We did have a wet spring and have seen some cases of suspected fire blight so that is a possibility. Our conditions this spring were favorable for the disease. If you didn't see signs of the disease this spring, it is possible this is related to water. 

Have you checked the soil moisture around the tree? You can find some information on how to do that in this publication, as well as information on how best to water trees. Trees do best with less frequent, but deep watering.

I can't see the base of the tree in your photo, but if a tree is planted too deeply, that can predispose it to other issues. (see here: Science of Planting Trees.)

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