Leveraging metatranscriptomics for the characterisation of bovine blood viromes

Understanding the diversity of the bovine virome is essential for assessing their potential impact on cattle health and transmission risks. Viruses present in the blood comprise both those that establish persistent infections in blood cells and those present during transient viremia. Farm management practices, such as the reuse of syringes for treatments, vaccinations, and supplements, may inadvertently contribute to the spread of blood-borne pathogens, emphasizing the need for improved biosecurity measures. Herein, we used a metatranscriptomic approach to analyse 20 bovine blood transcriptomes from dairy cows in New South Wales, Australia, along with 577 publicly available blood transcriptomes from studies in Australia and Kenya. Our analysis identified several viruses that are known to infect blood cells, transmitted either by direct contact or by vectors, including bovine viral diarrhea virus, bovine gammaherpesvirus 6, hepacivirus, foamy virus, ephemeroviruses and a new species of a coltivirus. Our findings highlight the complexity of the bovine blood virome and underscore the importance of sustained surveillance to identify emerging pathogens and assess their potential role in cattle health. This study provides a framework for integrating transcriptomic data into disease monitoring efforts, ultimately contributing to improved cattle management and biosecurity practices.