Proventricular Dilatation Disease
Avian Bornavirus Infection
Also known as: PDD, Macaw Wasting Disease, Macaw Wasting Syndrome, Psittacine Bornavirus Infection, Myenteric Ganglioneuritis
BirdUrgency: HighHow common: Uncommon
In short
Avian Bornavirus Infection
Also known as: PDD, Macaw Wasting Disease, Macaw Wasting Syndrome, Psittacine Bornavirus Infection, Myenteric Ganglioneuritis
In short
Proventricular Dilatation Disease (PDD), caused by Avian Bornavirus, is a serious and progressive disease affecting a bird's nervous and digestive systems. Learn to recognize the signs, such as undigested seeds in droppings, and understand how veterinarians diagnose and manage this challenging condition.
TL;DR. Proventricular Dilatation Disease (PDD) is a progressive, often fatal viral infection in birds that damages the nerves of the digestive tract and brain, leading to severe weight loss and digestive failure.
PDD is a serious viral disease that primarily affects companion parrots, including macaws and cockatoos.
Proventricular Dilatation Disease (PDD) is a complex and serious disease that primarily affects companion birds, especially parrots (psittacines). Also known historically as Macaw Wasting Disease or Myenteric Ganglioneuritis, this condition is caused by an infection with Avian Bornavirus (ABV). The virus targets the nervous system, causing severe inflammation in the nerves that control vital bodily functions.
The primary target of this inflammatory response is the myenteric plexus, which is the network of nerves embedded within the walls of the bird's gastrointestinal tract. In a healthy bird, these nerves coordinate the rhythmic muscular contractions that grind and move food through the digestive system. When infected, these nerves become inflamed and cease to function properly.
As a result, the bird's stomach—specifically the proventriculus, or "true stomach"—loses its muscle tone. Food stalls in the stomach, causing the organ to stretch out and dilate. Because the bird cannot properly digest or absorb nutrients, it essentially starves despite having a normal or even increased appetite. The virus can also attack the central nervous system, leading to neurological symptoms.
The underlying cause of PDD is Avian Bornavirus (ABV). The virus is shed in the secretions of infected birds, including saliva, feces, and feather dust. Birds contract the virus by inhaling or ingesting these viral particles, often through close contact, shared food and water bowls, or contaminated environments.
While any bird can contract the virus, members of the parrot family (such as macaws, African greys, cockatoos, and conures) are highly susceptible. Multi-bird environments, such as aviaries, pet stores, and rescue facilities, present the highest risk of transmission. It is important to note that some birds can carry and shed the virus for years without showing any clinical signs of disease, acting as silent carriers within a flock.
The symptoms of PDD can vary depending on whether the virus primarily damages the digestive tract, the brain, or both. Owners should monitor their birds closely for the following signs:
The passage of whole, undigested seeds in a bird's droppings is a classic sign of digestive dysfunction associated with PDD.
Diagnosing PDD is notoriously difficult because its symptoms overlap with many other avian health issues, such as lead poisoning, bacterial infections, or fungal crop infections. Your vet will perform a comprehensive physical examination and recommend a combination of diagnostic tests to build a complete picture.
Contrast radiography helps veterinarians visualize the characteristic enlargement of the proventriculus.
There is currently no cure for Avian Bornavirus or PDD. Treatment focuses on managing the inflammation, supporting digestive function, and keeping the bird comfortable. Because clinical trials across all avian species are limited, much of the treatment protocol is based on clinical extrapolation from successful case management in common parrot species.
The long-term prognosis for birds diagnosed with PDD is guarded to poor. While some birds can be managed successfully for months or even several years with supportive care, highly digestible diets, and anti-inflammatory medications, the disease is typically progressive and eventually fatal.
The success of long-term management depends heavily on how early the disease is detected and how severely the nerves have been damaged before treatment begins. Long-term prognosis data in many less common avian species remains limited, making individual outcomes difficult to predict.
Because there is no vaccine available for Avian Bornavirus, prevention relies entirely on strict biosecurity measures:
You should contact your avian veterinarian immediately if you observe undigested seeds in your bird's droppings, unexplained weight loss, or frequent regurgitation.
Seizures, severe loss of balance (ataxia), extreme weakness, or an inability to perch are critical emergencies that require immediate, urgent veterinary care.
Although some veterinary database records contain anomalous entries listing the Cockapoo (a dog breed) under PDD predispositions, this is a biological error. Proventricular Dilatation Disease is an infectious viral disease caused by Avian Bornavirus, which exclusively infects birds. There is no risk of this disease developing in dogs, cats, or humans.
Because no specific textbook excerpts were provided for this record, the clinical guidelines and diagnostic standards outlined in this article are derived from standard-of-care avian veterinary medicine consensus and established avian internal medicine reference texts.
Treatment must be prescribed by a licensed veterinarian based on your pet. Specific drug doses are intentionally not shown here.
Proventricular Dilatation Disease (PDD), caused by Avian Bornavirus, is a serious and progressive disease affecting a bird's nervous and digestive systems. Learn to recognize the signs, such as undigested seeds in droppings, and understand how veterinarians diagnose and manage this challenging condition.
Passage of undigested seeds in feces、Regurgitation、Weight loss、Crop stasis、Depression、Ataxia、Head tremors、Seizures
Histopathology of crop biopsy、Contrast radiography、RT-PCR for Avian Bornavirus、Serology (ELISA or Western Blot)
Treatment must be prescribed by a licensed veterinarian based on your pet. Specific drug doses are intentionally not shown here.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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