There are many different herpesviruses that are found in birds, including commercial poultry, ornamental, wild and zoo birds. New viruses are also regularly found in these animal groups. Several herpesviruses have been described in parrots, too. The bestknown and perhaps clinically most relevant one is psittacid herpesvirus 1 (PsHV-1). PsHV-1 is responsible for Pacheco's disease in parrots and is therefore also called Pacheco’s virus . The clinical course depends on the genotype or serotype and the affected psittacine species. For budgerigars and cockatiels, mild to subclinical courses with virus shedding are reported. In large parrots, such as macaws, amazon parrots, cockatoos or grey parrots, an infection often leads to death. If symptoms occur, they are usually unspecific and consist of anorexia, apathy and poorly developed feathers. Changes in faeces and an increase in uric acid excretion may occur, too. Occasionally, CNS symptoms are also observed. The disease particularly breaks out in stressful situations, e.g. capture and quarantine of imported birds, change of owner, hospitalisation, beginning of breeding or the onset of sexual maturity. Therefore, a suitable preliminary examination of birds that are to be integrated into the flock is recommended in order to avoid posing a threat to the other birds.

An examination for herpesviruses may also be appropriate for other animals with systemic diseases, diseases of the respiratory system, the liver or with skin lesions or lesions of the mucous membrane at the cloaca or around the beak. In amazon parrots and cockatoos, psittacid herpesviruses can also be detected in papillomas in the throat and the cloaca.