In my metropolis, I grimace when I see my dog do his business on tiny spots of dirt and grass because thousands of other dogs have done the same.
Can he introduce diseases into our home from other dogs' urine and feces? Human sickness requires an extremely robust bug and a lot of it.
Dogs in cities are exposed to different germs than those in rural areas or farmland, which won't appear like the pathogens that stick to your dog's fur when they swim in lakes and ponds.