One specimen doesn't have to eat or sleep in the feces of an 'infected' specimen in order to transmit parasites (internal/external) or bacteria infections...snakes OR lizards.
Much of the transmission can be done by the keeper and poor husbandry techniques.
I know I would never knowingly buy anything from a breeder who introduces WC animals into his collection without quarantining the WC animal first.
Quarantining an animal can save your collection. I have heard stories of individuals losing many animals from an unknown epidemic after introducing a WC animal to their collection without treating/quarantining it first.
Now the OP said the skink is in another home away from his other animals. That is fine.
But it may be a good idea to familiarize yourself with quarantining animals.
It goes a lot farther than just sleeping and eating feces.
Remember kids...safety first!!
http://ball-pythons.net/forums/showt...ght=quarantine