Parasites can be a problem. Have the vet run a fecal test and they will be able to prescribe the correct medication to eliminate them.
Ants, Rodents, etc. are not a bigger problem than normal, however gnats can live in the dirt in your plants. I use a layer of sand topped with river rock to prevent them.
Ants can be a huge problem for a chameleon trapped in a cage. Babies are especially prone to being killed. Diotomaceous earth spread around stand legs is a easy way to keep them out of cages.