Emergence of Porcine epidemic diarrhea virus in the United States: clinical signs, lesions, and viral genomic sequences

ABSTRACT Coronaviruses are known to infect humans and other animals and cause respiratory and gastrointestinal diseases. Here we report the emergence of porcine epidemic diarrhea virus (PEDV) in the United States and determination of its origin, evolution, and genotypes based on temporal and geographical evidence. Histological lesions in small intestine sections of affected pigs and the complete genomic sequences of three emergent strains of PEDV isolated from outbreaks in Minnesota and Iowa were characterized. Genetic and phylogenetic analyses of the three U.S. strains revealed a close relationship with Chinese PEDV strains and their likely Chinese origin. The U.S. PEDV strains underwent evolutionary divergence, which can be classified into two sublineages. The three emergent U.S. strains are most closely related to a strain isolated in 2012 from Anhui Province in China, which might be the result of multiple recombination events between different genetic lineages or sublineages of PEDV. Molecular clock analysis of the divergent time based on the complete genomic sequences is consistent with the actual time difference, approximately 2 to 3 years, of the PED outbreaks between China (December 2010) and the United States (May 2013). The finding that the emergent U.S. PEDV strains share unique genetic features at the 5′-untranslated region with a bat coronavirus provided further support of the evolutionary origin of PEDV from bats and potential cross-species transmission. The data from this study have important implications for understanding the ongoing PEDV outbreaks in the United States and will guide future efforts to develop effective preventive and control measures against PEDV. IMPORTANCE The sudden emergence of porcine epidemic diarrhea virus (PEDV), a coronavirus, for the first time in the United States causes significant economic and public health concerns. Since its recognition in May 2013, PEDV has rapidly spread across the United States, resulting in high mortality in piglets in more than 17 States now. The ongoing outbreaks of Middle East respiratory syndrome coronavirus in humans from countries in or near the Arabian Peninsula and the historical deadly nature of the 2002 outbreaks of severe acute respiratory syndrome coronavirus create further anxiety over the emergence of PEDV in the United States due to the lack of scientific information about the origin and evolution of this emerging coronavirus. Here we report the detailed genetic characterization, origin, and evolution of emergent PEDV strains in the United States. The results provide much needed information to devise effective preventive and control strategies against PEDV in the United States.

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Origin, Evolution, and Virulence of Porcine Deltacoronaviruses in the United States

mBio ◽

10.1128/mbio.00064-15 ◽

2015 ◽

Vol 6 (2) ◽

Cited By ~ 93

Author(s):

Yuanmei Ma ◽

Yu Zhang ◽

Xueya Liang ◽

Fangfei Lou ◽

Michael Oglesbee ◽

...

Keyword(s):

United States ◽

Porcine Epidemic Diarrhea Virus ◽

Clinical Signs ◽

The United States ◽

Immune Serum ◽

Watery Diarrhea ◽

Economic Losses ◽

Genetic Characteristics ◽

Diarrhea Virus ◽

Porcine Epidemic Diarrhea

ABSTRACTA novel porcine deltacoronavirus (PdCV) was first discovered in Ohio and Indiana in February 2014, rapidly spread to other states in the United States and Canada, and caused significant economic loss in the swine industry. The origin and virulence of this novel porcine coronavirus are not known. Here, we characterized U.S. PdCV isolates and determined their virulence in gnotobiotic and conventional piglets. Genome analyses revealed that U.S. PdCV isolates possess unique genetic characteristics and share a close relationship with Hong Kong and South Korean PdCV strains and coronaviruses (CoVs) of Asian leopard cats and Chinese ferret-badgers. The PdCV-positive intestinal content (Ohio CVM1) and the cell culture-adapted PdCV Michigan (MI) strain were orally inoculated into gnotobiotic and/or conventional piglets. Within 1 to 3 days postinfection, profuse watery diarrhea, vomiting, and dehydration were observed. Clinical signs were associated with epithelial necrosis in the gastric pits and small intestine, the latter resulting in severe villous atrophy. Mild interstitial pneumonia was identified in the lungs of PdCV-infected piglets. High levels of viral RNA (8 to 11 log RNA copies/g) were detected in intestinal tissues/luminal contents and feces of infected piglets, whereas moderate RNA levels (2 to 5 log RNA copies/g) were detected in blood, lung, liver, and kidney, indicating multisystemic dissemination of the virus. Polyclonal immune serum against PdCV but not immune serum against porcine epidemic diarrhea virus (PEDV) reacted with PdCV-infected small-intestinal epithelial cells, indicating that PdCV is antigenically distinct from PEDV. Collectively, we demonstrate for the first time that PdCV caused severe gastrointestinal diseases in swine.IMPORTANCEPorcine coronaviruses (CoVs) are major viral infectious diseases of swine. Examples of porcine CoVs include porcine transmissible gastroenteritis coronavirus (TGEV), porcine epidemic diarrhea virus (PEDV), and porcine respiratory coronavirus (PRCV). In February 2014, another porcine CoV, porcine deltacoronavirus (PdCV), emerged in Ohio and Indiana and subsequently spread rapidly across the United States and Canada,causing significant economic losses. Here, we report the detailed genetic characterization, phylogeny, and virulence of emergent PdCV strains in the United States. We found that PdCV caused severe diarrhea, vomiting, and dehydration in gnotobiotic and conventional piglets, signs that were clinically indistinguishable from those caused by PEDV and TGEV. In addition to extensive intestinal lesions, PdCV caused significant lesions in the stomach and mild pulmonary lesions that have not been reported for TGEV and PEDV. The finding that PdCV is a significant enteric disease of swine highlights the need to develop effective measures to control this disease.

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Evaluation of serological cross-reactivity and cross-neutralization between the United States porcine epidemic diarrhea virus prototype and S-INDEL-variant strains

BMC Veterinary Research ◽

10.1186/s12917-016-0697-5 ◽

2016 ◽

Vol 12 (1) ◽

Cited By ~ 23

Author(s):

Qi Chen ◽

Joseph T. Thomas ◽

Luis G. Giménez-Lirola ◽

John M. Hardham ◽

Qinshan Gao ◽

...

Keyword(s):

United States ◽

Porcine Epidemic Diarrhea Virus ◽

The United States ◽

Cross Reactivity ◽

Diarrhea Virus ◽

Cross Neutralization ◽

Porcine Epidemic Diarrhea

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Response of the National Biosurveillance Integration Center to the Emergence of Porcine Epidemic Diarrhea Virus in the United States

Online Journal of Public Health Informatics ◽

10.5210/ojphi.v7i1.5777 ◽

2015 ◽

Vol 7 (1) ◽

Author(s):

Yandace K. Brown ◽

Tyann Blessington

Keyword(s):

United States ◽

Porcine Epidemic Diarrhea Virus ◽

The United States ◽

United States Department ◽

Department Of Agriculture ◽

States Department ◽

Diarrhea Virus ◽

Porcine Epidemic Diarrhea ◽

Inspection Service ◽

Plant Inspection

The United States Department of Agriculture (USDA) Animal and Plant Inspection Service (APHIS) announced the first diagnosed case of PEDV in U.S. swine on May 17, 2013. NBIC has been monitoring this epidemic primarily due to economic concerns. Without a formal response protocol by a single coordinating agency, PEDV spread rapidly between states. Though APHIS have been actively involved from the beginning of emergence, the Federal Order announced on June 5, 2014 marks more formalized and coordination response, which NBIC predicts will exert greater control over the epidemic despite the predicted viral surge in the colder months.

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