Canine parvovirus, Light micrograph of a section from an affected dog liver. Canine parvovirus is a contagious virus mainly affecting dogs, and thought to originate in cats. Parvovirus is highly contagious and is spread from dog to dog by direct or indirect contact with their faeces. Vaccines can prevent this infection, but mortality can reach 91% in untreated cases. Treatment often involves veterinary hospitalization. Canine parvovirus may infect other mammals; however, it will not infect humans. Because the parvovirus attacks quickly regenerating cells in the intestines, there can be short term and long term damage to the digestive system. Parvovirus can also cause long term kidney or liver damage and weaken the immune system permanently. Magnification: x150 when printed at 10 centimetres wide.