Comparative Evaluation of Four Potent Neospora caninum Diagnostic Antigens Using Immunochromatographic Assay for Detection of Specific Antibody in Cattle.

Ragab M Fereig,Yoshifumi Nishikawa,Hanan H Abdelbaky

doi:10.3390/microorganisms9102133

Ragab M Fereig, Yoshifumi Nishikawa + Show 1 more

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https://doi.org/10.3390/microorganisms9102133

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Abstract

Neospora caninum is an intracellular protozoan parasite responsible for numerous abortion outbreaks and neonatal abnormalities in cattle. Rapid and accurate diagnosis is critical for N. caninum control owing to the lack of vaccine or drug-based control strategies. Herein, we evaluated the performance of four frequently used antigens in the diagnosis of N. caninum infection using immunochromatographic tests (ICTs) as a rapid, affordable, and field applicable tool. These antigens included recombinant proteins of N. caninum surface antigen 1 (NcSAG1), dense granule proteins 7 (NcGRA7) and 6 (NcGRA6), in addition to native Neospora lysate antigen (NLA). Our study revealed the utility of all antigen-based ICTs for detection of specific antibodies to N. caninum. However, the NcSAG1-based ICT was the best for detection of all control N. caninum-infected mouse or cattle sera, while NcGRA7 and NcGRA6-based ICTs exhibited specific ability to detect samples from acute and sub-acute infection in mice and cattle, respectively. Analyses of the NcSAG1-based ICT against enzyme-linked immunosorbent assays (ELISAs) of the same antigen revealed its efficiency in detection of field cattle samples as observed in high sensitivity (84.2%), specificity (93.5%), agreement (90%), and kappa value (0.78). The current knowledge provides an efficient platform for N. caninum control through on-site diagnosis of infected cattle.

Highlights

Anti-NcGRA7 antibodies appear to be specific for early N. caninum infection in cattle, dog, and mouse sera, whereas anti-N. caninum surface antigen 1 (NcSAG1) antibodies are persistent and can be detected during acute, sub-acute, or chronic N. caninum infection [9,13,14,15]
We developed several immunochromatographic tests (ICTs) based on potential diagnostic antigens of N. caninum
Even the Neospora lysate antigen (NLA)-based ICT might be useful in reducing the hazards of N. caninum infection in cattle because it is potent, affordable, and easy to prepare

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Neosporosis is a protozoan parasitic disease caused by Neospora caninum, which has been recorded among a wide variety of animal hosts and in most countries [1]. Three developmental stages have been recorded for N. caninum: tachyzoite (rapidly growing stage), bradyzoite (slowly growing stage), and sporozoite (fecal oocyst). Canines act as definitive hosts while many other animals, cattle, sheep, and other ungulates, are intermediate hosts. N. caninum is responsible for abortion in cattle, resulting in drastic financial losses in the livestock industry attributable to the abortion per se, loss of milk production, and costly control measures involving treatment and culling procedures [4,5]

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