A survey of porcine reproductive and respiratory syndrome among wild boar populations in Korea

No information is currently available on porcine reproductive and respiratory syndrome virus (PRRSV) infection in wild boars (Sus scrofa) in Korea. In this study, the status of PRRS in wild boars was investigated. Blood samples were collected from 267 wild boars from eight provinces in Korea. Four of the samples tested (1.5%) were positive for PRRSV antibodies and eight (3.0%) were positive for antigens. Of the virus-positive samples, three and five samples were typed as containing European (EU, type 1) or North American (NA, type 2) viruses, respectively. Two amplicons (one from type 1 and one from type 2) were used to analyze the PRRSV open reading frame 7 (ORF7) sequence. The nucleotide sequences of type 1 PRRSV ORF7 had identities between 96.1% and 98.4% with PRRSVs from domestic pigs in Korea. The sequences of type 2 PRRSV ORF7 had identities of 100% with the PRRSV strain VR-2332, which was prototypic North American strain. These results show that PRRSVs are present in wild boars in Korea, and effective PRRSV surveillance of the wild boar population might therefore be useful for disease control.     

Effect of matrigel on the osteogenic potential of canine adipose tissue-derived mesenchymal stem cells

Adipose tissue-derived mesenchymal stem cells (Ad-MSCs) are a promising source of cells for bone tissue engineering. Matrigel is a basement membrane extract containing multiple extracellular components. This mixture may promote the osteogenic differentiation of MSCs and provide a more appropriate microenvironment for transplanted cells. Here, we investigated the effect of Matrigel on the osteogenic potential of Ad-MSCs. Canine Ad-MSCs were cultured in 2D and 3D matrices and implanted into subcutaneous pouches of dogs either with or without Matrigel. Culture mineralization, cell adhesion efficiency, cell proliferation, osteoid matrix production and alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase activities were quantified and compared. Ad-MSCs grown in 2D cultures with Matrigel showed higher levels of calcium deposition and ALP activity than those grown in the absence of Matrigel under osteogenic conditions. In 3D cultures, the cells cultivated with Matrigel showed greater attachment, proliferation and osteogenic differentiation than those grown without Matrigel. In vivo, Ad-MSCs implanted with Matrigel showed higher osteogenic potential than those without Matrigel. In conclusion, these data suggest that the use of Matrigel can increase the osteogenic potential of canine Ad-MSCs.     

Concurrent multicentric hemangiosarcoma and ovarian teratoma in an aged Père david's deer (Elaphurus davidianus).

A 20-yr-old female Père David's deer (Elaphurus davidianus) died following a 3-wk history of depression, anorexia, and progressive respiratory distress. At necropsy, numerous soft to firm, tan or blood-filled nodular structures, 1-6 cm in diameter, were noted in the lung and the visceral and parietal pleura and within the mediastinum. Similar nodules were also found in the liver, spleen, kidney, and lymph nodes. Histologically, the nodules were diagnosed as hemangiosarcoma. A benign teratoma was present in the left ovary.     

Monoclonal antibody-based immunohistochemical detection of porcine epidemic diarrhea virus antigen in formalin-fixed, paraffin-embedded intestinal tissues.

An immunohistochemistry technique was developed for the diagnosis of porcine epidemic diarrhea virus (PEDV). The technique was tested on formalin-fixed, paraffin-embedded intestinal tissues from piglets naturally infected with PEDV. Five different monoclonal antibodies (MAbs) were tested in this study. PEDV antigen was consistently detected in the PLP (4% paraformaldehyde, 100 mM L-lysine dihydrochloride, 10 mM sodium m-periodate in phosphate-buffered saline)-fixed PEDV-infected Vero cells or formalin-fixed, paraffin-embedded intestinal tissues from piglets naturally infected with PEDV. The C9-2-2 MAb gave the strongest reactivity and least background staining, detecting 10 of 10 infected pigs. The positive reaction was cytoplasmic. Positive enterocytes were distributed over the tip and along the sides of atrophied or fused villi in the jejunum and ileum. Positive-staining cells were not detected in the crypts. No staining was observed in cecum and colon. No positive cells were observed when the C9-2-2 MAb was reacted with the tissue sections from noninfected piglets or from transmissible gastroenteritus virus (TGEV)- and rotavirus-infected piglets. The selected anti-PEDV MAbs tested on formalin-fixed, paraffin-embedded tissue sections are useful for diagnosis when virus isolation is not available. This method would be of particular value in countries where both PEDV and TGEV are epizootic and would aid in differentiating between PEDV and TGEV infection.     

Sero-survey on Aino, Akabane, Chuzan, bovine ephemeral fever and Japanese encephalitis virus of cattle and swine in Korea

Vector-borne arboviruses produce mild to severe symptoms in domestic animals. Bovine ephemeral fever (BEF), Akabane, Aino, and Chuzan virus have been primarily attributed to reproductive disorders or febrile diseases in cattle, and Japanese encephalitis virus (JEV) is mainly associated with reproductive failures in swine. We investigated antibody titers from domestic swine against four bovine arboviruses (BEF, Akabane, Aino, and Chuzan virus) and from cattle against JEV in Korea. While the positive rates for Akabane and BEF were 37.4% and 15.7%, the positive incidence of Chuzan and Aino were relatively low, with positive rates of 3.04% and 0.4%, respectively, based on a virus neutralization assay. Antibody titers against more than one virus were also frequently detected in domestic swine. The incidence of JEV was 51.3% among domestic cattle. In addition, one positive case was detected in the thoracic fluids from 35 aborted calves, based on the hemagglutination inhibition test. Our results indicate that swine are susceptible hosts of bovine arboviruses without showing clinical symptoms in a natural environment. Moreover, we confirmed that JEV could be associated with reproductive failure in pregnant cattle, as were other vector-borne bovine arboviruses assessed in this study.     

Molecular cloning of vitellogenin cDNA in rockfish (Sebastes schlegeli) and effects of estrogenic substances on its gene expression

In this study, we have cloned a partial cDNA of 620 bases encoding a vitellogenin gene of rockfish (rfVTG), Sebastes schlegeli. The expression levels of rfVTG mRNA increased 48 h after the 4-nonylphenol (NP) treatment (10 mg/kg BW) in both sexes. On the other hand, the mRNA levels of rfVTG increased 48 h in males and 12 h in females after injection when higher dose (25 mg/kg BW) of 4-NP was applied. It suggested that 4-NP induced VTG gene expression in both male and female immature rockfish. Therefore, the cloned rfVTG cDNA in this study can be used as a tool for monitoring endocrine disruptors in rockfish.