"Parvo" is an extremely contagious viral disease of dogs that causes severe vomiting, diarrhea, and even death. It occurs almost exclusively in puppies less than 1 year old, though parvo affects dogs of any age.
Parvovirus affects the bone marrow cells, impairing the dog's immune system. The virus also attacks the rapidly growing cells of the intestinal tract, causing severe destruction of the intestinal lining. Parvovirus infection is a serious disease, but most dogs recover with early and aggressive treatment.
Risk factors and detection
Parvovirus affects dogs with little or no immunity to the virus. It's usually a disease of the young—puppies who received insufficient antibodies from their mothers' milk and puppies with weak immune systems or inadequate vaccine immunity. Certain breeds, including rottweilers, Doberman pinschers, English springer spaniels, pit bull terriers, and Labrador retrievers, are most susceptible.
Because parvovirus is transmitted in feces, such areas as breeding kennels, animal shelters, and pet shops are potential sources of infection.
In many puppies, the first sign of parvovirus infection is extreme lethargy followed by vomiting. In most cases, watery and often bloody diarrhea begins later in the disease. Other problems, such as fever, dehydration, and low blood sugar levels, also can occur. Severely affected dogs go into shock from the overwhelming infection that develops when bacteria escape from the damaged intestinal tract and enter the bloodstream. In rare cases, the heart muscle becomes infected and lethargy is the only sign owners may notice before the puppy's sudden death.
Parvovirus infection must be distinguished from other puppy diseases that cause similar signs. Your veterinarian may test for intestinal parasites, foreign body obstruction, and other infectious causes of diarrhea. These tests may include fecal examinations and cultures, X-rays, and blood tests. Typically, though, if your veterinarian suspects parvovirus infection, he or she will test for virus particles in the dog's feces.
Prevention
The three best ways to prevent parvovirus infection are to:
1. Minimize exposure to the virus. Until your pup builds a strong immunity against parvovirus, keep him away from high-risk areas, such as obedience or puppy classes, dog shows, and dog release areas in public parks.
2. Adhere to your veterinarian's vaccination protocol. Be sure you take your puppy in for his first vaccinations at 6 to 8 weeks of age. Return to the veterinary clinic for booster vaccinations every three to four weeks until the puppy is 16 to 18 weeks old. Ask for high-titer parvovirus vaccines, which break through interference from the pup's maternal antibodies. Most veterinarians also recommend annual boosters.
3. Use strict sanitation when handling a dog infected by parvovirus to prevent the spread of infection to other dogs. Remember that the virus is shed in large amounts by affected dogs and can survive in the environment for five months or longer. Use diluted bleach (1 ounce of bleach in 1 quart of water) to kill the virus on surfaces, and avoid skin or other direct contact with the solution.
Treatment
Treatment for parvovirus infection is aimed at correcting severe dehydration from fluids lost through vomiting and diarrhea; resting the gastrointestinal tract; and protecting the dog against secondary bacterial infection, which can result from a weakened immune system and debilitated intestinal tract.
Fluid therapy and antibiotics are the mainstays of treatment. In most cases, fluid losses are severe enough to require hospitalization and intravenous fluid replacement. Most dogs need fluid therapy for several days until the intestine repairs itself, the vomiting ceases, and they can hold down water and a bland food. Recovery at that point is usually rapid, though your dog may need a bland diet for several weeks.
