Parvo, short for canine parvovirus infection, is a highly contagious viral disease that primarily affects dogs, especially puppies and unvaccinated animals. The virus attacks rapidly dividing cells, particularly in the intestines and bone marrow, leading to severe gastrointestinal illness. Symptoms commonly include vomiting, bloody diarrhea, lethargy, loss of appetite, fever, and dehydration. Because the virus weakens the immune system and can cause rapid fluid loss, parvo can become life-threatening if not recognized promptly. It spreads through direct contact with infected dogs or contaminated environments, as the virus can survive for extended periods on surfaces. Vaccination and proper hygiene are critical in preventing infection.