Comparison of four different assays for the detection of porcine epidemic diarrhea virus (PEDV) in different stages of the infection in Italy.

Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) represent new threats to the swine industry. To aid in early detection of virus, monitor shedding, or differentiate viral species, real-time PCR has proven a useful diagnostic tool. The aim of this study was to measure the sensitivity of real-time PCR assays for the detection of PEDV and PDCoV on field samples at different times of the infection.

A total of 20 samples were tested on four different real-time PCR assays, including three commercial assays and one in-house assay. The samples included feces from five animals at different times of the infection. The in-house assay was represented by two versions with different primers and probe concentrations of the real-time PCR assay developed by the University of Minnesota. One of the commercial assays was the recently launched RealPCR PEDV/PDCoV Multiplex RNA Test from IDEXX, which can be run on a modular platform with any other RealPCR test, with the two other ones being commercial multiplexes for PEDV and transmissible gastroenteritis virus (TGEV) and PEDV/TGEV/PDCoV. 200 µl of a 10 % feces homogenate was used as starting material and extracted using the Macherey-Nagel NucleoMag® VET 96 kit. The PCR reaction was prepared according to the manufacturer’s instructions and amplified using a Bio-Rad CFX96™ real-time PCR instrument.

All assays correctly identified the samples tested, with PEDV being positive in all samples. The TGEV and PDCoV targets were negative with all assays, as expected. The IDEXX RealPCR PEDV/PDCoV Multiplex RNA Test reached the lowest Ct-value in 16 samples out of the 20 samples tested, demonstrating the high sensitivity of the assay.

These results demonstrate the high sensitivity and specificity of the IDEXX RealPCR PEDV/PDCoV Multiplex RNA Test. The RealPCR tests for swine enteric coronaviruses from IDEXX are configured as either single target, PEDV, PDCoV, and TGEV tests, or as a PEDV/PDCoV multiplex test. All configurations include an ISC for the detection of swine RNA as an internal control.

Disclosure of Interest: None Declared.