Application of molecular and immunological diagnostics to the prevention and control of bluetongue virus and related orbiviruses

Bluetongue virus (BTV), epizootic hemorrhagic disease virus (EHDV), and African horse sickness virus (AHSV) are orbiviruses that present major threats to UK agriculture, causing economically important disease in ruminant livestock, deer and horses.

Transmitted by Culicoides biting midges, numerous BTV strains are circulating in Europe, presenting a high risk to the UK.

This project aims to advance the state-of-the-art molecular diagnostic capabilities within the Non-Vesicular Reference Laboratory (NVRL) at Pirbright to guarantee the timely detection and identification of any circulating orbivirus. 

We will develop new molecular diagnostic assays and validate serological tests for BTV antibodies. Our genome sequencing pipeline will enable strain identification and trace viral spread, improving our understanding of genome reassortment and emerging strains.

The project will also improve evidence that cattle imported into the UK from European countries with ongoing BTV circulation have been appropriately vaccinated as required under current import regulations. 

Although existing BTV vaccines have worked well in controlled trials, there are concerns that some cattle vaccinated in the field do not show detectable antibodies. This makes it hard to confirm their vaccination status and protection level.

To address this, we will use a combination of serological assays to detect antibodies in vaccinated cattle. Additionally, we will additionally conduct a UK study on cattle vaccinated with BTV-8, monitoring their immune response over a year. By comparing these findings with previous infection studies, we aim to ensure better verification of vaccination and improve our understanding of cattle's immune responses to BTV.

We will also continue to develop new immunological assays to enhance our knowledge of the ruminant immune response to BTV infection and vaccination and critically advance our serological diagnostic capability as well as our ability to improve vaccine research.