Is it true that parvovirus infection is a new disease?

April 13, 2012

Canine parvovirus is a deadly disease. In severe cases a dog can die within 48 to 72 hours if treatment is not administered. For unknown reasons, parvovirus is more prevalent in Doberman Pinchers, Rottweiler and in Pittbull terriers. This disease that infects dogs of all ages has a high mortality rate in puppies. The mortality rate is as high as 91% in untreated cases. Aggressive treatment has significantly increased the survival rate. Vaccination programs have protected dogs from this virulent and highly contagious disease.

Scientists believe that parvovirus is a relatively new disease. The causative virus is unknown in the early 1970s. The virus that has spread worldwide was first recognized by scientists in 1978. It was believed that the virus has mutated from the virus that causes feline distemper. Canine parvovirus type 2 (CPV2) or what is commonly known as parvo is 98% identical with Feline panleukopenia, the viral infection that affects cats. CPV2 has mutated several times. In 1979, CPV2a, a different strain of the virus was identified. Another strain, the CPV2b was identified in 19884. These two strains have replaced CPV2, the original type. Of the two strains, the CPV2b is the most prevalent strain that infects dogs nowadays.

There are 2 forms of parvovirus – cardiac and intestinal. Intestinal form of the virus that causes the inflammation of the intestines is more common. Once the virus is ingested it would reproduce in the lymphoid tissues, enter the bloodstream and attack the dividing cells and destroy the intestinal crypts causing bloody diarrhea. The dog would vomit as well. Secondary bacterial infections can develop due to the ulceration of the intestines. This would result to dehydration and a drop in white blood cells. Internal parasite infestation will exacerbate the virulence of the virus. The cardiac form of parvovirus is less common. Puppies inside the uterus and newborns are most affected. The virus’ attack to the cardiac muscles causes respiratory and heart problems. 90% of infected puppies that suffer breathing difficulties die.

Parvovirus is extremely tough. Clinical symptoms will be noticed a week or two after a dog is infected. However, the dog would already shed the virus 3 days after infection. The virus that was passed with the feces will stay and survive in the environment for long periods of time. An infected dog would still shed the virus a few days after it has fully recovered. Transmission of the disease is therefore very easy especially in kennels or in households with several dogs.

Symptoms of parvovirus widely vary. Some dog would be severely affected while some dogs would barely show symptoms. Severity of infection depends on the dog involved, the age when the dog was affected and the number of virus that has affected the dog. The severity of infection would also depend on the amount of maternal antibodies present in the affected dog. As mentioned parvovirus has a more serious effect in puppies due to their underdeveloped immune system. A puppy that has received little or no maternal antibodies would have little chance of survival. Fever, loss of appetite, depression, vomiting and foul smelling bloody stool are the most common symptoms of this disease.

Vaccination is the only way by which an owner can ensure that the pet would not succumb to this virulent and highly contagious disease. The pet has to be protected through immunization as this extremely hardy virus cannot be killed by very cold and very hot temperatures. This virus is resistant to phenol disinfectants as well. Surprisingly, the virus can be deactivated by the ordinary household bleach. Parvovirus is a viral disease, one that practically has no cure. Treatment would be directed towards preventing dehydration. Antibiotics are given to prevent secondary viral infections.