Parvoviral Enteritis (Parvo) in Dogs
Overview of Canine Parvoviral Enteritis
Parvovirus (Parvoviral Enteritis or "Parvo," for short) is a virus causing severe infection in puppies and dogs. It invades and destroys rapidly growing cells in the intestine, bone marrow and lymphoid tissue resulting in nausea, vomiting and severe hemorrhagic (bloody) diarrhea. The invasion of the bone marrow cells causes a decrease in the white blood cell count leading to increased susceptibility to bacterial infections and sometimes to a shock-like condition called endotoxemia. The disease can vary from mild to fatal if not properly treated.
Parvovirus is extremely contagious to other dogs. Infection is generally attributed to ingestion of material contaminated by dog feces and can occur when a dog smells or licks the ground. Direct contact with another dog is not necessary for infection. Parvovirus is shed in the feces of infected dogs for approximately two weeks after initial ingestion and can live in the environment for years. The virus is species specific and is not contagious to cat or humans.
Dogs at highest risk for infection are unvaccinated puppies or those who have not yet completed their vaccine series. It is most common in dogs less than 8 months old. Especially susceptible breeds include Doberman pinschers, Rottweilers, German shepherd, Staffordshire terriers, black Labrador retrievers, and dachshunds. Dogs of all ages can be infected, but puppies and younger dogs are most susceptible. Intact male dogs may also be susceptible for unknown reasons.
Unsanitary and/or overcrowded kennels may increase chance of infection and concurrent infection with parasites, other bacteria or viruses may also increase susceptibility to infection. Proper vaccination of your pet can best prevent the disease.
Parvovirus is an acute and serious disease, not a chronic condition. Virtually all cases need proper diagnosis and hospitalization. If your pet is having active symptoms, it is important to see your veterinarian. Parvovirus can be fatal if not properly treated.
What to Watch For
Clinical signs in dogs generally are seen 3 to 14 days after exposure to the virus. Signs may include:
- Loss of appetite (anorexia)
- Diarrhea (often containing foul-smelling blood)
Diagnosis of Parvoviral Enteritis in Dogs
Diagnosis is usually based on clinical signs. Diagnostic tests are needed to recognize parvovirus, and exclude other diseases. Tests may include:
- Complete medical history and physical examination
- Testing the feces for the presence of the virus
- Blood tests and abdominal X-rays to determine the severity of the infection or exclude other causes of the symptoms.
Treatment of Parvoviral Enteritis in Dogs
Your veterinarian will probably recommend hospitalization. Therapy is dependent upon the severity of the clinical symptoms and is aimed at treating the dehydration, controlling vomiting and diarrhea and preventing secondary infection. If bacterial infection and dehydration can be prevented, clinical signs will usually resolve in 2 to 5 days. Therapy may include:
- Intravenous (IV) fluid therapy, antibiotics and/or other drugs used to replace electrolyte and fluid losses and control nausea and vomiting.
- In very severe cases, referral to a 24-hour critical care center may be recommended.
At home, allow your pet to rest and regain his strength. Once vomiting and diarrhea have stopped, encourage water intake. Offer your pet a small amount of water and a bland diet. Your veterinarian may recommend a prescription diet.
It takes a few days for stools to normalize. Nevertheless, it is important that you pick up feces and keep the environment clean. It is likely that the feces will contain the virus and other dogs may contract the disease.
If your pet is not eating or drinking, is continually tired, vomiting and/or still has diarrhea, call your veterinarian.
Prevention is possible by vaccinating your pet regularly to help prevent infection. (NOTE: Immunity to parvovirus develops after infection, but it is necessary to schedule booster immunizations ("shots") with your veterinarian to protect from other viruses).
Keep your dog away from fecal waste of other dogs when walking along neighborhood streets or parks. If your dog leaves his own "deposit" be sure to remove it and dispose of it at home.
You should also minimize contact of unvaccinated puppies with other dogs that may be sick or unvaccinated. This should include avoiding areas where other sick pets may have been (parvo can live in the environment for 2 years). Your dog is most at risk until fully vaccinated (usually 20 to 24 weeks of age).