PESTIFEROUS \pes-TIF-uh-ruhs\, adjective:
1. Bearing or bringing disease.
2. Infected with or contaminated by a pestilential disease.
3. Morally evil or dangerous to society; pernicious.
4. Bothersome; troublesome; annoying.
I consider people who don't pick up their dog's poo at the park to be of pestiferous personality and demeanor. (See 'Random Thought' posting below...)