Ask a Vet - Pacheco's Disease -- What is It?

by Linda Pesek, DVM

This article originally appeared in SQUAWK, the newsletter of the Big Apple Bird Association and is reprinted with permission.

Pacheco's disease is a contagious and often fatal viral hepatitis of parrots caused by a herpes virus. Many species of parrots such as African greys, Eclectus, Amazons, macaws, pionus, Quakers, Rosellas, lovebirds and budgies are susceptible to Pacheco's. Nanday conures and Patagonian conures are thought to be resistant to the infection and may serve as sources of infection for other species of psittacines.

Pacheco's virus is shed in oral secretions and feces. Some hens can pass the virus to their eggs, producing latently infected chicks. The virus may also be spread by people who come in contact with infected birds.

Infected birds may die suddenly, without showing any signs of illness, or die several days later after a brief period of anorexia, depression, diarrhea, increased thirst and urination, lime green urates, ataxia (loss of balance), tremors, and convulsions. Any bird that recovers from Pacheco's disease or survives an outbreak should be considered a latent carrier.

Latent carriers often appear normal but are able to shed large amounts of virus when they are stressed such as during the breeding season, when new birds are introduced, during changes in temperature, or when infected with other diseases.

It is very difficult to determine which birds are asymptomatic carriers of this virus. An inactivated vaccination has been developed to protect high risk psitticines, such as those in pet shops, quarantine facilities, aviaries and bird shows. The vaccination is given subcutaneously to small psittacines and either subcutaneously or intramuscularly to large psittacines. Young birds should be vaccinated at weaning age and again four to eight weeks later. Adults should be vaccinated twice -- with the second vaccination given four to eight weeks after the first. Yearly booster vaccinations are recommended. Breeding birds should have their vaccinations completed a minimum of four weeks before breeding season.