Around here, another hazard is just that there are so many big dogs running loose, that any small dog is vulnerable if one of them wants to get rough. When my dogs were small, bout 15 pounds, one of the neighbor's dogs, a monster of a black Lab, suddenly appeared and started playing rough. My dogs like it really rough, and had a great time with him. But my other neighbor's Yorkie/Jack Russell got hurt by him a few weeks later. Not on purpose, just playing. My neighbor was screaming at the top of her lungs "Help, Ginger is getting killed!" She still insists to this day the Lab was "attacking". I think he could have swallowed Ginger in one gulp, if he really wanted to.
He wasn't, it just looked like he was and all that happened was Ginger got stepped on.