Canine Viruses

Learn more about canine viruses

Canine Distemper Virus

In canines, distemper affects several body systems, including the gastrointestinal and respiratory tracts and the spinal cord and brain, with common symptoms that include high fever, eye inflammation and eye/nose discharge, labored breathing and coughing, vomiting and diarrhea, loss of appetite, lethargy and hardening of nose and footpads. The viral infection can be accompanied by secondary bacterial infections and can present eventual serious neurological symptoms.

In domestic dogs, while the acute generalized form of distemper has a high mortality rate, disease duration and severity depends mainly on the animal’s age and immune status and virulence of the infecting strain of the virus. Despite extensive vaccination in many regions, it remains a major disease of dogs, and was the leading cause of infectious disease death in dogs, prior to a vaccine becoming available.

Canine Parvovirus

Canine parvovirus is a highly contagious virus that can affect all dogs, but unvaccinated dogs and puppies younger than four months old are the most at risk. Dogs that are ill from canine parvovirus infection are often said to have “parvo.” The virus affects dogs’ gastrointestinal tracts and is spread by direct dog-to-dog contact and contact with contaminated feces (stool), environments, or people. The virus can also contaminate kennel surfaces, food and water bowls, collars and leashes, and the hands and clothing of people who handle infected dogs. It is resistant to heat, cold, humidity, and drying, and can survive in the environment for long periods of time. Even trace amounts of feces from an infected dog may harbor the virus and infect other dogs that come into the infected environment. The virus is readily transmitted from place to place on the hair or feet of dogs or via contaminated cages, shoes, or other objects.

Infectious Canine Hepatitis (ICH)

Infectious canine hepatitis (ICH) is an acute liver infection in dogs caused by Canine mastadenovirus A, formerly called Canine adenovirus 1 (CAV-1). The virus is spread through feces, urine, blood, saliva, and nasal discharge of infected dogs. It is contracted through the mouth or nose, where it replicates in the tonsils. The virus then infects the liver and kidneys, with an incubation period of 4 to 7 days.

Symptoms include fever, depression, loss of appetite, coughing, and a tender abdomen. Corneal edema and signs of liver disease, such as jaundice, vomiting, and hepatic encephalopathy, may also occur. Severe cases will develop bleeding disorders, which can cause hematomas to form in the mouth. Death can occur secondary to this or the liver disease. However, most dogs recover after a brief illness, although chronic corneal edema and kidney lesions may persist.

Rabies

Rabies is a viral infection of the nervous system that mainly affects carnivores and bats, although it can affect any mammal. It is caused by the rabies virus. It causes sudden, progressive inflammation in the brain and spinal cord. Once clinical signs appear, it is fatal. Rabies is found throughout the world, although a few countries are declared rabies-free due to successful elimination programs. Islands that have a strict quarantine program in effect are often rabies-free. In North America and Europe, rabies has been mostly eliminated in domestic dogs, although it affects wildlife, especially foxes, raccoons, skunks, and bats.

Transmission is almost always by the bite of an infected animal when the saliva containing the rabies virus is introduced into the body. The virus can be in the body for weeks before signs develop. Most cases in dogs develop within 21 to 80 days after exposure, but the incubation period may be considerably shorter or longer.