You can't tell if a frog has chytridmycosis unless you take a swab for a PCR test, lots of healthy looking frogs have carried this fungus. All animals are potential carriers of this fungus, it can attach itself and lay dormant for some time until it finds another wet enviroment. Caudates will carry the fungus, though it doesn't seem to effect them the same way it does frogs or toads. In fact, a lot of imported caudates are testing positive for chytrid. They potentially could do the most harm to captive collections, as visually healthy appearing animals are passed through hands much faster than animals that may appear ill. Imagine all the hands that infected animals come in contact with along the way from collection to the retail in of the pet trade.
For the OP... Unless you wish to provide a cool enviroment for keeping newts, it's proabably better to go with the frogs.