From negative to positive - new diagnostics to identify the aetiology of unknown viral infections in horses

Today, a number of different diagnostic tools are used to identify the cause of disease outbreaks but despite this, the aetiology i.e. the cause of the disease remains unknown in many cases, especially in the case of horses exhibiting fever and/or various neurological symptoms. Therefore, in this project we aim to use so-called viral metagenomics to examine samples from these horses and try to identify which virus is possibly behind the disease.

Virus metagenomics is a method that uses large-scale sequencing and bioinformatics to simultaneously identify all viruses in a sample without having to decide in advance which virus to look for as in traditional virus diagnostics. This method can also be used to detect completely new viruses. By identifying which virus or viruses are associated with disease, traditional diagnostics can be extended to include them in the future.

Progress in the project

During the project, samples from over 150 horses have been collected, not only from Sweden but also from other Scandinavian countries. These samples come from horses with fever, with diarrhoea and with neurological symptoms. Horses not showing signs of any infectious disease have also been included for comparison. The samples have been analysed by viral metagenomics and preliminary results show the presence of several different viruses in these horses, some of which show a high divergence from previously described viruses.

Current studies are ongoing to characterise the viruses identified and to study their possible association with disease.