Hello, I'm new to the box turtle forum, but I"m sure many of you know me from elsewhere.
Symbiotic parasites is a contradiction. Symbiotics are one thing, and there is definately benificial flora withen the gut of any animal. Parasite defines a relationship where one specimen benefits, and the other loses out somewhere.
The usage of dewormers should always be done under veterinary prescription. A previous post is correct, that owners of large collections, with lots of experience often do this on their own, and I'm happy he mentioned this was done after initial experience was gained from previous vet appointments. After a vet/client relationship exists the vet may feel comfortable making a prescription without an examination.
The suggestion that veterinarians make websites to coerce people and "protect their business" is rather futile. What vet includes reptiles as a major part of their income and if so, is deworming a major portion of this? Nope. There are always a few corrupt individuals in any proffesion, but believe it or not, a veterinarian is more afraid of getting his arss suide off for not recommending what is best for the animal, then missing $15-20 for a fecal or $30-60 for an exam.
Back to parasites though, a new wave of thinking is slowly working it's way throughout the proffesion. Every parasite does not need to be treated. If symptoms, yes, then consider the pro's and con's of treatment. If not, optimal husbandry equals optimum health in captive herps. Optimum health means that the reptile can control it's own parasite population to non-invasive numbers.
Ian
ps, I don't have a pic of my three-toed "Stubbs" but being a fan of photo's myself, I"d like for you to enjoy my Russian tort chowing down 
