Introduction
Canine parvoviral (CPV) infection, commonly called “parvo,” is primarily a gastrointestinal disease of puppies under 8 months of age and of unvaccinated adult domestic dogs.
Symptoms of Parvoviral Infection
Most dogs begin to show symptoms of illness following a 5-to-10 day incubation period after exposure to feces from an infected dog. Infected dogs typically start shedding the virus in their own feces before they develop observable symptoms. Owners of dogs in the acute stage of parvoviral disease usually observe one or more of the following clinical signs:
- Depression
- Lethargy (usually appears very suddenly; acute in onset)
- Loss of appetite (inappetance; anorexia)
- Weight loss
- Diarrhea (profuse; often bloody)
- Bloody stool (hematochezia)
- Mucus in stool (steatorrhea)
- Vomiting (emesis)
- Retching
- Fever (usually fluctuating; can be extremely high)
- Elevated heart rate (tachycardia)
- Abdominal pain
- Tucked-up abdomen
- Dehydration (tacky gums)
- Shock
- Collapse
Some people believe that the feces from dogs with CPV infection has a distinctly characteristic, foul odor, while others are convinced that it is impossible to diagnose parvo simply based upon smell.
Dogs at Increased Risk
Parvoviral infection can affect dogs of any age, although most cases occur in young puppies between 6 weeks and 6 months of age. Unvaccinated or partially vaccinated animals have a greatly increased risk of developing parvo. Certain breeds are described as being predisposed to CPV infection, including the Doberman Pinscher, Rottweiler, English Springer Spaniel, German Shepherd, American Pit Bull Terrier and Dachshund. These breeds also tend to develop more severe symptoms once they become infected. The reason for reduced resistance to parvoviral infection in these breeds is not known. Also for some unknown reason, Toy Poodles and Cocker Spaniels seem to have a reduced risk of CPV infection. Puppies whose mothers have been routinely vaccinated are also less commonly and less seriously affected, because vaccination of the dam boosts circulating maternal antibody levels in her young puppies.