Please try to organize your thoughts better, that was difficult to read.
You obviously have a limited understanding of the effect parasites on an animal. The problem most people have is understanding how much parasites infections occur in wild animals, because as humans we are rarely subjected to their effects. You can assume that ALL, and yes that means all, wild animals have parasites. When an animal is in the wild, there is usually a balance between the parasites and the health of the animal. When an animal is brought into captivity there is a considerable amount of stress involved. Parasites are held in check by the immune system, but under stress the immune system is not as strong and parasites and diseases can proliferate. Some zoos have a mandatory quarantine of three months, and this is with treatment for parasites. To assume that after only three months in captivity that the animal is parasites and disease-free without actually testing it, is extremely ignorant. Sometimes it can take a year for serious illnesses to manifest themselves.
Raising them as tadpoles does not exempt them from the possibility of having parasites. There are several in fact, that are passed directly from the mother to the eggs as she is laying them.
It is always a good precaution to have any animal in your collection checked and treated for parasites. If it is wild on or has been through a pet store, there should be a greater emphasis on the treatment.
I strongly encourage you to read the link below to learn a little bit more about parasites.
click here for the link...
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*Humans aren't the only species on earth... we just act like it.
".the oldest task in human history: to live on a piece of land without
spoiling it."
Aldo Leopold (1938)