• Korean Journal of Veterinary Research
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• v.63 no.1
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• pp.23.1-23.1
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• 2023

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.32-32
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• 2003

Intestinal infections are common in growing pigs and can be caused by multiple pathogens, environmental and management factors [1]. Among the most important viruses in swine enteritis are porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine enteric calicivirus (PECV), porcine group A rotavirus (PRV gp A) and bacteria are Escherichia coli and Salmonella spp. and protozoa is Isospora suis [1]. The DNA chip system can serve as a powerful tool that can be utilized for simultaneous detection of specific pathogenic bacteria strains and viruses [2,3]. The combination of PCR and DNA chip technology will provide a novel method for the detection of porcine enteric pathogens thus revolutionize the diagnosis and management of the disease. The aim of this study is to develop DNA chip system for the rapid and reliable detection of five major porcine enteric pathogens based on oligonucleotide DNA chip hybridization. (omitted)

• Journal of Veterinary Clinics
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• v.23 no.3
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• pp.300-307
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• 2006

In the present study, methods of the reverse transcription-polymerase chain reaction(RT-PCR) were evaluated for the rapid detection and differentiation of transmissible gastroenteritis virus(TGEV), porcine epidemic diarrhea virus(PEDV) and rotavirus in piglets suffering from diarrhea. For the purposes, the PCR conditions were first confirmed for the amplification of VP7 gene of rotavirus and N gene of TGEV and PEDV using each specific primers and their annealing temperature. Multiplex RT-PCR methods were further determined to distinguish these viral infections and the results are as follows. For the specific amplification of these viral genes, the reliable PCR condition was determined as 30 cycles of reaction consisting each 1 min of denature at $94^{\circ}C$, annealing at $42^{\circ}C$ and polymerization at $72^{\circ}C$ with 1.0 mM $MgCl_2$. It was able to differentiate these viral infections in the intestines and feces of piglets suffering from diarrhea by duplex PCR for TGEV and PEDV and single PCR for rotavirus with a primer-annealing temperature of $42^{\circ}C$. When the multiplex RT-PCR were undertaken for the field samples, 17 cases of PEDV and 5 cases of rotavirus infections were differential diagnosed in a total of 92 samples of intestines and feces of the piglets with diarrhea.

• Journal of Veterinary Clinics
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• v.26 no.5
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• pp.463-466
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• 2009

A swine farm located in the Kyungpook province (designated as farm D that have been suffering from PED for several years was selected to study the etiology and the outbreak pattern of PED by clinical and laboratory examinations. Clinical examination indicated that sows exhibited signs of mastitis resulting in an inadequate transfer of lactogenic immunity against PEDV to newborn piglets. Furthermore, serological tests revealed that all sow groups and their piglets had low levels of anti-PEDV antibody. These data suggest that improper vaccination program has been indeed performed in this farm. Remarkably, despite no symptoms of PED in weaners, the presence of PEDV was identified by RT-PCR from fecal samples of weaning piglets, indicating persistent PEDV circulation in the herd. Based on these results, the following basic control schemes were executed for the control of PEDV circulation in the farm; a) A quick removal of affected pigs and disinfection of affected sheds. b) restructuring of vaccination program and employment of consultant. c) prompt treatment of mastitis and removal of poor lactogenic sows, and d) enhancement of biosecurity of farrowing house by acquisition of additional space. We evaluated risk factors and implementation of control measures in two months and were unable to found any case related to PEDV infection. Taken together, our data indicate that the method described above is effective for the control of PED outbreak in farm persistently suffering from PEDV infection.

• Korean Journal of Veterinary Pathology
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• v.6 no.1
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• pp.19-26
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• 2002

The purpose of this study was to investigate to potective effects against porcine epidemic diarrhea virus (PEDV) infection in piglets by administration of the PEDV antiserum orally at 2 hrs, 24hrs and 36hrs after birth. six piglets administered the antiserum were experimentally infected with PEDV at five-day-old. Control group were four piglets infected with PEDV only. Serum antibody titers against PEDV were examined by serum neutralization (SN) test, dectection for PEDV or PEDV antigen from feces and small intestines was tested by reverse transcription-polymerase chain reaction (RT-PCR) and indirect immunoflurescence (IFA). The results obtained were as follows; 1. The piglets administered the PEDV antiserum showed higher antibody titers than those of control group and sustained during the experimental period. 2. The detection rate of PEDV in feces and small intestines by RT-PCR were 26.2% and 16.7% in PEDV antiserum treated group and 48.1 % and 75.0% in control group, respectively. 3. The detection rate of PEDV antigen in the small intestine by IFA were 0% in PEDV antiserum treated group and 50.0% in control group, respectively. It was concluded that oral administration of antiserum against PEDV to piglets was effective in preventing PEDV infection.

• Journal of Veterinary Science
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• v.22 no.4
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• pp.48.1-48.15
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• 2021

Background: Porcine epidemic diarrhea virus (PEDV) is a swine enteropathogenic coronavirus that has devastated the swine industry in South Korea over the last 30 years. The lack of an effective method to control the endemics has led to a surge in PEDV recurrences in affected farms throughout the country. Objectives: In the first step toward establishing systematic monitoring of and active control measures over the swine populations, we constructed an assessment model that evaluates the status of (1) biosecurity, (2) herd immunity, and (3) virus circulation in each of the PEDV-infected farms. Methods: A total of 13 farrow-to-finish pig farms with a history of acute PEDV infection on Jeju Island were chosen for this study. The potential risk of the recurrence in these farms was estimated through on-site data collection and laboratory examination. Results: Overall, the data indicated that a considerable number of the PEDV-infected farms had lax biosecurity, achieved incomplete protective immunity in the sows despite multi-dose vaccination, and served as incubators of the circulating virus; thus, they face an increased risk of recurrent outbreaks. Intriguingly, our results suggest that after an outbreak, a farm requires proactive tasks, including reinforcing biosecurity, conducting serological and virus monitoring to check the sows' immunity and to identify the animals exposed to PEDV, and improving the vaccination scheme and disinfection practices if needed. Conclusions: The present study highlights the significance of coordinated PEDV management in infected farms to reduce the risk of recurrence and further contribute towards the national eradication of PEDV.

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.581-588
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• 1998

Eight monoclonal antibodies(MAbs) against bovine coronavirus(BCV) were produced and characterized. Three MAbs(1G9, 4H12, 5C1) specific to the S glycoprotein and two HE glycoprotein-specific MAbs(2A5, 5G4) were found to neutralize the BCV in fluorescence focus neutralization(FFN) test. Two HE-specific MAbs from the neutralizing MAbs inhibited the hemagglutinating activity of the BCV. None of the N protein-specific MAbs(1C1, 5A12, 6H1) neutralized the virus infectivity. Bovine coronavirus and mouse hepatitis virus, which belong to group II coronaviruses, were differentiated from other groups of coronaviruses(porcine transmissible gastroenteritis virus, porcine epidemic diarrhea virus, canine coronavirus) by all MAbs in fluorescence antibody test(FA), but not in FFN test.

• Korean Journal of Veterinary Service
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• v.32 no.3
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• pp.201-207
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• 2009

Porcine transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhea virus (PEDV) and rotaviruses are considered as the most important causative agents of diarrhea in piglets. The study established 3 method vaccination programs to prevent PEDV. A (LL)group inoculated twice vaccinations on 2-weeks-interval during the late term of pregnant sows with PEDV live vaccine. The B (LKK) group was applied that one time single PEDV live vaccine at the pre-mate followed by the TGEV PEDV combined inactivated vaccine (twice vaccination on 2-weeks interval at the third-trimester). C (KK) group was applied to sow which inoculated twice vaccination on 2-weeks-interval during the late term of pregnant sows with by the TGEV, PEDV combined inactivated vaccine. As the result of SN test on sows in the pig farm before vaccination, antibody titers was showed 9/45 (20.0%). By comparison with the serum neutralizing antibody titers against PEDV of the vaccination programs after PEDV of the vaccination, A group and B group vaccination method was higher than those of C group in sows. In the piglets up to 2 weeks of age, A group was showed antibody titers of 17/22 (81.8%) that showed 2-128, and B group was showed antibody titers of 30/37 (81.1%) that showed 2-512, and C group was showed antibody titers of 14/28 (50.0%) that showed 2-32. On the other hand, PEDV antibody titers were tested for the survey. As the results of SN test, Aujeszky's disease survey in 54 pig farms from november 2005 to august 2006, antibody titers of 47/286 (16.4%) showed above 2. Five breeding farms were antibody titers of 38/77 (49.4%), Wanggung zone farms antibody titers of 59/85 (69.4%). In pigs farms vaccinated the first of twice PEDV live vaccine, and after 6 month, the second of twice TGEV PEDV combined inactivated vaccine (LLKK, 256-1024 titer) method was higher than those of vaccinated twice the early term of pregnant, and twice the late term of pregnant sows of PEDV live vaccine (LLLL, 32 titer).

• Korean Journal of Veterinary Service
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• v.43 no.4
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• pp.237-244
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• 2020

Porcine transmissible gastroenteritis (TGE) has been a significant cause of economic losses in pig farming industry since 1950s. Although transmissible gastroenteritis virus (TGEV) has declined in recent years, it should not be excluded because of its characteristics; the frequency of gene mutation, the mortality in piglets, and the possibility for sudden incidence. Therefore, the herd-level monitoring of the virus is important to prevent further circulation of TGE. The aim of this study is to develop a large-scale sandwich enzyme-linked immunosorbent assay (ELISA) with high specificity to rapidly detect TGEV in feces by using monoclonal antibodies (Mabs). The TGEV specific Mabs were produced in hybridoma cells. Among the Mabs belonged to the IgG class developed by this study, the final selected 8H6, 1B7, 4G3, and 1F8 were identified to have the neutralization ability against TGEV. The sandwich ELISA was established using 8H6 as a reporter antibody and 1B7 and the reported 5C8 as a capture antibody. The developed sandwich ELISA was able to distinguish TGEV from other pathogenic diarrheal agents (porcine rotavirus, porcine reovirus, porcine epidemic diarrhea virus (PEDV), E. coli, and C. perfringens) in tissue culture as well as fecal samples. And the detection rate of TGEV in feces was 80% compared with RT-PCR. The results suggested that the developed sandwich ELISA may be useful in the herd-level monitoring for effective preventive measures due to the early diagnosis of TGEV using a large amount of samples.

• Korean Journal of Veterinary Service
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• v.44 no.2
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• pp.73-83
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• 2021

Although many swine farms continuously vaccinated to sow to prevent Porcine epidemic diarrhea(PED), PED has occurred annually in swine herds in Jeonbuk province, Korea. In the present study, the small intestine and feces samples from 17 farms where severe watery diarrhea and death of newborn piglets occurred in 2019 were collected, amplified by RT-PCR and determined the complete nucleotide sequences of the spike (S) glycoprotein genes of nine Jeonbuk PEDV isolates. The spike (S) glycoprotein is an important determinant for molecular characterization and genetic relationship of PEDV. These nine complete S gene isolates were compared with other PEDV reference strains to identify the molecular diversity, phylogenetic relationships and antigenicity analysis. 9 field strains share 98.5~100% homologies with each other at the nucleotide sequence level and 97.3~100% homologies with each other at the amino acid level. The nine Jeonbuk PEDV isolates were classified into G2b group including a genetic specific signal, S-indels (insertion and deletion of S gene). In addition, comparisons the neutralizing epitopes of S gene between 9 field strains and domestic vaccine strains of Korea mutated 12-15 amino acids with SM-98-1 (G1a group) and mutated 0-3 amino acids with QIAP1401 (G2b group). Therefore, the development of G2b-based live vaccines will have to be expedited to ensure effective prevention of endemic PED in Korea. In addition, we will need to be prepared with periodic updates of preventive vaccines based on the PEDV variants for the re-emergence of a virulent strain.