PDD vs. Avian Bornavirus, A Layman’s Interpretation

PDD digestionOver the years, some birds have died from a dreaded disease called PDD, or proventricular dilatation disease. It was first noticed in macaws that could not properly digest their food. In some other species, like greys and cockatoos, it caused neurological problems. It is a mysterious disease that we do not thoroughly understand. It is still not completely explainable. And anything inexplicable can leave us feeling concerned, afraid, and even irrational at times.

What some researchers thought in 2010: ABV = PDD
In 2010, a major research project declared that the cause of PDD was the avian bornavirus (ABV). It said ABV = PDD. That’s a very declarative statement! So, at last we thought we knew the answer and could finally cope with the perplexing PDD challenge, saving our birds from future harm. Unfortunately, this “answer” caused many bird owners and veterinarians to rush to judgment, even euthanizing birds that tested positive for ABV.

What some researchers think now: ABV does not always, or even often, mean PDD
Now we have come to learn that many birds are ABV positive, and most never succumb to PDD. Then there are those birds that die of PDD, confirmed on necropsy, but they are ABV negative. What are we to think? What are we to do? Yes, ABV can be an important component in causing PDD, but an ABV positive bird is not automatically doomed to contract PDD, and in most cases they do not.

How might ABV be spread?
Some veterinarians believe that birds are born with ABV, passing it through the egg; or that birds possibly acquire ABV through the exchange of fluids during mating. Sounds kind of like HIV, right?  ABV and HIV are both auto-immune diseases.

As a person who strives to make sure that birds have a succession of good homes, here is my concern — do we need to worry about ABV positive birds? It is my personal opinion that we do not – assuming that the bird is otherwise healthy and thriving. We have asked many veterinarians this question over the years, and most agree that an otherwise healthy bird can be re-homed without reservation.

Tips to promote overall health for our birds, and prevent disease
Avian bornavirus, like many other disease challenges in our environment, can certainly place extra stress on a bird. If a bird is sick for unknown reasons, testing for ABV might be a valuable piece of diagnostic knowledge. However, there are other things we can do to prevent many diseases, and in my opinion, these are equally important!

6432 cage for grey

An environment that can contribute to physical and mental health. Used with permission from naturalinspirationsparrotcages.com

  • We can make sure the quality-of-life we provide parrots in captivity includes ample space to move, explore, and exercise.
  • We can provide access to nutritious food and not crappy seed from the big box store.
  • terrible cage.png

    Does NOT lead to good health

    We can make sure our bird sees a true avian veterinarian on a regular basis – and receives the labs and gram stains that help give us early information about disease.

  • And we can learn how to live with a parrot without expectations of inappropriate touching, over-stressing environments, or unnecessary insecurities.

Support more ABV and PDD research
Meanwhile, we whole-heartedly applaud the continued efforts of the veterinary and scientific community to research both diseases; to understand more definitively what their connections might be; and to encourage balance and reason about both potential problems with their clients. Birds do not need to die when they are not truly suffering from a disease, so let’s be careful not to overreact.

You can learn more about both PDD and avian bornavirus from Dr. Susan Orosz, PhD, DVM, DABVP (Avian), DECZM (Avian) here: https://lafeber.com/pet-birds/unraveling-the-puzzle-of-avian-bornavirus-pdd/ and here http://www.birdandexotics.com/medical-news.pml

Stay tuned for our next blog post about a bird that was diagnosed and presumed sick because of avian bornavirus, and as a consequence its heart disease diagnosis was totally missed!  by Ann Brooks

Radiograph image source

Last, Robert, Herbert Weissenböck, Nora Nedorost, & H.L. Shivaprasad. “Avian bornavirus genotype 4 recovered from naturally infected psittacine birds with proventricular dilatation disease in South Africa.” Journal of the South African Veterinary Association [Online], 83.1 (2012): 4 pages. Web. 24 Aug. 2018.

 

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