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Background 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.
PEDV, currently classified into classical genotype 1a (G1a), first emerged in England and devastated swine production in numerous European countries during the 1970s. However, acute PEDV epidemics in Europe markedly declined in the 1980s–1990s, and only sporadic outbreaks have been reported since then. PEDV (G1a) crossed into Asia in the early 1980s to the detriment of the Asian pork industry and poses a huge financial threat. In contrast to the PEDV status in Europe, PEDV epidemics in Asia are more brutal, causing high mortality in nursing piglets, and the disease has frequently converted to become endemic in multiple Asian countries.
Although PEDV has mainly raged on Asian pork-producing countries for the past four decades, the threat from this porcine CoV was not globally recognized. However, a seismic shift in PEDV reputation was undergone in early 2013 with the sudden outbreak of highly pathogenic (HP)-PEDV, grouped into genotype 2b (G2b), in the United States (US), producing $0.9–1.8 billion in annual losses to US swine producers. The US emergent strain-like HP-G2b viruses spread to adjacent countries, including Canada, Mexico, Colombia, and Peru and eventually reached East Asian countries and Europe, causing a PEDV pandemic during 2013–2014. In South Korea, HP-G2b PEDV was introduced in late 2013 and swept across the nation, including Jeju Island, causing nationwide PED disasters.
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Methods N/A - Review article
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Results 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.
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Data Summary PEDV (G1a) caused high mortality in nursing piglets in Asia. The 2013 HP-G2b outbreak in the US produced $0.9–1.8 billion in annual losses. PEDV is enveloped and roughly spherical or pleomorphic with a diameter of 95–190 nm, including the club-shaped, trimerized projections that measure 18–23 nm.
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Conclusions The intervention measures for stabilizing herd immunity and eliminating virus circulation may be the cornerstone of establishing regional or national PED eradication programs. 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.
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Practical Significance 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, active monitoring and surveillance of the virus in herds and their environments are necessary for eradication in FTF farms.