I am so sorry for your loss, YUMgrinder. I hadn't seen this thread until this morning on the way to work. My heart goes out to you and your flock. I could see from your posts how very much Cheddar meant to you. But as so many here have so beautifully expressed, Cheddar's life was greatly enriched by your presence in it. Don't diminish that in any way, shape or form by taking any of the blame for her passing. You did all that you could.
I can speak to you on this with a deep understanding of where you're coming from, because my first ekkie, Bixby, also died of the manifestation of PDD wherein it attacks the autonomic nervous system... at a year and a half... after a bloodiest that he was just too weak to endure. (I was a little more fortunate in that Bixby didn't pass until we'd gotten home around 3 or so hours later, but in all other respects an uncanny resemblance.)
Like you, I blamed myself for consenting to the blood draw. "I should've known he was too weak." Or ""If I only waited until he was stronger." But the truth is, we both did everything that we could for our birds. If either of us hadn't consented to that blood draw, and our birds passed anyway, we'd be second-guessing that as well. Wondering if an answer could've been found had we only had the courage at the time to allow that test. See the downward spiraling path that kind of thinking leads us toward?
No.That's not what Bixby would have wanted for me, and it's certainly not what Cheddar would've wanted for you. Though her time was short, she made sure to leave you with a lifetime's worth of memories to treasure and cherish. Because of you, she was able to have a life beyond the confines of a "hospital closet" in some pet store. Because of you, she got to LIVE rather than simply survive and endure. And in return, she loved you with all that she had. Every moment she spent nestled along your neck or in your lap was her gift to you. The gift of her love and gratitude for her knight in shining armor who passed all the healthy and perky birds and instead, against all odds, chose the sweet little one quarantined away in what amounted to a closet.
Take this time to grieve, my friend. Lord knows I did. But as time passes, allow yourself to focus less on the pain of her passing and more upon the joy that she brought into your life.
And another thing. I know that you are worried that the rest of your flock is now facing the inevitable. I'd like to share with you some of what I wound up learning about PDD in the wake of Bixby's passing. The information I've gleaned was partly through exhaustive research, though largely from in-depth discussions with 2 veterinarians, one of whom was a pioneer in PDD research when it was first being classified, and the other who continues to research avian disease pathology even as he treats parrots in his capacity as a CAV.
First thing, the one mode of transmission that seems to be universally agreed upon is vertical (Parent-to-child) transmission. This is almost certainly what occurred in Cheddar's (and Bixby's) case. She was likely born with one of the strains of ABV (Avian Borna Virus), which lacks any clinical signs until it comes into contact with an as yet unidentified catalyzing agent that triggers the progression to clinical PDD (Proventricular Dilation Disease). That mystery catalyst is seen as a potential key to defeating PDD. If it could be identified, it could conceivably be blocked... thus keeping ABV in its relatively harmless state.
Okay, so far as horizontal (bird-to-bird) transmission goes, PDD is nowhere near as contagious as PBFD or Pacheco's or any number of other avian diseases. The extent to which it is transmissible, however, is not truly known. Birds have been housed together for years without infecting the other. (And I don't mean carrier status. These are cases in which the companion birds were necropsied after their natural deaths and shown to be free of PDD and ABV.) But it is believed that PDD is transmissible via feces, so cage environs should be kept as clean as is possible. This part is important, because I don't want you thinking that your flocks' infection is a given. It most certainly is not. (Maya never contracted Bixby's variant of PDD. I once believed she had a different type, but I no longer think so.)
Which brings us to testing. Your vet said that you can't test for PDD, which isn't strictly true... though I understand why he/she said it. First, the only blood-test available for this is a test for ABV. Sounds good on the face of it, since ABV is the pre-cursor to PDD. But it turns out that there are around 9 different strains of ABV... only 2 of which have the potential to progress into PDD. The other 7 don't have any measurable effect whatsoever. And unfortunately, the test can't tell you which strain of ABV, if any, it has detected in your bird. Further complicating matters is the fact that some 40 or so percent of pet birds are infected with one of said 9 strains. (Obviously, most of that 40% has the 7 "benign" strains.) And then, as if that all didn't make it tough enough, the test also has the limitation of only being able to detect ABV when it's actively shedding.
So in short, even if the test is given when the bird is actively shedding and tests positive, all it tells you for certain is that your bird is one of the 40%. And if the test comes back negative, that still doesn't tell you much, as it might be a false negative. The test does hold value if there is a preponderance of evidence, however. Like as supporting evidence along with certain clinical symptoms, or with an x-ray.
Speaking of x-rays, I consider them one of the most important tests for the autonomic nervous system variant of PDD. If it has progressed to a clinical stage, enlargement of the proventriculus would be a huge red flag. As would the presence of undigested food particles throughout the digestive tract. (The main complication of this form of PDD is an enlarged proventriculus, which means the walls of that "stomach" can't reach the food passing through to break it down. This is why food is excreted undigested and the bird loses weight. Bixby went from an average of around 420-30 down to 295 or so.)
There are other more invasive tests that can be performed, such as a crop biopsy, but even that can be hit or miss depending on where the lesions have spread to at the time of the procedure. There's also another kind of biopsy, even more invasive, but the specifics of that one escape me at the moment.
The only 100% certain way to confirm PDD is with a necropsy, unfortunately. But a preponderance of evidence can bring you to a state of relative certainty. In the meantime, however, I'd suggest being VERY thorough with their hygiene. Clean up every bit of poop in any communal areas. And don't allow them to feed one another.
And lastly, if it does turn out that they are positive for PDD (which I honestly doubt they will be), it is important to know that early detection can allow them to lead long lives. It can be managed to a greater extent than PBFD could, as long as one is vigilant against flare-ups. You're alerted to the possibilities, now. If anything jumped off, you'd have an idea of what might be going on.
I'm sorry this post wound up being so long. I usually try not to be so long-winded, but I wished somebody could've told me this stuff a few years back. If you have any questions or concerns, feel free to either post here or hit me on a pm.
And again, I'm so deeply sorry for your loss.
