The Veterinary Virology is the diseases which are affected to non-human animals.it is an important branch of veterinary medicine. Many other viruses, including caliciviruses, herpes viruses, adenoviruses and parvoviruses, circulate in marine mammal populations. Fish too have their viruses. They are particularly prone to infections with rhabdoviruses, which are distinct from, but related to rabies virus. Companion animals such as cats, dogs, and horses, if not vaccinated, can catch serious viral infections. Canine parvovirus is caused by a small DNA virus, and infections are often fatal in pups.