Pacheco's disease

Pacheco's disease is a highly infectious and acute bird disease caused by a species of herpesvirus, Psittacid alphaherpesvirus 1 (PsHV-1). All psittacine species are susceptible to Pacheco's disease, mainly those in zoological collections and aviaries in any geographic regions. Pacheco's disease most commonly occurs in Amazon parrots, followed by African grey parrots, parrots, macaws, cockatoos and conures. Due to a very high mortality rate within these susceptible species, concerns are brought to companion bird markets and breeders.

The main sign of Pacheco's disease is a sudden and rapid death of birds. It is often preceded by short, severe illnesses, which includes diarrhoea, lethargy, anorexia and inactivity. The virus is transmitted between birds through ingestion, by contaminated food or water, as well as through inhalation and conjunctival exposure. The rate that the virus can spread is highly influenced by its environment and living conditions. Birds can then develop signs and symptoms weeks after being in contact with the virus. If a bird survives Pacheco's disease, it may later develop internal papilloma disease in its gastrointestinal tract.

Pacheco's disease is diagnosed through a DNA probe or chemical and serological testings. No vaccine directly cures Pacheco's disease. There are only treatments with acyclovir and formalin-inactivated vaccine that helps prevent the virus from replicating.

The first case of Pacheco's disease occurred in Brazil in 1930. Since then, there have been multiple outbreaks globally including in Europe, Japan, Middle East and the U.S. The main source of these outbreaks is mainly due to the importation of birds. The disease is named after the veterinarian Genésio Pacheco (1890–1973), who first described the disease in 1930 while working at the Biological Institute of São Paulo in Brazil.