Very interseting case. Negative in bacterial infection. Positive in viral infection. And after drug administration, the issue is still the same. There's also a fact that test can sometime yield to false negative results or vice versa. Im also interested in knowing the medicine provided to your snake, specially in this case since it was later diagnosed as a viral infection. But what kind of viral infection? I have a few added questions though, how old is the snake? how long have you been keeping it and was it already showing the symptom when you acquired it?