I've extracted the following from a New Scientist Article on the subject. It's not all bad news.
Its [Ash Dieback] progress is almost impossible to halt. "There are few measures you can take," says Jens Peter Skovsgaard, a professor at the Southern Swedish Forest Research Centre, who worked in Denmark during the worst of their ash dieback.
On the plus side, ashes are genetically diverse, and a significant number of trees are resistant to the fungus. That means the outbreak won't be as catastrophic for the landscape as Dutch elm disease, Skovsgaard says.
But there is still a lesson to be learned here: we use non-native plants at our peril. Want to keep out invasive foreign pathogens? Don't buy imported ornamental trees, now the major source.