Pets with Parvo

Parvovirus is extremely contagious and usually affects young dogs. It needs live cells--those that are actively dividing--in order to reproduce, and it therefore attacks the gastrointestinal tract, bone marrow, lymph system and heart tissue, wreaking havoc in its path.

Parvovirus is one of the most common causes of infectious diarrhea in young dogs. Most infections occur by oral exposure to contaminated feces, and the virus enters the body through lymph nodes in the mouth and nose or at the tonsils and pharynx.

In puppies under eight weeks old, the result is usually death from heart failure; in older dogs the virus spreads to the intestinal epithelial cells. If the infection occurs in the fetal state (from the placenta) the virus heads for the heart muscle, which results in permanent heart damage or death within the first three months of life. Death can occur in two days if the patients are very young or very weak, so it is important to seek medical attention immediately if your pet shows signs of parvo.

SYMPTOMS: Dogs who develop the intestinal form of the disease have severe vomiting followed by diarrhea, loss of appetite and dehydration. The diarrhea is often bloody. Since these symptoms are common to many illnesses, it is important to perform diagnostic tests on the dog's stool or blood to confirm the presence of parvo.

PREVENTION: As infected feces are the most common cause of parvo, nearly all veterinarians recommend keeping puppies indoors until they have been fully vaccinated at 16 weeks old. This is especially important for city dwellers, although the disease is also spread by coyotes, wolves and foxes, which is an issue for those who live in the country. Illness is more likely and more severe if the puppy is parasitized or infected with other intestinal viruses, which makes it even more important for the puppy's stool to be analyzed for worms.

Vaccinations at a young age help prevent infection. It is widely recommended to give a series of three to four vaccines starting at six to eight weeks of age, repeating every three to four weeks until the puppies are 16 to 18 weeks old. It is then recommended to repeat the vaccination once annually. Older dogs may not require annual revaccination for parvo and a blood test can be performed to see if they carry protective antibodies against the virus.

TREATMENT: Medical care is similar to how any case of diarrhea and vomiting would be handled. Pets are placed on intravenous fluids and antibiotic therapy, and food and water are withheld until the vomiting and diarrhea stop. If necessary, antiemetics (drugs that stop vomiting) are used. In severe cases treatment involves use of antiendotoxin serum or transfusion of hyperimmune plasma, both of which are extremely costly. Pups that survive the first three to four days usually make a quick recovery, usually within one week. Once recovered, pups remain immune to infection for at least 20 months and many for life. There are no lingering problems unless the infection occurred before birth, in which case those pets will suffer from heart disease for the remainder of their lives.

FYI
Rottweilers, pit bulls, German shepherds and Doberman pinschers are all at increased risk of getting parvovirus, whereas poodles and cocker spaniels are least in danger.

Dr. Peter Kross, DVM, has had his own veterinary practice, the Rivergate Veterinary Clinic in New York City, since 1989. He lives in Manhattan with his three white boxers, Buchanan, Wilhelmina and Laila.