Coinfection by Mycobacterium marinum and Mycolicibacterium fortuitum in a captive adult diamondback water snake causing disseminated mycobacteriosis with acute cutaneous ulceration.

An adult male captive diamondback water snake (Nerodia rhombifer) was found dead after a 1-d history of lethargy and cutaneous ulcers. The snake had eaten 2 sunfish (Mola spp.) 5 d before death. Gross examination revealed white-to-tan nodules in the lung and liver and segmental intestinal impactions with digested fish. Histopathology confirmed disseminated granulomas with numerous intrahistiocytic acid-fast bacteria in the skin, skeletal muscle, lung, liver, and intestines. Mycobacterium marinum and Mycolicibacterium fortuitum were identified by culture of the hepatic granuloma, followed by PCR and rpoB gene sequencing. To our knowledge, this is the first description of M. marinum and M. fortuitum coinfection in this species. Although M. fortuitum has been isolated from reptiles, lesions associated with its presence in tissues have not been described previously. Interestingly, the mineralization within granulomas that we observed in our case is not reported in mycobacterial infection in reptiles, whereas this finding is common in mammals.

Assessment of a vessel and tissue-sealing device for ovariectomy in chickens to evaluate the potential application of the procedure to other avian species.

OBJECTIVE: To assess the feasibility of a novel technique involving a vessel and tissue-sealing device (VTSD) for ovariectomy in chickens to evaluate the potential application of the procedure to other avian species. ANIMALS: 20 domestic laying hens (Gallus domesticus), of which 10 were immature (< 4 months old) and 10 were adults (> 18 months old). PROCEDURES: Ovariectomy was performed with a VTSD through a left lateral celiotomy. Birds were allowed to recover for 14 days after the procedure and then were euthanized for necropsy. A board-certified veterinary pathologist performed complete necropsies, with particular attention to identifying any remaining ovarian tissue. RESULTS: All birds survived the procedure. For the mature and juvenile birds, the mean ± SD durations of anesthesia (interval from intubation to extubation) were 67.2 ± 7.6 minutes and 50.5 ± 5.1 minutes, respectively, and mean durations of surgery were 45.3 ± 8.5 minutes and 31.6 ± 5.1 minutes, respectively. Three birds had severe hemorrhage during ovariectomy. At necropsy, ovarian tissue was present grossly in 2 mature birds and histologically in 6 additional birds (2 mature and 4 juvenile birds), indicating incomplete excision in 8 (40%) birds. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the evaluated VTSD can be used to successfully perform ovariectomies in both juvenile and mature chickens, although the procedure was associated with major hemorrhage and incomplete excision of ovarian tissue in some cases. Use of this VTSD for ovariectomy in birds of other species, particularly birds with reproductive tract disease, should be investigated.

NLRP6 modulates neutrophil homeostasis in bacterial pneumonia-derived sepsis.

Bacterial pneumonia is a significant cause of morbidity, mortality, and health care expenditures. Optimum neutrophil recruitment and their function are critical defense mechanisms against respiratory pathogens. The nucleotide-binding oligomerization domain-like receptor (NLRP) 6 controls gut microbiota and immune response to systemic and enteric infections. However, the importance of NLRP6 in neutrophil homeostasis following lung infection remains elusive. To investigate the role of NLRs in neutrophil homeostasis, we used Nlrp6 gene-deficient (Nlrp6-/-) mice in a model of Klebsiella pneumoniae-induced pneumonia-derived sepsis. We demonstrated that NLRP6 is critical for host survival, bacterial clearance, neutrophil influx, and CXC-chemokine production. Kp-infected Nlrp6-/- mice have reduced numbers of hematopoietic stem cells and granulocyte-monocyte progenitors but increased retention of matured neutrophils in bone marrow. Neutrophil extracellular trap (NET) formation and NET-mediated bacterial killing were also impaired in Nlrp6-/- neutrophils in vitro. Furthermore, recombinant CXCL1 rescued the impaired host defense, granulopoietic response, and NETosis in Kp-infected Nlrp6-/- mice. Using A/J background mice and co-housing experiments, our findings revealed that the susceptible phenotype of Nlrp6-/- mice is not strain-specific and gut microbiota-dependent. Taken together, these data unveil NLRP6 as a central regulator of neutrophil recruitment, generation, and function during bacterial pneumonia followed by sepsis.

Ablation of IL-33 Suppresses Th2 Responses but Is Accompanied by Sustained Mucus Obstruction in the Scnn1b Transgenic Mouse Model.

Cystic fibrosis is characterized by dehydration of the airway surface liquid layer with persistent mucus obstruction. Th2 immune responses are often manifested as increased mucous cell density (mucous cell metaplasia) associated with mucus obstruction. IL-33 is a known inducer of Th2 immune responses, but its roles in mucus obstruction and related phenotypes in a cystic fibrosis-like lung disease model (i.e., Scnn1b-Tg-positive [Tg+]) mouse, remain unclear. Accordingly, IL-33 knockout (IL-33KO) Tg+ mice were examined and compared with IL-33 heterozygous (IL-33HET) Tg+ mice. As compared with IL-33HET/Tg+ mice, IL-33KO/Tg+ mice had complete absence of bronchoalveolar lavage fluid eosinophilia, accompanied with significant reduction in bronchoalveolar lavage fluid concentration of IL-5, a cytokine associated with eosinophil differentiation and recruitment, and IL-4, a major Th2 cytokine. As compared with IL-33HET/Tg+ mice, IL-33KO/Tg+ mice had significantly reduced levels of Th2-associated gene signatures (Slc26a4, Clca1, Retnla, and Chi3l4), along with complete loss of intracellular mucopolysaccharide staining in the airway epithelium. As compared with IL-33HET/Tg+ mice, although the IL-33KO/Tg+ mice had significantly reduced levels of MUC5AC protein expression, they showed no reduction in the degree of mucus obstruction, MUC5B protein expression, bacterial burden, and neonatal mortality. Interestingly, the histological features, including subepithelial airway inflammation and alveolar space enlargement, were somewhat exaggerated in IL-33KO/Tg+ mice compared with IL-33HET/Tg+ mice. Taken together, our data indicate that although IL-33 modulates Th2 inflammatory responses and MUC5AC protein production, mucus obstruction is not dependent on IL-33.

Myxosarcoma Associated with the Kidney in a Cat: Case Report.

A 12 yr old spayed female domestic shorthair with a history of lethargy, anorexia, and a pendulous abdomen was referred after a cranial abdominal mass was palpated on physical examination. Thoracic radiographs and an abdominal ultrasound revealed a mass associated with the kidney and moderate hemoperitoneum. Exploratory laparotomy revealed abdominal hemorrhage originating from a right renal mass that was adhered to the caudal vena cava. Following a right nephrectomy, histopathology diagnosed the mass as a perirenal/renal myxosarcoma. Based upon thoracic radiographs and abdominal ultrasound, the patient remains disease free at 14 mo postoperatively.

Meroterpenoid-Rich Fraction of the Ethanol Extract of Sargassum Serratifolium Suppresses Collagen-Induced Rheumatoid Arthritis in DBA/1J Mice Via Inhibition of Nuclear Factor κB Activation.

SCOPE: Rheumatoid arthritis (RA) is an autoimmune disorder related to the inflammation of cartilage due to the infiltration of inflammatory cells. Sargassum serratifolium, a brown alga, possesses strong anti-inflammatory activities. METHODS AND RESULTS: The effect of meroterpenoid-rich fraction from the ethanol extract of S. serratifolium (MES) on RA and its underlying mechanisms on the inhibition of RA using a collagen-induced arthritis (CIA) mouse model are examined. The results show that MES ameliorates paw swelling and reduces the arthritis score. MES considerably decreases the secretion of pro-inflammatory cytokines in the serum and joint tissue of mice. Histopathological analysis demonstrates that MES strongly inhibited bone damage and inflammatory cell intrusion in the joint tissue. The expression of inflammatory enzymes and adhesion molecules is significantly inhibited in the serum and joint tissue of MES-fed mice. In addition, MES downregulates the nuclear factor κB (NF-κB) signaling pathway by suppressing the phosphorylation of protein kinase B, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinases. CONCLUSIONS: MES supplementation remarkably reduces inflammatory response in CIA mouse model. These results indicate that MES can be used as a pharmaceutical agent against RA.

Factors Affecting Growth Kinetics and Spontaneous Metastasis in the B16F10 Syngeneic Murine Melanoma Model.

Melanoma is an immunogenic tumor that can metastasize quickly to proximal and distal sites, thus complicating the application of therapeutic modalities. Numerous mouse model systems have been used to gain understanding of the immunobiology and metastatic potential of melanoma. Here, we report the optimization of a syngeneic mouse melanoma model protocol using the mouse B16-derived melanoma cell line B16F10 that ensures the production of tumors on mice pinnae that are similar in size between animals and that enlarge in a time-dependent manner. In this model, B16F10 cells are first allowed to develop tumors after injection in the interscapular area or flank of C57BL/6J mice. Subsequently, the tumors are harvested, cells dissociated and injected into mouse pinnae. Dose-dependent studies revealed that injection of 2 × 105 cells allowed for slow tumor enlargement, producing tumors averaging 100 mm³ within 2 to 3 wk with a metastatic frequency of 100%. This experimental protocol will be useful in dissecting the immunobiology of melanoma tumor development and metastasis and the evaluation of immunotherapeutic antimelanoma therapies.

Impact and regulation of lambda interferon response in human metapneumovirus infection.

UNLABELLED: Human metapneumovirus (hMPV) is a respiratory paramyxovirus that is distributed worldwide and induces significant airway morbidity. Despite the relevance of hMPV as a pathogen, many aspects of the immune response to this virus are still largely unknown. In this report, we focus on the antiviral immune response, which is critical for viral clearance and disease resolution. Using in vitro and in vivo systems, we show that hMPV is able to induce expression of lambda interferon 1 (IFN-λ1), IFN-λ2, IFN-λ3, and IFN-λ4. The induction of IFN-λ expression by hMPV was dependent on interferon regulatory factor 7 (IRF-7) expression but not on IRF-3 expression. Treatment of hMPV-infected mice with IFN-λ reduced the disease severity, lung viral titer, and inflammatory response in the lung. Moreover, the IFN-λ response induced by the virus was regulated by the expression of the hMPV G protein. These results show that type III interferons (IFN-λs) play a critical protective role in hMPV infection. IMPORTANCE: Human metapneumovirus (hMPV) is a pathogen of worldwide importance. Despite the relevance of hMPV as a pathogen, critical aspects of the immune response induced by this virus remain unidentified. Interferons (IFNs), including IFN-λ, the newest addition to the interferon family, constitute an indispensable part of the innate immune response. Here, we demonstrated that IFN-λ exhibited a protective role in hMPV infection in vitro and in an experimental mouse model of infection.

Intraocular and periocular lymphoma in dogs and cats: a retrospective review of 21 cases (2001-2012).

OBJECTIVE: To immunologically phenotype and histologically classify canine and feline intraocular and periocular lymphomas. METHODS: The databases of four veterinary medical diagnostic laboratories were searched to identify cases of intraocular or periocular lymphoma in dogs and cats between 2001 and 2012. Hematoxylin and eosin (H&E) stained slides were reviewed for confirmation and classification of lymphoma, and immunohistochemistry for CD3 (T-cell marker) and CD79a and/or CD20 (B-cell markers) was examined to determine the lineage of the neoplastic lymphocytes. RESULTS: Six canine and 15 feline cases of ocular lymphoma were identified. In the canine cases, there were three intraocular and three periocular lymphomas where two intraocular and one periocular lymphomas were B-cell, one of each intraocular and periocular lymphomas were T-cell and one periocular lymphoma was nonreactive with CD3, CD79a or CD20. In the feline cases, there were six intraocular and nine periocular lymphomas where five intraocular and six periocular lymphomas were B-cell, and one intraocular and three periocular lymphomas were T-cell. Only one canine case had concurrent generalized lymphadenopathy, only one canine conjunctival lymphoma had simultaneous cutaneous lymphoma, and only one feline case had bilateral ocular involvement when they were diagnosed. CONCLUSION: Canine and feline intraocular and periocular lymphomas are often of B-cell phenotype. Although in general terms lymphoma is not considered a primary tumor when it occurs in or adjacent to the globe, these tumors frequently first become evident in the globe and/or periocular area. An accurate early diagnostic approach is crucial for the patient's quality of life because B-cell lymphomas are generally more amenable to chemotherapy than T-cell lymphomas.

Pulmonary histiocytic sarcoma in a rabbit.

An approximately 8-year-old male castrated Dutch rabbit was evaluated for a 6-day history of respiratory signs, which began as sneezing and progressed to tachypnea with anorexia. On physical examination, tachypnea and pale mucous membranes were noted. Thoracic radiographs revealed a soft tissue pulmonary mass, fine-needle aspirates of which confirmed a neoplasia with malignant features suspicious for a histiocytic sarcoma. The rabbit was discharged and due to a rapidly deteriorating condition, the owner declined chemotherapy with Lomustine and elected euthanasia of the rabbit. The affected lung was submitted for histopathology. Histologic sections of the lung were characterized by clusters of histiocytic cells and multinucleated giant cells with occasional invasion of blood and lymphatic vessels. The histologic diagnosis was histiocytic sarcoma. To the authors' knowledge, this is the first case report of histiocytic sarcoma in a rabbit. Based on the clinical and radiologic findings in this case, histiocytic sarcoma should be included in the list of differentials for rabbits presenting with respiratory signs and evidence of a pulmonary mass.

NLRC4 inflammasome-mediated production of IL-1ß modulates mucosal immunity in the lung against gram-negative bacterial infection.

Bacterial flagellin is critical to mediate NLRC4 inflammasome-dependent caspase-1 activation. However, Shigella flexneri, a nonflagellated bacterium, and a flagellin (fliC) knockout strain of Pseudomonas aeruginosa are known to activate NLRC4 in bone marrow-derived macrophages. Furthermore, the flagellin-deficient fliC strain of P. aeruginosa was used in a mouse model of peritonitis to show the requirement of NLRC4. In a model of pulmonary P. aeruginosa infection, flagellin was shown to be essential for the induction of NLRC4-dependent caspase-1 activation. Moreover, in all P. aeruginosa studies, IL-1ß production was attenuated in NLRC4(-/-) mice; however, the role of IL-1ß in NLRC4-mediated innate immunity in the lungs against a nonflagellated bacterium was not explored. In this article, we report that NLRC4 is important for host survival and bacterial clearance, as well as neutrophil-mediated inflammation in the lungs following Klebsiella pneumoniae infection. NLRC4 is essential for K. pneumoniae-induced production of IL-1ß, IL-17A, and neutrophil chemoattractants (keratinocyte cell-derived chemokines, MIP-2, and LPS-induced CXC chemokines) in the lungs. NLRC4 signaling in hematopoietic cells contributes to K. pneumoniae-induced lung inflammation. Furthermore, exogenous IL-1ß, but not IL-18 or IL-17A, partially rescued survival, neutrophil accumulation, and cytokine/chemokine expression in the lungs of NLRC4(-/-) mice following infectious challenge. Furthermore, IL-1R1(-/-) mice displayed a decrease in neutrophilic inflammation in the lungs postinfection. Taken together, these findings provide novel insights into the role of NLRC4 in host defense against K. pneumoniae infection.

Discospondylitis caused by Staphylococcus aureus in an African black-footed penguin (Spheniscus demersus).

A 22-year-old female African black-footed penguin (Spheniscus demersus), housed indoors with other African and rockhopper penguins, was presented acutely with lethargy, ataxia, and hind limb weakness after a molt. The penguin would assume a hunched position and, when resting, sat on its hocks or lay on its keel. Physical and neurologic examination revealed hind limb paraparesis, proprioceptive deficits, and tiptoe walking. Results of a complete blood cell count and biochemical analysis revealed mild heterophilic leukocytosis, anemia, mild hypoalbuminemia, hypokalemia, and hyperuricemia. Results of whole-body radiographs and coelioscopy were unremarkable. Two computed tomographies of the spine at a 3-month interval revealed a lesion at the mobile thoracic vertebra proximal to the synsacrum with associated spinal cord compression. The penguin was treated with itraconazole, doxycycline, and meloxicam, and it initially improved with return to near normal gait and behavior. However, 5 months after the onset of clinical signs, the penguin was euthanatized after a relapse with worsening of the neurologic signs. Postmortem and histopathologic examination revealed focal granulomatous discospondylitis at the penultimate mobile thoracic vertebra, with intralesional bacteria from which Staphylococcus aureus was cultured.

Bilateral seminoma with hepatic metastasis in a cockatiel (Nymphicus hollandicus).

Abstract: An 18-year-old, intact male cockatiel (Nymphicus hollandicus) presented with a clinical history of dyspnea, lethargy, and reluctance to perch. Coelomic ultrasonographic examination revealed hypoechoic nodules in the proximity of, and within, the liver. The bird did not respond to supportive care and was euthanatized. At necropsy, the testes were bilaterally enlarged, whitish-tan, firm, and multilobulated. The right hepatic lobe contained a mass that had a similar color and consistency to those in the testes. On histologic and ultrastructural examinations, the diagnosis was bilateral testicular seminoma with hepatic metastasis. To our knowledge, this is the first case of a metastatic bilateral testicular seminoma reported in a cockatiel.

Vulvar epithelioid hemangiosarcoma with solar elastosis in a mare.

A 15-year-old female gray Appaloosa horse was presented with history of a mass over the right dorsal commissure of vulva for the past 7 months. Based on histopathological examination, and positive staining with factor VIII-related antigen, vimentin, and Verhoeff-van Gieson stain, the vulvar mass was diagnosed as hemangiosarcoma with marked solar elastosis.

Vaccine-associated fibrosarcoma with keloidal differentiation in a cat.

A 6-year-old Domestic Shorthair cat was presented with a history of subcutaneous mass of the lateral left hind limb. The subcutaneous mass developed over a period of approximately 16 months subsequent to administration of Feline leukemia virus vaccines. Based on the histopathological and immunohistochemical examination, the subcutaneous mass was diagnosed as vaccine-associated fibrosarcoma with keloidal differentiation.