Proventricular Dilatation Disease

General Information
First recognized in the early 1970's, proventricular dilatation was originally called "Macaw Wasting Disease", as the disease caused a gradual wasting of macaws. Since that time, the disease has affected many species of pet birds.

What is proventricular dilatation syndrome?
Proventricular dilatation syndrome is a condition affecting the nerves supplying the gastrointestinal tract of birds, mainly the proventriculus or true stomach. Nerves supplying other organs may also be affected, and in some cases an encephalitis (inflammation of the brain) may also occur.

What causes the condition?
It is unknown what is the exact cause of proventricular dilatation syndrome, although a virus is suspected. To date, no one virus has been isolated from birds with the condition. Microscopically, the affected nerves are inflamed with an infiltration of certain types of white blood cells.

What are the signs of birds affected with proventricular dilatation syndrome?
The old name, "Macaw Wasting Disease", aptly describes affected birds. Birds have a lack of appetite, show regurgitation, may pass undigested seeds in their feces, and exhibit weight loss. Neurologic signs such as seizures or tremors may also occur. No one sign is definitive for the condition; however, proventricular dilatation should be suspected in birds with chronic unexplained regurgitation, weight loss, and any time undigested foods are seen in the droppings.

How is the condition diagnosed?
Clinical signs may suggest proventricular dilatation syndrome. Radiographs (X-rays), including a barium series may also strongly suggest the condition. The only definitive way to diagnose proventricular dilatation syndrome is with a biopsy of the proventriculus, although a biopsy of the crop (grinding part of the stomach), which is easier to perform, is accurate most of the time.

How do birds acquire the condition?
Because we don't know the exact cause, it's unknown how the condition is spread. Not all birds that are exposed to an infected bird will develop the condition, although the condition can spread throughout a flock of birds. To be safe, birds diagnosed with proventricular dilatation syndrome should be isolated from healthy birds.

Can the disease be treated?
There is unfortunately no treatment for affected birds. Supportive care, including treatment of secondary diseases and forced feeding as needed, can be given, but the condition is ultimately fatal.