The Center for Disease Control information on this listed several endemic areas. One was in northern Europe and the primary carrier was foxes.
Let me preface the following comments with this. I am not a wolf lover. I have disagreed with the reintroduction from the beginning, and have been a very vocal opponent of WDFWs wolf plan. I strongly feel that sporstmen took the shaft with the reintroduction, and that promises were not kept by delisting wolves in the mid 2000s when recovery goals were clearly met. All that said....
There is some serious fear mongering that goes on here. As a hunter, I like to support my arguments with facts. Nothing frustrates me more than to read propaganda that we are "wiping out the wolves" by hunting them in ID, MT, and WY. Now, the same label is attached to WA because OMG we are eliminating a pack. We expect the wolf lovers to use common sense not spread mistruths and emotional propaganda. However, we as hunters do the same thing with rumors of 200 pound wolves, posting graphic pictures of a wolf depredation, and acting like Hytadid disease will wipe out the US population.
A wolf kill is no more graphic than the thousands of roadkills that happen every month. We don't need to sensationalize them. We don't need to spread myths about an introduction of a superwolf from the Twilight series. And Hytadid disease is not rampant across the Rocky Mountains.
All of this stuff really makes us look like fools and takes away from out credibility. My brother is a very intelligent person and a non-hunter. If I were to take "literature" from LoboWatch to try and further my arguments he'd think I was a complete hack.