They can have a parasite load without any noticeable symptoms. If the parasite load is bad an experience keeper will see the outward signs such as lack of appetite, lethargy, and being underweight for age. But you do not see these signs if they have a low parasite load. So you want to get a fecal sample to rule out a parasite load, I would personally do 2 at least like 3 weeks apart when they come into your home. Not all parasites are the same and neither is the cleaning required to get rid of the eggs that come out in the fecal that they can recontaminate themselves with.Did your chameleon have any symptoms?