This is a parasitic illness. The parasite lives in contaminated water. Upon drinking the water, the host is unwittingly infected by the parasite. Pets like dogs are susceptible to parasitic diseases like giardia as they drink water from stagnant puddles. Untreated, unfiltered water is far more likely to contain parasites. Dogs who have giardia will show symptoms such as vomiting, diarrhea, bloody stools, and live worms in their feces. Humans will also exhibit bloody stools, stomach aches, and coughing. Antiparasitic treatment is required for pets and their owners who get the parasite.
Pet owners should avoid drinking unclean water and should carry treated water with them when they take their dogs out. Dogs should be encouraged to drink water from their owners rather than from bodies of contaminated water. Immediate treatment for an infected dog will kill the parasite before it can be passed onto the owner.