Development of a Microsphere-based Immunoassay for Serological Detection of African Horse Sickness Virus and Comparison with Other Diagnostic Techniques.

The study focuses on developing a more efficient method to detect the African Horse Sickness Virus (AHSV) using a microsphere-based immunoassay, known as the Luminex assay. This tool uses AHSV structural protein (VP7) coated beads to identify any serotype of AHSV, proving to be more sensitive and faster in detecting the virus compared to the traditional Enzyme-Linked Immunosorbent Assay (ELISA) and Lateral Flow Assay (LFA).

Objective and Methodology of the Research

• The researchers aimed to develop a more rapid, sensitive, and specific diagnostic test for AHSV to assist effective surveillance programs and countermeasure preparations.
• The research was conducted using serum samples from uninfected horses, a reference library of all AHSV serotypes, samples from horses experimentally infected with AHSV, and samples from West African horses suspected of suffering from AHS.
• A novel microsphere-based immunoassay, the Luminex assay, was developed. In this assay, beads are coated with the AHSV structural protein 7 (VP7), which detects antibodies against any AHSV serotype.

Findings of the Study

• The Luminex assay and ELISA gave the same negative results while testing samples from uninfected horses.
• Both these methods detected antibodies to all nine AHSV serotypes. It means they can be used universally across all variants of the virus.
• However, the Luminex assay showed a higher detection rate of anti-VP7 positivity in the West African field samples than ELISA or LFA. It means the new method is more sensitive in identifying the virus in equine populations.
• In an experimental scenario, the Luminex assay managed to detect anti-VP7 positivity in infected horses as early as 7 days post-infection, compared to 13 days for ELISA. It demonstrates the greater speed of the new test.

Implications of the Research

• The Luminex assay proves to be a comprehensive and efficient platform for detecting multiple AHSV antigens simultaneously, providing an advantage over traditionally used methods.
• This innovation could also be instrumental in segregating infected horses from those only vaccinated, thereby streamlining the diagnosis and treatment procedures.
• Earlier and sensitive detection of AHSV means quicker response times in implementing quarantine or other treatment protocols. Thus, the Luminex assay can meaningfully help mitigate the impact of the disease on the equine industry.