Tuesday, November 11, 2014

Avian Diseases - Proventricular Dilatation Disease (PDD)

Even though we here at Word Bird Sanctuary are constantly on the lookout for any signs of disease or other problems that could affect our birds, we thought that our readers (especially bird owners) might be interested in a discussion of some of the problems that could affect avian species.

Many people may be familiar with some of the more commonly discussed diseases that affect birds.  Most of us have heard of West Nile Virus, a disease spread by mosquitoes and affecting many species of animals (including humans).  We heard a lot about avian influenza a few years ago in the news.  But, unless you are a pet bird owner, you may not have heard of Proventricular Dilatation Disease, or PDD as it is known.  That’s because it is a disease that is not transmissible to humans, and only recently have we begun to unravel the mysteries of its causes and effects.

Baby Parrots (photo: Melissa Moore)

It is believed this disease was first recognized in a macaw in 1978, and was named “Macaw Wasting Syndrome.”  Affected birds usually show neurologic symptoms (like a weakened grip in their feet), and often exhibit digestive symptoms as well.  The digestive problems often include severe weight loss (thus the “wasting” moniker) and changes in appetite.  When examined internally, there is often a lot of food in the digestive tract, but it appears as though the internal organs were not doing their job to break down the food.  The “proventriculus”, a portion of the stomach, was often full of this undigested material.

These symptoms were identified in many other species, and so the name was changed to “Proventricular Dilatation Syndrome.”  As you might imagine, this disease could create a great deal of concern for bird owners.  For many years, very little was known about this syndrome, making it even more worrisome.

Eclectus Parrot (photo: Melissa Moore)

Then, in 2008, the cause of this syndrome was identified as a virus called the Avian Bornavirus.  Bornaviruses are known to affect many other species of animals, including mammals, but this particular virus appears to be unique to birds, and perhaps only to members of the parrot family.  By 2012 blood tests had been developed for this virus, so its presence in a bird may now be identified.  More research has also been conducted into this virus’ natural occurrence, and it has been shown to exist far more often than it causes disease.  And once again the disease has gained a new name, this time called ABV.

This topic is somewhat different than topics covered previously in World Bird Sanctuary blogs.  It came to my attention recently as I am a long-time Eclectus parrot owner with a normally healthy bird who had to make a trip to the avian vet recently.  Although my bird, Toby, is doing fine now (and tested negative for the Bornavirus), I was surprised to learn how much progress had been made in the field of avian diseases. ABV and many other diseases were quite unknown only seven years ago.

Some references to check out for more information on PDD:

Submitted by Melissa Moore, World Bird Sanctuary 

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