Porcine epidemic diarrhea virus (PEDV) detection and antibody response in commercial growing pigs

Abstract

BackgroundLongitudinal samples from two production sites were used to (1) describe the pattern of PEDV shedding (rRT-PCR) in individual rectal swabs, pen fecal samples, and pen oral fluids (OF); (2) describe the kinetics of PEDV antibody by ELISA (IgA, IgG) testing of pig serum and pen oral fluid samples; and (3) establish cutoffs and performance estimates for PEDV WV ELISAs (IgA, IgG). Site One was PEDV positive; Site Two was PEDV negative. On Site One, pen samples (feces and oral fluids) and pig samples (rectal swabs and sera) were collected both before and after the population was exposed to PEDV.ResultsOn Site Two, pen oral fluid samples and individual pig serum samples were negative for both PEDV antibody and nucleic acid. On Site One, PEDV was detected by rRT-PCR at 6 days post exposure (DPE) in all sample types. The last rRT-PCR positives were detected in rectal swabs and oral fluids on 69 DPE. IgG and IgA were detected in oral fluids and serum samples by 13 DPE. Analysis of the PEDV serum IgG WV ELISA data showed that a sample-to-positive (S/P) cutoff of ≥ 0.80 provided a diagnostic sensitivity of 0.87 (95 % CI: 0.82, 0.91) and specificity of 0.99 (95 % CI: 0.98, 1.00). Serum IgG results declined slowly over the monitoring period, with 60 % of serum samples positive (S/P ≥ 0.80) at the final sampling on 111 DPE. Analysis of the PEDV oral fluid IgA WV ELISA found that a cutoff of S/P ≥ 0.80 provided a diagnostic sensitivity of 1.00 (95 % CI: 0.92, 1.00) and a diagnostic specificity of 1.00 (95 % CI: 0.99, 1.00). The oral fluid IgA response increased through 96 DPE and began to decline at the last sampling on 111 DPE.ConclusionsThis study showed that oral fluid-based testing could provide an easy and “animal-friendly” approach to sample collection for nucleic acid and/or antibody-based surveillance of PEDV in swine populations.

Porcine Epidemic Diarrhea Virus Shedding and Antibody Response in Swine Farms: A Longitudinal Study

“…At the moment, very limited data have been published on the PEDV viral load during an outbreak under field conditions (Bjustrom-Kraft et al, 2016). The qPCR assay used in this study was validated according to the minimum information for quantitative real-time PCR experiments guidelines (Bustin et al, 2009; Table 3 ; Supplementary Table 7).…”

“…At the moment, very limited data have been published on the PEDV viral load during an outbreak under field conditions (Bjustrom-Kraft et al, 2016). …”

Porcine deltacoronavirus: Overview of infection dynamics, diagnostic methods, prevalence and genetic evolution

“…Due to low success rate of PDCoV VI in cell culture, currently PDCoV VI is not a reliable assay to determine whether infectious virus is present in a clinical specimen or if 'X' treatment will inactivate the virus. For PEDV, swine bioassay has been commonly used to assess infectivity of PEDV present in various samples, including feed and feed ingredients after disinfectant or other treatments (Bowman et al, 2015b;Dee et al, 2014b;Dee et al, 2015). Notably, some samples were PEDV VI negative after treatment but swine bioassay positive (Dee et al, 2015), emphasizing the importance and necessity of performing swine bioassay to reliably determine virus infectivity of a sample.…”

“…IgG, IgA, and IgM) in various specimen types. For example, PEDV ELISAs have been used to detect IgG and/or IgA antibodies in serum, oral fluid, and feces samples (Bjustrom-Kraft et al, 2016;Gerber et al, 2014;Gerber and Opriessnig, 2015). No publications have described dynamics of PDCoV antibody production and antibody duration as measured by PDCoV ELISAs.…”

Quantifying the effect of lactogenic antibody on porcine epidemic diarrhea virus infection in neonatal piglets

“…Analysis of the PEDV serum IgG WV ELISA data showed that a S/P cutoff of ! 0.40 provided a diagnostic sensitivity of 0.99 (95% CI: 0.96, 1.00) and specificity of 0.98 (95% CI: 0.97, 0.99) (Bjustrom-Kraft et al, 2016). No cutoffs have been established for mammary secretion samples.…”