Psittacine herpesvirus infection resembling pacheco's parrot disease

Herpesvirus was detected by electron microscopy in hepatocytes of psittacine birds that died at a Florida aviary. The virus was identified in hepatocytes of chick embryos and budgerigars that were given injections of liver suspensions from naturally infected psittacines. Infected hepatocytes had prominent intranuclear inclusions that contained naked nucleocapsids. Both naked and enveloped virions were seen in the cytoplasm of hepatocytes, and enveloped nucleocapsids occasionally were seen in the perinuclear cisternae and extracellularly. The experimental and spontaneous disease mimicked a condition in parrots described previously by Pacheco. The viral agent was classified as Herpesvirus on the bases of the character of the intranuclear inclusions, the size and conformation of the agent as determined by electron microscopy and filtration, and the sensitivity of the agent to ether.