Developing Indirect rRVFV-NP based ELISA Protocol for Detection of IgG Against Rift Valley Fever Virus

Rift Valley fever virus (RVFV) is a zoonotic arbovirus that causes significant infectious diseases in humans and in a wide array of domestic livestock. A notable epidemic of RVFV occurred in Saudi Arabia and Yemen in 2000, resulting in severe public health ramifications and high mortality rates among both human and animal populations. Despite the urgency of the situation, no approved vaccine or specific antiviral treatment for human use has been developed to date. There are currently no commercially available ELISA assays for RVFV. This study aims to develop an in-house ELISA utilizing purified recombinant nucleoprotein (NP) of RVFV. A total of 232 serum samples from slaughterhouse workers were employed to optimize this assay, which was validated against the SNT. The developed assay demonstrated a specificity of 96.64% and a sensitivity of 100% with a cut-off value of 0.36 when using the in-house RVFV-NP as the coating antigen. In comparison, a commercially available RVFV-NP-based ELISA exhibited a specificity of 96.23% and a sensitivity of 100% with a cut-off value of 0.37. Furthermore, the absorbance values of positive samples showed a significant correlation with their corresponding SNT titers. The in-house ELISA developed in this study offers a robust diagnostic and screening tool for RVFV. It provides a valuable mechanism for early detection, surveillance, and control of RVFV infections, thereby contributing to effective management and prevention of future outbreaks.