Severe bronchiectasis resulting from chronic bacterial bronchitis and bronchopneumonia in a jungle cat.

Bronchiectasis is irreversible bronchial dilation that can be congenital or acquired secondary to chronic airway obstruction. Feline bronchiectasis is rare and, to our knowledge, has not been reported previously in a non-domestic felid. An ~10-y-old female jungle cat (Felis chaus) was presented for evaluation of an abdominal mass and suspected pulmonary metastasis. The animal died during exploratory laparotomy and was submitted for postmortem examination. Gross examination revealed consolidation of the left caudal lung lobe and hila of the cranial lung lobes. Elsewhere in the lungs were several pale-yellow pleural foci of endogenous lipid pneumonia. On cut section, there was severe distension of bronchi with abundant white mucoid fluid. The remaining lung lobes were multifocally expanded by marginal emphysema. Histologically, ectatic bronchi, bronchioles, and fewer alveoli contained degenerate neutrophils, fibrin, and mucin (suppurative bronchopneumonia) with rare gram-negative bacteria. Aerobic culture yielded low growth of Proteus mirabilis and Escherichia coli. There was chronic bronchitis, marked by moderate bronchial gland hyperplasia, lymphoplasmacytic inflammation, and lymphoid hyperplasia. The palpated abdominal mass was a uterine endometrial polyp, which was considered an incidental, but novel, finding. Chronic bronchitis and bronchopneumonia should be considered as a cause of bronchiectasis and a differential diagnosis for respiratory disease in non-domestic felids.

Pancreatic Torsion Resulting in Acute Pancreatic Necrosis in a Young Dog.

We report a case of 7 mo old French bulldog who was referred to North Carolina State University Small Animal Emergency and Triage Services because of acute abdomen, regurgitation, lethargy, and fever. The patient had a history of pulmonic stenosis, which was corrected by balloon valvuloplasty 3 wk before presenting for the current complaint. The patient had nonspecific changes noted on blood work at his referring veterinarian. An abdominal ultrasound examination showed pathological changes that were supportive of a left-limb pancreatic torsion that was confirmed postmortem.

Bilateral patellar aplasia in a foal.

A 2-day-old Cleveland Bay colt was referred to the Equine Emergency Service of the Farm Animal and Equine Veterinary Medical Center at North Carolina State University's College of Veterinary Medicine for evaluation of decreased nursing behaviour and right hindlimb lameness of 2 days' duration. When assisted to stand, the foal was unable to extend either hindlimb or bear weight on the hindlimbs, the right patella was luxated laterally and unable to be reduced, and the foal assumed a crouched position. Stifle radiographs revealed minimal, heterogeneous, ill-defined ossification of both patellae. Due to the severity of the musculoskeletal defects, humane euthanasia was elected. Post-mortem examination identified a congenital malformation of both patella bones with failure of ossification and cardiac changes suggestive of right atrioventricular valve dysplasia. Histology of the patellae showed no evidence of osteoid deposition or ossification. To our knowledge, bilateral congenital patellar aplasia has not been previously described in foals.

YERSINIA PSEUDOTUBERCULOSIS INFECTION IN LIONS (PANTHERA LEO) AT A ZOOLOGICAL PARK.

Two co-housed 17-yr-old male lions (Panthera leo) and one 15-yr-old female lion in an adjacent enclosure developed acute lethargy, depression, anorexia, and ataxia at a zoological park in central North Carolina, United States. One of the male lions and the female lion were found dead 5 and 4 d after the onset of clinical signs, respectively. The other male lion recovered without any clinical treatment. A third male lion housed with the female lion never developed clinical signs. Postmortem examination, microscopic evaluation, and bacterial culture of the liver from both deceased lions confirmed systemic Yersinia pseudotuberculosis infection. Susceptibility testing revealed resistance to amoxicillin-clavulanic acid and cefazolin. To investigate the extent of the outbreak, qualitative real-time polymerase chain reaction (PCR) for Y. pseudotuberculosis was performed on feces and substrate from 15 enclosures housing nondomestic felids and canids, resulting in a positive sample from one enclosure housing four asymptomatic lions. This enclosure was adjacent to housing of the deceased female lion. Enrofloxacin was administered to all animals in the vicinity at doses of 5 mg/kg in nondomestic felids and 10 mg/kg in nondomestic canids, orally q24h for 14 d. Repeated fecal PCR performed 1 wk after completing the antibiotic treatment protocol found no positive samples. The source of the infection was not identified despite PCR testing of environmental samples from all enclosures in the vicinity, the remains of a prey item fed out prior to the outbreak, and a single dead rodent found on grounds. No further clinical cases have occurred within the following year.

Case Report: Novel Disseminated Paecilomyces formosus Infection in a Dog.

A 2.5-year-old, 25.5 kg, spayed female Australian Shepherd dog had a 2-month history of shifting leg lameness in all limbs, tetraparesis, progressive lethargy, and severe pain. On the physical examination, fever (40.61°C), tachycardia, tachypnea, mild diffuse pelvic limb muscular atrophy, left prescapular and right popliteal lymphadenomegaly were observed. Due to the poor prognosis and difficult pain management, humane euthanasia was elected. Macroscopic and histological findings revealed multifocal to coalescing granulomas with central areas of lytic necrosis within the right femur, left humerus, left scapula, left biceps brachii, right semimembranosus muscle, liver, spleen, and lymph nodes. The necrotic areas contained myriad intralesional, intracellular, and extracellular negatively stained, non-pigmented, septate acute angle branching hyphae with parallel walls measuring 3-6 µm in width with polar bulbous projections measuring 7-13 µm in width. Fresh samples of the liver were submitted for fungal culture. Panfungal PCR targeting the major conserved genes-ITS, TUB, CAL-confirmed Paecilomyces formosus. Paecilomyces spp. are members of anamorphic fungi classified under the phylum Ascomycota. Paecilomycosis is an uncommon fungal infection caused by Paecilomyces spp with a disease reported in humans and animals ranging from superficial to systemic clinical forms affecting both immunocompromised and immunocompetent individuals. In dogs, disseminated paecilomycosis has been reported, but the species of fungi are not always determined. To our knowledge, this is the first case of disseminated paecilomycosis caused by P. formosus infection in a dog.

Outbreak in African lions of Yersinia pseudotuberculosis infection, with aberrant bacterial morphology.

A concurrent outbreak of infection with Yersinia pseudotuberculosis occurred in adult captive African lions (Panthera leo). Two 17-y-old male lions and one 14-y-old female lion developed respiratory distress, lethargy, ataxia, and hyporexia. Within 3-5 d of the onset of clinical signs, one male and the female lion died and were submitted for postmortem examination. Macroscopically, the liver and spleen had multifocal-to-coalescing, semi-firm, pale-tan nodules throughout the parenchyma. The lungs were non-collapsed and marked by petechiae. Histologic examination identified lytic, necrosuppurative foci in the liver, spleen, lungs, and kidney, with abundant intralesional gram-negative coccobacilli in the male lion. Similar findings were seen in the female lion in the liver, spleen, kidney, and mesenteric lymph node; however, the intralesional bacterial colonies were more pleomorphic, comprising rod and filamentous morphologies. Aerobic bacterial culture of the liver, spleen, and lung revealed Y. pseudotuberculosis growth. The source of infection is unknown, and an epidemiologic study was performed. Sources to be considered are from the predation of rodent and/or bird reservoirs, or contaminated soil or water. Mortality associated with Y. pseudotuberculosis has been described in an African lion cub, however, to our knowledge, Y. pseudotuberculosis has not been reported in adult African lions, and this is only the second report of Y. pseudotuberculosis with aberrant bacterial morphology observed histologically.

Concurrent Clostridial Enteritis and Oviductal Adenocarcinoma with Carcinomatosis in an Adult Alpaca (Vicugna pacos).

An adult alpaca (Vicugna pacos) with a history of colic and anorexia was euthanized because of failure to respond to treatment. Macroscopically, pale-tan, multifocal to coalescing, firm nodules and plaques markedly expanded the omentum, mesentery and the parietal and visceral peritoneum of multiple abdominal organs, especially the right oviduct and associated mesosalpinx. Abundant dark-red watery digesta were present in the duodenum and jejunum. Histological evaluation of the right oviduct, abdominal visceral nodules and plaques and mesenteric lymph nodes revealed transmural expansion and replacement by an epithelial malignant neoplasm, comprised of tubules and acini of ciliated columnar cells supported by abundant fibrous connective tissue. Both ovaries were histologically normal. On the basis of the ciliated morphology of the neoplastic cells, the focus on the proximal reproductive tract and the unremarkable ovaries, a reproductive tubal adenocarcinoma with carcinomatosis was diagnosed, with both the endometrium and oviduct considered as the tissues of origin. The prominent ciliated morphology of the neoplastic cells and the classification of human fallopian tube (oviduct) neoplasia lead us to propose oviductal adenocarcinoma with widespread carcinomatosis as the definitive diagnosis. The lamina propria of the small intestine was infiltrated segmentally by lymphocytes, plasma cells and neutrophils, and Clostridium perfringens with beta2 toxin production was identified by polymerase chain reaction in the small intestinal contents. To our knowledge, this is the first report of these two distinct diseases in an alpaca.

MORTALITY REVIEW FOR THE NORTH AMERICAN SNOW LEOPARD (PANTHERA UNCIA) ZOO POPULATION FROM JANUARY 1999 TO DECEMBER 2019.

The objective of this 20-yr retrospective study was to review and summarize causes of mortality in the North American (NA) snow leopard population to inform and enhance animal health and husbandry practices. Pathology reports were requested from all NA zoological institutions housing snow leopards that died between 01 January 1999 and 31 December 2019. Data were reviewed and cause of death (COD) and concurrent diseases were summarized and compared by age group, organ system, and disease process. The 241 snow leopards in this report include 109 males, 130 females, and two of undetermined sex. Among them were 116 geriatric snow leopards (>15 yr), 72 adults (15-3 yr), 16 juveniles (3 yr to 2 mo), 32 neonates (2 mo to 0 days), and five fetuses (<0 days). Overall, noninfectious diseases were the most common COD across all age groups (73%). In adult and geriatric snow leopards, chronic renal disease (CRD) (38.8%) and malignant neoplasia (19.7%), including oral squamous cell carcinoma (6.4%), were a common COD. In juveniles and neonates, perinatal death and congenital diseases, including ocular coloboma (15.6%), were a common COD. Individuals with CRD were 13.5 and 4.36 times more likely to have veno-occlusive disease and cardiac fibrosis, respectively. Snow leopards with urolithiasis were 5.27 times more likely to have CRD. Infectious (14.1%) and inflammatory diseases (8.7%) for which no specific etiology was identified were less common overall and more common in juveniles and neonates (25% and 21%, respectively). Neoplasms not previously reported in snow leopards or that are generally uncommon in the veterinary literature included transitional cell carcinoma of the urinary bladder (n = 7) and mesothelioma (n = 1).

Pathologic Lesions of the Budgett Frog (Lepidobatrachus laevis), an Emerging Laboratory Animal Model.

Lepidobatrachus laevis, commonly called the Budgett frog, is a member of the horned frog family (Ceratophryidae), which has become increasingly popular among amphibian hobbyists. L. laevis is also used in biologic research on embryonic development, providing a novel model species for the study of organogenesis, regeneration, evolution, and biologic scaling. However, little scientific literature details disease processes or histologic lesions in this species. Our objective was to describe spontaneous pathologic lesions in L. laevis to identify disease phenotypes. We performed a retrospective analysis of 14 captive L. laevis frogs (wild-caught and captive-bred), necropsied at the NC State University College of Veterinary Medicine between 2008 and 2018. The majority of frogs exhibited renal changes, including varying combinations of tubular epithelial binucleation, karyomegaly, and cytoplasmic vacuolation; polycystic kidney disease; and renal carcinoma. Many of the renal changes are reminiscent of a condition described in Japanese (Bufo japonicus) and Chinese (Bufo raddei) toad hybrids that progresses from tubular epithelial atypia and tubular dilation to polycystic kidney disease to renal carcinoma. A second common finding was variably sized, randomly distributed bile duct clusters (biliary proliferation). Other noteworthy findings included regional or generalized edema, intestinal adenocarcinoma, aspiration pneumonia, and parasitism. This retrospective analysis is the first description of histologic lesions identified in captive L. laevis populations, providing new insight into spontaneous disease processes occurring in this species for use in disease diagnosis and clinical management.

Radiographic anatomy and barium sulfate contrast study of the gastrointestinal tract of eastern box turtles (Terrapene carolina carolina).

Gastrointestinal disorders are an important cause of morbidity in box turtles (Terrapene carolina Carolina), however published information is currently lacking on the normal radiographic anatomy, transit, and emptying times of the gastrointestinal tract. A total of 15 healthy box turtles were recruited for this prospective, anatomic, reference interval study. Three-view radiographic series (vertical beam dorsoventral, horizontal beam latero-lateral, and horizontal beam rostrocaudal views) were acquired prior to contrast administration, and following contrast administration at 0, 20, 40, 60, and 90 min, 2, 4, 8, 12, and 24 h post administration, and every 24 h thereafter until all contrast was eliminated (15 mL/kg barium sulfate diluted to 30% weight per volume was administered via orogastric gavage). Vertical beam dorsoventral and horizontal beam latero-lateral views were of excellent quality to identify gastrointestinal structures. The horizontal beam rostrocaudal view immediately postcontrast administration provided gastric and pyloric identification but had lesser diagnostic use at later time points due to anatomical superimposition. The gastrointestinal tract was composed of a tubular stomach, a pyloric sphincter near midline, a duodenum with a cranial flexure in the right cranial coelomic cavity, small intestines within the right coelom, a small cecal bulb, and a transverse and descending colon. Contrast media entered the large intestine by 24 h in all turtles, and a pyloro-colic indentation was noted at the proximal descending colon. The large intestinal emptying was highly variable due to the interindividual variability of contrast sequestration within the cecal bulb. Findings from the current study serve as a reference on the gastrointestinal anatomy, transit, and emptying times in healthy eastern box turtles; and introduce a novel, horizontal beam, rostrocaudal view for gastrointestinal contrast studies in chelonians.

The left-right asymmetry of liver lobation is generated by Pitx2c-mediated asymmetries in the hepatic diverticulum.

Internal organs exhibit left-right asymmetric sizes, shapes and anatomical positions, but how these different lateralities develop is poorly understood. Here we use the experimentally tractable Xenopus model to uncover the morphogenetic events that drive the left-right asymmetrical lobation of the liver. On the right side of the early hepatic diverticulum, endoderm cells become columnar and apically constricted, forming an expanded epithelial surface and, ultimately, an enlarged right liver lobe. In contrast, the cells on the left side become rounder, and rearrange into a compact, stratified architecture that produces a smaller left lobe. Side-specific gain- and loss-of-function studies reveal that asymmetric expression of the left-right determinant Pitx2c elicits distinct epithelial morphogenesis events in the left side of the diverticulum. Surprisingly, the cellular events induced by Pitx2c during liver development are opposite those induced in other digestive organs, suggesting divergent cellular mechanisms underlie the formation of different lateralities.

Frogs as integrative models for understanding digestive organ development and evolution.

The digestive system comprises numerous cells, tissues and organs that are essential for the proper assimilation of nutrients and energy. Many aspects of digestive organ function are highly conserved among vertebrates, yet the final anatomical configuration of the gut varies widely between species, especially those with different diets. Improved understanding of the complex molecular and cellular events that orchestrate digestive organ development is pertinent to many areas of biology and medicine, including the regeneration or replacement of diseased organs, the etiology of digestive organ birth defects, and the evolution of specialized features of digestive anatomy. In this review, we highlight specific examples of how investigations using Xenopus laevis frog embryos have revealed insight into the molecular and cellular dynamics of digestive organ patterning and morphogenesis that would have been difficult to obtain in other animal models. Additionally, we discuss recent studies of gut development in non-model frog species with unique feeding strategies, such as Lepidobatrachus laevis and Eleutherodactylous coqui, which are beginning to provide glimpses of the evolutionary mechanisms that may generate morphological variation in the digestive tract. The unparalleled experimental versatility of frog embryos make them excellent, integrative models for studying digestive organ development across multiple disciplines.

Budgett's frog (Lepidobatrachus laevis): A new amphibian embryo for developmental biology.

The large size and rapid development of amphibian embryos has facilitated ground-breaking discoveries in developmental biology. Here, we describe the embryogenesis of the Budgett's frog (Lepidobatrachus laevis), an unusual species with eggs that are over twice the diameter of laboratory Xenopus, and embryos that can tolerate higher temperatures to develop into a tadpole four times more rapidly. In addition to detailing their early development, we demonstrate that, like Xenopus, these embryos are amenable to explant culture assays and can express exogenous transcripts in a tissue-specific manner. Moreover, the steep developmental trajectory and large scale of Lepidobatrachus make it exceptionally well-suited for morphogenesis research. For example, the developing organs of the Budgett's frog are massive compared to those of most model species, and are composed of larger individual cells, thereby affording increased subcellular resolution of early vertebrate organogenesis. Furthermore, we found that complete limb regeneration, which typically requires months to achieve in most vertebrate models, occurs in a matter of days in the Budgett's tadpole, which substantially accelerates the pace of experimentation. Thus, the unusual combination of the greater size and speed of the Budgett's frog model provides inimitable advantages for developmental studies-and a novel inroad to address the mechanisms of spatiotemporal scaling during evolution.

Identification of a tissue-specific, C/EBPß-dependent pathway of differentiation for murine peritoneal macrophages.

Macrophages and dendritic cells (DC) are distributed throughout the body and play important roles in pathogen detection and tissue homeostasis. In tissues, resident macrophages exhibit distinct phenotypes and activities, yet the transcriptional pathways that specify tissue-specific macrophages are largely unknown. We investigated the functions and origins of two peritoneal macrophage populations in mice: small and large peritoneal macrophages (SPM and LPM, respectively). SPM and LPM differ in their ability to phagocytose apoptotic cells, as well as in the production of cytokines in response to LPS. In steady-state conditions, SPM are sustained by circulating precursors, whereas LPM are maintained independently of hematopoiesis; however, both populations are replenished by bone marrow precursors following radiation injury. Transcription factor analysis revealed that SPM and LPM express abundant CCAAT/enhancer binding protein (C/EBP)-ß. Cebpb(-/-) mice exhibit elevated numbers of SPM-like cells but lack functional LPM. Alveolar macrophages are also missing in Cebpb(-/-) mice, although macrophage populations in the spleen, kidney, skin, mesenteric lymph nodes, and liver are normal. Adoptive transfer of SPM into Cebpb(-/-) mice results in SPM differentiation into LPM, yet donor SPM do not generate LPM after transfer into C/EBPß-sufficient mice, suggesting that endogenous LPM inhibit differentiation by SPM. We conclude that C/EBPß plays an intrinsic, tissue-restricted role in the generation of resident macrophages.

Activation-induced cytidine deaminase mediates central tolerance in B cells.

The Aicda gene product, activation-induced cytidine deaminase (AID), initiates somatic hypermutation, class-switch recombination, and gene conversion of Ig genes by the deamination of deoxycytidine, followed by error-prone mismatch- or base-excision DNA repair. These processes are crucial for the generation of genetically diverse, high affinity antibody and robust humoral immunity, but exact significant genetic damage and promote cell death. In mice, physiologically significant AID expression was thought to be restricted to antigen-activated, mature B cells in germinal centers. We now demonstrate that low levels of AID in bone marrow immature and transitional B cells suppress the development of autoreactivity. Aicda(-/-) mice exhibit significantly increased serum autoantibody and reduced capacity to purge autoreactive immature and transitional B cells. In vitro, AID deficient immature/transitional B cells are significantly more resistant to anti-IgM-induced apoptosis than their normal counterparts. Thus, early AID expression plays a fundamental and unanticipated role in purging self-reactive immature and transitional B cells during their maturation in the bone marrow.

Morphogenesis of the primitive gut tube is generated by Rho/ROCK/myosin II-mediated endoderm rearrangements.

During digestive organogenesis, the primitive gut tube (PGT) undergoes dramatic elongation and forms a lumen lined by a single-layer of epithelium. In Xenopus, endoderm cells in the core of the PGT rearrange during gut elongation, but the morphogenetic mechanisms controlling their reorganization are undetermined. Here, we define the dynamic changes in endoderm cell shape, polarity, and tissue architecture that underlie Xenopus gut morphogenesis. Gut endoderm cells intercalate radially, between their anterior and posterior neighbors, transforming the nearly solid endoderm core into a single layer of epithelium while concomitantly eliciting "radially convergent" extension within the gut walls. Inhibition of Rho/ROCK/Myosin II activity prevents endoderm rearrangements and consequently perturbs both gut elongation and digestive epithelial morphogenesis. Our results suggest that the cellular and molecular events driving tissue elongation in the PGT are mechanistically analogous to those that function during gastrulation, but occur within a novel cylindrical geometry to generate an epithelial-lined tube.