Inter cellular Uronema can't be treated effectively - oral metronidazole might work at 1% in the diet, but generally, by the time it has been diagnosed, the fish have stopped eating.
I've been able to kill free living Uronema with formalin or chloroquine - but that won't work for the internal uronema.
Luckily, internal Uronema does not seem to be contagious - fish pick it up in the supply chain somehow and then then show up with the classic lesions in the LFS or your home, but by then, it is too late.
I "treat" Uronema by avoiding small green chromis and cheap anthias - they seem to have it most often.