Does anyone know any names of diseases in dogs?

Hello I was just wondering if anyone knows any names of any common diseases found in dogs that I could use as a deterrent to other dog walkers? I live in a small town and there are many dogs in the village we live. So many owners have their dogs off leash with no recall and some are even aggressive, so many of them come up to my already reactive dog and are the ones that try to attack her, get all up in her face, the usual🤦‍♀️ i have found that nearly every owner that lets their dog do this do not even care to come and get their dogs when I say she is not friendly or she is reactive so I thought hey, maybe they will listen if I shout that she has some sort of disease? Can anyone help me out or tell me if this is silly ?