1 Advisor: Our scientists have discovered the link between the plagues.
1 Allosaurus: Raaarrrhh?
2 Advisor: Apparently, hatmaking chemicals cause mutations leading to giant frogs!
3 Advisor: So we’re going to vaccinate the frogs.
3 Allosaurus: Raaarrrhh??
4 Advisor: No. Getting rid of the chemicals would be sensible, so clearly no government on Earth is going to do that.

Frogs will be issued vaccination passports, so they can travel freely without risking spreading the plague to other frogs.