• Korean Journal of Veterinary Service
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• v.35 no.4
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• pp.263-268
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• 2012

From the end of July 2012, several cases of abortion have been happened at the Korean indigenous cattle farm with 124 heads in Chungbuk province, Korea. Serological tests such as Rose-bengal test (RBT) and standard tube agglutination test (STAT) have been performed according to the standard official protocols of bovine brucellosis and 41 cattle turned out to be brucellosis-positive simultaneously. To find out the main factors of brucellosis outbreaks and spreads, additional serological, etiological and molecular investigation were applied. Totally, 11 B. abortus were isolated from 10 cattle's specimens including lymph-nodes and/or testis, and drinking water in cowhouse. In genotyping by multi-locus VNTR assay (MLVA) using 17 loci markers, the present B. abortus isolates were shown all the same pattern, D1 genotype, which has been reported in Gyeonggi and Gangwon province, Korea. These results suggest that the input of brucellosis might come from neighboring farms directly or indirectly, even if by unknown factor and expansion within farm would accelerate by materials related with aborting cows.

• Proceedings of the Korean Society of Veterinary Service Conference
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• 2001.06a
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• pp.176.2-177
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• 2001

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.725-729
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• 2006

A method was developed for the determination of fructooligosaccharides and raffinose contents in infant formula. The samples were extracted and analyzed by liquid chromatography equipped with carbohydrate column and evaporative light scattering detector. The mobile phase used for the gradient mode was water-acetonitrile, at a flow rate of 1.0mL/min. The method showed a mean recovery of 95-99%, the relative standard deviation obtained in the precision study was 0.774-8.982%, the quantification and detection limits were 25-50mg/L.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.543-549
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• 2000

The pathogenicity of Br abortus RB51 strains, producted by commercial vaccine companies in Republic of Korea and USA, were evaluated in mouse and guinea pig. BALB/c and ICR mice were intraperitoneally inoculated with RB51 vaccines or virulent field strain and the existence of RB51 including its ratio of spleen to weights and persistence in spleens were examined. Groups of guinea pigs on day 55-58 of received subcutaneously with various RB51 vaccines, RB51 field isolates (Daehungjin) or virulent field isolates(Sangju) to compare the histopathogenicity in uterus. All the mice received RB51 vaccines or RB51 field isolates survived for 10 days, but the groups of mice received virulent field isolates died 5 from 11 (45.5%) in case of BALB/c mice and 12 from 12 (100%) in ICR mice, respectively. The number of RB51 in the groups of mice given with vaccine strains and RB51 field isolates were declined rapidly were in spleens between 12 and 20 days after inoculation. In contrast the mice given with the virulent field isolates rose in number of bacteria up to 20 days after inoculation. In the groups of mice infected with virulent field isolates, the ratio of spleen weights to body weight were significantly higher than those in control or in the groups inoculated with RB51 strain, including RB51 field isolates, at 12 and 20 days after inoculation. At ten days after inoculation, placentas of both the pregnant and non-pregnant guinea pigs were conducted for histopathological examination. Although any abnormal lesions were not observed in non-pregnant guinea pigs, all the strains caused the inflammation of the placenta, implying pathogenecity of RB51 in pregnant guinea pigs.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.533-541
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• 2000

Biochemical and genetic analysis were carried out to investigate the potential recovery of pathogenecity or related mutations of Brucella abortus RB51 vaccine strains. RB51 strains were recovered from commercial vaccines, including related seed stocks from private companies in Republic of Korea, strain from USA, a reference strain from C university and a field isolate (Daehungjin) from aborted dairy cow after RB51 vaccination were compared with two identified virulent wild strains (S2308 and a field strain isolated from dairy cow in Korea) at the same conditions. All the strains examined, except identified pathogenic strains, revealed the identical characteristics to the original RB51 in biochemical properties, antigen and bacteriophage typing. Outer membrane protein (OMP) profiles from strains of RB51 showed the same patterns with standard RB51 in SDS-PAGE. In addition, Western blotting with the brucella specific monoclonal antibody also indicated that all the vaccine strains were completely deficient in their LPS compared to the pathogenic Br abortus strains. The differences in DNA structures among strains were also possible to detect after PCR. All vaccine strains, except S19, S1119-3, S1075, S544 and Br suis, were amplified a 178bp DNA fragment of eri-gene, and 364bp of IS711 elements. In contrast, 498bp DNA product was only found with Br abortus. Overall evidences in the present study confirmed that the RB51 strains for vaccine production in Korea did not originated from the phenomena of possible recovery of pathogenicity or related to any potential mutation event at all.

• Korean Journal of Poultry Science
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• v.37 no.2
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• pp.159-165
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• 2010

Field strains of Ornithobacterium rhinotracheale (OR) were tested on their virulence in specific pathogen free (SPF) embryonated chicken eggs and 3-week-old broilers. When infected with three different OR isolates (OR-161, OR-240 and OR-295) through yolk sac infection route, all strains appeared to be highly pathogenic with responsible mortality 66% and 100% within 12 days post infection (DPI). To test the virulence of OR in the commercial broilers, 3 week-old broilers were grouped depends on the inoculation route of OR isolate (OR-295) through five different infection routes; group 1 (IT: intratracheal), group 2 (IM: intramuscular), group 3 (IV: intravenous), group 4 (aerosol) and group 5 [Mixed: NDV (LaSota)+OR aerosol]. Within 5 to 7 days after inoculation, only broilers given NDV+OR were slightly depressed and coughing, and had mild facial redness. Grossly, foamy and yellow-white yogurt like exudate in the air sacs, predominantly in the abdominal air sacs was present. In histology, infiltration of the air sac epithelium and lamina propria by macrophage and polymorphonuclear granulocytes was seen with cell debris and inflammatory cells, correlated with the presence of OR antigen, as demonstrated by immunohistochemistry. Field strains of OR were able to induce high mortality in the embryonated chicken eggs, whereas broilers were less susceptible to OR infection. Interestingly, in the absence of NDV infection, the four groups of OR single infection only different route showed minimal and temporary microscopic air sac lesions. Thus, Newcastle disease virus (LaSota strain) showed triggering effects on the OR infection in chickens.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.110-116
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• 2000

Duck viral hepatitis is an acutic, highly infectious viral disease of young ducklings. The most practical means for controlling duck viral hepatitis is the vaccination of ducklings or of a breeding stock. We attempted to develop a vaccine strain of duck hepatitis virus (DHV) using a Korean isolate by serial chicken embryo passages. The propagation of DHV in chicken embryos was carried 140 passages. After the $50^{th}$ passage, of which the virus was non-pathogenic for ducklings, approximately every $20^{th}$ passage of the virus was tested for vaccinal efficacy. Both the $70^{th}$ and $90^{th}$ passage of the virus gave good protection against challenge infection to a DHV-DRL reference strain(type 1) and a virulent Korean isolate. The $110^{th}$, $125^{th}$ and $140^{th}$ passage of the virus were less protective than the $70^{th}$ and $90^{th}$ passage, which means that more than $110^{th}$ passage may lead to over-attenuation of the virus. Ducklings vaccinated with the chicken-embryo-adapted virus by oral, intramuscular or eye drop administration showed earlier resistance to challenge infection from 3 to 7 days postvaccination. Of the above methods, ducklings vaccinated intramuscularly presented the most rapid resistance against challenge. The minimum immune dose of the chicken-embryo-adapted virus in ducklings was also studied. Ducklings inoculated with a dose of $10^{2.0}\;ELD_{50}$ and below were not fully protected against challenge with a virulent DHV, showing a protection rate of 67% to 73%, but ducklings inoculated with a dose of $10^{3.0}\;ELD_{50}$ and over were completely protected. The virus yield of the chicken-embryo-adapted DHV was examined at 24hrs and 48hrs of the incubation time in the allantoic fluid, embryo head and embryo minus head of the embryonating egg. In all three components, the titer of the virus was higher at 48 hours than that at 24 hours after incubation. And the titer of the virus was higher in the embryo minus head, embryo head and the allantoic fluid, in order. Field trials for evaluating the efficacy of the attenuated DHV as a live vaccine were done in duck farms with about 25% mortality of flocks resulting from duck viral hepatitis. After the use of the experimental vaccine, the mortality due to duck viral hepatitis was dramatically reduced in the farms. These results indicated that the attenuated DHV using a Korean isolate could be a good candidate as a live vaccine strain of DHV in Korea.

• Journal of Food Hygiene and Safety
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• v.25 no.4
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• pp.341-345
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• 2010

Three-hundred samples of powdered infant formula milk and related products from four different manufacturers in 2010 were collected and surveyed their contaminations for aerobic bacteria, coliform, Enterobacter(Cronobacter) sakazakii, and food-borne pathogens. Fifteen samples of sterilized infant formula milk were all negative on these microorganisms. In all collected products of un sterilized infant formulas and follow-on infant formulas, aerobic bacteria were detected at 239 (83.9%) among 285 samples, and they all were found below $10^3$ cfu/g. Coliform bacteria were also detected at four among 285 samples. Salmonella spp. and Ent. sakazakii, weren't detected at the all samples. Bacillus cereus was detected at 24 (8.4%) among 285 samples. The level of B. cereus was below 100 cfu/g but it was suitable for the range of specification of B. cereus in infant formulas. Clostridium perjringens, Escherichia coli O157:H7, Staphylococcus aureus and Listeria monocytogenes weren't also detected. In consequence, it was suitable for total viable count, coliform and potential pathogen to the specification of infant formulas and related products.

• Journal of Veterinary Clinics
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• v.26 no.3
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• pp.226-230
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• 2009

We evaluated the efficacy of $\beta$-hemolytic Streptococcus(S.) iniae vaccine on cultured olive flounder. Three hundred flounders(weight $50{\pm}5$ g) were obtained from two farm at Wando and Taean in the southern and western coast of Korea at May and June 2007, respectively. Twenty of flounders moved in 0.5 tons aquaria in land-marine tank system of National Veterinary Research and Quarantine Service. Seawater was transported from the sea of Inchon in western Korea, and water temperature maintained to $22^{\circ}C$ and $25^{\circ}C$ during the vaccination and challenge test, respectively. We used the formalin-inactivated $\beta$-hemolytic S. iniae vaccine produced by domestic manufacturers. The vaccine was intraperitoneally administered to fish. The vaccinated and control group were challenged with intraperitoneal injection by virulent S. iniae SI-36 isolates with $5.0{\times}10^8$ CFU/fish at 3 weeks after vaccination. We evaluated the vaccine efficacy by calculating numbers of dead fish, and observing of clinical signs, exterior and gross lesions, and examining bacteria isolation and identification. Thirty-four(25.2%) of 135 control and vaccinated group fish were dead with serious anemia, abdominal extension, and hernia of intestine during 3 weeks post vaccination. We isolated Neoheterobothrium hirame from the buccal cavity and Edwardsiella tarda from kidney of dead and diseased fish. When infected fish with these agents were challenged with S. iniae SI-36 isolates, the cumulative mortality of control and vaccinated group were 86.7, and 46.7%, respectively. However, significant differences(p<0.05) were observed on cumulative mortality between control(20.0%) and vaccinated group(95.0%) at second trials with 40 healthy, and relative percent survival(RPS) was 78.0%. We confirmed that the efficacy of $\beta$-hemolytic S. iniae vaccine on olive flounder were impacted by health condition such as bacterial and parasitic diseases.

• Korean Journal of Microbiology
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• v.41 no.4
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• pp.269-274
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• 2005

We evaluated the PCR assay and two commercialized PCR kits for the detection of mycoplasma in veterinary via live vaccines. The PCR assay could specifically detect all the tested Mycoplasma spp. and Acholeplasma spp., whereas two commercialized PCR kits did not. Also, the specificity of the PCR assay showed that 4 reference strains and 7 field isolates belonging to avian mycoplasma species could be all detected. The sensitivity of the PCR assay was determined using pure cultured Mycoplasma spp. and Acholeplasma spp. with a range of 1 to 100 colony forming units/ml in 9 CFR Mycoplasma broth. To test the availability of the PCR assay for veterinary live viral vaccines, A. laidlawii was artificially inoculated into the swine transmissible gastroenteritis-rota virus combined vaccine and canine parvovirus vaccine, respectively and the sensitivity of the PCR assay was similar with the result of cultured samples. In this study, the PCR assays could be used as rapid and sensitive methods for the detection of mycoplasma in veterinary live viral vaccines.