Evolution, antigenicity and pathogenicity of global porcine epidemic diarrhea virus strains

Abstract

Emerging and re-emerging coronaviruses cause morbidity and mortality in human and animal populations, resulting in serious public and animal health threats and economic losses. The ongoing outbreak of a highly contagious and deadly porcine epidemic diarrhea virus (PEDV) in Asia, the Americas and Europe is one example. Genomic sequence analyses of PEDV variants have revealed important insights into the evolution of PEDV. However, the antigenic variations among different PEDV strains are less explored, although they may contribute to the failure of PEDV vaccines in Asian countries. In addition, the evolution of PEDV results in variants with distinct genetic features and virulence differences; thus PEDV can serve as a model to explore the molecular mechanisms of coronavirus evolution and pathogenesis. In this article, we review the evolution, antigenic relationships and pathologic features of PEDV strains. This information and review of researches will aid in the development of strategies for control and prevention of PED.

Novel Porcine Epidemic Diarrhea Virus (PEDV) Variants with Large Deletions in the Spike (S) Gene Coexist with PEDV Strains Possessing an Intact S Gene in Domestic Pigs in Japan: A New Disease Situation

“…However, we speculated otherwise because the reported PEDV strains PC177-P2 and Tottori2 possessing the same deletions found in the variants of this study could replicate well in cell culture and cause cytopathic effect [17, 19]. Besides, the mutant strain PC177-P2 can propagate well and induce diarrhea in piglets [43]. A deletion of 215 aa (position 19–233) in the N-terminal domain of the S protein analogous to the deletion observed in the variants revealed a not impaired propagation of PEDV in vivo [44].…”

Appearance of US-like porcine epidemic diarrhoea virus (PEDV) strains before US outbreaks and genetic heterogeneity of PEDVs collected in Northern Vietnam during 2012-2015

“…G2 was further divided into G2‐1 and G2‐2, and G1 was divided into G1‐1, G1‐2 and G1‐3 as shown in Figure . G1‐1 includes the prototype European strain CV777, other global historic S INDEL strains isolated between 1970 and 2010 (Lin et al., ), and vaccine strains that were developed in Asian countries such as KPEDV‐9 and attenuated DR13 from South Korea, P5‐V from Japan and attenuated CV777 from China. One Vietnamese strain (VN232/HB2013) in this study was clustered into this subgroup, and it was closely related to the previously reported Vietnamese strain HUA‐PED67 (2013) and Chinese strains CH7 (2011), JS‐2004‐2 (2004) and LJB03 (2006).…”

“…In comparison with the sequence of the initial prototype strains in North America (high virulent NA prototype strains), the Vietnamese field strains VN262/HB/2014 and VN232/2013 possessed three deletions (a 1‐nucleotide deletion at position 166, an 11‐nucleotide deletion at positions 172–182 and a 3‐nucleotide deletion at positions 414–416) and a 6‐nucleotide insertion between positions 474 and 475 in the S gene. These insertions and deletion in the S gene are typical for the S INDEL type of PEDV (Vlasova et al., ; Lin et al., ). Of note, two classical Japanese strains in G1‐2 (NK and KH) do not possess these typical INDELs in the S gene.…”

“…Jarvis et al., () reported that the evolution of US strains is estimated to have begun around July 2009 to August 2012. Although NA non‐S INDEL strains were proposed to have evolved from different emerging Chinese strains via recombination (Tian et al., ; Vlasova et al., ), no NA non‐S INDEL strains were isolated in China (Lin et al., ). The timing and mechanism of the appearance and global spread of the NA PEDV type remain unclear.…”

“…Later, the second type of PEDV in the US with lower virulence in the field, designated S INDEL PEDV, was detected in samples collected beginning in June 2013 (Vlasova et al., ). Subsequently, US‐like strains have been reported in South Korea, Japan, Taiwan and European countries such as Ukraine, Belgium, Germany, France, Slovenia and Netherlands (Lin, Saif, Marthaler, & Wang, ). In Vietnam, PED outbreaks were firstly confirmed by reverse transcription polymerase chain reaction (RT‐PCR) in the southern provinces in early 2009 (Duy, Toan, Puranaveja, & Thanawongnuwech, ).…”