Pathological findings of mammary gland carcinoma and hemangiosarcoma cases in two African wild dogs (Lycaon pictus).

There are few studies on diseases affecting endangered African wild dogs. We report our findings on malignant tumors in two African wild dogs. Case 1 was a 6-year-old intact female diagnosed with inflammatory mammary carcinoma with pulmonary metastasis. Case 2 was an 11-year-old male diagnosed with primary hemangiosarcoma of the left atrial coronary sulcus with metastasis to multiple organs. Additionally, the tumor had grown through the cardiac wall, causing cardiac tamponade. The identification of disease incidence trends provides important information which will allow for the early detection and treatment of malignant tumors, and aid in the conservation of this species.

Apolipoprotein C-III amyloidosis in white lions (Panthera leo).

Apolipoprotein C-III (ApoC-III) amyloidosis in humans is a hereditary amyloidosis caused by a D25V mutation in the APOC3 gene. This condition has only been reported in a French family and not in animals. We analyzed a 19-year-old white lion (Panthera leo) that died in a Japanese safari park and found renal amyloidosis characterized by severe deposition confined to the renal corticomedullary border zone. Mass spectrometry-based proteomic analysis identified ApoC-III as a major component of renal amyloid deposits. Amyloid deposits were also positive for ApoC-III by immunohistochemistry. Based on these results, this case was diagnosed as ApoC-III amyloidosis for the first time in nonhuman animals. Five additional white lions were also tested for amyloid deposition retrospectively. ApoC-III amyloid deposition was detected in 3 white lions aged 19 to 21 years but not in 2 cases aged 0.5 and 10 years. Genetic analysis of white and regular-colored lions revealed that the APOC3 sequences of the lions were identical, regardless of amyloid deposition. These results suggest that ApoC-III amyloidosis in lions, unlike in humans, may not be a hereditary condition but an age-related condition. Interestingly, lion ApoC-III has a Val30 substitution compared with other species of Panthera that have Met30. Structural predictions suggest that the conformation of ApoC-III with Met30 and ApoC-III with Val30 are almost identical, but this substitution may alter the ability to bind to lipids. As with the D25V mutation in human ApoC-III, the Val30 substitution in lions may increase the proportion of free ApoC-III, leading to amyloid formation.

Postmortem magnetic resonance imaging findings of tricuspid atresia with ventricular and atrial septal defects and subvalvular pulmonic stenosis in a Japanese native Noma horse.

The necropsy of a 2-day-old Noma horse that died of weakness showed an enlarged cardiac base and a narrow cardiac apex, suggesting cardiac malformation. The excised heart underwent imaging to investigate its luminal structure. On three-dimensional magnetic resonance imaging, the right atrium and right ventricle were discontinuous. The right atrium communicated with the left atrium and the left ventricle communicated with the right ventricle. The lumen narrowed near the pulmonary artery valve. Since the same findings were observed on gross examination, the foal was diagnosed with tricuspid atresia with ventricular and atrial septal defects, along with subvalvular pulmonic stenosis.

Effects of Oxygen Gas Injection on the Subsequent Development of Chick Embryos in a Shell-Less Culture System.

The effects of oxygen gas injection starting on day 17 of incubation (D17) in a chick shell-less culture system (cSLC) on the subsequent embryo development were examined on day 19 of incubation (D19). On D19 of cSLC, the plasma phosphorus and total cholesterol concentrations of the embryos were significantly higher (P<0.05), while the plasma calcium concentrations were significantly lower (P<0.05) than those in the intact control (IC) group. However, no significant differences in embryo viability and other major blood component levels were observed among the experimental groups (P>0.05). The percutaneous oxygen saturation was lower in D17-cSLC embryos before oxygen gas supplementation than in the IC (P<0.05) embryos. Severe renal tubular degeneration of the metanephros was observed in D19-cSLC embryos despite oxygen gas injection starting from D17. These results indicate that D19-cSLC embryos are hypoxia even after injecting oxygen gas starting on D17.

REMOVAL OF PSEUDO-ODONTOMAS VIA LATERAL MAXILLOTOMY IN THREE RICHARDSON'S GROUND SQUIRRELS (UROCITELLUS RICHARDSONII).

Pseudo-odontoma can occur in some species with elodont teeth. Pseudo-odontomas affecting maxillary dentition may result in obstruction of the nasal cavities and lead to dyspnea. Effective treatments for the disease in Richardson's ground squirrels (Urocitellus richardsonii) have not yet been established. Three Richardson's ground squirrels exhibiting dyspnea and with maxillary pseudo-odontomas, based on diagnostic imaging, were surgically treated. The animals were placed under general anesthesia, and following excision of skin and subcutaneous tissue at the midpoint of the line connecting the medial canthus and ipsilateral nasal opening, maxillotomy of the incisive bone was performed. The reserve crown of the maxillary incisor tooth was exposed via the maxillotomy site and was sectioned into labial and palatal fragments, and the diseased tooth was completely extracted. In all three cases, dyspnea improved immediately after surgery. In one case, no recurrence was observed 600 d following surgery. These results suggest that the procedure used provides a practical approach for treating maxillary pseudo-odontomas in Richardson's ground squirrels.

DEVELOPMENTAL STAGES OF GRASSENEMA PROCAVIAE PETTER, 1959 (COSMOCERCOIDEA: ATRACTIDAE) FOUND IN THE STOMACH OF CAPE HYRAX (PROCAVIA CAPENSIS).

Morphological examination was made of the larval forms of Grassenema procaviae (Cosmocercoidea: Atractidae), an autoinfective and viviparous nematode parasite in the stomach of Cape hyrax (Procavia capensis). Three different larval stages (second-, third- and fourth-stages), and the adult stage were found among the worms collected at necropsy of 3 hosts, which were reared in a zoo in Japan. Molting phases between the larval stages and the final molt to the adult stage were also observed. It was considered that the gravid female delivers the second-stage larva, which develops to the adult stage through 3 molts. The cephalic structure was identical throughout the second to adult stages; all with transparent filaments extending from the mouth. Because starch grains were frequently found attached to the filaments and the worm intestinal lumen also contained starch grains ingested, the filaments were surmised to act as nutrient catchers.

An anatomical study of the skull, the dorsal and ventral nasal conchal bullae and paranasal sinuses in normal Noma horses: Computed tomographic anatomical and morphometric findings.

Noma horses have the smallest body size among native Japanese horses and are classified as pony breeds by their size. Additionally, the Japanese horse breeds are classified into a single lineage, which includes Mongolian horses. Great intraspecific differences reportedly exist in the head shapes of domesticated horses, which have been investigated in various horse breeds. The present study aimed to evaluate the size of the nasal conchal bullae, and the paranasal sinuses of Noma horses in relation to the skull dimensions using computed tomography. Reconstructed images of the heads of five adult Noma horses were used. Skull and paranasal sinus parameters were measured and analysed in relation to each other and were compared with the data in the literature on the skulls of various horse breeds. In comparison with pony breed, Shetland ponies and donkeys had a shorter nasal length than cranial length, while Noma horses had a longer nasal length than cranial length, similar to the larger breeds. In the nasal conchal bullae, Shetland ponies showed a negative correlation between the head and bullae size, while Noma horses, similar to larger breeds, had a positive correlation. In conclusion, our findings suggest that Noma horses, despite having a body size that belongs to the pony breed, had a distinguishing ratio of the skull and paranasal sinuses similar to that of the larger breeds. Our results provide information on the physiological morphology of the head and comparative anatomy based on genetic diversity in horses.

Effects of Calcium Lactate on the Development of Chicken Embryos in a Shell-less Culture System up to Day Seventeen of Incubation.

This study examined the effects of calcium lactate on the development of chicken embryos in a shell-less culture system (cSLCS) up to the seventeenth day of incubation. In the presence of calcium lactate, a significant reduction in embryo viability was observed during the first week of incubation in cSLCS. On day 17 of embryo development, no significant difference was observed in the blood plasma calcium concentration or tibia bone density between cSLCS and intact control embryos, whereas the tibia length was significantly shorter in cSLCS embryos than in the intact control. These results suggest that calcium lactate supplementation in cSLCS supports bone formation in developing chicken embryos, but has adverse effects on the viability of embryos, particularly during the first week of embryo development.

Isolation and whole-genome sequencing of a novel aviadenovirus from owls in Japan.

Adenoviruses have been reported to infect a variety of birds. Here, we isolated a novel adenovirus from the liver of a dead owl chick (Bengal eagle owl; Bubo bengalensis) at a raptor-breeding facility in Japan and determined the complete genome sequence of the virus. We performed necropsies on the dead owl chicks and found that they had enlarged livers, pericardial edema, and focal necrosis of the liver tissue. Transmission electron microscopy of the liver tissue revealed a virus-like structure, appearing as paracrystalline arrays in the nucleus, and immunohistochemical staining with anti-adenovirus antibodies showed positive reactions in hepatocytes and other cells. Attempts to isolate the virus from homogenized liver tissue of a dead owl chick showed a cytopathic effect on chicken-derived cultured cells after multiple blind passages. Further, we determined the complete genome sequence of this virus and performed phylogenetic analysis, revealing that this adenovirus belongs to the genus Aviadenovirus, forming a cluster with fowl and turkey aviadenoviruses. The amino acid sequence divergence between the DNA polymerase of this virus and its closest known adenovirus relative is approximately 29%, implying that this virus can be assigned to a new species in the genus Aviadenovirus. Based on our data, this novel owl adenovirus is a likely cause of fatal infections in owls, which may threaten wild and captive owl populations. Further, this virus is unique among raptor adenoviruses in that it infects chicken-derived cultured cells, raising the importance of further investigations to evaluate interspecies transmission of this virus.

Spontaneous multiple cutaneous mixed tumors in Japanese giant salamander Andrias japonicus.

We examined 7 cutaneous mixed tumors in 2 wild-captured Japanese giant salamanders Andrias japonicus. The tumors were either already present and/or increased in size, or newly occurred during capativity. We sampled the 7 tumors from these animals and 3 verrucose protrusions from 3 unaffected animals, as controls, and examined them pathologically and virologically. The tumors (5 mm to 4 cm in size) were papillary protrusions or pendulated on the skin surface. The cut surface of the tumors was white, lobulated, partially hard, and contained mucus. All tumors presented similar histological characteristics of a hyaline structure and exhibited biphasic proliferation, with neoplastic epithelial cells partially composing the pseudo-ductal structure and staining positive for cytokeratin AE1/AE3. Vimentin 3B4-positive blast-like mesenchymal cells proliferated to fill the gaps in the epithelial components. Transition from unique mucous gland to neoplastic tissue was observed. The hyaline structure was stained blue by AZAN stain, Alcian blue-periodic acid-Schiff (PAS) double stain, and toluidine blue (TB) stain of pH 7.0, but was unstained by TB with pH values of 4.1 and 2.5. The mucus in the neoplastic tissue and in the mucous gland in verrucose protrusions was stained blue by Alcian blue-PAS double stain; TB staining at pH 7.0, 4.1, and 2.5 revealed metachromasy. No virus was detected in the tumors. The 7 tumors were diagnosed as cutaneous mixed tumors, and it was confirmed that the neoplastic cells originated from the mucous gland in the dermis. The biological behavior and pathological development of tumors should be elucidated because the tumors have the potential to negatively affect A. japonicus.

First demonstration of Strongyloides parasite from an imported pet meerkat - Possibly a novel species in the stercoralis/procyonis group.

Strongyloides is a genus of parasitic nematodes of vertebrates that contains over 50 species, each with a variable host range. A recent molecular phylogenetic analysis on this genus showed that Strongyloides spp. from various carnivore hosts form a strongly supported clade together with Strongyloides stercoralis, a major pathogen of humans and dogs (named the "stercoralis/procyonis group"). In the present study, we obtained DNA sequencing data of Strongyloides sp. isolated from an imported meerkat (Suricata suricatta). Based on the phylogenetic analysis, we considered this a new member of the stercoralis/procyonis group. This study represents the first isolation and molecular characterization of a Strongyloides species from hosts belonging to the family Herpestidae (mongooses and meerkat). However, whether the meerkat serves as a natural host of this Strongyloides species remains to be investigated.

First report of ophidiomycosis in Asia caused by Ophidiomyces ophiodiicola in captive snakes in Japan.

Ophidiomycosis is an emerging infectious disease caused by the fungus Ophidiomyces ophiodiicola, which has been affecting wild and captive snakes in North America, Europe, and Australia. We report 12 cases of suspected ophidiomycosis in captive colubrid snakes in Japan. Pathological and microbiological examinations were performed, and the results confirmed the diagnosis of ophidiomycosis in two snakes, which indicated that the remaining sympatrically raised snakes also had ophidiomycosis since they exhibited similar lesions. This is the first report of ophidiomycosis in Asia caused by O. ophiodiicola. To prevent the expansion of ophidiomycosis in the natural environment in Japan, there is a need to evaluate the ophidiomycosis carrier status of imported snakes, the pathogenicity of the infection in native snakes, and the prevalence and distribution of O. ophiodiicola in wild and captive snakes. Measures also must be taken to prevent endemicity globally.

Role of autopsy imaging-computed tomography in the post-mortem study of farm animals.

BACKGROUND: Autopsy imaging (Ai) is used to determine the cause of death, providing pre-dissection information. Ai is often used in the field of human forensic medicine but has never been applied on farm animals. METHODS: Ai-computed tomography (CT) was performed before necropsy for farm animals (one goat, one ox, one cow and three calves) that died or were euthanised. RESULTS: Ai-CT findings of rib fractures (case 1), urethral calculi (case 2), multiple osteolytic bone lesions (case 3 and 4) and hair balls (case 4) were confirmed by dissection. However, a tentative diagnosis of actinomycosis was made in an ox (case 5) using antemortem radiography and Ai-CT, and the mass was identified as ameloblastic fibro-odontoma on histological examination. A tentative diagnosis of maxillary abscess was made from antemortem radiography in a cow (case 6); however, the lesion was shown to be maxillary neoplasia on Ai-CT. The mass was identified as hemangiosarcoma on histopathological examination. CONCLUSION: Ai is helpful in pathological examination because the specific findings are known before the dissection, the lesions can be pinpointed in the pathological dissection, facilitating workflow; furthermore, the oversight of lesions can be reduced. In addition, Ai-CT images, including three-dimensional images and a three-dimensional printed model, allowed an easy understanding of pathology among students and farmers. Ai-CT for farm animals represents a novel option for veterinary education.

Morphological observation and first molecular characterization of Grassenema procaviae Petter, 1959 (Cosmocercoidea: Atractidae) in the stomach of Cape hyrax (Procavia capensis) raised in a zoo in Japan.

The superfamily Cosmocercoidea comprises three families: Cosmocericidae, Kathlaniidae and Atractidae. Information on the nucleotide sequences of the Cosmocercoidea is quite limited, and the molecular classification of the whole superfamily has been slow to progress. The genus Grassenema of the family Atractidae is a parasitic nematode group that occurs in the digestive tract of hyraxes and includes three species: Grassenema procaviae, G. dendrohyraci, and G. hyracis. The type species of the genus, G. procaviae, was isolated from the digestive tract of Cape hyraxes (Procavia capensis) and has the potential to cause gastric ulcers. Although G. procaviae is a common parasite of Cape hyraxes, no genetic information for the parasite is currently available. In this study, we obtained the first genomic sequences of G. procaviae and performed detailed morphological observations. Furthermore, molecular phylogenetic analysis was performed, and the taxonomic position of the parasite was evaluated using 18S and 28S rDNA sequences. Those data will be useful for molecular identification of G. procaviae and future phylogenetic analysis within the Atractidae.

Pyogenic meningitis and trigeminal neuritis secondary to periodontogenic paranasal sinusitis in a red deer (Cervus elaphus).

An adult female red deer died of a severe seizure and dysbasia. Postmortem computed tomography (CT) and magnetic resonance imaging (MRI) were performed. On CT, deciduous right maxillary second and third premolar teeth were observed, and the right infraorbital canal was disrupted. MRI showed that the right trigeminal nerve was enlarged and the right subarachnoid cavity was occupied by fluid and gas. On gross examination, the right paranasal sinus, swollen muscles of the orbit and tonsils, right trigeminal nerve, and right cerebrum surface contained a yellowish-white, cheese-like pus. Based on these findings, the deer was believed to have developed pyogenic meningitis caused by a neuropathic infection secondary to periodontogenic paranasal sinusitis.

Rabbit hemorrhagic disease virus type 2 epidemic in a rabbit colony in Japan.

Twenty-three of 42 European rabbits (Oryctolagus cuniculus), belonging to the same rabbit colony, died in March 2020 (55% mortality) in Chiba prefecture, Japan. The disease course was extremely acute without indicators of death or hemorrhage. Necropsy revealed liver swelling, discoloration, cloudiness and fragility, and pulmonary edema. Histologically, severe hepatocellular necrosis (mainly peripheral) and intra-glomerular capillary hyalin thrombi were observed. On molecular-biological examination, reverse transcription polymerase chain reaction analysis of RNA from tissues detected a rabbit hemorrhagic disease virus, confirmed as a RHDV-2 VP60 fragment, which shared 99.42% nucleotide identity with the homologous fragment of RHDV-2 German isolate by nucleotide sequence analysis. This report shows the outbreak of rabbit hemorrhagic disease caused by RHDV-2, an emerging infectious disease, in Japan.

Feline Spongy Encephalopathy With a Mutation in the ASPA Gene.

Canavan disease is an autosomal recessive leukodystrophy caused by mutations in the gene encoding aspartoacylase (ASPA), which hydrolyses N-acetylaspartate (NAA) to acetate and aspartate. A similar feline neurodegenerative disease associated with a mutation in the ASPA gene is reported herein. Comprehensive clinical, genetic, and pathological analyses were performed on 4 affected cats. Gait disturbance and head tremors initially appeared at 1 to 19 months of age. These cats eventually exhibited dysstasia and seizures and died at 7 to 53 months of age. Magnetic resonance imaging of the brain revealed diffuse symmetrical intensity change of the cerebral cortex, brainstem, and cerebellum. Gas chromatography-mass spectrometry analysis of urine showed significant excretion of NAA. Genetic analysis of the 4 affected cats identified a missense mutation (c.859G>C) in exon 6 of the ASPA gene, which was not detected in 4 neurologically intact cats examined as controls. Postmortem analysis revealed vacuolar changes predominantly distributed in the gray matter of the cerebrum and brain stem as well as in the cerebellar Purkinje cell layer. Immunohistochemically, these vacuoles were surrounded by neurofilaments and sometimes contained MBP- and Olig2-positive cells. Ultrastructurally, a large number of intracytoplasmic vacuoles containing mitochondria and electron-dense granules were detected in the cerebral cortex. All 4 cats were diagnosed as spongy encephalopathy with a mutation in the ASPA gene, a syndrome analogous to human Canavan disease. The histopathological findings suggest that feline ASPA deficiency induces intracytoplasmic edema in neurons and oligodendrocytes, resulting in spongy degeneration of the central nervous system.

Forestomach developmental failure in an 11-month-old Japanese Black steer with severely retarded growth and chronic ruminal tympany.

This study reports findings from the pathological examination of the forestomach of an 11-month-old Japanese Black steer with severely retarded growth (41% of expected weight) and chronic ruminal tympany. The ruminal papillae were weakly formed (0.3-0.5 cm long) and unevenly distributed. The cellulae and cristae reticuli were underdeveloped; the cristae were 0.4-0.7 cm in height and milky white. The keratinized layer in the stratified squamous epithelium was thickened. Ruminal pH was 5.25, and ruminal volatile fatty acid concentration was 11.7 mM. The steer's severely retarded growth was considered to be caused by malnutrition due to developmental and functional failure of the forestomach.

New canine parvovirus 2a infection in an imported Asian small-clawed otter (Aonyx cinereus) in Japan.

Post-import from the Republic of Indonesia to Japan in 2017, two juvenile, captive bred Asian small-clawed otters (Aonyx cinereus) exhibited gastrointestinal symptoms, including vomiting, diarrhea, and hematemesis, and died. One of them was examined postmortem. Microscopically, the small intestinal mucosa was necrotic with crypts lined by regenerating large epithelial cells. A gastric cardiac mucosal ulcerative lesion containing fungal yeasts and pseudohyphae morphologically indicated Candida spp. The lymph nodes exhibited marked lymphoid depletion. Canine parvovirus 2 (CPV-2) was isolated from an oral swab, and virus protein 2 (VP2) gene sequencing revealed new CPV-2a. To our knowledge, this is the first new CPV-2a infection report in Asian small-clawed otters. This infection should be considered in gastrointestinal symptom-related cases in this species.