Evaluation and optimization of a conventional SPCE for FMD post-vaccination monitoring

Yeong-Lim Kang,Hwi-Yeon Choi,Yumei Liu,Joong-Bok Lee,Ho-Jong Lee,Beom-Joo Lee,Ki-Hyun Cho,Ji-Yun Jeong,So-Hyun Lee,Seung-Yong Park,Sang-Won Lee,Jong-Chul Choi,Yanhong Zhang

doi:10.1186/s12917-018-1686-7

Yeong-Lim Kang, Hwi-Yeon Choi + Show 11 more

Open Access

https://doi.org/10.1186/s12917-018-1686-7

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Abstract

BackgroundFoot-and-mouth disease (FMD) can be controlled by either stamping out or vaccination, a choice which depends on both the economic importance of the livestock sector as well as the disease status. In FMD-free countries with vaccination, such as Korea, vaccination programs should guarantee prevention against transmission of FMD. Monitoring of vaccination programs is also essential for ensuring sufficient coverage that will limit the transmission of FMDV. There are several methods to screen FMD virus (FMDV) structural protein (SP) antibodies including SPCE (Solid-phase competitive ELISA), LPBE (Liquid-phase blocking ELISA), and VNT (Virus neutralization test). Among these, SPCE is widely used for serological monitoring since VNT—the gold standard method—has certain practical limitations, such as high costs in terms of time and labor. However, whether SPCE can ensure the vaccination status of individual animals and whole farms is unclear. In this study, SPCE, LPBE and VNT were compared with respect to correlation with each other and sensitivity at commercial pig farms.ResultsThe positive results obtained by PrioCHECK SPCE differed from those obtained by LPBE and VNT. The sensitivity of SPCE relative to those of the other tests was fairly low. The raw data of SPCE were most highly correlated with those of VNT with XJ strain, while their positivity and negativity were most highly correlated with LPBE. The results of ROC analysis proposed new cut-off for PrioCHECK SPCE higher than the previous 50% inhibition.ConclusionsThe high false positive rate of PrioCHECK SPCE suggested that high seropositivity by SPCE may not guarantee a true vaccination coverage. Adjusting the cut-off percentage (%) inhibition value for SPCE is needed to address this problem, and it is highly recommended that routine FMDV serological monitoring programs using PrioCHECK SPCE should be combined with alternative methods such as LPBE or VNT.

Highlights

Foot-and-mouth disease (FMD) can be controlled by either stamping out or vaccination, a choice which depends on both the economic importance of the livestock sector as well as the disease status
Foot-and-mouth disease (FMD) is a viral disease caused by the FMD virus (FMDV), which belongs to the genus Aphthovirus in the Picornaviridae family [1]
We investigated whether PrioCHECK Solid phase competition ELISA (SPCE) is appropriate for determining the FMD vaccination status of farms by comparing the vaccination coverage and correlation to those obtained by other structural protein (SP) antibody test methods and by assessing the relative sensitivity and specificity of the assay

Summary

Introduction

Foot-and-mouth disease (FMD) can be controlled by either stamping out or vaccination, a choice which depends on both the economic importance of the livestock sector as well as the disease status. Solid-phase competition enzyme-linked immunosorbent assay (ELISA) (SPCE) [8,9,10], liquid-phase blocking ELISA (LPBE) [11, 12], and the virus neutralization test (VNT) [13] are typically used for SP antibody screening. They are performed in support of four main purposes: 1) to certify individual animals prior to import or export; 2) to confirm suspected cases of FMD; 3) to substantiate absence of infection; and 4) to demonstrate the efficacy of vaccination [14]

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