Is he still at the vet's?
Did your vet tell you the name of the infection?
How old is your little guy (what's his name)?
The more you can tell me about what's being done, how long it's been going on, where he is now - whatever you can add will help.
I know how hard this is for you. You're doing ALL the right things though. He's got a very much higher chance of getting through this with the care you're making sure he's getting.
Bacterial infections include: Chlamydia, mycobacteria, salmonella, pasteurella, yersinia and others. Tests should include sampling (and culture) of the nares (nostrils), oral cavity, cloaca, etc., but if the vet isn't knowledgeable about the normal flora in the bird species they are examining, the results may not mean much. Inexperienced vets will find that the culture grows something and often base their diagnosis on what they know of mammals. Cockatiels are known to contract Bacterial Enteritis - caused by salmonella, E.coli, coliforms and other bacteria infecting the intestinal tract. Common symptoms include diarrhea and going off their food; fluffing, lethargy, picking at and scratching their vent (bottom end), preferring the bottom of the cage and perhaps what looks like seizures (shaking, shivering).
The good news is that even a very sick bird can recover from this with a quick veterinary intervention and administration of the proper antibiotic (which will depend on the type of bacteria is found).
Exposure to other sources of contamination like the infected feces of another bird may also occur.
Of course he looks sad. He's stressed and he's scared, but when he comes back feeling much better it'll be worth it.
Just be prepared for him to act a bit 'off' for a few days, even up to a week. These little birds with great big hearts and bigger personalities may take a while to shake off the insult of a hospitalization like this. Tender loving care, calm surroundings and all the indulgences you want to give him will help.
Let me know what they find and I'll be pleased to go over it with you as much as you need ok?
And I'd say 'don't worry', but I know you're going to anyway. At least don't worry as much. He's in good hands!
It will depend on the type of infection. Did he go outside at all? Or to a groomer?
Maybe some of his fresh (any wet) food was left out more than an hour or two?
It could be anything really. It's not terribly uncommon.
'tiels are pretty smart and they love to be loved by humans. He obviously got lost all those years ago and may have been on his own for many days before deciding that he really needed a human again.
It was a 'tiel that started my exotic bird rescue and rehab efforts (I had been working with wildlife and raptors before that). I have a HUGE soft spot for these birds. So I mean it when I say I would like to know how he does.
All you have to do is re open this question anytime. Do not press accept again.
I'm here every day, though my hours may vary, so please be patient.
Good luck with him ok and God bless,
Amy my heart broke to hear this. I'm so sorry for you and the silence in your home now.
Nothing I can say will take away the pain. I know how deeply it hurts and only time will take the sting away.
Please, please know that you did the right thing for him. You tried your best and that has to give you some peace.
If you'd like to follow up again with the culture results, again you can just re open this (don't press 'accept' again).
My heart is with you