Mycotic aneurysm caused by Graphium species in a dog

A 10-year-old castrated male mixed-breed dog exhibited vomiting, lethargy and anorexia. An abdominal ultrasound examination revealed a focal dilation of the abdominal aorta. The dog died 2 days after examination, and necropsy revealed a ruptured aneurysm at the abdominal aorta between the kidneys. Histological examination revealed severe granulomatous and necrotizing pan-arteritis with fungal organisms. Graphium species was identified through DNA sequence analysis of the PCR product from formalin-fixed paraffin-embedded samples. To our knowledge, this is the first report of aortic aneurysm caused by Graphium species in a dog.     

Syphacia (Syphacia) maxomyos sp. n. (Nematoda: Oxyuridae) from Maxomys spp. (Rodentia: Muridae) from Sulawesi and Sumatra,Indonesia

The present report describes Syphacia (Syphacia) maxomyos sp. n. (Nematoda: Oxyuridae) from two species of spiny rats, Maxomys musschenbroekii from Sulawesi and M. whiteheadi from Sumatra. It is characterized by a cephalic plate extending laterally with dorsoventral constriction and stumpy eggs with an operculum rim reaching pole. It is readily distinguishable by the former feature from all of hitherto known representatives of this genus in Indonesia, but it resembles parasites in Murini and Hydromyni rodents in continental Asia and Sahul. This is the first Syphacia species distributed in both the Sunda Shelf and Sulawesi with the exception of Syphacia muris, a cosmopolitan pinworm found in rodents of the of genus Rattus. It is surmised that S. maxomyos is specific to Maxomys and that it was introduced to Sulawesi by dispersal of some Maxomys from the Sunda Shelf.     

Spontaneous Malignant T Cell Lymphoma in a Young Male Common Marmoset (Callithrix jacchus)

We histopathologically and immunohistochemically investigated a case of malignant lymphoma that spontaneously developed in a male common marmoset at two years of age. Beginning at two years four months of age, the animal had an enlargement of the submandibular and inguinal lymph nodes, small subcutaneous nodules near the right breast and an approximately fivefold increase in peripheral lymphocyte count compared with the previous examination value. The postmortem findings at two years eight months of age showed lymphadenopathy with enlargement of the thymus and spleen. Small- to intermediate-sized neoplastic lymphocytes had diffusely proliferated in the enlarged nodes. The neoplastic cells were pleomorphic and had irregularly shaped nuclei. The nuclear chromatin staining revealed hyperchromatism in the small-sized cells, and the intermediate-sized cells exhibited vesicular staining. An immunohistochemical examination indicated that the neoplastic lymphocytes were positive for CD3 and negative for CD20, thus suggesting that they had originated from T cells. In addition, the proliferation of high endothelial venules and reactive epithelioid histiocytes was observed. Scattered tingible body-laden macrophages were infrequently detected. Neoplastic lymphocytes were also observed in the thymus, spleen, heart, lungs, liver, kidneys, adrenal glands and femoral and sternal bone marrow. This malignant lymphoma in a young male common marmoset was considered to fit the category of “peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS)” according to the new WHO system of classification.     

Common variable immune deficiency in a Pomeranian with Pneumocystis carinii pneumonia

A Pomeranian dog, 1 year- and 8 month-old neutered female, was presented with persistent respiratory distress and recurrent generalized demodicosis. Physical examination revealed cyanosis, rough respiratory sounds, multifocal alopecia and dermal erosions on the dorsal side of the forelimbs, perineal area and skin around the eyes. A severe diffuse interstitial lung pattern was observed on thoracic radiographs. The blood examination revealed neutrophilia and hypoglobulinemia. Serum immunoglobulin concentrations of IgG and IgA were low. Histopathological examination revealed severe diffuse interstitial pneumonia with Pneumocystis carinii infection. Severe lymphoid depletion was observed in the spleen and other organs with lymphoid follicles consisted mainly of CD3-positive T cells and few cells of B-cell lineage. B-cell hypoplasia with subsequent antibody deficiency was suspected.     

Areolae of the Placenta in the Antarctic Minke Whale (Balaenoptera bonaerensis)

In this study, we examined the existence and structure of areolae and the steroidogenesis of areolar trophoblast cells in the Antarctic minke whale placenta morphologically and immunohistochemically. Placentas were collected from the 15th, 16th and 18th Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. The opening and cavity of fetal areolae formed by taller columnar trophoblast cells (areolar trophoblast cells) with long microvilli and a bright cytoplasm, as compared with the trophoblast cells of the chorionic villi interdigitating with the endometrial crypts, were recognized in observations of serial sections. The opening of the areolar cavity was hidden by chorionic villi with areolar trophoblast cells. Furthermore, a closed pouch-like structure lined by tall columnar cells similar to areolar trophoblast cells within the stroma of chorionic villi was noticed and continued to the areolar cavity, with the opening seen on serial sections. In a surface investigation of the chorion and endometrium by SEM, maternal (endometrial) areolae irregularly surrounded by endometrial folds were obvious. Moreover, we distinguished areolar trophoblast cells with long microvilli attached with many blebs from trophoblast cells. In our immunohistochemical observations, a steroidogenic enzyme, cytochrome P450 side chain cleavage enzyme (P450scc), was detected with strong immunoreactivity in trophoblast cells. However, areolar trophoblast cells showed weak or no immunoreactivity for P450scc.     

A case of nontraumatic gas gangrene in a common marmoset (Callithrix jacchus)

The common marmoset is widely used in neuroscience and regenerative medicine research. However, information concerning common marmoset disorders, particularly infectious diseases, is scarce. Here, we report a case of a female common marmoset that died suddenly due to gas gangrene. The animal presented with gaseous abdominal distention at postmortem, and Clostridium perfringens type A was isolated from several tissues. Vacuoles, a Gram-positive bacteremia and intravascular hemolysis were observed microscopically in the muscles, liver and lungs. On the basis of these findings, we diagnosed nontraumatic gas gangrene caused by Clostridium perfringens type A in this common marmoset.     

Pathological findings of hemorrhagic bowel syndrome (HBS) in six dairy cattle cases

Six adult dairy cows clinically diagnosed as hemorrhagic bowel syndrome (HBS) were the subjects of this study. The involved intestinal lesions were fixed in formalin and examined macroscopically and histopathologically. Pathological examinations revealed large intramural hematomas with necrotic foci, resulting in luminal obstruction. The mucosal layer in the lesions was detached from the intestinal wall, and there were no hemorrhagic changes in the lumen. The intramural hematomas were sometimes covered with histologically intact mucosal layer. These pathological findings were not consistent with those of “intraluminal blood clots” reported previously. Gram-positive and anti-Clostridium antibody-positive short bacilli were found in hemorrhagic necrotic areas. However, the exact relationship between Clostridium spp. observed in the lesions and HBS remains unclear, because this bacterium is a normal inhabitant in cattle.     

Isolation and antimicrobial susceptibility of Plesiomonas shigelloides from great cormorants (Phalacrocorax carbo hanedae) in Gifu and Shiga Prefectures,Japan

Plesiomonas shigelloides is a causal agent of gastroenteritis, sepsis and meningitis in humans. We examined the prevalence of P. shigelloides among great cormorants (Phalacrocorax carbo hanedae) in Japan and the antimicrobial susceptibility of isolates. P. shigelloides was isolated from 33 (47.8%) of 69 fecal samples from great cormorants in 2014. All 33 isolates were subjected to antimicrobial susceptibility testing using broth microdilution methods, which showed resistance to ampicillin (31 isolates, 93.9%), tetracycline (two isolates, 6.1%) and trimethoprim (one isolate, 3.0%). The high prevalence of P. shigelloides in the great cormorants implicates the possible microbiological risk to public health.     

Yersiniosis caused by Yersinia pseudotuberculosis in captive toucans (Ramphastidae) and a Japanese squirrel (Sciurus lis) in zoological gardens in Japan

Two captive Keel-billed toucans and a Chestnut-mandibled toucan in another zoological garden died suddenlywithout any pre-existing symptoms, and three months later, a Japanese squirrel died of diarrhea. All theseanimals showed necrotic enteritis and multifocal necrosis in the liver and spleen with Gram negative bacilli.The bacilli showed strong positive immunolabeling for Yersinia pseudotuberculosis O4 in theKeel-billed toucans, Y. pseudotuberculosis O2 in the Chestnut-mandibled toucan and Y.pseudotuberculosis O1 in the Japanese squirrel, while Y. pseudotuberculosis 4b, 2band 1b were respectively isolated from the lesions. To our knowledge, this might be the first reported case offatal yersiniosis in a Japanese squirrel in the world as well as in toucans in Japan.