Prevalence and distribution of six bee viruses in Korean Apis cerana populations.

The prevalence and distribution of six bee viruses was investigated in 527 Apis cerana samples which were collected from five provinces in South Korea. The most prevalent virus, black queen cell virus (BQCV), was present in 75.11% of 446 adult bee samples, followed by sacbrood virus (SBV) in 30.71%. Deformed wing virus (DWV), Kashmir bee virus (KBV), and chronic bee paralysis virus (CBPV) were present at lower levels of 8.07%, 1.56%, and 0.44%, respectively. The most prevalent virus in 81 larvae samples was SBV, with an incidence of 60.49%, followed by BQCV in 48.14%, DWV in 6.17%, and KBV in 1.23% of samples. CBPV infection was not detected in larvae samples, and acute bee paralysis virus (ABPV) was not present in both larvae and adult bee. Simultaneous infections with up to four viruses were also identified. Of these, infections with SBV and BQCV were most frequent in 25.61% of samples. The distribution of these viruses varied considerably throughout the geographic regions investigated. The three provinces of Gyeongbuk, Jeonnam, and Chungbuk had the highest frequency of bee viruses.

Myocarditis by nematodes infection, presumably Sarconema eurycerca, in a wild whooper swan (Cygnus cygnus) in Korea.

A dead whooper swan was found in an area of cropland near a stream and was submitted to the National Veterinary Research and Quarantine Service (NVRQS) in Korea. The affected animal was in relatively good condition. Grossly, the heart was enlarged and had pale and dark red stripes. A white, elongate parasite was seen on the cut surface of the heart. Histopathologically, severe lymphohistiocytic inflammation, myocardial necrosis, many adult heart worms and microfilariae were observed in the myocardium. Hemorrhage, lymphocytic inflammation, mineralization, and myocardial degeneration were also seen around the adult worms. No bacteria or viruses were isolated from the affected bird. The pathological findings indicate that the whooper swan was infected with nematodes, presumably Sarconema eurycerca, resulting in non-suppurative myocarditis.

Phylogenetic analysis and characterization of Korean orf virus from dairy goats: case report.

An outbreak of orf virus infection in dairy goats in Korea was investigated. Suspected samples of the skin and lip of affected goats were sent to the laboratory for more exact diagnosis. Orf virus was detected by electron microscopy and viral DNA was identified by PCR. To reveal the genetic characteristics of the Korean strain (ORF/09/Korea), the sequences of the major envelope protein (B2L) and orf virus interferon resistance (VIR) genes were determined and then compared with published reference sequences. Phylogenetic analysis revealed that the ORF/09/Korea strain was closest to the isolates (Taiping) from Taiwan. This is believed to be the first report on the molecular characterization of orf virus in Korea.

Characterization of tissue distribution and histopathological lesions in Neospora caninum experimentally infected gerbils.

Gerbils (Meriones unguiculatus) were inoculated intraperitoneally (i.p.) with Neospora caninum tachyzoites to examine parasite distribution and histological lesions at different time points over a 9-day period of infection. Gerbils were sacrificed 12 h post-infection (PI), then daily intervals up to day 9 PI. The parasite was detected by PCR assay targeting the Nc5 sequence of N. caninum. The parasite was not found in any organs until day 5 PI, however, from day 8 PI onwards, they were detected in all the organs examined as demonstrated by PCR. The first target organs in acute N. caninum infection were liver, spleen, and kidney, but not the blood as was expected. Histologic lesions were detected in the liver and spleen only, no lesions were found in other organs examined until the end of the experiment. Notably, the focal miliary hepatitis was observed in the liver of infected gerbils just after 1 day post-inoculation, whereas splenic lesions were not found until day 5 PI. These results reinforce the applicability of gerbils as a suitable model of acute neosporosis and provide new insights into the response of gerbils to N. caninum intraperitoneal infection.

Eosinophilic encephalomyelitis in horses caused by protostrongylid parasites.

Four thoroughbred horses showing lameness, ataxia, circling, depression, recumbency, and seizures, were examined. The horses had gross, pale- to dark-red manifestations and foci in the central nervous system (CNS). Multifocal to coalescing eosinophilic necrotizing encephalomyelitis was observed histologically in the CNS along with intact or degenerated nematodes. Nematodes had polymyarian-coelomyarian musculature, a smooth thin cuticle, and intestines lined by multinucleated cells with microvilli. These traits suggested the nematodes belonged to the family Protostrongylidae, which includes Parelaphostrongylus tenuis. It was concluded that the horses were infected by nematodes, presumably Parelaphostrongylus tenuis, resulting in eosinophilic necrotizing encephalomyelitis.

Color-dilution alopecia in dogs.

Color-dilution alopecia is a relatively uncommon hereditary skin disease seen in "Blue" and other color-diluted dogs. This syndrome is associated with a color-dilution gene. The initial clinical signs are the gradual onset of a dry, dull and poor hair coat quality. Hair shafts and hair regrowth are poor, and follicular papules may develop and progress to frank comedones. Hair loss and comedo formation are usually most severe on the trunk, especially color-diluted area on the skin. Six cases of color-dilution alopecia are reported in 3 months to 10 years old dogs. The breeds of dogs are blue Doberman Pinscher, Miniature Pinscher, Dachshund, and Schnauzer. Grossly, extensive partial hair loss was seen on the skin. Histopathologically, the epidermis is relatively normal but may be hyperplastic. Hair follicles are characterized by atrophy and distortion. Heavily clumped melanin is present in the epidermis, dermis and hair follicles.

Short communication: Proteomic characterization of tuberculin purified protein derivative from Mycobacterium bovis.

Bovine tuberculin purified protein derivative (bPPD) is used as an intradermal test (IT) reagent to detect bovine tuberculosis (bTB) in most countries. Identification of bPPD proteins is critical to understanding the immunological reaction of IT at the molecular level. While bPPD from the United Kingdom (UK) and Brazil (BR) have been recently defined at the proteomic level, bPPD from the Republic of Korea (KR) has not yet been analyzed. Here, bPPD KR proteome was examined for the first time. In total, 271 proteins were identified, including Mycobacterium bovis-specific proteins Mb0854c and Mb2898, and 42 known T cell antigens. On comparing with proteomes of bPPD UK and BR, 33 proteins were found to be common among all three bPPDs, of which 15 proteins were T cell antigens. M. bovis-specific antigens with T cell activity in bPPD may be novel candidates for use as alternatives to currently available bPPD in diagnostics.

A case of chronic wasting disease in an elk imported to Korea from Canada.

A seven-year-old male elk (Cervus elaphus nelsoni) was euthanized and necropsied after having a 3-week history of body weight loss, emaciation, excessive salivation, teeth grinding, fever, anorexia, and respiratory distress. The elk was imported into Korea from Canada on March 9, 1997. Gross pathologic findings were restricted to a diffuse fibrinous pneumonia. Microscopic lesions included mild neuronal vacuolation and spongiform change in the neuropil of selected brain stem nuclei and generalized astrocytosis. Immunohistochemistry for protease-resistant prion protein (PrP(res)) was positive in all brain sections but more pronounced in the section of the obex of the medulla. And the PrP(res) was also detected by western immunoblotting in the brain and spinal cord. All the remaining elk and deer that had been in contact with this elk were destroyed and negative for chronic wasting disease (CWD). To our knowledge, this is the first case of CWD occurring outside of the U.S.A. and Canada.

Mycobacterium bovis infection in a farmed elk in Korea.

A case of tuberculosis is reported in an eight-year-old, male, elk (Cervus elaphus nelsoni). The elk showed severe coughing, respiratory distress, abdominal breathing, anorexia, and severe progressive emaciation in the elk farm. At necropsy, the elk appeared in poor body condition. Mild enlargement of retropharyngeal and submandibular lymph node was observed in the head. Diffuse fibrinous pleuritis and purple red lobar pneumonia were found in the thorax. Well demarcated numerous dark yellow discrete or confluent nodules from 0.3 to 2 cm in diameter were scattered in the whole lung. Bronchial and mediastinal lymph nodes were also enlarged. Histopathologically, lungs had typical classical tuberculous granulomas, multiple abscesses, and numerous macrophages and Langhans giant cells infiltration in alveolar lumen. In the lymph nodes, there were small clusters of necrosis and infiltration of numerous macrophages, epithelioid cells, and Langhans giant cells. With the acid-fast staining, numerous mycobacteria were revealed in the lung and lymph nodes. According to this study, there are differences of the histopathologic lesions and the numbers of acid-fast bacilli in the lesions between this elk and cattle. Mycobacterium bovis was confirmed as a causative agent in this elk using bacterial isolation, biochemical characteristics, and PCR technique. The isolate was negative for niacin test, nitrate reductase, and pyrazinamidase. This is a first report for bovine tuberculosis of farmed elk in Asia.

Meningoencephalitis caused by Halicephalobus gingivalis in a thoroughbred gelding.

A 6-year-old Thoroughbred gelding was euthanized after a 2-month period of abnormal neurological signs, such as circling left in his pen and hitting his head and body against the wall. After the horse was euthanized on the farm, a half of the brain and whole blood were submitted for diagnostic tests. Histopathological examination of the brain revealed granulomatous and eosinophilic meningoencephalitis with numerous intralesional nematodes, predominantly affecting the cerebrum. Multifocal malacic foci were scattered in the brain parenchyma. The intralesional parasites were identified as Halicephalobus gingivalis by morphological features and PCR testing. To the best of our knowledge, this is the first report of meningoencephalitis caused by H. gingivalis in the horse in Korea.

Outbreak of botulism (Clostridium botulinum type C) in wild waterfowl: Seoul, Korea.

Over a 6-day period beginning on 15 October 2008, 93 dead or sick wild waterfowl, including Mallards, Spotbills, and teal species, were found along the shore of a branch stream of the Hangang River, which flows through Seoul, Korea, and were submitted to the National Veterinary Research and Quarantine Service (NVRQS) for diagnosis. Clinically, the affected birds showed flaccid paralysis of the legs and wings and paralysis of the neck. Grossly, no bird showed any lesions, but all had almost empty stomachs. Histopathologic findings included mild lymphocytic hepatitis and mild lymphocytic interstitial nephritis. Clostridium botulinum type C toxin was identified in sera collected from the birds using a mouse bioassay for botulinum toxins; however, no bacteria were isolated from any of the affected birds. In addition, a low-pathogenic avian influenza virus was isolated from two Spotbills, and pesticides such as diazinon and phorate, were detected in seven Mallards. The cause of this outbreak is not clear, but an increase in organic materials from sewage due to drought, increased temperatures, and an increased number of aquatic carcasses resulting from pesticide contamination may have increased the replication of C. botulinum, contributing to the release of botulinum toxins into the waterfowl food chain.

An outbreak of highly pathogenic H5N1 avian influenza in Korea, 2008.

In spite of intensive surveillance programs for the control of HPAI, an outbreak of highly pathogenic avian influenza (HPAI) H5N1 in Korea in April 2008 caused serious damage to poultry farms, as did previous outbreaks in 2003/2004 and 2006/2007. Six viruses were selected from the Korean 2008 isolates for genetic analysis, and all eight gene segments from each of the influenza viruses were sequenced. A phylogenetic analysis showed that all of the viruses were of the same virus type and that the hemagglutinin (HA) gene was clustered with that of clade 2.3.2 viruses. However, the internal and neuraminidase (NA) genes were closely related to those of the clade 2.3.4 viruses (recent human and bird isolates from Southeast Asia).

Porcine abortion outbreak associated with Toxoplasma gondii in Jeju Island, Korea.

This report deals with the acute onset of an abortion outbreak and high sow mortality in one pig herd consisted of 1,200 pigs and 120 sows on Jeju Island, Korea. Affected pregnant sows showed clinical signs, including high fever, gradual anorexia, vomiting, depression, recumbency, prostration, abortion, and a few deaths. Four dead sows, five aborted fetuses from the same litter, and 17 sera collected from sows infected or normal were submitted to the Pathology Division of the National Veterinary Research and Quarantine Service for diagnostic investigation. Grossly, hepatomegaly and splenomegaly were observed in sows. Multiple necrotic foci were scattered in the lungs, liver, spleen, and lymph nodes. Microscopically, multifocal necrotizing lesions and protozoan tachyzoites were present in the lesions. Tachyzoites of Toxoplasma (T.) gondii were detected immunohistochemically. Latex agglutination showed that the sera of 7 of 17 (41.2%) sows were positive for antibody to T. gondii. The disease outbreak in this herd was diagnosed as epizootic toxoplasmosis. To our knowledge, this is the first report of porcine toxoplasmosis with a high abortion rate and sow mortality in Korea.

The differential protein expression profiles and immunogenicity of tachyzoites and bradyzoites of in vitro cultured Neospora caninum.

We report a study on the variations in the protein expression profiles of tachyzoites and bradyzoites of Neospora caninum. The in vitro stage conversion of N. caninum-infected Vero cells was induced by continuous treatment of infected cultures with 70 muM sodium nitroprusside (SNP) for up to 9 days. The stage conversion indicated by the expression of the bradyzoite-specific antigen BAG1 was analyzed by immunofluoresence assay. Morphological changes between tachyzoites and bradyzoites and localization of nuclei were demonstrated by transmission electron microscopy. Notably, we showed the differential protein expression profiles of tachyzoites and bradyzoites of N. caninum upon treatment with SNP. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis indicated different protein patterns between tachyzoites and bradyzoites. Furthermore, Western blotting using rabbit polyclonal antibodies directed against tachyzoites revealed several reactive bands, one of which represented a tachyzoite-specific antigen of approximately 40 kDa remarkably expressed in the tachyzoite stage, but was absent from bradyzoites. Moreover, rabbit polyclonal serum raised against bradyzoites recognized a significant increased expression of an antigen with a MW of approximately 25 kDa in bradyzoites by Western blotting, suggesting that this protein is specifically expressed at the bradyzoite stage. Taken together, our data showed that differential protein expression profiling is a useful tool for discriminating between the two stages during tachyzoite-bradyzoite interconversion in N. caninum infections.