Development of an accurate lateral flow immunoassay for PEDV detection in swine fecal samples with a filter pad design

Abstract

Porcine epidemic diarrhea virus (PEDV), as the main causative pathogen of viral diarrhea in pigs, has been reported to result in high morbidity and mortality in neonatal piglets and cause significant economic losses to the swine industry. Rapid diagnosis methods are essential for preventing outbreaks and transmission of this disease. In this study, a paper-based lateral flow immunoassay for the rapid diagnosis of PEDV in swine fecal samples was developed using stable color-rich latex beads as the label. Under optimal conditions, the newly developed latex bead-based lateral flow immunoassay (LBs-LFIA) attained a limit of detection (LOD) as low as 103.60 TCID50/mL and no cross-reactivity with other related swine viruses. To solve swine feces impurity interference, by adding a filtration unit design of LFIA without an additional pretreatment procedure, the LBs-LFIA gave good agreement (92.59%) with RT-PCR results in the analysis of clinical swine fecal samples (n = 108), which was more accurate than previously reported colloidal gold LFIA (74.07%) and fluorescent LFIA (86.67%). Moreover, LBs-LFIA showed sufficient accuracy (coefficient of variance [CV] < 15%) and stable (room temperature storage life > 56 days) performance for PEDV detection, which is promising for on-site analysis and user-driven testing in pig production system.

A DNA Barcode‐Based Aptasensor Enables Rapid Testing of Porcine Epidemic Diarrhea Viruses in Swine Saliva Using Electrochemical Readout

“…[8] Immunoassays are popular alternatives to PCR for PEDv detection, which reduce sample-to-result time and assay complexity by eliminating the need for reverse transcription and target amplification. These assays rely on the use of antibodies as bio-recognition elements and are often integrated into engineered detection platforms or devices for rapid testing such as lateral flow assays (LFAs), [9][10][11] enzyme-linked immunosorbent assays (ELISA), [12][13][14][15][16][17] and electrochemical assays. [18][19][20] Although rapid, these methods, all based on antibody-based sandwich assays, either require multi-step processing such as washing, labeling, or addition of reagents (ELISA and electrochemical assays) or suffer from low clinical sensitivity and specificity partly stemming from the poor stability and crossreactivity of the antibodies (LFAs).…”

Point-of-Care Tests for Rapid Detection of Porcine Epidemic Diarrhea Virus: A Systematic Review and Meta-Analysis

“…In this systematic review and meta-analysis, we identified 11 articles of ICA-based POCTs published since 2015, and 2 of them used portable strip readers to analyze the detection results of ICA [ 19 , 21 ]. Moreover, a smartphone camera and immunofluorescent analyzer were also applied to quantify the results of ICA for detecting PEDV [ 18 , 22 ]. These handheld instruments provide convenient tools for reading the information of the ICA strip and make the results more precise, objective, and sensitive.…”

“…Our results showed that there was no significant heterogeneity factor in our subgroup analysis in relation to sample type. It is well known that the fecal–oral route is believed to be the primary mode of PEDV transmission; feces are considered a rapidly obtainable and readily available sample for PEDV detection [ 18 , 46 ]. When comparing the diagnostic performance of ICA-based POCTs for different sample types, however, we found that the overall sensitivity of the feces sample was lower than that of other types of samples including rectal swab, small intestine, colostrum, and serum (0.95 vs. 0.96; p = 0.00), which revealed that the diagnostic performance of feces specimen was not necessarily superior to other specimens in ICA-based POCTs for PEDV infection.…”

“…First, most of the diagnostic studies enrolled samples from field farms with diarrhea outbreaks and were not blind-designed, which might lead to an overestimation of the diagnostic value. Among 24 studies for inclusion in this review, 6 studies used the samples that confirmed PEDV definitely prior [ 18 , 22 , 30 , 33 , 36 , 37 ] and only one study provided relatively detailed clinical information of fecal samples [ 34 ]. Second, the number of studies enrolled in this analysis is still relatively small, which might limit the power of regression to detect significant effects and lead to biased results.…”

“…The following supporting information can be downloaded at: https:// www.mdpi.com/article/10.3390/v14071355/s1, Figure S1 S1: Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) summary items for risk of bias (A) and applicability concerns (B) for all studies. References [18,20,22,26,29,30,33,[36][37][38][39][40] are cited in the supplementary materials.…”