Inclusion Body Disease of Falcons

A viral agent has been isolated from five fatal cases of naturally occurring inclusion body disease in three different falcon species, namely, the prairie falcon (Falco mexicanus), the red-headed falcon (F. chiquera), and the peregrine falcon (F. peregrinus). The virus has been shown to possess the physical, chemical, and biological properties of a herpesvirus and has been used to reproduce inclusion body disease in the prairie falcon, merlin (F. columbarius), and American kestrel (F. sparverius). A similar disease was also produced with this virus in the great horned owl (Bubo virginianus), screech owl (Otus asio), and ring-necked turtle dove (Streptopelia risoria). Serological comparison of the falcon herpesvirus with other known avian herpesviruses revealed that the virus is antigenically closely related to a pigeon herpesvirus and an owl herpesvirus while differing from the former in host range. No antigenic relationship to infectious laryngotracheitis virus, duck virus enteritis, or Marek's disease virus could be demonstrated.