I have the same question but as I looked at it, the difference between the two is:
Gambling Fever : Temporary and fades away after some time, the person experiencing this still have some control. and is not a health condition since it fades away eventually.
Gambling Addiction: Gambling disorder, permanent if not treated, a health condition, the person experience have an uncontrol urge to gamble.
Actually, I never heard of this gambling fever before.
It still looks the same if they both have the urge to gamble; the only difference is, like anyone here said, it's temporary, or it fades away quickly. This can be treated early until your adrenaline and dopamine drop.
I think this is the first episode of the gambling addiction. If you are not treated early, you might end up becoming an addicted gambler.