From what I have read about dogs and ebola thus far, it appears that dogs do not actually come down with ebola, but they do carry it, and can be contagious to humans.
Apparently, dogs have built up an immunity to the virus, and that is why they don't get sick and die from it; however other animals DO get sick and die from the ebola virus, so the whole thing is still pretty unclear.
If the dog cannot be infected, it would seem like they could not pass the virus to anyone else if their immune system has attacked and killed the ebola in their body. But, at the same time, I have read about other animals or insects like mosquitoes or ticks that carry the disease; but they pass it along by biting the person and infecting the bloodstream.
If that is also the case with dogs, then you should be fine unless they bit you, it seems like.
Even so, I think that if there is a chance that the animal could spread the disease, it should either be put down, or quarantined; however, I think the owner should have the option of deciding which they do.
In the case of Excalibur, the dog was put down against the owners wishes, and there was no proof that he would be contagious.
This is a whole different thing than if a dog contracts rabies, and it is known that if he bites someone they can die. The dog also suffers and dies from rabies; so in this case putting them to sleep is the most humane thing to do for the dog, as well as protecting hom from infecting humans or other animals.
With the ebola virus, it just isn't as clear cut, at least not yet.
