Because they are insectivores almost all chams will have some parasites during their lives. Was yours cbb or wc? Unless you have a vet analyze a fecal sample as part of a routine health check you may not have known if he had a large population or not. A healthy cham can handle some parasite load and it is almost impossible (or necessary) to get rid of every single one. Some types are more dangerous than others. Most likely there was some other health problem going on that suppressed his immune response and allowed the parasite load to increase over what he could normally tolerate. Without a necropsy you'll never know. Sorry you lost him.