Herpesvirus strigis, a new species of the genus Herpesvirus, is a pathogen for several species of owls in the order Strigiformes. Natural infection has been observed in the Eagle Owl (Bubo bubo L.), Long-eared Owl (Asio otus L.) and Snowy Owl (Nyctea scandiaca L.) In addition the Little Owl (Athene noctua Scopoli) and Tengmalms Owl (Aegolius funereus L.) was experimentally infected. On the other hand the Tawny Owl (Strix aluco L.) and Barn Owl (Tyto albo Scopoli) proved resistant to a massive experimental infection. Of representatives from nine other orders of birds and mammals, only the Old World Kestrel (Falco tinnunculus L.) was found susceptible to this virus.

Distribution of viral antigen in various organs of infected owls, as determined by immunofluorescence and by quantitative virus assay, was in accordance with the occurrence of macroscopic and microscopic lesions.