Pacheco’s Disease in Macaws
- See your vet immediately. Pacheco’s disease is a highly contagious psittacine herpesvirus infection that can kill a macaw very quickly, sometimes before many signs appear.
- Macaws are one of the parrot groups commonly affected. Signs can include lethargy, not eating, regurgitation, green droppings, bright yellow or watery urates, weakness, and sudden death.
- Birds can carry the virus for life and shed it during stress, including after moving, breeding, illness, or introduction to a new bird.
- Diagnosis may involve oral and cloacal swabs, bloodwork, and PCR testing, but some cases are only confirmed after death with necropsy and tissue testing.
- Typical same-day evaluation and testing cost range in the US is about $250-$900, while hospitalization and outbreak management for exposed birds can raise total care into the $800-$3,500+ range.
What Is Pacheco’s Disease in Macaws?
Pacheco’s disease is a severe viral infection caused by psittacine herpesvirus 1 (PsHV-1). In parrots, it is best known for causing sudden, often fatal liver disease. Macaws are among the New World parrot species commonly affected, along with Amazons and conures.
One of the hardest parts for pet parents is how fast this illness can move. Some macaws show vague signs like low energy, poor appetite, or regurgitation for only a short time. Others may be found critically ill or dead with little warning. Because the virus spreads easily between susceptible birds, any suspected case should be treated as an emergency for the sick bird and for other birds in the home or aviary.
Pacheco’s disease also has a long-term management side. Birds that survive can remain infected for life and may intermittently shed virus, especially during stress. In some survivors, internal or cloacal papillomas can develop later, so follow-up with your vet matters even after the initial crisis.
Symptoms of Pacheco’s Disease in Macaws
- Sudden death with little or no warning
- Lethargy, weakness, or sitting fluffed and quiet
- Not eating or rapid drop in appetite
- Regurgitation or vomiting-like behavior
- Bright yellow, watery urates or unusually wet droppings
- Green droppings or diarrhea
- Depression or reduced interaction
- Eye or nasal discharge
- Papilloma-like growths around the mouth or cloaca in survivors
See your vet immediately if your macaw seems weak, stops eating, has regurgitation, develops very wet or yellow urates, or if another bird in the home has died suddenly. Pacheco’s disease does not have one unique sign, so even mild changes can matter.
This is especially urgent if your macaw was recently exposed to a new bird, boarding facility, breeder, bird fair, rescue intake, or a stressful move. In multi-bird homes, one sick bird can mean other birds were exposed before anyone noticed a problem.
What Causes Pacheco’s Disease in Macaws?
Pacheco’s disease is caused by psittacine herpesvirus 1. The virus spreads through direct contact, aerosolized respiratory material, and contamination from droppings, food, water, or surfaces. Reported incubation is often about 3 to 14 days, though some birds may appear to decline even faster once clinical illness begins.
A major challenge is that apparently healthy birds can carry the virus and shed it intermittently. Stress is a common trigger for viral shedding. That can include shipping, rehoming, breeding, introduction of a new bird, crowding, illness, or other major routine changes.
Macaws are considered a susceptible group, and outbreaks are often linked to bird-to-bird exposure rather than a problem that starts spontaneously in one household. In some species, carrier states are especially important, which is why your vet may recommend testing and quarantine protocols for all exposed birds, not only the one that looks sick.
How Is Pacheco’s Disease in Macaws Diagnosed?
Diagnosis can be difficult in a live bird because the disease may progress so quickly. Your vet may start with a history of recent exposure, a physical exam, and baseline bloodwork. Reported lab changes can include marked leukopenia and increased AST, which may support concern for severe viral liver disease.
Specific testing often includes PCR or DNA probe testing from combined oral and cloacal swabs, and sometimes blood samples. These tests can help identify viral shedding or infection in a living bird, although timing matters. A negative test does not always fully rule out disease if the bird was tested early or is not shedding at that moment.
If a macaw dies suddenly, your vet may recommend necropsy with tissue testing. Postmortem findings can include enlarged liver, spleen, and kidneys, liver discoloration, and characteristic intranuclear inclusions on histopathology. In a multi-bird home, confirming the diagnosis can guide isolation, testing, and preventive care for exposed birds.
Treatment Options for Pacheco’s Disease in Macaws
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Urgent exam with an avian veterinarian
- Isolation from other birds at home
- Focused supportive care plan
- Basic bloodwork and/or limited swab testing based on budget
- Discussion of exposure risk for other birds
- Home monitoring instructions and strict biosecurity steps
Recommended Standard Treatment
- Same-day avian exam and stabilization
- CBC/chemistry with liver-focused assessment
- PCR testing from oral/cloacal swabs and selected blood testing
- Fluid therapy and nutritional support as needed
- Antiviral discussion, often including acyclovir for exposed birds or outbreak management when your vet feels it is appropriate
- Treatment for secondary problems such as dehydration or secondary bacterial infection
- Isolation and flock exposure plan for other birds in the household
Advanced / Critical Care
- Emergency hospitalization with intensive avian monitoring
- Injectable or assisted fluid support and thermal support
- Tube feeding or assisted nutrition when not eating
- Serial bloodwork and repeat reassessment
- Broader supportive medications for pain, inflammation, nausea, or secondary infection when indicated by your vet
- Outbreak management for exposed birds, including testing and preventive treatment discussions
- Necropsy and tissue diagnostics if a bird dies, to protect remaining birds
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Pacheco’s Disease in Macaws
Bring these questions to your vet appointment to get the most out of your visit.
- Based on my macaw’s signs and exposure history, how likely is Pacheco’s disease compared with other causes of sudden illness?
- Which tests are most useful today—PCR swabs, bloodwork, or both—and what can each test tell us?
- Does my macaw need hospitalization now, or is monitored home care reasonable for this stage?
- What isolation steps should I use at home to protect my other birds?
- Should my other birds be tested or treated because they were exposed?
- If you are considering acyclovir or other medications, what is the goal, what are the limits, and what side effects should I watch for?
- If my macaw survives, what long-term follow-up is needed for carrier status, liver health, or papillomas?
- If my bird dies suddenly, should we do a necropsy to confirm the cause and guide care for the rest of the flock?
How to Prevent Pacheco’s Disease in Macaws
You cannot reduce risk to zero, but you can lower it meaningfully with careful flock management. Quarantine any new bird before contact with resident birds, and ask your vet about the right quarantine length and testing plan for your household. Avoid sharing bowls, perches, carriers, or cleaning tools between quarantined and resident birds.
Because healthy carriers can shed virus during stress, prevention also means reducing avoidable stressors. Keep routines steady, avoid overcrowding, support good nutrition and housing, and be cautious with breeding, boarding, bird fairs, and mixed-species exposure. If one bird becomes ill or dies suddenly, separate all birds right away and contact your vet before moving birds between rooms or homes.
Disinfection matters after a suspected case. Remove droppings carefully, clean surfaces thoroughly, and follow your vet’s instructions for safe disinfectants and handling. If your household includes species known to be potential carriers, your vet may recommend separate housing or a more cautious long-term management plan.
Vaccination is not a routine prevention tool for most pet macaws. Older vaccine approaches have had safety concerns, and vaccine use is not a substitute for quarantine, testing, and biosecurity.