Pet rat suddenly extremely ill

Question
Hi there,
I just got two baby rats about 2 months ago. One of them ended up sneezing and wheezing quite a bit so we took him to the vet who said that he had a respiratory infection but luckily we caught early. He prescribed 2 antibiotics which we diligently gave to Fox twice a day for 3 weeks. He seemed better and we picked up that he sneezes when he gets anxious or excited (new place to play in, he sneezes, new person to play with, he sneezes, new food, he sneezes, you get the idea). He turned out to be the sweetest pet I have ever had. He prefers spending his time on my shoulder or lap and give kisses unlike his brother Zip who spends the whole time running and climbing.
Yesterday both were playing outside on the balcony, Fox in a potted Lavender plant that he likes. This morning I found Fox covered in blood - not the first time, though we assumed the first time it was because they got into a fight. This time, we realized he was bleeding out of his nose. All day he has been spraying blood out of his nose every time he sneezes, he then clots, picks the clot and sprays blood. Over a 5 hour period he degenerated and is now barely moving and refusing even the most rare and favorite of treats (chocolate).
Our vet just gave us antibiotics and said to try that, but I think he's dying. So my questions are, what can I do to make him more comfortable? Is there any hope? And finally, can he be contagious to humans (my parents are worried that it might be a rare viral infection that is able to contaminate cross-species)?

Answer
He has pneumonia from mycoplasmosis  (it is NOT contagious to humans at all so do not worry, I PROMISE)  However, he needs to see the vet NOW and needs on different antibiotics.  I am sure he was probably put on doxy and baytril for 3 weeks.  Problem is, he should have never been taken off of the medications as this is something he will have for life. Its a long complicated thing that rats get so to make it easier, please refer to my website, sandyscrittercity.com and refer to RAT ILLNESSES and look under mycoplasmosis.  The bloody nose?  Its NOT blood. It is called PORPHYRIN.  Also look this up on my site to see what this is.  You see this more in rats that are sick and sometimes when they get it from their nose they spread it on their fur when they groom.  I am concerned that your rat has lung scarring from the myco infection that he had.  There IS hope as long as the vet knows how to treat him, which again, you will read how on my website. Please let me know after you read this info.