...by "room" do you mean actual room in the house?
...how contagious are they to each other? It sounds like the parasites can travel pretty easily is given distance.
Howdy,
Quarantining in separate rooms can help keep you from spreading parasites, but it's really more of an issue to keep from spreading airborne microorganisms like bacteria, viruses etc.
Coccidia don't travel on their own. They need to hitch a ride in or on something like
fecally contaminated fingers, plants, chameleons, feeders, enclosures, splashed liquids etc.
As Jim said, an environment that is free of Coccidia during your chameleon's treatment is imperative to eliminate external re-infection, especially later into the treatment regiment.
I was especially concerned with re-infection the first time that I had to treat a chameleon with Coccidia. I had heard from Vets and others just how hard it was to get rid of it (if that is even possible). After almost daily tracking during months of various drug regiments for that tough Coccidia case, I came to the conclusion that the fact that Coccidia can somewhat safely hide in the nooks and crannies of certain chameleon organs may lead keepers to think that their chameleon was re-infected from environmental sources when it may have been the re-emergence of a somewhat dormant Coccidia infection that wasn't completely cleared during treatment. That also means that if a dormant case re-appears without you knowing it, you may inadvertently spread it to others through your contact with it.
This all may sound pretty bleak but don't let it get you down

. Ponazuril, the Coccidia drug that is somewhat new on the
chameleon scene, shows to be very effective with a minimum of side-effects. It is often prescribed for 3 days straight with another 3 day round again a week later. My suggestion is to assume that there are still Coccidia present until you have testing done several weeks later that shows no evidence of the infection. You may find that you have to continue treatment for another round or two or more to get clean results. It's times like these that having your own microscope comes in handy

.