The issue with IDO is that it can be chronically activated to suppress both pathogens as well as inhibit tissue damage in immunologically privelaged sites like the heart and brain. Think of it as a sort of a truce between host and pathogen. For example, elevated kynurenin is often found in the cfs fluid of neuroborreliosis. IDO breakdown metabolites like quinolinic acid are also neurotoxic.
In lieu of really good direct antiviral/antibiotics, lifting the IDO breaks can lead to some pathology so its a catch 22. Other than 1-methyl-tryptophan which is a potent IDO inhibitor, compounds in neem appear to inhibit IDO as well.
I think broad spectrum natural compounds in sufficient doses over time may be the way to go to work down pathogen loads before lifting the immune/IDO break. Like many of you, I read tons of posts from all kinds of forums and have come to the conclusion that single pathogen chasing is unlikely to yield results in many cases. There is so much overlap between chronic lyme, cfs, cebv, candida, mycoplasma etc. Most people dont know with certainty what the main culprit is. Probably several. The best antecdotal results I have seen have been with broad sprectrum higher dose natural antimicrobials dosed over longer periods if time.