Isolation and genetic analysis of a variant porcine epidemic diarrhea virus in China

Abstract

Porcine epidemic diarrhea virus (PEDV) is having a severe effect on the pig breeding industry in central China. The mucosa and the content of the small intestine from newborn pre-weaned piglets with diarrhea were tested for the presence of PEDV by molecular and morphologic methods, and found to be positive. Negative-staining electron microscopy (EM) revealed the presence of coronavirus-like particles in the samples. The result of molecular detection by nested RT-PCR based on the amplification of the M gene was positive. Using a novel alternative method we successfully propagated the PEDV strain (CH/QX-2) in Vero cells, confirmed by ultrathin sections of the cells and Immunofluorescence assay (IFA). Phylogenetic analysis based on the partial S gene showed that the CH/QX-2 isolate was genetically closer to strains more commonly found in China, but differed genetically from two domestic strains (CH/S, 1986 and LZC, 2007), Korean strains (DR13, 2007, and the vaccine strain (CV777 vs) currently being used in China. CH/QX-2 formed a unique clade in the derived phylogenetic tree indicating that the CH/QX-2 strain currently circulating in central China is a new variant of PEDV. This study extends current knowledge on the diversity and epidemiology of PEDV.

Coexistence of multiple genotypes of porcine epidemic diarrhea virus with novel mutant S genes in the Hubei Province of China in 2016

“…Since the emergence of new PEDV strains in China in 2010, PEDV has continued to cause economic losses in almost all districts in the Hubei Province of China despite several control methods including biosecurity and vaccination. One important reason for this is the emergence of novel PEDV variants ( Jung and Saif, 2015 ; Li et al, 2016a ; Li et al, 2016b ). However, genetic information on PEDV in Hubei is quite limited; therefore, for better prevention and control of the spread of PEDV in the future, it is crucial to investigate the genetic diversity and variation of PEDV in fields.…”

Characterisation of porcine epidemic diarrhea virus isolates during the 2014–2015 outbreak in the Philippines

“…According to researches, the PEDV is clustered into two groups: the classical PEDV strains that first emerged in 1970s in Europe and the highly virulent PEDV strains that emerged in 2010 in China [ 3 , 17 ]. The G1 PEDV strains are the classical PEDV, which can be clustered further into G1a where the prototype vaccine strain CV777 belongs; and G1b which includes new PED variants identified in South Korea, China, US and Europe [ 3 ].…”

“…Between 1971 and 1980, the virus reportedly spread rapidly in Europe and it was in 1982 when the first outbreak in Asia occurred that caused severe cases of diarrhea in neonate piglets that contributed to high mortality [ 3 ]. Several years later, the virus was reported in China [ 10 – 17 ], Japan [ 18 , 19 ], South Korea [ 20 – 22 ], Thailand [ 23 , 24 ], Vietnam [ 25 , 26 ] and the Philippines [ 5 , 27 ] (May 17, 2013, the United States Department). In May 17, 2013, the United States Department of Agriculture ( https://www.aphis.USDA2013.gov/animal_health/animal_dis_spec/swine/downloads/ped_tech_note.pdf ) National Veterinary Service Laboratory (NVSL) confirmed the first PEDV diagnosis in Iowa, United States [ 2 – 4 , 28 , 29 ] ( https://www.aphis.USDA2013.gov/animal_health/animal_dis_spec/swine/downloads/ped_tech_note.pdf ).…”

Isolation and characterization of a new porcine epidemic diarrhea virus variant that occurred in Korea in 2014

“…They were confirmed to be PEDV based on CPEs, IFA, EM, and RT-PCR results. An appropriate trypsin concentration and Vero cell line were essential for isolating PEDV in cell culture [ 8 13 ]. In this study, we found that ATCC-CCL81 Vero cells were more suitable for propagating field PEDV than were ATCC-1586 Vero cells, and 2 µg/mL trypsin at 37℃ for 1 h before inoculation into the Vero cells and medium containing 1 or 1.5 µg/mL crystalized trypsin were critical for propagating PEDV (data not shown).…”