Bjørnar Ytrehus is a Norwegian veterinarian born in 1971. He was educated at the Norwegian School of Veterinary Science in Oslo and took his PhD in bone and joint pathology at the same institution in 2004. Since 2005 he has spent most of his time working with wildlife pathology and diagnostics and wildlife health surveillance at the Norwegian Veterinary Institute (current) and research and animal welfare at the Norwegian Institute for Nature Research (2014-2020). His main interest is the interplay between environment, pathogens and individual animal factors and its effects on animal health and welfare. His research currently focuses on causes of poor growth and increased mortality in moose calves, chronic roe deer diarrhoea, footrot in reindeer, chronic wasting disease and avian influenza.