This bacterium is spread through feces of infected dogs and is most commonly found in puppies that have developed the disease after exposure to infected adult dog's feces. (caninejournal.com)
CPV can spread to dogs from any animal, human, or object that comes in contact with feces of an infected dog. (vaccinateyourpet.net)
Luckily, dogs and cats can not infect each other or humans with heartworm, and they can not get it by sniffing feces of infected dogs or being around them in the dog park. (cesarsway.com)