Development and Application of an ELISA for the Detection of Porcine Deltacoronavirus IgG Antibodies

Abstract

Porcine deltacoronavirus (PDCoV), also known as porcine coronavirus HKU15, was first detected in North America in early 2014 and associated with enteric disease in pigs, resulting in an urgent need to further investigate the ecology of this virus. While assays detecting nucleic acids were implemented quickly, assays to detect anti-PDCoV antibodies have not been available. In this study, an indirect anti-PDCoV IgG enzyme-linked immunosorbent assay (ELISA) based on the putative S1 portion of the spike protein was developed and utilized to determine the prevalence of anti-PDCoV IgG in U.S. pigs. The diagnostic sensitivity of the PDCoV ELISA was 91% with a diagnostic specificity of 95%. A total of 968 serum samples were tested including samples with confirmed infection with PDCoV, porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus or porcine respiratory coronavirus. There was no cross-reactivity with any of the other coronaviruses. Among 355 arbitrarily selected serum samples collected in 2014 and originating from 51 farms across 18 U.S. states, anti-PDCoV IgG antibodies were detected in 8.7% of the samples and in 25.5% of the farms whereas anti-PEDV IgG was detected in 22.8% of the samples and in 54.9% of the farms. In addition, anti-PDCoV IgG antibodies were detected in archived samples collected in 2010, perhaps indicating an earlier undetected introduction into the U.S. pig population. Overall, the obtained data suggest that PDCoV seroprevalence in U.S. pigs is lower compared to PEDV and PDCoV may have been introduced to the U.S. prior to PEDV.

The detection and phylogenetic analysis of porcine deltacoronavirus from Guangdong Province in Southern China

“…All coronavirus spike proteins share the same two functional components: an N‐terminal subunit and a membrane‐anchored subunit (C‐terminal) that are covalently bound. The S protein of PDCoV can be similarly subdivided into S1 (1–573 aa) and S2 (574–1161 aa) regions (Thachil, Gerber, Xiao, Huang, & Opriessnig, ). S1 is a dominant viral antigen and an ELISA is available for its detection (Thachil et al., ).…”

“…The S protein of PDCoV can be similarly subdivided into S1 (1–573 aa) and S2 (574–1161 aa) regions (Thachil, Gerber, Xiao, Huang, & Opriessnig, ). S1 is a dominant viral antigen and an ELISA is available for its detection (Thachil et al., ). Three different groups of S1 proteins from co‐viral infections shared less than 12% amino acid sequence identities with each other (Wang, Deng et al., ).…”

Isolation, genomic characterization, and pathogenicity of a Chinese porcine deltacoronavirus strain CHN-HN-2014

“…With increased concern about this newly emerging enteric disease, reverse-transcription polymerase chain reaction (RT-PCR), real-time RT-PCR, nested RT-PCR, and singleplex RT insulated isothermal PCR methods have been developed to detect PDCoV in clinical samples Wang et al, 2014a;Song et al, 2015;Zhang et al, 2015Zhang et al, , 2016. Enzyme-linked immunosorbent assays for PDCoV-specific serum antibodies, based on the PDCoV S1 or nucleocapsid protein, have also been used to determine the prevalence of anti-PDCoV immunoglobulin G (IgG) in pig serum (Su et al, 2015;Thachil et al, 2015).…”

Prevalence, complete genome sequencing and phylogenetic analysis of porcine deltacoronavirus in South Korea, 2014-2016

“…Although the origin of PDCoV in the US remains unclear, sequence analyses suggest the possible introduction of a Chinese PDCoV strain into US swine (Li et al., ; Marthaler, Jiang, et al., ; Wang et al., ). However, recent retrospective evaluation revealed that PDCoV antibodies could be detected in archival serum samples collected in 2010, suggesting that the virus may have already existed as early as 2010 (Thachil, Gerber, Xiao, Huang, & Opriessnig, ). Shortly after its emergence in the US, PDCoV was also detected in South Korea from two diarrhoea samples independently collected in April and June 2014, which were positive for porcine rotavirus (PRV) and negative for other enteric viruses, respectively (Lee & Lee, ).…”