A quarantine should be done with every animal you bought from another owner or for every chameleon which parasitic state is unclear (which is in fact every new bought chameleon). For an effective quarantine, 12 weeks in isolation are recommended – a quarantine of only one week is silly. For this purpose you should equip a well ventilated, easy to clean cage (glass cages with modified ventilations areas are good) sparsely with removable branches. As easy removable ground, you can use newspapers or towel papers. These and all faeces and urate is removed daily. During quarantine, you should bring at least three fecals to your reptile experienced veterinarian at intervals of a few weeks. This raises the probability to discover a parasite burden.
Chameleons that are in quarantine should always have their own feeding materials et.c to avoid infecting other reptiles with potencial parasites. The best way would be to have an own room for quarantine cages, so the other reptiles are safe. Wearing gloves when working nearby or inside the cage makes sense, and you need to throw them away before leaving the room.
Unfortunately, quarantine is not a standard yet for many chameleon keepers. Usually, quarantine is neglected. Thus the majority of chameleons in captivity is infected with parasites, especially with species such as coccidia that are difficult to remove by disinfection. But a parasite burden is not part of a healthy chameleon!