Pacheco’s Disease in Birds

Angelina Childree, LVT

Angelina Childree, LVT

. Reviewed by Jessica Hockaday, DVM
Updated Apr. 28, 2024
Small blue parrot at the vet

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In This Article


What Is Pacheco’s Disease in Birds?

Pachecos disease is a virus that commonly infects the parrot family. Pet birds that are susceptible to this virus include:

Unfortunately, the virus that causes Pachecos disease is highly contagious and often fatal for birds. Humans and non-avian pets are not susceptible to the virus.

If you suspect that your bird may have symptoms of Pachecos disease or has been exposed, take them immediately to an emergency avian veterinarian. Pachecos disease in birds has a high mortality rate (up to 100% in flocks) and should always be treated as an emergency. 

Symptoms of Pacheco’s Disease in Birds

There are no unique signs of Pacheco’s disease, but knowing what is normal for your bird and quickly identifying any sign of illness is key. Clinical signs often appear 10–14 days after exposure in birds, and may include:

  • Yellow, watery urates (urine portion of bird’s droppings—this should be more formed and white)
  • Lethargy

  • Depression

  • Not eating

  • Ruffled feathers

  • Eye discharge/runny eyes

  • Nasal discharge

  • Green feces

  • Regurgitation

  • Papillomas on the oral or cloacal mucosa/tissue, as well as internal

  • Sudden death (within a few hours of exposure)

Causes of Pacheco’s Disease in Birds

Pachecos disease is caused by Psittacine herpesvirus 1 (PsHV1). There are multiple strains of this virus, with varying degrees of illness, but all should be treated as potentially fatal. The virus is highly contagious—it can be shed from the droppings or respiratory secretions of carrier birds, even those that are positive for the virus but dont show signs of actually being sick.

Pacheco’s disease in birds can be spread through direct contact or exposure to infected feces and respiration secretions (airborne). Birds that carry the virus are not always contagious (asymptomatic), but during times of stress, infected birds may start shedding the virus and become sick. Environmental changes, moving your birds, changes in routine, and sudden noises can all be stressful for pet birds. They should be avoided if your veterinarian suspects your bird is a carrier. In many cases, serial testing of your bird’s blood will be suggested to monitor them.

If you suspect that your bird may have symptoms of Pacheco’s disease or has been exposed, take them immediately to an emergency avian veterinarian.

Any sort of stressor could cause a carrier bird to have a reactivation (flare-up). Also, the virus can be transferred from mother to embryo, so birds carrying the virus should not be bred. A PCR test of the droppings and a blood test can be evaluated to help establish your birds’ status.

How Veterinarians Diagnose Pacheco’s Disease in Birds

Unfortunately, Pachecos disease in birds is often identified after the bird has died. Further testing can be done on the bird after their death to confirm the disease.

A swab sample from a bird can be taken from the cloaca (vent/posterior opening) or choana (cleft in the mouth) and tested. If infection particles are found, this would be considered a positive test result. Blood samples are checked for antibodies to establish if a bird has been exposed to Pacheco’s disease, and if they are infectious.

A presumptive diagnosis can be made from your bird’s history, any clinical signs, and any symptoms of other birds in the flock.

Treatment of Pacheco’s Disease in Birds

Birds with Pachecos disease will receive supportive care for their symptoms. This can include:

  • Fluid therapy to treat dehydration

  • Antiviral medications

  • Antibiotics (for secondary bacterial infections)

  • Anti-inflammatories

  • Pain medications

  • Surgical interventions if papillomas are evident and causing lesions (ulcers)

Birds who are not eating may need a feeding tube to supplement meals. Birds exposed to Pachecos disease may also be prescribed acyclovir, to help reduce severe disease after exposure.

Recovery and Management of Pacheco’s Disease in Birds

Pacheco's disease is often fatal. Hospitalization will give birds the best chance at recovery, rather than at home.

Birds that recover from Pacheco's disease often develop internal papillomas (benign growths), especially in the cloaca, and hepatomas, which are liver growths. Survivors may also have liver problems caused by the viral infection.

Any bird with Pachecos disease should be isolated from other birds in the house/aviary. The virus is highly resistant and can live outside a host for some time.

Birds that have survived the infection will still have the virus present in their body and can still pass the virus to other birds, even during flare-ups. These birds are now virus carriers for the rest of their lives. Since the virus is still present in the body, it can "reactivate" during times of stress. Stressful events should be avoided to help prevent another active virus infection.

Prevention of Pacheco’s Disease in Birds

You can’t completely prevent Pacheco's disease in birds, but there are steps you can take to minimize the virus from spreading bird to bird. First, always avoid overcrowding birds. If you have multiple birds, any new birds need to be quarantined before joining your flock. Before purchasing a new bird, be sure to do research on the breeder or the bird’s background.

General health management, such as quality diet and proper housing, can help reduce the chance of disease in your birds.


1. Hoppes S. Viral Diseases of Pet Birds — Exotic and Laboratory Animals. Merck Veterinary Manual. 2021.

2. Hagen M. An Outbreak of Herpes Virus and its Future Prevention in an Indoor Parrot Breeding Facility. Hagen Avicultural Research Institute.


Angelina Childree, LVT


Angelina Childree, LVT

Veterinarian Technician

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