To answer you quickly I've seen all kinds of specialists including endocronologists neurologist id doctors gastroentologists, etc
I don't need to pay a lab hundreds of dollars to id a specimen that looks exactly like medical textbook picture of certain parasites. I'm not sure if you're aware of parisitiology ignorance with the medical community if you're not then you know very little about it.
Also I agree with parazapper altho personally I don't see how a zapper could be more effective than medication but generally people arent stupid if theu are seeing these things, posting pictures of them and having debalitating symptoms then yes a big majority on the parasite forums likely do have them.
Also not true about length of treatment the longer someone has some diseases could mean harder and longer time to treat. That can be the case with many diseases.