Parvovirus

Parvovirus

Causative Agent

Parvovirus is an infectious viral disease that affects some wild and domestic carnivores.
Worldwide, several variants of the virus have been identified, each associated with a single wild animal host that acts as a “reservoir of infection” for a particular geographic area.

Distribution

Geographic:

Worldwide.

Seasonality:

Throughout the year; but most often in late spring and early summer when there is an abundance of susceptible animals, i.e., young of the year.

Click on the photo to enlarge.

Inflammation of the inner walls of the intestine are commonplace in parvovirus infections as observed in this coyote.

Hosts, Transmission and Life Cycle

Hosts:

In BC, the potential hosts of parvovirus include susceptible wild and domestic animals: dogs, cats, raccoons, mustelids, foxes, and bears.

Transmission and Life Cycle:

Transmission generally occurs through ingestion of viral particles passed in the feces of an infected animal rather than through direct contact with another animal.
Parvovirus are hardy, stable when frozen, and capable of surviving for at least several months under dark, cool, and moist conditions.
Birds, rats, flies and inanimate objects have been implicated in mechanical transmission of parvovirus.
Life cycle in animals greater than 4 weeks in age:
- upon entering the body, the virus begins replication in the tissues of lymphoid tissue
- virus spreads throughout the body via blood vessels and infected lymph cells
- in particular, parvovirus targets rapidly dividing cells in the body, such as those in the intestinal walls
- damage occurs through the killing of intestinal wall cells which cannot regenerate. As a result, tissue fluids and blood are lost into the intestine. Diarrhea follows, often containing blood and mucous
- with the loss of fluids, dehydration occurs and the potential of uptake of toxins normally voided in the feces increases
- provided animals survive this initial phase of the disease, complete recovery is possible as cell populations regenerate
Life cycle in animals less than 4 weeks in age:
- infection of the gut is not observed in young animals
- infection of the developing brain or heart has been observed in kittens and puppies, respectively
Immunity may be passed from mother to offspring in dogs.
After exposure to the virus, if an infected animal lives, natural immunity usually persists.
Parvovirus is not thought to have any population level effects in wildlife except in small populations, isolated from sources of immigration such as on islands.

Signs and Symptoms

4-5 days after exposure, infected animals may seem pale (anemic from loss of blood), dehydrated, depressed, tired and lack an appetite followed by fever, vomiting and diarrhea.
Parvoviral diarrhea is watery, pasty or porridge-like, foul-smelling, and often contains blood and mucous.
Animals that resume eating within 3-4 days after infection usually survive, most animal that die from the infection do so within 4-5 days. Infected animals can shed the virus for up to 2 weeks.

Meat Edible?

Carnivore meat is usually not consumed. However, with an animal suspected of being infected with parvovirus, care should be in removing the intestines as infectious particles may still be present and may contaminate the local environment.
Areas contaminated with feces containing parvovirus should be cleaned with bleach.

Human Health Concerns and Risk Reduction

No evidence to suggest that humans are vulnerable to parvovirus infection.

Samples for Diagnosis

Parvovirus is usually detected in the feces.
Diagnosis of parvovirus infection can be made during post-mortem examination of the gastrointestinal tract.