• Journal of Veterinary Science
• /
• v.24 no.4
• /
• pp.58.1-58.25
• /
• 2023

Porcine epidemic diarrhea virus (PEDV) has posed significant financial threats to the domestic pig industry over the last three decades in South Korea. PEDV infection will mostly result in endemic persistence in the affected farrow-to-finish (FTF) herds, leading to endemic porcine epidemic diarrhea (PED) followed by year-round recurrent outbreaks. This review aims to encourage collaboration among swine producers, veterinarians, and researchers to offer answers that strengthen our understanding of PEDV in efforts to prevent and control endemic PED and to prepare for the next epidemics or pandemics. We found that collaboratively implementing a PED risk assessment and customized four-pillar-based control measures is vital to interrupt the chain of endemic PED in affected herds: the former can identify on-farm risk factors while the latter aims to compensate for or improve weaknesses via herd immunity stabilization and virus elimination. Under endemic PED, long-term virus survival in slurry and asymptomatically infected gilts ("Trojan Pigs") that can transmit the virus to farrowing houses are key challenges for PEDV eradication in FTF farms and highlight the necessity for active monitoring and surveillance of the virus in herds and their environments. This paper underlines the current knowledge of molecular epidemiology and commercially available vaccines, as well as the risk assessment and customized strategies to control PEDV. The intervention measures for stabilizing herd immunity and eliminating virus circulation may be the cornerstone of establishing regional or national PED eradication programs.

• Korean Journal of Veterinary Research
• /
• v.35 no.3
• /
• pp.575-581
• /
• 1995

Both immunoelectron microscopy(IEM) and immunogold conjugate immunoelectron microscopy (IGC-IEM) techniques were developed for the detection of porcine epidemic diarrhea virus(PEDV) from the feces. Fecal samples were incubated sequentially with anti-PEDV monoclonal antibody(MoAb) and immunogold conjugated goat anti-mouse IgG+IgM. Then negatively stained, mounted on the formvar carbon-coated copper EM grids and observed by the transmission electron microscope. By the direct electron microscopy(DEM), coronavirus particles were observed from 17 cases of total 33 fecal samples of grower pigs and sows. The virons of coronavirus were moderately pleomorphic but mostly spherical, with a diameter ranged from 90 to 190nm. PED virus particles were identified from 15 cases of 17 DEM positive samples by the IEM and IGC-IEM techniques. Aggregates of PED virus coated with specific antibody were seen in fecal samples incubated with homologous anti-PED virus MoAb but not in control samples incubated with anti-TGE virus MoAb. Following incubation with immunogold-conjugated secondary antibody, the gold granules were usually distributed around and among the virus particles and soluble and viral particle-associated antigen. So, IEM and IGC-IEM techniques were proved a rapid and sensitive methods for detection and identification of PED virus from fecal and intestinal contents.

• Korean Journal of Veterinary Service
• /
• v.23 no.3
• /
• pp.301-306
• /
• 2000

In an outbreak of acute porcine diarrhea in newborn piglets, an etiological study was carried out using piglets submitted in Cheju Province Institute for Livestock Promotion(Cheju Veterinary Service for the disease diagnosis). Sixteen piglets(2-7 days old) were collected from 4 farms during outbreaks of diarrhea disease(from January to April 2000). Specimens were taken after necropsy and examined by immunohistochemistry using of monoclonal antibodies for porcine epidemic diarrhea(PED) virus, transmissible gastroenteritis(TGE) virus, and porcine rotavirus. Immunohistochemistry showed that PED virus antigens, but both TGE virus and rota virus antigens not, were localized in the some epithelial cells of the intestines of 14 animals among 16 piglets examined. PEB virus antigens were mainly detected in the cytoplasm of enterocytes. Infected cells, which were most abundant in the villous epithelial cells of the jejunum and ileum, were uncommon in the crypt, epithelial cells, the lamina propria and Peyer's patches of piglets examined. The results suggest that PED virus is one of the most prevailing agents in an outbreak of fatal diarrhea in newborn piglets on Cheju island and PED virus was need to further study to prevent this disease.

• Proceedings of the Korean Society of Veterinary Pathology Conference
• /
• 2003.10a
• /
• pp.43-43
• /
• 2003

Porcine epidemic diarrhea (PED), transmissible gastroenteritis (TGE) are an acute viral enteritis. colibacillosis by E coli is a microbial enteritic disease in suckling piglets[1]. These infectious intestinal diarrheal diseases cause severe diarrhea to suckling piglets, so that lead to enormous economical loss in swine-product industries. Ig-Top (AD Biotech, Korea) is a immunomodulator with IgY the specific yolk-antibody for PED, TGE and E. coli and oligosaccharide. The purpose of this study was to investigate protective effects against PED virus, TGE virus E.coli and in suckling piglets by oral administration of the Ig-Top. (omitted)

• Korean Journal of Veterinary Research
• /
• v.37 no.4
• /
• pp.809-816
• /
• 1997

In this presented study, we established a method for diagnosis of porcine epidemic diarrhea(PED) by in situ hybridization(ISH), which made distinct progress in diagnostic pathology. We also carried out the retrospective diagnosis through ISH to assume the exact time of the first outbreak and incidence of PED in Korea. The outbreak of PED in Korea reported in 1992. However, since the end of 1980's, some researches of pig-industry have already suspected the outbreak of PED, not transmissible gastroenteritis(TGE). In this experiment, we performed the ISH using 80 formalin-fixed and paraffin-embedded tissues of porcine intestine which were requests for pathological diagnosis from 63 farms whose primary sign was diarrhea from 1984 to 1991. We prepared biotinylated cDNA probe(492base pairs) for ISH by nick translation method and carried out the ISH, using $Microprobe^{TM}$ capillary action system(Fisher $Biotech^R$). We detected PED virus in intestinal mucosa of 2 cases in 1992, 1 case in 1988, and 1 case in 1987. As a result, we assume that the outbreak of PED in Korea have already started since 1987.

• Korean Journal of Veterinary Pathology
• /
• v.3 no.1
• /
• pp.35-44
• /
• 1999

The morphologic changes of small intestinal epithelium in pigs diagnosed as porcine epidemic diarrhea(PED} by virus isolation and immunohistochemistry were studied through light microscope and transmissible electron microscope. On semi-thin section, the histologic findings showed severe villous atrophy and fusion with hyperplasia of cuboidal epithelium in the villi, inflammatory cell infiltration in lamina propria, and increased mitotic figures in the crypt. The structural changes were mostly restricted to the cytoplasm of affected absorptive epithelium of villi. 3 types of epithelial changes were found; degenerated virus-affected cells, undifferentiated cuboidal cells, and normal columnar cells. On electron microscopy, round to spherical viral particles of 50∼l00nm in diameter were found within the dilated vesicles and endoplasmic reticulums of degenerated cells, which had decreased their cytoplasmic electron density due to dilated and missing organelles(e.g. mitochondria, ERs, etc.). Microvilli were shortened and sparse, leaving denuded terminal web of the villous epithelial cells. Fat globules were often found within slightly degenerated enterocytes. On the tip of villi, severely damaged cells were exfoliated and replaced by undifferentiated cuboidal cells We found distinct ultrastructural changes in the jejunal epithelium confirming PED virus infection is involved in malabsorptive diarrhea.

• Korean Journal of Veterinary Service
• /
• v.47 no.1
• /
• pp.9-17
• /
• 2024

Porcine epidemic diarrhea (PED) is a highly contagious enteric viral disease of pigs with watery diarrhea in piglets, which ultimately results in huge economic losses in the swine industry. The spike (S) protein plays an important role in viral pathogenicity, tissue tropism, infection, dissemination and the trypsin-dependent proliferation of the PED virus (PEDV). In the present study, we determined the full-length spike (S) gene sequences of twenty PEDV field strains detected in Jeonbuk province in 2022. Phylogenetic analysis showed that the twenty PEDV field strains were classified into G2b group and shared 98.6~100% of nucleotide homology and 97.4~100% of amino acid homology with each other. Mutations of amino acid sequences on the neutralizing epitope of S protein were observed in the twenty field strains compared to the previous vaccine strain SM-98-1 (G1a group). Therefore, these amino acid mutations in the PEDV S protein may result in a new genotype of the virus and highly pathogenic virus, so continuous monitoring is required.

• Journal of Veterinary Clinics
• /
• v.20 no.2
• /
• pp.150-154
• /
• 2003

A disease with severe diarrhea occurred in a herd of one thousand, 1-week-old piglets in Chinju, Korea, and was diagnosed as porcine epidemic diarrhea by the detection of N gene of porcine epidemic diarrhea virus (PEDV) from small intestines. A PEDV, named as Chinju99, was also isolated from the intestines after two blind-passages in Vero cells supplemented with trypsin (10 ug/ml). and the biological and physicochemical properties of the isolate were characterized. The virion was roughly spherical in shape and had spike peplomers on its outer surface. The virus exhibited cytopathic effects such as rounding degeneration at initiation of infection and syncytia formation later in Vero cells. The virus was labile to 20% ether and 5% chloroform but stable in acid with pH 4-7 at $4^{\circ}C$. The infectivity of the virus was maintained at $50^{\circ}C$ for 180 min, and the buoyant density of the virus in sucrose was 1.180 g/ml. All biological and physicochemical properties of the virus were typical features of coronaviruses.

• Korean Journal of Veterinary Research
• /
• v.61 no.3
• /
• pp.23.1-23.8
• /
• 2021

Porcine epidemic diarrhea (PED) is characterized by acute enteritis, watery diarrhea, weight loss, dehydration, and death with high mortality in neonatal piglets. In this study, 3 virus isolates collected in Vietnam between 2016 and 2017 were successfully propagated in Vero cells at high virus titers. Sequence analysis of the full-length spike (S) gene revealed that all 3 isolates belong to genogroup 2a, which is closely related to other prevalent Asian strains. Amino acid sequence comparisons revealed 98.19% to 99.13% homology with the Vietnam isolates circulating during 2013-2015, suggesting that field PED viruses (PEDVs) evolve continuously. Experiments in animals demonstrated that antisera from guinea pigs immunized with the vaccine strain resulted in higher levels (5 log₂) of neutralizing antibody against the homologous strain, and showed a relatively lower level of neutralizing antibody against the field isolates. This finding would be helpful in choosing a PEDV strain for vaccine development.

• Korean Journal of Veterinary Research
• /
• v.63 no.2
• /
• pp.18.1-18.8
• /
• 2023

Porcine epidemic diarrhea (PED) is characterized by acute enteritis, watery diarrhea, weight loss, dehydration, and death, with high mortality in neonatal piglets. In this study, 3 virus isolates collected in Vietnam between 2016 and 2017 were propagated successfully in Vero cells at high virus titers. Sequence analysis of the full-length spike (S) gene showed that all 3 isolates belong to genogroup 2b, which is closely related to other prevalent Asian strains. A comparison of the amino acid sequence revealed a 98.19% to 99.13% homology with the Vietnam isolates circulating during 2013-2015, suggesting that field PED viruses (PEDVs) are evolving continuously. Experiments in animals showed that the antisera from guinea pigs immunized with the vaccine strain resulted in higher levels (5 log₂) of neutralizing antibodies against the homologous strain and a relatively moderate level of neutralizing antibodies against the field isolates. This finding would be helpful in selecting a PEDV strain for vaccine development.