VectorTest™ West Nile Virus Antigen Assay in an Inhibition Platform as Field Screening Tool for Flavivirus Group-Specific Antibodies in Brazilian Equines

Abstract

Current methods for detecting Flavivirus antibodies are enzyme-linked immunosorbent assays (ELISAs) and neutralization tests, both of which require laboratories and trained staff. We evaluated the VectorTest™ West Nile Virus Antigen Assay in an inhibition platform (VecTest-inhibition assay [VIA]) as a simpler screening method for detecting antibodies for a variety of flaviviruses among a population of equines from Brazil. We found that the VIA is a field-deployable rapid method with 100% sensitivity and 64% specificity compared with blocking ELISA for the detection of group-specific Flavivirus antibodies in equine serum samples. The VIA is a potentially useful field test for rapid field-based Flavivirus antibody detection in equine serum samples.

West Nile Virus in the State of Ceará, Northeast Brazil

“…Epitope-blocking ELISA has a good sensibility and specificity for animal samples, but it has demonstrated some limitations for human samples [ 72 , 73 , 74 ]. VIA, which is a field-deployable rapid test has a high sensitivity for a variety of flaviviruses among a population of equines from Brazil and merits further evaluation [ 75 ].…”

Xenosurveillance proof-of-principle: Detection of Toxoplasma gondii and SARS-CoV-2 antibodies in mosquito blood meals by (pan)-specific ELISAs

“…However, many parasites are sequestered in the host and not present at all or in very low numbers in blood and, therefore, the detection of antibodies directed against them is preferred. Indeed, antibodies against pathogens could be detected in mosquito blood meals by standard ELISA ( Lackie & Gavin, 1989 ; Barbazan et al., 2009 ; Leighton et al., 2014 ; Komar et al., 2015 ; Pauvolid-Corrêa & Komar, 2017 ). In these studies, antibodies against vector-borne pathogens were detected in naturally fed insects or in vectors artificially fed on blood spiked with antibodies.…”

An Overview of Neglected Orthobunyaviruses in Brazil

“…FC has greater specificity when compared to HI, but requires specifically trained personnel [ 132 ]. The VNT or PRNT are considered gold standards for confirmation of serological test results, as they are sensitive and present high specificity allowing the differentiation among related viruses [ 30 , 143 ]. However, because VNT and PRNT require the use of cell cultures and infectious viruses to be manipulated by highly trained personnel in high-level biosafety facilities, these methods are considered laborious, expensive and time-consuming for large scale testing.…”

“…However, because VNT and PRNT require the use of cell cultures and infectious viruses to be manipulated by highly trained personnel in high-level biosafety facilities, these methods are considered laborious, expensive and time-consuming for large scale testing. For this reason, VNT and PRNT have been used primarily as confirmatory tests [ 28 , 30 , 143 ]. The great challenge for serology for orthobunyaviruses in Brazil relies on the concomitant circulation of several antigenically related viruses, which increases cases of false positive results.…”

“…The suitable screening method would ideally be a fast and qualitative kit for the detection of specific neutralizing antibodies on competitive ELISA or chromatographic immunoassay platforms. Few options with a similar approach are already available for the investigation of flaviviruses, including epitope-blocking ELISA and the VecTest-inhibition assay, and merit further evaluation [ 143 ].…”