Parvovirus (Canine Parvovirus)

Condition Overview

Canine parvovirus is an acute, highly contagious disease of dogs that was first described in the early 1970's. The virus has a tendency to attack rapidly reproducing cells, such as those lining the gastrointestinal tract.

Symptoms

Following an incubation period that averages 4-5 days, the acute illness begins with depression, vomiting, and diarrhea. Some dogs have no fever, while others have high fever (up to 106 degrees F, 41.1C). Puppies with severe abdominal pain exhibit a tucked-up abdomen. Diarrhea is profuse and contains mucus and/or blood. Dehydration develops rapidly.

All symptoms +

Causes

The virus is she in large amounts in the stools of acutely infected dogs for up to several weeks following infection. The disease is transmitted by oral contact with infected feces. Parvo can be carried on the dog's hair and feet, as well as on contaminated crates, shoes, and other objects. The the dog licks the fecal material off this hair, feet, or anything that came into contact with infected feces, he acquires the disease.

Diagnosis

Suspect parvo in all puppies with the abrupt onset of vomiting and diarrhea or bloody diarrhea. The most efficient way to diagnose parvo is to identify either the virus of virus antigens in stools. An in-office blood serum test (ELISA) is available for rapid veterinary diagnosis. False negatives do occur. Virus isolation techniques are more precise, but require an outside laboratory.

Treatment

Dogs with this disease require intensive veterinary management. In all but the most mild cases, hospitalization is essential to correct dehydration and electrolyte imbalances. Intravenous fluids and medications to control vomiting and diarrhea are often required. More severe cases may require blood plasma transfusions and other intensive care.

Puppies and dogs should not eat or drink until the vomiting has stopped, and require fluid support at that time. This can take 3-5 days. Anitbiotics are prescribed to prevent septicemia and other bacterial complications, which are the usual cause of death.

The outcome depends upon the virulence of the specific strain of parvovirus, the age and immune status of the dog, and how quickly the treatment is started. Most pups who are under good veterinary care recover without complications.

Prevention

Thoroughly clean and disinfect the quarters of infected animals. Parvo is an extremely hardy virus that resists most household cleaners and survives on the premises for months. The most effective disinfectant is household bleach in a 1:32 dilution. The bleach must be left on the contaminated surface for 20 minutes before being rinsed.

Vaccinations starting by 8 weeks of age will prevent most (but not all) cases of parvovirus infection. During the first weeks of life, puppies are protected by high levels of maternal antibodies. As these levels decline, there is a period lasting from 2-4 weeks during which puppies are susceptible to infection because vaccinations have not yet taken full effect. This susceptible period varies from pup to pup, which is why puppies between 6 and 20 weeks of age can be especially susceptible to parvo. Nearly all apparent vaccination failures are due to exposure during this period.

Newer high titer-low passage vaccines are narrowing the window of susceptibility. These modified live virus vaccines contain a higher number of virus particles (high titer), which are less attenuated(low passage - a low passage vaccine contains virus particles that have been less attenuated (or weakened), than those in the average vaccine). That means high titer-low passage vaccines can generally elicit an immune system response in young animals who have a maternal antibody level that would normally prevent them from responding.

It is still important to isolate young puppies as much as possible from other dogs and from potential sources of infection until they complete the parvo vaccination series at 16 weeks of age. Current recommendations are for a booster a year from the initial vaccine series and then revaccination every 3 years.

Support

Please contact your veterinarian for more information regarding this condition.