Nam-Yong Park

Detection and molecular characterization of porcine enteric calicivirus in Korea, genetically related to sapoviruses.

Summary Porcine enteric calicivirus (PECV) shares morphological and genetical similarities with Sapoviruses (SVs), which are the leading cause of epidemic, non‐bacterial gastroenteritis in children worldwide. The aim of this study was to identify the prevalence of PECV infection in pig farms in Korea, and to compare the evolutionary inter‐relationships between Korean PECVs and other caliciviruses. Among 102 diarrhoeic faecal samples of sucking (n = 50) and weaned (n = 52) piglets from 31 different farms in Korea, five samples (4.9%) were detected positive by reverse‐transcriptase polymerase chain reaction (PCR), but nine (8.8%) by nested‐PCR. Furthermore, we found that Korean PECVs are closely related to SVs.

Detection of canine parvovirus in fecal samples using loop-mediated isothermal amplification.

Loop-mediated isothermal amplification (LAMP) is a novel, sensitive, and rapid technique for detection of genomic DNA. The end-product of the technique is a white precipitate of magnesium pyrophosphate that is visible without the use of gel electrophoresis. The LAMP method was applied to the detection of canine parvovirus (CPV) genomic DNA. A set of 4 primers, 2 outer and 2 inner, were designed from CPV genomic DNA targeting the VP2 gene. The optimal reaction time and temperature for LAMP were determined to be 60 minutes and 63°C. On the basis of results for 50 canine fecal samples using polymerase chain reaction (PCR) analysis as the gold standard, the relative sensitivity of LAMP was 100% and the relative specificity was 76.9%. The detection limit of the LAMP method was 10−1 median tissue culture infective doses (TCID50)/ml, compared with 10 TCID50/ml for PCR analysis. In addition to the advantage resulting from visual detection of the end product, the LAMP method is very rapid, requiring only 1 hour to complete. This assay would be a viable alterative to PCR analysis for diagnosis of CPV infection in dogs. The LAMP method holds promise for use as a diagnostic assay for CPV detection in a clinical setting.

Molecular analysis of S gene of spike glycoprotein of winter dysentery bovine coronavirus circulated in Korea during 2002-2003.

Abstract Since the molecular analysis of spike (S) glycoprotein gene of bovine coronavirus (BCoV) has been conducted and compared mainly among American and Canadian isolates and/or strains, it is unclear whether BCoV circulated in the other countries are distinctive in genetic characteristics. In the present study, we analyzed the S glycoprotein gene to characterize 10 winter dysentery (WD) coronavirus strains circulated in Korea during 2002–2003 and compared the nucleotide (nt) and deduced amino acid (aa) sequences with the other known BCoV. The phylogenetic analysis of the entire S glycoprotein gene revealed that the aa sequences of all Korean WD strains were more homologous to each other and were very closely related to respiratory bovine coronavirus (RBCV) strain OK and enteric bovine coronavirus (EBCV) strain LY-138, but were distinct from the other known BCoVs. Based on the phylogenetic analysis of the hypervariable region of the S1 subunit, all Korean WD strains clustered with the respiratory strain OK, BCQ3994 and the enteric strain LY-138, while the Canadian BCQ calf diarrhea and WD strains, and the American RBCV LSU, French EBCV F15 and avirulent VACC, L9, and Mebus strains clustered on a separate major branch. These data suggest that the WD strains circulated in Korea had a genetic property of both RBCV and EBCV and were significantly distinct from the ancestral enteric strain.

Detection of canine distemper virus in blood samples by reverse transcription loop-mediated isothermal amplification.

Summary Reverse transcription loop‐mediated isothermal amplification (RT‐LAMP) was used to detect canine distemper virus (CDV) genomic RNA. A set of four primers, two outer and two inner, were designed from CDV genomic RNA targeting the nucleocapsid protein gene. The optimal reaction time and temperature for LAMP were determined to be 60 min at 65°C. The relative sensitivity and specificity of RT‐LAMP was found to be 100% and 93.3%, respectively, based on 50 canine blood samples and using RT‐PCR as the gold standard. The detection limit of the RT‐LAMP method was 100 times lower than with RT‐PCR (10‐1TCID50 ml−1 versus 10TCID50 ml−1). In addition to the advantage resulting from the visual detection of the end‐product, the LAMP method is fast, requiring only 1 h to complete the assay. The LAMP method is a viable alternative to RT‐PCR for diagnosing CDV infection in dogs. The LAMP method might be useful as an on site diagnostic assay for detecting CDV.

Balantidiasis in the gastric lymph nodes of Barbary sheep (Ammotragus lervia): an incidental finding.

A 4-year-old female Barbary sheep (Ammotragus lervia) was found dead in the Gwangju Uchi Park Zoo. The animal had previously exhibited weakness and lethargy, but no signs of diarrhea. The carcass was emaciated upon presentation. The main gross lesion was characterized by severe serous atrophy of the fat tissues of the coronary and left ventricular grooves, resulting in the transformation of the fat to a gelatinous material. The rumen was fully distended with food, while the abomasum evidenced mucosal corrugation with slight congestion. Microscopic examination revealed the presence of Balantidium coli trophozoites within the lymphatic ducts of the gastric lymph node and the abdominal submucosa. On rare occasions, these organisms may invade extra-intestinal organs, in this case the gastric lymph nodes and abomasum.

Disseminated mycobacteriosis due to Mycobacterium avium in captive Bengal tiger (Panthera tigris).

A 2-year-old captive female Bengal Tiger (Panthera tigris) died after prolonged anorexia in the Gwangju Uchi Park Zoo, Gwangju, Republic of Korea. Necropsy revealed multiple nodules of varying sizes in the lung, liver, kidney, and spleen. Histopathologic examination revealed a typical granuloma composed of caseous necrotic areas surrounded by lymphocytes with a few giant cells and foamy macrophages. Periodic acid-Schiff stain and Gomori methenamine silver stain did not reveal any fungal bodies. The Ziehl-Neelsen acid-fast stain revealed few acid-fast organisms in the lung, liver, kidney, and spleen. A polymerase chain reaction assay of the lung, liver, kidney, and spleen yielded a positive result for Mycobacterium avium subsp. avium. This is an unusual case of disseminated infection of a wild mammal with avian mycobacteriosis, and is believed to be most likely associated with the feeding of tigers with culled chickens infected with M. avium.