The Symptoms of Parvo
Parvovirus disease is remarkable in that symptoms can vary from none at all to a fatal disease. Four factors govern the severity of the disease: age at exposure, the size of the virus dose, the presence of maternal antibody, and the breed of dog involved.
Dogs receive transient maternal antibody from their mothers through their first milk or colostrum. This antibody gives the puppy resistance to the disease. Puppies that are housed in a parvo-filled environment rarely break with the disease until they reach 14-20 weeks of age. At that time their mother’s immunity no longer protects them and they may die of the disease.
Dogs over six month of age develop natural resistance to the effects of parvovirus. Many of these dogs show only transient diarrhea. By the time the dog reaches one or two years of age the disease can be so mild that it passes unnoticed by the owners.
For unknown reasons, Doberman Pinschers, Rottweilers and Pit Bull Terriers become more ill with this disease than other breeds.
The most common form of parvovirus infection is a sudden (acute) inflammation of the small intestine or enteritis. This is characterized by depression, vomiting, diarrhea and profound dehydration. Bloody stools and a drop in white blood cell numbers are common. Some puppies die as soon as diarrhea occurs but many linger on for 4-6 days. Those that survive eight days usually recover. The lack of white blood cells and ulceration of the lining of the small intestine lead to secondary bacterial infections. There are many other virus and bacteria that can cause bloody diarrhea in dogs. This leads to misdiagnosis where not all cases of “Parvo” in puppies and adults are actually due to this virus.