My setting is very simple, just use a plastic box with a sponege set aside, with very shallow water. Changing water daily, feed with cricket.
I will think of some infection but this is cause by food or the holding facility?
Who know's how or why they develop infections. I have two red-eyed leaf frogs in the same enclosure, one has an infection the other doesn't. It's a mystery why one is sick and the other is fine.
Just make sure your frog sees a vet soon.