Isolation and characterization of a Korean porcine epidemic diarrhea virus strain KNU-141112

Abstract

Severe outbreaks of porcine epidemic diarrhea virus (PEDV) have re-emerged in Korea and rapidly swept across the country, causing tremendous economic losses to producers and customers. Despite the availability of PEDV vaccines in the domestic market, the disease continues to plague the Korean pork industry, raising issues regarding their protective efficacy and new vaccine development. Therefore, PEDV isolation in cell culture is urgently needed to develop efficacious vaccines and diagnostic assays and to conduct further studies on the virus biology. In the present study, one Korean PEDV strain, KOR/KNU-141112/2014, was successfully isolated and serially propagated in Vero cells for over 30 passages. The in vitro and in vivo characteristics of the Korean PEDV isolate were investigated. Virus production in cell culture was confirmed by cytopathology, immunofluorescence, and real-time RT-PCR. The infectious virus titers of the viruses during the first 30 passages ranged from 10(5.1) to 10(8.2) TCID50 per ml. The inactivated KNU-141112 virus was found to mediate potent neutralizing antibody responses in immunized guinea pigs. Animal studies showed that KNU-141112 virus causes severe diarrhea and vomiting, fecal shedding, and acute atrophic enteritis, indicating that strain KNU-141112 is highly enteropathogenic in the natural host. In addition, the entire genomes or complete S genes of KNU-141112 viruses at selected cell culture passages were sequenced to assess the genetic stability and relatedness. Our genomic analyses indicated that the Korean isolate KNU-141112 is genetically stable during the first 30 passages in cell culture and is grouped within subgroup G2b together with the recent re-emergent Korean strains.

Two Distinct Genotypes of Porcine Epidemic Diarrhoea Virus in Vaccinated Pig Flocks in Shandong Province of China, 2012-2015

“…The five US strains were reported to belong to North American clades I and II, following the PEDV outbreak in April 2013 (Vlasova et al., ). The three Korean strains are thought to be co‐circulating in Korea and showed high homology with the five US strains (Choi et al., ; Lee et al., ). The 31 isolated strains occupied all the 13 cities, suggesting that G3 was the most prevalent genotype in Shandong Province (Fig.…”

Wild boars harboring porcine epidemic diarrhea virus (PEDV) may play an important role as a PEDV reservoir

“…However, the pig population in Korea has plummeted due to a foot-and-mouth disease (FMD) outbreak in 2010-2011. As a consequence of strict biosecurity measures and a decreased pig population, outbreaks of PEDV have been attenuated (Lee et al, 2015). Even with the reduction of PEDV outbreaks in domestic pigs in this period, wild boar strains of PEDV were still detected.…”

Endemic outbreaks due to the re‐emergence of classical swine fever after accidental introduction of modified live LOM vaccine on Jeju Island, South Korea

“…Clinical samples of aborted foetuses and dead pigs that suffered from severe diarrhoea and atrophy before dying from five different unvaccinated swine farms during 2017–2018 outbreaks were independently submitted for laboratory analysis (Table S1). Tissue specimens including tonsil, lymph node, spleen and lung were taken from each carcass, and all samples were prepared into 10% suspensions as described previously (Lee, Kim, & Lee, ). The initial combined RT‐PCR and sequencing analysis of CSFV 5′‐UTR showed that these samples were positive for LOM (Kim et al., ).…”