Publications by authors named "Hyejean Cho"

The objective of this field trial was to determine the efficacy of a recombinant toxoid vaccine against Shiga toxin 2e (Stx2e) in piglets suffering from edema disease (ED). Three farms with confirmed ED cases were selected for the field trials. On each farm, a total of 40 4-day-old pigs were randomly allocated to either the vaccinated or unvaccinated group, with 20 pigs per group (10 males and 10 females).

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This study was designed to investigate the different sequential order of infection for porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV). Thirty-six pigs were randomly assigned to six different treatment groups. The first (hereafter referred to as PRRSV-PCV2) group was inoculated with PRRSV first followed by PCV2d.

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Background: The objective of this field trial was to evaluate the efficacy of a new plant-based porcine circovirus type 2a (PCV2a) vaccine. This vaccine was a recombinant capsid subunit PCV2a vaccine based on the Nicotiana benthamiana expression system.

Methods: Three farms were selected for the study based on their history of subclinical PCV2 infection.

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The objective of the current study was to compare the virulence of four porcine circovirus type 2 (PCV2) genotypes (PCV2a, 2b, 2d, and 2e) in pigs. Pigs were inoculated at 42 days of age with one of four PCV2 genotypes, then necropsied at 63 days of age. PCV2 genotype groups were evaluated through a comparison of clinical outcomes, antibody titers, level of PCV2 loads in blood and lymph nodes, and lymphoid lesion severity.

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The objective of this study was to compare the virulence of four porcine circovirus type 2 (PCV2) genotypes (2a, 2b, 2d and 2e). Pigs were infected with one of these four genotypes. Pigs were also dually infected with Mycoplasma hyopneumoniae and one of the four PCV2 genotypes.

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The objective of this study was to evaluate the efficacy of a recombinant porcine circovirus type 2 (PCV2) vaccine based from a Nicotiana benthamiana expression system against four different co-challenges with PCV2 genotypes (2a, 2b, 2d, and 2e) and porcine reproductive and respiratory syndrome virus (PRRSV). Pigs in the vaccinated groups each received a 1.0 mL intramuscularly of plant-based PCV2a vaccine in the neck muscle at 21 days of age.

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The objective of this study was to compare two different bivalent vaccines containing porcine circovirus type 2 (PCV2) and . One vaccine contained PCV2a and the other contained PCV2b, and both were administered on a farm suffering from subclinical PCV2d infection and enzootic pneumonia. A total of 180 pigs were randomly divided into 3 groups (60 pigs per group; male pigs = 30 and female pigs = 30).

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The objective of this study was to develop multiplex polymerase chain reaction (PCR) for the simultaneous detection of porcine circovirus 2 (PCV-2) and differentiation among 4 PCV-2 genotypes (2a, 2b, 2d, and 2e) in collected clinical lymph node samples. The multiplex PCR detected each of 4 PCV-2 genotypes (2a, 2b, 2d, and 2e) to a dilution of 2 × 10 copies/μL. PCV-2a, PCV-2b, PCV-2d, and PCV-2e were propagated in tissues prior to DNA extraction for use in multiplex PCR for the simultaneous detection and differentiation of 4 PCV-2 genotypes.

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The objective of this field trial was to compare the effect of 3 different types of combination vaccines on growth performance in pigs under field conditions. The vaccines compared were: a trivalent vaccine containing porcine circovirus type 2a and 2b (PCV-2a/b); and a mixable bivalent vaccine containing PCV-2a and and a ready-to-use bivalent vaccine containing PCV-2a and . Two farms were selected on the basis of their history of subclinical PCV-2d infection and enzootic pneumonia.

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The objective of this study was to assess the clinical, immunological, microbiological, and pathological evaluation of trivalent vaccine containing porcine circovirus types 2a/b (PCV2a/b) and Mycoplasma hyopneumoniae given by two different needle-free injection devices compared with conventional needle-syringe injection in a herd with subclinical PCV2d infection and enzootic pneumonia. A total of 240 21-day-old pigs, which weighed between 5 to 6 kg, were randomly divided into four groups (60 pigs per group, 30 = male and 30 = female per group). Injection site reactions in the pigs were minimal for the two needle-free injection devices and needle-syringe injection.

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Background: This field trial was designed to evaluate the efficacy of a new trivalent vaccine containing porcine circovirus type 2a and 2b (PCV2a/b), and Mycoplasma hyopneumoniae at three independent locations.

Methods: Three farms were selected based on their history of PCV2 and M. hyopneumoniae co-infection.

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The objective of this study was to determine the pathogenicity of porcine circovirus type 2d (PCV2d) in pigs inoculated intranasally with PCV2d alone, PCV2d in combination with Mycoplasma hyopneumoniae or PCV2d in combination with porcine reproductive and respiratory syndrome virus (PRRSV). Pigs infected with PCV2d alone were asymptomatic. All pigs inoculated with either M.

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The objective of this study was to compare the virulence of three different porcine circovirus type 2 (PCV2) genotypes (PCV2a, PCV2b, and PCV2d) in pigs infected with either one of these three PCV2 genotypes versus pigs dually inoculated with and PCV2. Pigs were inoculated intratracheally with at 4 weeks of age followed by another intranasal inoculation at 6 weeks of age with one of three PCV2 genotypes. Dual infection with two pathogens produced moderate and severe dyspnea, lethargy, and reduced weight gain in pigs regardless of the PCV2 genotype evaluated compared with pigs only inoculated with PCV2.

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The aim of this study was to compare the virulence of porcine circovirus type 2 (PCV2) genotypes in dually inoculated pigs with both three genotypes (a, b, and d) of PCV2 and porcine reproductive and respiratory syndrome virus-2 (PRRSV-2) versus pigs singularly inoculated with the same three PCV2 genotypes (a, b, and d). Differences in this comparison were found in PCV2 viremia levels, lung and lymphoid lesion severity, and the amount of PCV2 antigen within the lymphoid lesions. Regardless of PCV2 genotypes, pigs that were dually inoculated with PCV2/PRRSV had significantly higher clinical scores, less average daily weight gain, higher levels of PCV2 viremia, and more severe lug and lymphoid lesions compared to pigs singularly inoculated with PCV2.

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The present field trial compared two combined vaccines of porcine circovirus type 2 (PCV2) and , each administered in herd with subclinical PCV2d infection and enzootic pneumonia. One vaccine was a bivalent containing PCV2a and and the other was a trivalent vaccine containing PCV2a and 2b (PCV2a/b), and . The defining difference between these two vaccines was the inclusion or absence of PCV2b antigen.

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The purpose of this study was to evaluate the efficacy of a new, single-dose bivalent vaccine containing porcine circovirus type 2b (PCV2b) and against a dual PCV2b and challenge. At -25 days post challenge (dpc, 10 days of age), one pig group (designated as the vaccinated/challenged group) received a single, 1.0 ml dose of bivalent vaccine.

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The purpose of this experimental study was to evaluate the efficacy of a new trivalent vaccine containing porcine circovirus types 2a/b (PCV2a/b) and Mycoplasma hyopneumoniae. Pigs were administered the vaccine intramuscularly as either at 3 and 24 days of age with 1.0 mL or at 21 days of age with 2.

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The objective of this study was to evaluate the efficacy of a new bacterin against a Korean challenge under experimental conditions. Fifteen pigs were allocated randomly into 3 groups (5 pigs per group) that were designated in 1 of 3 ways: vaccinated-challenged, unvaccinated-challenged, or unvaccinated-unchallenged. The pigs in the vaccinated-challenged group were immunized with an whole-cell bacterin at a 1.

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Background: The field efficacy of a bivalent vaccine containing porcine circovirus type 2b (PCV2b) and Mycoplasma hyopneumoniae was evaluated on three pig farms.

Methods: Three pig farms were used, two of which had a history of subclinical PCV2 and clinical M. hyopneumoniae infections between 84 and 126 days of age while concurrent porcine circovirus-associated disease and clinical M.

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The objective of this study was to compare the efficacy of commercially available porcine circovirus type 2 (PCV2) and vaccines. A total of 80 pigs was randomly divided into 6 treatment groups; 4 of the groups each received a different vaccine as well as a dual challenge. The remaining 2 groups were used as controls, 1 of which also received a dual challenge.

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This study describes the first isolation and genetic characterization of the newly emerging porcine circovirus type 2e (PCV2e) from Korean pigs. The PCV2e isolate did not produce a cytopathic effect in PCV-free PK-15 cells; therefore, PCV2e infection was demonstrated by immunohistochemistry with polyclonal PCV2a antibodies and polymerase chain reaction with primers specific for PCV2e. As the infected PCV-free PK-15 cells were passaged, the amount of infectious virus correlated with an increase in the amount of viral DNA (i.

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The present study evaluated the efficacy of swine vacciation using a combination of mixable monovalents for porcine circovirus type 2 (PCV2) and against a ready-to-use bivalent vaccine under experimental conditions. Pigs at 21 days of age were administered either a combination of two mixable monovalent vaccines or a bivalent vaccine containing PCV2 and . Vaccination was followed with an challenge at 42 days of age (-14 days post challenge, dpc) and a PCV2d challenge at 56 days of age (0 dpc).

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The objective of this study was to compare the virulence of 3 major Korean porcine circovirus type 2 (PCV2) genotypes in terms of clinical signs, PCV2 viremia and antibody titers, lymphoid lesions, and PCV2-antigen within lymphoid lesions in experimentally infected pigs. Pigs were infected at 7 weeks with PCV2a, PCV2b, and PCV2d strains and necropsied at 28 days post-infection. No statistical differences were observed in clinical signs, PCV2 viremia and antibody titers, lymphoid lesions scores, and numbers of PCV2 antigens among the 3 major Korean PCV2 genotypes.

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The objective of this study was to evaluate the efficacy of a modified-live virus (MLV) porcine reproductive and respiratory syndrome virus (PRRSV) vaccine against a heterologous PRRSV-2 challenge in late-term pregnancy gilts under experimental conditions. Eighteen gilts were randomly assigned to vaccinated-challenged, unvaccinated-challenged, and unvaccinated-unchallenged groups ( = 6 gilts per group). Pregnant gilts in the vaccinated-challenged and unvaccinated-unchallenged groups were able to carry their pregnancies to full term and farrowed after 114 to 115 days of gestation.

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Background: Four commercial porcine reproductive and respiratory syndrome virus (PRRSV) modified-live vaccines (MLV) was compared to protect growing pigs against dual challenge of PRRSV-1 and PRRSV-2.

Methods: Two of the vaccines were based on PRRSV-1, and two on PRRSV-2. A total of 72 PRRSV-naïve pigs were divided into six groups (12 pigs/group).

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