. Leukemic cells first appeared in the peripheral blood 6 weeks after transplantation when subcutaneous nodules reached an average diameter of one cm. Subsequently, leukemic changes progressed in recipients as MCL-YSK grew larger. The recipients died during the period from 8 to 12 weeks after transplantation, showing anemia, depression, splenohepatomegaly and lymph node enlargement. Diffuse or focal proliferation of sprinkled tumor cells was present in many organs. Hematologic changes suggestive of hemolytic anemia, elevated plasma enzymes and decreased drug-metabolizing enzymes, indicative of hepatic malfunction, were seen in transplant recipients. MCL-YSK was easily transplanted into athymic nude mice. The transplanted mice showed leukemic changes similar to those observed in rats with transplanted MCL-YSK.     

Chronic malignant catarrhal fever: a case in a sika deer (Cervus nippon)

A condition resembling chronic malignant catarrhal fever was seen in a 9-month-old pet sika hind (Cervus nippon). From an initial acute depression, pyrexia, and anorexia, the condition progressed to include hypopyon, keratitis, lethargy, loss of condition, sloughing of one hoof and eventually death after seven weeks. There were multiple, 5 to 8mm diameter dark-red nodules throughout the mesenteries and mediastinum, along abdominal organ ligaments, and about the uterus and kidneys. Histopathology showed the nodules to be organising vascular thrombi. Concurrent perivascular mononuclear infiltrations and intravascular thrombi in many tissues confirmed that the condition was malignant catarrhal fever.     

Multicentric lymphoblastic lymphoma in a loggerhead sea turtle (Caretta caretta)

A juvenile female loggerhead sea turtle (Caretta caretta) stranded in Gran Canaria was submitted for necropsy. The turtle had exhibited anorexia and lethargy for 2 weeks prior to its death. At necropsy, the thymus was enlarged by two white and firm nodules. White nodules similar to those in thymus were observed in the plastron, thyroid gland, heart, aorta, left lung, spleen, liver, kidneys, stomach, and small intestine. Histopathology revealed a neoplastic proliferation of round cells identified as lymphoid cells. Ultrastructurally, the neoplastic cells were consistent with lymphoblastic cells, and viruses were not detected. The diagnosis was multicentric lymphoblastic lymphoma. This is the first report of a lymphoid neoplasm in a sea turtle.     

Bacterial pseudomycetoma in dwarf hamster, Phodopus sungorus

A case of a dwarf hamster with two progressively growing nodules on the right fore limb is described. These were excised following ineffective medical treatment and were submitted for histopathological examination, which revealed bacterial pseudomycetoma in both nodules. To the authors' knowledge this is the first reported case of bacterial pseudomycetoma in a dwarf hamster.     

Sterile panniculitis in dogs: new diagnostic findings and alternative treatments

The objective of this study was to analyse the underlying diseases, diagnostic findings and treatment outcomes in 10 dogs with sterile panniculitis. There was no significant breed association in this study (P = 0.86).The median age of the dogs was 7.4 years. Concurrent diseases included atopic dermatitis (four dogs), acute pancreatitis (two dogs) and primary hypoadrenocorticism (one dog), with no concurrent conditions detected in three dogs. There was no significant association with the sterile panniculitis (P = 0.57). Well-circumscribed firm nodules were noted in seven dogs, and ill-defined soft nodules were observed in three dogs. Bacterial and fungal cultures of biopsy samples were negative in all cases. Fine-needle aspiration cytology of the nodules revealed pleomorphic mesenchymal cells in all of the well-circumscribed firm nodules, whereas numerous inflammatory cells and adipose cells were evident in soft nodules. These results indicate that firm nodules in panniculitis could be misdiagnosed as tumours. Immunosuppressive therapy was used in eight cases. Topical dexamethasone was used in four dogs, intralesional dexamethasone in one dog, oral prednisolone plus ciclosporin in two dogs and oral prednisolone only in one dog. The remaining treatments were surgical excision and systemic cefalexin in one dog each. The lesions regressed within 1 week in all cases, with more rapid remission following systemic immunosuppressive therapy. This study suggests that cytology may be misinterpreted as neoplastic, especially with firm lesions. In addition, topical glucocorticoid therapy should be further evaluated as a potential treatment for canine sterile panniculitis.     

Efficacy of injectable doramectin in the therapy and control of Dermatobia hominis infestations in Latin America

Three studies were conducted in Latin America, one in Brazil, one in Venezuela and one in Argentina, using a common protocol to investigate the efficacy of a single subcutaneous injection of doramectin at 200 μg kg⁻¹ (1 ml per 50 kg) for the treatment and control of Dermatobia hominis infestations in cattle raised under commercial conditions. In each study, two groups of 20 animals each were allocated on the basis of D. hominis nodules present 24 h before treatment to a treated group (T1), or to a control group (T2) which received saline solution at 1 ml per 50 kg of live weight. All cattle were injected in the mid-dorsal cervical region and examined on treatment day and 2, 7, 15 and 30 days post-treatment (p.t.). At each observation day the number of D. hominis nodules was counted and the viability of the larvae inside them was assessed and recorded. Treatment with doramectin was 100% effective in eliminating D. hominis larvae and in controlling the re-establishment of the parasite under field conditions of continuous reinfestation. During the first 48 h p.t., dead larvae of different ages were found outside or partially outside the nodules in animals of the doramectin groups. After 48 h p.t., no live larvae were found inside existing nodules, nor did new nodules develop in animals of the doramectin groups in any of the three studies. When compared with nodule counts in the control group on the same observation day or with parasite burdens on the same animal before treatment, doramectin-treated animals began to eliminate parasitic nodules at 48 h p.t. Efficacy reached 100% at 7 days p.t. and remained at 100% on subsequent observation days (P<0.05). None of the doramectin-treated animals exhibited any clinical signs of adverse reaction to medication.     

RETROSPECTIVE ASSESSMENT OF THORACIC RADIOGRAPHIC FINDINGS IN METASTATIC CANINE HEMANGIOSARCOMA

Twenty-one dogs with histopathologically confirmed hemangiosarcoma were evaluated by thoracic radiography for metastatic disease. All dogs had histopathologic examinations of the lungs within two weeks of thoracic radiography. Fourteen dogs had histopathologic evidence of pulmonary hemangiosarcoma; metastatic disease was detected radiographically in eleven of these dogs. The most common radiographic pattern was that of poorly defined small coalescing nodules (8 dogs); other radiographic patterns included well-circumscribed nodules (3 dogs) and alveolar infiltrates secondary to hemorrhage (2 dogs). Differential diagnoses for diffuse, poorly defined, coalescing pulmonary opacities should include hemangiosarcoma in addition to edema, lymphoma, systemic mycoses, fibrosis, allergy, toxicosis, and carcinomas.     

Anaerobic bacterial pneumonia with septicemia in two racehorses

Anaerobic bacterial pneumonia with septicemia was diagnosed in 2 Thoroughbred racehorses referred with respiratory tract disease that had failed to respond to initial treatment with various antibiotics including penicillin and trimethoprim-sulfamethoxazole. Multiple anaerobic organisms, including Bacteroides spp and Fusobacterium spp, were isolated from blood and transtracheal aspirates obtained from both horses and from aspirates of cutaneous nodules obtained from 1 horse. The latter horse responded to metronidazole treatment followed by procaine penicillin G administration and regained its health over the following 6 months. The other horse did not respond as favorably to a similar antibiotic regimen and died following an acute episode of pulmonary hemorrhage after remaining intermittently febrile for 7 weeks. Although in vitro antimicrobial susceptibility tests indicated that all anaerobic organisms isolated from both horses were susceptible to penicillin, the infection in these horses responded poorly to initial treatments with this drug. We speculated that adequate penicillin concentration was not attained in the deep foci of infection in the lungs. Animals with anaerobic bacterial infections that fail to respond to penicillin or from which penicillin-resistant anaerobes are isolated may benefit from treatment with metronidazole.     

Pathogenicity of immature Fascioloides magna in white-tailed deer.

The pathogenesis of early prepatent Fascioloides magna infection was investigated in seven fawns (Odocoileus virginianus) given 500 metacercariae and examined at one, two, three, five, eight, 12 and 13 weeks postinoculation. Blood samples were taken from eight inoculated deer every two weeks up to 16 weeks postinoculation. Eosinophilia with a mild transitory anemia were the main clincopathological features. Postmortem examination at two weeks postinoculation revealed extensive migration of immature flukes. Subcapsular tracks in the liver, nodules on the blind sacs of the rumen, as well as retroperitoneal granulomas on flanks and necrotic tracks on the diaphragm were found. Evidence of penetration of flukes into the lung was found at two weeks postinoculation and there was early granuloma formation at three weeks postinoculation. Flukes migrating into tissues other than the liver were destroyed in large granulomas, although remnants of degenerating parasites were not found. At eight weeks postinoculation, widespread granuloma formation characterized the infection with this lesion present in nodes along the gastrointestinal tract, in the mesentery, flanks, psoas muscles, diaphragm, between the ribs and in the lungs. By 12 weeks postinoculation subcapsular tracks were observed in the liver.     

Genital neoplasms treated by en bloc resection and penile retroversion in horses: 10 cases (1977-1986)

The medical records of 10 horses with invasive neoplasms of the penis, prepuce, and/or superficial inguinal lymph nodes in which treatment involved en bloc resection and penile retroversion were reviewed. All were geldings and ranged in age from 12 to 25 years (mean, 19 years). Evaluation of biopsy specimens obtained before surgery confirmed lymphosarcoma in 1 horse and squamous cell carcinoma in 9 horses. Typical history included swelling, ulceration, and abscessation of the penis and prepuce and large superficial inguinal lymph nodes. Complications after surgery included dehiscence of the urethrostomy site (4 horses), dehiscence of the ventral skin incision (1 horse), urine scalding of 1 hind limb (1 horse), cystitis (1 horse), severe hemorrhage (1 horse), and diarrhea (1 horse). One horse was euthanatized during hospitalization, because of severe dehydration secondary to diarrhea. At necropsy, firm nodules were scattered in the pulmonary parenchyma, myocardium, thyroid gland, parathyroid glands, cranial mediastinum, kidneys, and hilar lymph nodes. Microscopic examination of the nodules revealed undifferentiated carcinoma. Nine horses were discharged from the hospital between 1 and 5 weeks after surgery. The mean follow-up interval was 27 months (range, 6 to 96 months). Eight horses had no evidence of recurrence. One horse had recurrence of neoplasm at 6 months and was euthanatized 12 months later.