Interestingly enough, this virus did not exist prior to the late 1970's.  Canine parvovirus (CPV) is thought to be transmitted by the fecal waste of infected dogs.  This extremely hardy virus can survive for up to 6 months - even in colder weather under a covering of snow. 

The virus initially attacks the lymph system, moves to the blood and then the small intestine.  Once there, symptoms become evident as it attacks the intestinal track.  Severe symptoms would include vomiting, diarrhea and  extreme dehydration.  The disease then dumps bacteria and toxins in the blood stream which ultimately causes death.

Young dogs (usually at age 2-6 months) are the most susceptible to CPV due to the fact that the protective antibodies from their mother's milk decreases at this age.  CPV is spread by dog-to-dog contact and can be picked up at dog shows, obedience trials, breeding and boarding kennels, pet shops, humane shelters, parks and playgrounds.  This disease can only be transmitted to dogs and others within the dog family.  However, other animals and also people can be a carrier if they come into contact with the virus and can then pass it on to your dog.

Early detection and aggressive therapy are important in treatment of this disease.  You can prevent canine parvovirus through vaccination.