Prevalence and pathologic study of porcine epidemic diarrhea in Jeju

From April 2014 to September 2015, 153 piglets from 52 farms in Jeju were diagnosed with porcine epidemic diarrhea (PED). The major PED cases were focused on suckling piglets (144 piglets, 94.1%), particularly in 1-7-day-old piglets. Histopathologically, severe villous atrophy was observed in the small intestine, especially in the jejunum and ileum. The mean villous height to crypt depth ratios of the jejunum and ileum were 1.4:1 and 1.5:1, respectively. The major histopathologic findings of the small intestine were cytoplasmic vacuolation, cuboidalization, squamation, and exfoliation of the mucosal enterocytes in the villi. The cytoplasmic vacuolations in the enterocytes were the most prevalent lesions in the small intestine and were more severe in the ileum than in the jejunum. According to immunohistochemistry methods, the PED virus (PEDV) antigens were presented in the cytoplasms of the enterocytes, and were distributed more prevalently in the ileum than in the jejunum. PEDV antigens were also detected in the colon of 29 piglets (19.5%). Sequence comparison and phylogenetic analysis indicated that 12 PEDV had more than a 98.9% homology with each other. These PEDV strains were highly homologous with the genogroup 2 North American group.

Congenital swinepox of neonatal pigs in a Korean domestic farm

Three neonatal pigs from the same litter in a domestic farm were born with skin lesions. Grossly, multiple wellcircumscribed, round papules distributed over the skin of the three piglets. Two piglets were submitted for a diagnosis of skin disease.Microscopically, epidermal hyperplasia with ballooning degeneration of stratum spinosum keratinocytes was observed. Some keratinocytes contained eosinophilic intracytoplasmic inclusions and a central nuclear vacuole and chromatin margination. Swinepox (SWP) virus was detected by polymerase chain reaction and nucleotide sequencing, and Staphylococcus hyicus was isolated in skin lesions. Based on the gross findings and laboratory results, these piglets were diagnosed with congenital SWP with a secondary staphylococcal infection.

Congenital swinepox of neonatal pigs in a Korean domestic farm

Three neonatal pigs from the same litter in a domestic farm were born with skin lesions. Grossly, multiple wellcircumscribed, round papules distributed over the skin of the three piglets. Two piglets were submitted for a diagnosis of skin disease.Microscopically, epidermal hyperplasia with ballooning degeneration of stratum spinosum keratinocytes was observed. Some keratinocytes contained eosinophilic intracytoplasmic inclusions and a central nuclear vacuole and chromatin margination. Swinepox (SWP) virus was detected by polymerase chain reaction and nucleotide sequencing, and Staphylococcus hyicus was isolated in skin lesions. Based on the gross findings and laboratory results, these piglets were diagnosed with congenital SWP with a secondary staphylococcal infection.

Prevalence and pathologic study of porcine salmonellosis in Jeju

Salmonella (S.) Typhimurium is highly contagious, and its infection may rapidly spread within pig populations of herd. According to the survey (1,191 pigs) from 2003 to 2012, 155 pigs (13.0%) were diagnosed as salmonellosis in Jeju. Major porcine salmonellosis cases (88.4%) were concentrated in 4- to 12-week-old weaned pigs, but 6 pigs (3.9%) under 4 weeks old were also diagnosed. Based on the histopathologic examinations, ulcerative enteritis (63.9%) in the large intestine and/or paratyphoid nodules formation (57.4%) in the liver were most prevalent lesions in porcine salmonellosis. Single infection of S. Typhimurium and mixed infection with more than 2 pathogens were detected in 38 (24.5%) and 117 (75.5%) in pigs, respectively. Co-infections of Porcine reproductive and respiratory syndrome virus and Porcine circovirus type 2 were very common in porcine salmonellosis in Jeju and detected in 84 (54.2%) and 59 (38.1%) pigs, respectively. Based on the serotyping tests using 41 bacterial isolates, S. Typhimurium and S. Rissen were confirmed in 39 (95.1%) and 2 (4.9%) cases, respectively.

Recent vaccine technology in industrial animals

Various new technologies have been applied for developing vaccines against various animal diseases. Virus-like particle (VLP) vaccine technology was used for manufacturing the porcine circovirus type 2 and RNA particle vaccines based on an alphavirus vector for porcine epidemic diarrhea (PED). Although VLP is classified as a killed-virus vaccine, because its structure is similar to the original virus, it can induce long-term and cell-mediated immunity. The RNA particle vaccine used a Venezuela equine encephalitis (VEE) virus gene as a vector. The VEE virus partial gene can be substituted with the PED virus spike gene. Recombinant vaccines can be produced by substitution of the target gene in the VEE vector. Both of these new vaccine technologies made it possible to control the infectious disease efficiently in a relatively short time.

Proposed Motor Scoring System in a Porcine Model of Parkinson's Disease induced by Chronic Subcutaneous Injection of MPTP

Destruction of dopaminergic neurons in the substantia nigra pars compacta (SNpc) is a common pathophysiology of Parkinson's disease (PD). Characteristics of PD patients include bradykinesia, muscle rigidity, tremor at rest and disturbances in balance. For about four decades, PD animal models have been produced by toxin-induced or gene-modified techniques. However, in mice, none of the gene-modified models showed all 4 major criteria of PD. Moreover, distinguishing between PD model pigs and normal pigs has not been well established. Therefore, we planned to produce a pig model for PD by chronic subcutaneous administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), neurotoxin. Changes in behavioral patterns of pigs were thoroughly evaluated and a new motor scoring system was established for this porcine model that was based on the Unified Parkinson's Disease Rating Scale (UPDRS) in human PD patients. In summary, this motor scoring system could be helpful to analyze the porcine PD model and to confirm the pathology prior to further examinations, such as positron emission tomography-computed tomography (PET-CT), which is expensive, and invasive immunohistochemistry (IHC) of the brain.

Cutaneous peripheral nerve sheath tumors in 15 dogs / 대한수의학회지

Peripheral nerve sheath tumors (PNSTs) are heterogeneous tumor groups of peripheral nerves that originate from either Schwann cells or modified Schwann cells, fibroblasts, or perineural cells. In this study, signalment and clinical data such as tumor location and size were evaluated for 15 cases of PNSTs collected from local animal hospitals. The mean age of dogs with malignant PNST was higher than that of dogs with benign PNST. Additionally, the male to female ratio in dogs with PNST was 1 : 4. In dogs with PNST, the primary sites of involvement were the hindlimb, forelimb, around the mammary glands, the neck, and the abdomen. Histiopathologic examination revealed that eight PNSTs were benign and seven were malignant. The tumor cells were composed of loosely to densely arranged interlacing bundles and wavy spindle cells arranged in short bundles, palisading, and whirling. High mitotic figures, local invasion, multifocal necrosis and atypical multinucleated giant cells were observed in malignant PNST cases. All PNSTs showed immunoreactivity for vimentin and S-100. However, only 93.3% and 73.3% were immunoreactive for NSE and GFAP, respectively. Overall, these results indicated that immunohistochemical markers such as vimentin, S-100 and NSE could help confirm the diagnosis of canine PNSTs.

Malignant Sertoli cell tumor in Shih Tzu dog / 대한수의학회지

Malignant Sertoli cell tumor was diagnosed in a 5-year-old male Shih Tzu dog. Clinical features of the dog were anorexia, urinary incontinence, constipation, anemia, alopecia, and epistaxis. The dog also had unilateral cryptorchid testis in the abdomen. Several abdominal and thoracic masses were identified on radiography. Grossly, the cryptorchid testicular mass was markedly enlarged to 8 cm in diameter. On cut surface, firm and well demarcated milk-white neoplastic areas were irregularly separated by white fibrous bands. Histologically, the testicular mass was diagnosed as tubular pattern Sertoli cell tumor. In addition, abdominal and mediastinal lymph nodes metastasis were found. Immunohistochemically, the tumor cells were strongly positive for vimentin and neuron specific enolase, but negative for S-100 and cytokeratin.

Eosinophilic granulomas in two dogs / 대한수의학회지

Eosinophilic granuloma is a common hypersensitive inflammatory skin disease in cats, and rare in dogs and horses. The skin biopsies of 5 years old female Cocker spaniel and 2 years old female mixed dog had the clinical signs of skin nodules with alopecia were submitted for diagnosis. Solitary skin nodules and papillary nodules were presented on the left external ear and back of Cocker spaniel and on the external ear of mixed dog, respectively. Histopathologically, epidermis of skin showed mild to severe hyperplasia with multifocal ulceration. Small to large irregular, brightly eosinophilic foci with degenerating eosinophils and homogeneous degenerated collagens were existed in the dermis of both ear and back skin. Typical 'flame figures', a mixture of degenerated collagen and degranulated eosinophils, were observed in both cases. Based on the histopathologic findings and special staining characters, 2 cases were diagnosed as canine eosinophilic granuloma. This is the first report for the eosinophilic granuloma of dogs in Korea.

Epidemiological characteristics of pulmonary pneumocystosis and concurrent infections in pigs in Jeju Island, Korea

Epidemiological characteristics of swine pulmonary Pneumocystis (P.) carinii and concurrent infections were surveyed on Jeju Island, Korea, within a designated period in 172 pigs submitted from 54 farms to the Department of Veterinary Medicine, Jeju National University. The submitted cases were evaluated by histopathology, immunohistochemistry, PCR/RT-PCR, and bacteriology. P. carinii infection was confirmed in 39 (22.7%) of the 172 pigs. Histopathologically, the lungs had moderate to severe lymphohistioctyic interstitial pneumonia with variable numbers of fungal organisms within lesions. Furthermore, porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV-2) co-infection was a common phenomenon (12.8%, 20.5%, and 48.7% were positive for PRRS, PCV-2, or both, respectively, as determined by PCR/RT-PCR). Infection was much more concentrated during winter (December to March) and 53.8% of the infected pigs were 7- to 8-weeks old. In addition, three pigs showed co-infection with bacteria such as Pasteurella multocida and Streptococcus suis. The results of the present study suggest that the secondary P. carinii infection is common following primary viral infection in swine in Korea. They further suggest that co-infection of P. carinii might be enhanced by the virulence of primary pathogens or might have synergistic effects in the pigs with chronic wasting diseases.

Prevalence of porcine parvovirus in pigs with postweaning multisystemic wasting syndrome in Jeju Island / 대한수의학회지

Postweaning multisystemic wasting syndrome (PMWS), which was first identified in western Canada in 1991 and more recently in the United States, Europe and Asia, is an emerging disease in pigs. Porcine circovirus type 2 (PCV-2) is the primary infectious viral agent causing PMWS, but the full expression of the disease may require the presence of other agents. It is reported that there is apparent synergism between PCV-2 and porcine parvovirus (PPV) in increasing the severity of the clinical signs and lesions of PMWS. From January 2006 to May 2008, a total of the 154 lymph node samples were collected from 4~12 weeks old pigs which had been submitted to the College of Veterinary Medicine, Jeju National University, Korea. These pigs were diagnosed as PMWS on the basis of clinical and pathological examination from 48 commercial herds in Jeju Island. Based on the immunohistochemistry, porcine parvovirus was detected in 69 cases (44.8%) from 154 weaned or grower pigs. PPV antigens were detected in the cytoplasm of histiocytic cells multifocally infiltrated in the cortex and paracortex of lymph nodes. The results of this study clarify that PPV is prevalent in pigs with PMWS on Jeju Island. Therefore PPV is one of the most important co-agents in the development of naturally acquired PMWS. This study may be helpful to the control of this disease and to epidemiological aspects.

Uterine Adenomyosis in Beagle Dogs / 한국실험동물학회지

Adenomyosis is a nonneoplastic hyperplastic lesion, characterized by invagination of proliferating endometrial glands into myometrium. In dogs, uterine adenomyosis is relatively rare and it is important in Toxicologic Pathology to differentiate other non-neoplastic and neoplastic lesions in uterus. In the present study, we report two cases of adenomyosis in the female beagle dogs used for a chemical toxicity test. Clinically, one out of the two female beagle dogs, 15 months of age, had vaginal bleeding for 2 weeks and the other one, 11 months of age, showed swelling of vulva for a week. At necropsy, the weight of uterus was markedly increased to 27.9 g and 15.8 g, compared with the mean value (4.01+/-2.37, n=6) of that of other normal dogs, respectively. The parameters of hematology and serum chemistry were ranged normal in both of the dogs with enlarged uterus. For differentiation of connective tissue with muscle fibers, Van Gieson stain was also performed in the serial tissue sections. Histopathologically, the lesions of the enlarged uteruses were characterized by proliferating endometrial glands into myometrium, surrounded by connective tissue. The endometrial glands were proliferating downward to myometrium or embedded in multiple clustered glands in deeper myometrium without compressing the adjacent muscle fibers. The gland epithelial cells are uniformly cuboidal shape with a dense and bottom-located nucleus. These gross and histological findings were consistent with adenomyosis.

Detection of swine hepatitis E virus in the porcine hepatic lesion in Jeju Island

Swine hepatitis E virus (HEV) is an emerging zoonotic pathogen due to its close genomic similarity to human HEV. The prevalence of swine HEV in the hepatic lesion of pigs from the Jeju Island was investigated by reverse transcriptase polymerase chain reaction (RT-PCR). In total, 40 pigs with hepatitis lesions were selected from 19 different farms, based on examination by microscopy. RTPCR findings revealed swine HEV in 22 cases (55%), including 18 suckling pigs and 4 growing pigs. Several histopathological lesions, including multifocal lymphoplasmacytic hepatitis, portal inflammation, and focal hepatocellular necrosis, were observed in liver sections of swine HEV PCR-positive pigs. The present study suggests that the prevalence of swine HEV is very high in the pig population in Jeju Island, and that pigs are infected at early stages of growth (under 2 months of age). The high prevalence of swine HEV in pigs in Jeju Island and the ability of this virus to infect across species puts people with swine-associated occupations at possible risk of zoonotic infection.