Disease associated with the canine parvovirus started appearing around 1978, and has now become one of the most common causes of vomiting and diarrhea in young dogs. Since so few dogs had developed natural antibodies in the late 1970's, a large number of dogs died from this disease. In some cases, the virus affected the heart, and caused death within a few hours. This form of the disease is almost nonexistent today because of natural antibodies.
The disease is caused by a highly contagious virus that is transmitted mostly by dogs orally contacting infected feces. As in many viral diseases of the intestinal tract, some dogs can pick up the disease and shed the virus without significant symptoms in themselves. The virus is extremely small, just 1 thimble full of stool can contain millions of virus particles. It is easy to see why contamination occurs so readily.
The majority of dogs presented with parvovirus show signs of lethargy, vomiting, diarrhea, and lack of appetite. In severe cases the diarrhea is very watery and frequently bloody, with a telltale odor. They are very ill, with significant abdominal pain. The virus is so strong that it literally causes the lining of the intestines to slough. It is painful to eat, and with the severe diarrhea and vomiting that is present, they rapidly become dehydrated. The also have a disruption in their electrolytes (sodium, potassium, chlorine) that adds to the weakness.
The diagnosis of canine parvovirus is frequently made by age of pet (usually under 6 months of age), symptoms exhibited, and physical exam. Other diseases can mimic the signs of parvovirus, so x-rays and routine blood samples are sometimes run to help eliminate them as a cause. A blood sample can be run looking for Parvo antibodies, but the results are open to interpretation as to whether the dog has an active infection or not.
A simple to perform and inexpensive test has been developed to test the feces for the virus. It is called a CITE test, and can be performed by our in hospital lab within 15 minutes:
A sample of feces is obtained from the rectum and placed in the first test well.
A special probe is placed sequentially in the 4 test wells over a 5 minute period of time.
The results are obtained by analyzing the blue dots on the bottom of the probe.
The test on the left is negative, the one on the right is positive.
Here are all the possible interpretations
Dogs with parvovirus need immediate veterinary care because they are usually very sick. This care involves large amounts of intravenous fluids, added electrolytes, antibiotics, and special medications to minimize vomiting. It is common for them to be hospitalized for 5 days. We do not feed them until they have gone 24 hours without vomiting. Dogs that continue to vomit in spite of therapy may also need a blood transfusion because they can become anemic and deplete their protein.
Fortunately, most dogs recover with our intensive therapy, although there still is an occasional dog that does not. This may be due to a weak immune system that can not produce adequate antibodies, or a particularly strong (virulent) strain of the virus that we encounter occasionally. Dobermans and Rottweilers seem to be especially sensitive to this virus, and have the most difficult time recovering from an infection.
As with all infectious disease, minimizing exposure from infected animals is the most effective means of prevention. Since infected dogs shed large amounts of virus in their stool, contamination is always a possibility. Using a chlorox solution is an effective means of disinfecting. Since this disease occurs mostly in puppies, worms (internal parasites) and poor nutrition add susceptibility.
Vaccines are highly effective, and should be given in a series of up to three injections due to the interference that maternal antibodies can cause in pups that are under 4 months. Puppies should not be exposed to other dogs or the feces of other dogs until the vaccine series is complete.
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