ASK THE VET (Proventricular Dilatation Syndrome, Neuropathic Gastric Dilatation or Macaw Wasting Disease)

Proventricular Dilatation Syndrome, Neuropathic Gastric Dilatation or Macaw Wasting Disease, is a very devastating, fatal disease affecting not only macaws, but many other species as well. This disease was first recognized in 1971 and since then has been seen in many species including cockatoos, conures, grey parrots, cockatiels, Eclectus parrots, thick billed Amazons, Blue fronted Amazons, and budgies, as well as macaws. These birds have been as young as 10 weeks of age and as old as 17 years.

This disease is thought to be caused by a virus. Birds often present with a history of regurgitation, chronic bacterial or fungal crop infections, pendulous crops, history of weight loss, passage of whole intact seeds in droppings, incoordination, or sudden death. These signs, unfortunately, are not specific for this disease. Other conditions such as lead poisoning, bacterial and fungal infections, foreign bodies and obstructions can mimic this disease.

Antemortem diagnosis of Proventricular Dilatation can be difficult. Suspicion of this disease is based upon history and physical examination. A complete workup should be performed which includes a CBC, blood chemistry, bacterial and fungal cultures and sensitivities, and a chlamydia test. Survey and contrast X-rays may demonstrate a dilated proventriculus (glandular stomach) and delayed passage of barium from the gastrointestinal tract. These findings further support a tentative diagnosis but are not conclusive. A definitive diagnosis is based upon a biopsy of the crop, ventriculous (gizzard) or proventriculous, demonstrating characteristic histopathologic changes. The characteristic lesions may not be uniformly distributed throughout the affected organ, so multiple biopsies are necessary.

Proventricular Dilatation Syndrome is a very difficult disease because its transmission, incubation and latency are unknown. Once it occurs in an aviary, it is difficult, if not impossible, to irradicate.

No effective treatment is known. Supportive care may help prolong the lives of affected birds. It is considered to be a fatal disease.