Reptiles can have normal and abnormal parasites. Internal parasites or "worms" are very common and can be normal and safe in wild and pet reptiles while external parasites, such as mites, are not considered normal.
These parasites are commonly referred to as "worms" even though most of them aren't worms and don't produce worms. Some kinds of internal or intestinal parasites are completely normal in small numbers in your pet reptile. Others can cause serious issues even in small amounts. To determine whether or not your pet has a problem with intestinal parasites you should have a fecal sample tested at your exotic vet clinic on a yearly basis. Read "Reptile Worms" for more detailed information on intestinal parasites and which ones you can get.
Benjamin Franklin said, "An ounce of prevention is worth a pound of cure" and he was right. It is much easier (and safer) to prevent your reptile from getting parasites then it is to treat them. One easy way to help prevent an infestation is to freeze all reptile bedding overnight before putting it in the enclosure. This will kill any eggs or parasites that are hanging out in there. You can also make sure you wash your hands between handling reptiles, get yearly fecal tests performed, and don't allow your pet any contact with wild or wild caught reptiles.