First thing that comes to mind as I read this....if you know your vet is not competent when it comes to treating reptiles...then why continue to bring your snakes there? If you have a reptutable herp shop that you shop at, have you considered asking them for a recommendation on a vet who knows what they are doing?

As for all the questions about parasites....I'm not an expert, and don't even consider myself particularly well-read on the subject, but I'll throw out what little I know.

No, they are transmitted through the air. For an infected snake to pass them on to a snake that didn't already have them, they would have to come in contact with fecal matter. Now....this does not have to be particularly visible...they don't have to crawl through a visible pile. If you put a mouse in one cage and the snake doesn't eat it...then you take that mouse out and put it in another snake's cage...it is possible that the rodent picked up some infected fecal matter on its feet and then pass it on to the second snake that way. Or if you don't wash up between handling different snakes. But if you're careful with the cleanliness, don't let them share tubs or enclosures, and you don't share rodents among your snakes, its very unlikely that they will pass parasites on to each other.

Other than the scenario mentioned above, I don't believe snakes catch worms from their prey. There might be some sort of host-cycle involving a particular worm, rodent, and snake....but if so, it is not common.

I WOULD treat worms if I found them. It seems inane to me for the vet to say in one breath "we don't normally even treat for this" and then to say "but since your snake is having trouble digesting, I guess we'll treat it".... If it had been caught and treated in the first place, the snake would not have developed digestion problems.

And IF I had a snake in my collection that was found with worms...I would definitely be taking fecals in from the rest of my animals to have them checked as well AND treated as necessary. However, it should not be necessary to take every single animal in for a hands-on check-up and should not cost more than the price of the fecal-float itself. BUT....I wouldn't do that until I found a vet I trusted to begin with.

Just my thoughts on the matter.