A new strain of dog flu (H3N8) has quietly been surfacing. You may not be aware of it but it appears to be spreading and is currently in Florida, NYC, Philadelphia, and Denver. That seems like a strange mix of locations to me and as the summer travel season hits and people board their dogs, I see it spreading.
There is a vacine now available for your dog. Vets know about it and can treat your dog if necessary. Apparently this flu variation is particularly hard on dogs with short snout like a Pug.
If you have any questions or concerns about your dog you should immediately see your vet.