On Friday, I got the confirmation that the budgie I lost in August did indeed die from AGY - however, there may have been some underlying cause that led to AGY. This budgie lived with a female budgie, in the same room as a mitred conure, and has been in "contact" (close range) with two cockatiels. His fecal test was clear. For the most part, his body was normal and beyond the visual signs (vomitting, weight loss, lethargy) showed no other signs of having AGY. Birds with AGY usually have inflammation inside the body - this bird either had very little or no inflammation.
I asked my a-vet about it, and she really didn't seem all that concerned about my other birds getting sick. In fact, she says she's treated many birds who had signs of it and couldn't completely get rid of the bacteria. There could be very many birds who are infected with AGY and show no clinical signs - more or less, they are carriers who may shed the organism, but are not directly effected by the organism itself. Not only that, but it's possible that AGY is a naturally occuring organism inside birds, and only becomes an issue when there is some other underlying problem. "We" just don't know.
Below are two links with some separate information. Each link has more information, but I'm just highlighting some particular info. I almost have to wonder if the dose of medication Carl is getting is not strong enough.... or if perhaps the AGY is somehow resistant to the meds he is getting... or, as you mentioned, Carl couldn't handle the proper meds and he just puked it back up, thus it wasn't helping at all.
Avian Gastric Yeast - 1Some researchers believe that AGY are normal inhabitants of the GI tract and others feel that this organism is responsible for causing disease in budgies.
Avian Gastric Yeast - 2The drug of choice for treating AGY is currently Amphotericin B, administered orally. Birds being treated with this medication should be closely monitored. Experimentally, Amphotericin B dosed at 100 mg/kg PO BID for 14 days resulted in 8 out of 10 birds testing negative. When dosed at 100 mg/kg PO BID for 28 days, the organism was eliminated in 100% of the test birds. Fluconizole, another antifungal medication, proved too toxic to eliminate AGY in test subjects, but when given at lower (safer) doses, it failed to eliminate the organism in many cases. This study was performed by Dr. David Phalen and his group at the Schubot Exotic Bird Health Center in 2002.
In regards to the Bicom treatment, honestly, it looked a bit like a sham. However, the A-vet says she's had a lot of good results using it, in fact the last patient she had treated before me was a very nervous dog. Somewhere part way through the treatment, he ended up laying down on the floor and passing out. She also treated one of the other employees who had back pain. This employee had the choice of taking medication and not being able to drive, or not taking it and drive to work and everything else she needed. She's also a mother of a 2 year old. Before the surgery, the first time she went through Bicom, she commented that it felt as if she were drugged, she was just so tired afterwards. Although the Bicom is not a cure for a slipped disk, it did aleviate the pain until she could get surgery.
By what the A-Vet did, supposedly she found a lot of toxins, including outlawed pesticides, some bacteria and fungal growth, a couple of metals, exhaustion, pain, bone pain, a blocked immune system, and more. I don't know exactly how she finds all this out using a blood sample without any actual testing on the sample or the bird (as is the way with our Western practices), but we did the Bicom treatment. Noel did quite a bit of moving about, fluffed up her feathers and scratched her head more than normal, but was otherwise rather calm and every now and then sleepy eyed. The A-Vet said that birds usually become agitated at the beginning of treatment, and calm down towards the end of it. I can't say that I really noticed that, since Noel, is for the most part, a rather sedentary bird. She's not your typical, healthy conure. In fact, Charlie is your typical conure, who's noisy, loveable, bitey, demanding, aggressive with toys, etc. Noel is the complete opposite. The most that I can say is that Noel seemed rather happy to be going home, more so than going in. I don't necessarily want to attribute that to the Bicom treatment, but perhaps it did change something. All I know for sure was that on the way home, I felt more tired than she looked... She did mention that Noel should be stiff for the next few days.... the only difference I've noticed thus far is that Noel's grip seems to be just a tad weaker than normal - her grip as it is isn't that strong to begin with. In comparison, Charlie, a mitred conure, or even a budgie, could hang upside down from my fingers - Noel could not.