n. pl. par·vo·vi·rus·es 1. Any of a family of very small DNA viruses that cause various diseases in animals, including feline panleukopenia, canine parvovirus, and fifth disease in humans.
2. a. A highly contagious infectious disease of dogs, especially puppies, characterized by lethargy, fever, vomiting, and diarrhea. It is spread through feces from infected animals.
b. The parvovirus that is the causative agent of this disease. In both subsenses also called canine parvovirus, parvo.