Pacheco's Disease in Birds

Pacheco's disease is a highly infectious and deadly bird illness. It is caused by the rapidly spreading Herpesvirus and especially affects birds in the parrot family. Once infected, the animal may or may not develop symptoms, but usually dies within a few days of contracting the disease.


Pacheco’s disease damages many of the bird’s organs, including the liver, spleen, and kidneys. If the bird does survive an infection, however, the organ damage will remain permanent.

The main symptoms of Pacheco's disease are: 

  • Green colored feces, due to liver damage
  • Listlessness
  • Diarrhea
  • Nasal discharge
  • Lack of appetite
  • Swelling
  • Redness of eyes
  • Tremors
  • Ruffled feathers

And while these signs usually appear within three to seven days of infection, not all birds will display symptoms.


Pacheco's disease is caused by the herpesvirus, usually contracted from the feces and nasal discharges of other infected birds. Feather dust, dander, and contaminated air, food, water and living surfaces also help spread this deadly disease. Stress due to losing a mate, breeding, relocation, climate changes and other environmental and emotional changes, can trigger the infection, as well.

It is important to note the Pacheco's disease herpesvirus can survive outside the bird’s body for a long time, and thus infect a bird from any contaminated surface.

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