• Korean Journal of Veterinary Service
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• v.37 no.1
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• pp.11-18
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• 2014

Porcine reproductive and respiratory syndrome (PRRS) causes a significant economic loss in the swine industry not only in Korea but also all over the world. Andong and Hapcheon region were selected for Area Regional Control (ARC) programme to reduce the shedding of PRRS virus (PRRSV) and decrease PRRS outbreaks. Before conducting the PRRS ARC, sera of pigs were tested for both antibody using ELISA and antigen using RT-PCR, then phylogenetic classifications was analysed. Pigs of 138/275 (50.2%) in Andong and 352/425 (82.8%) in Hapcheon were seropositive. Also, the RT-PCR results revealed that 27 heads (8.2%) in Andong, 112 heads (22.0%) in Hapcheon were positive for PRRSV antigen. PRRSVs were mainly detected between the ages of 40 to 60 days. PRRSV ORF5 regions were used to determine genetic clusters based on previous report. All PRRSV type I detected in both Andong and Hapcheon were classified as Cluster I. The PRRSV type II isolates in Andong were assorted to Cluster II, whereas the PRRSV type II isolates in Hapcheon were the viruses were unassembled into any cluster except one identified to Cluster III. Phylogenetic analysis indicated that new clusters of PRRSVs type II were prevalent in Hapcheon.

• Korean Journal of Animal Reproduction
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• v.16 no.2
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• pp.87-102
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• 1992

A rapid, sensitive, and specific enzyme-linked immuno-sorbent assay (ELISA) for bovine casein was developed. Biotinylated casein and peroxidase-conjugated avidin were used in the assay with antibody separated from yolks of immunized hens. Caseins were biotinylated with sulfo-N-hydroxy succinimido biotin and peroxi-dase-conjugated avidin bound the biotinylated casein which became bound to immobilized anti-body on a microplate. The antibodies were specific for bovine $\alpha$- and $\beta$-caseins, and their cross-reactivities with whey proteins, IgG, and serum albumin from bovine were not detectable by ELISA and Western blot. Various sensitivities ranging from 2ng/ml to 20${\mu}\textrm{g}$/ml of casein were achieved, and were controlled by adding vanous concentrations of the biotinylated casein. Parallelism was observed between standard and sample curves. The coefficients of variation of intra-assays and inter-assays from the most sensitive assay were 5.5 and 5.7%, respectively, at the 50% displacement. Casein contents of peripaturient milk samples showed that casein secretion rapidly increased 3d prepartum.

• Parasites, Hosts and Diseases
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• v.49 no.3
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• pp.309-311
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• 2011

Seroepidemiological status of toxoplasmosis among the residents of Jeju island was surveyed and evaluated by ELISA with crude extract of Toxoplasma gondii. The sera of 2,348 residents (male 1,157 and female 1,191) were collected and checked for the IgG antibody titers, which showed 13.2% positive rate (309 sera). The positive rates were increasing gradually according to the age from 4.3% in teenage to 20.6% in seventies. The positive rates were significantly different between the sex by 16.2% for male and 10.2% for female (P<0.05). This positive rate of toxoplasmosis in Jeju island residents is regarded relatively higher than any other regions of Korea. And the high positive rate may be maintained continuously among Jeju island residents without any clear reasons until now but due to some parts peculiar socio-cultural tradition of Jeju island. Therefore, it is necessary to study further the epidemiology of toxoplasmosis of Jeju island.

• Journal of Microbiology and Biotechnology
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• v.29 no.3
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• pp.482-488
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• 2019

Porcine circovirus type 2 (PCV2) is the causative agent of postweaning multisystemic wasting syndrome (PMWS) in pigs. Replicase (Rep) proteins are considered essential for viral replication. Capsid (Cap) protein is the primary immunogenic protein that induces protective immunity. Little is known about comparison on the immunogenicity of PCV2 Rep and Cap fusion protein and Cap protein. In the present study, recombinant baculoviruses expressing the Rep-Cap fusion protein (Bac-Rep-Cap) and the Cap protein (Bac-Cap) of PCV2 were constructed and confirmed with western blot and indirect fluorescence assay. Immunogenicities of the two recombinant proteins were tested in mice. The titers of antibodies were determined with a PCV2-specific enzyme-linked immunosorbent assay (ELISA) and a serum neutralization assay. The $IFN-{\gamma}$ response of immunized mice was measured by ELISA. The mice immunized with the Bac-Rep-Cap and Bac-Cap successfully produced Cap-specific immunoreaction. The mice immunized with the Bac-Cap developed higher PCV2-specific neutralizing antibody titers than mice injected with the Bac-Rep-Cap. $IFN-{\gamma}$ in the Bac-Rep-Cap group was increased compared to those in the Bac-Cap group. Vaccination of mice with the Bac-Rep-Cap showed significantly decreased protective efficacy compared to the Bac-Cap. Our findings will indubitably not only lead to a better understanding of the immunogenicity of PCV2, but also improved vaccines.

• ANNALS OF ANIMAL RESOURCE SCIENCES
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• v.28 no.2
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• pp.78-96
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• 2017

Foot-and-mouth disease (FMD) is a infection that can easily spread when it occurs and causes serious economic damage because of the existence of multiple serotypes of the virus and extreme contagiousness. The most effective method in preventing the transmission of FMD virus (FMDV) is the culling of livestock and additional vaccination in the other areas depending on the spreading rate and situation. Diagnostic methods are utilized not only for the definite diagnosis of FMD but also for identification of serotype, and confirmation of antibody production after vaccination. Although many methods have been developed to diagnose, they are not still enough to detect accurately the disease in a short time. Therefore, it has been needed new diagnostic methods improved from existing methods. Previous methods were based on the enzyme-linked immunosorbent assay (ELISA) as a serological diagnostic method, or polymerase chain reaction (PCR), which is a molecular genetic method. The recent technology has been performing about the combination of both methods and how to make it faster, less costly, more sensitive and accurate way.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.522-525
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• 2011

In this study, an established enzyme-linked immunosorbent assay and immuno-chromatography technique are combined to fabricate an immuno-strip sensor for the detection of S. aureus. The immuno-strip is manufactured by using four different functional membranes. The capture antibody is immobilized on the nitrocellulose membrane due to the high affinity and the capillary action through porous membranes induces a flow of sample. A colorimetric signal is appeared according to the enzyme reaction and is analyzed by the digital camera (qualitative analysis) and home-made image analysis software (quantitative analysis). Under the optimal conditions, samples with S. aureus in the range of $2.7{\times}10^4{\sim}2.7{\times}10^7CFU/mL$ can be detected by the colorimetric method within 30 min.

• Korean Journal of Veterinary Service
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• v.44 no.1
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• pp.27-33
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• 2021

Q fever is a worldwide zoonotic disease caused by Coxiella burnetii. Domestic ruminants are considered to be major source of human infection. The aim of this survey was to investigate seroprevalence of C. burnetii in ruminants in Gwangju area. A total of 1,000 samples (serum and lactoserum) were collected from 987 Korean native cattle, 5 Korean native goats, 2 beef cattle, 6 bulk-tank milk from each dairy farm in Gwangju area from January to October 2020 and analyzed by ELISA. The seroprevalence of C. burnetii in bulk-tank milk from each dairy farms was 50.0%. Korean black goat and beef cattle had negative antibody test results for C. burnetii. The seroprevalence of C. burnetii in Korean native cattle in Gwangju area was 7.1% and was higher in female (7.8%) than in male (3.4%) (P=0.024). The seroprevalence of C. burnetii in Korean native cattle appeared to increase with age (3.8% in 1 year-old, 7.1% in 3 year-old, and 10.7% in more than 5 year-old) (P<0.001). The seroprevalence of C. burnetii of Korean native cattle increased in spring and May was the highest in particular (P<0.001). As the distribution and density of tick-habitat are expected to increase due to climate crisis, this survey highlights the need for monitoring C. burnetii in domestic ruminants, including surveillance of C. burnetii infection in people working for livestock industry.

• Korean Journal of Veterinary Research
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• v.63 no.4
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• pp.37.1-37.7
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• 2023

Canine respiratory coronavirus (CRCoV) is a significant pathogen that causes respiratory diseases in dogs, collectively known as a canine infectious respiratory disease. The virus is highly contagious and exhibits high seroprevalence worldwide. Currently, bovine coronavirus (BCoV) enzyme-linked immunosorbent assay (ELISA) kits are used to detect CRCoV antibodies. However, BCoV-ELISA kits cannot differentiate between infections caused by BCoV and those caused by CRCoV. In this study, we evaluated the hemagglutination inhibition (HI) test for CRCoV by comparing it with the virus neutralization (VN) test. Subsequently, we evaluated the seroprevalence of CRCoV in 383 dog serum samples collected from South Korea utilizing the HI test. The HI test for CRCoV showed a strong correlation with the VN test (R = 0.83, p < 0.001). The analysis of seroprevalence revealed that 52.2% (95% confidence interval [CI], 47.2%-57.1%) of the Korean dog serum samples were positive. The seroprevalence exhibited varied with age, with a positivity rate of 43.9% in dogs under 1 year of age and 66.7% in dogs aged 3 to 5 years (odds ratio, 2.54; 95% CI, 1.43-4.59). In conclusion, the HI test to monitor CRCoV antibody proved to be closely related to the VN test. Furthermore, over half of the dogs in Korea tested positive for CRCoV antibodies. These findings contribute to a better understanding of the sero-epidemiology of CRCoV.

• Korean Journal of Veterinary Service
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• v.46 no.4
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• pp.263-268
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• 2023

Despite regular vaccinations, equine influenza virus (EIV) and Streptococcus equi subsp. equi (strangles) are the cause of highly contagious respiratory infections in horses. Many recent studies have reported that the concurrent administration of two vaccines could simplify horse management and minimize veterinary expenses. However, there is little information available regarding the efficacy of concurrent vaccinations against EIV and strangles. In this study, we evaluated EIV-specific antibody responses following the single EIV vaccination with the recombinant viral-vectored EIV vaccine or concurrent vaccination with the EIV and inactivated strangles vaccines. Blood samples were collected at 1-, 2-, 4-, and 8 weeks post-immunization (wpi) from each group. EIV-specific antibodies were evaluated by enzyme-linked immunosorbent assay (ELISA) and hemagglutination inhibition (HAI) assay. Both single and concurrent vaccination showed similar levels of EIV-specific serum immunoglobulin g (IgG) at 1 and 2 wpi. However, at 4 to 8 wpi, the EIV-only vaccination group showed significantly higher serum IgG levels than those from the concurrently vaccinated group. The HAI titers showed similar trends as the ELISA data, except at 8 wpi when both groups presented HAI titers with no significant differences. These data demonstrate that the concurrent vaccination against EIV and strangles could compromise the humoral immune response to equine influenza between vaccination intervals, which suggests the use of the consecutive vaccination protocol for EIV and strangles rather than concurrent vaccination.

• Parasites, Hosts and Diseases
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• v.56 no.1
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• pp.61-70
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• 2018

We developed a Rapid Diagnostic Test (RDT) kit for detecting IgG/IgM antibodies against Zika virus (ZIKV) using monoclonal antibodies to the envelope (E) and non-structural protein 1 (NS1) of ZIKV. These proteins were produced using baculovirus expression vector with Sf9 cells. Monoclonal antibodies J2G7 to NS1 and J5E1 to E protein were selected and conjugated with colloidal gold to produce the Zika IgG/IgM RDT kit (Zika RDT). Comparisons with ELISA, plaque reduction neutralization test (PRNT), and PCR were done to investigate the analytical sensitivity of Zika RDT, which resulted in 100% identical results. Sensitivity and specificity of Zika RDT in a field test was determined using positive and negative samples from Brazil and Korea. The diagnostic accuracy of Zika RDT was fairly high; sensitivity and specificity for IgG was 99.0 and 99.3%, respectively, while for IgM it was 96.7 and 98.7%, respectively. Cross reaction with dengue virus was evaluated using anti-Dengue Mixed Titer Performance Panel (PVD201), in which the Zika RDT showed cross-reactions with DENV in 16.7% and 5.6% in IgG and IgM, respectively. Cross reactions were not observed with West Nile, yellow fever, and hepatitis C virus infected sera. Zika RDT kit is very simple to use, rapid to assay, and very sensitive, and highly specific. Therefore, it would serve as a choice of method for point-of-care diagnosis and large scale surveys of ZIKV infection under clinical or field conditions worldwide in endemic areas.