What is parvovirus?

It is a virus that attacks the cells of the small intestine of dogs. It causes a thinning of the intestinal lining, permitting the passage of intestinal bacteria and it’s toxins into the bloodstream, therefore causing a generalized infection. Furthermore, the virus attacks the dog’s immune system leaving him defenseless against infection. The following symptoms can appear: depression, loss of appetite, vomiting, diarrhea often hemorrhagic, dehydration and shock possibly leading to death. Severity of symptoms can vary from dog to dog. The large majority of dogs affected are puppies under the age of 8 months and non-vaccinated adults. Certain breeds seem to be more susceptible: Doberman, Rottweiler, pit-bull, German shepherd and dachshund.

The virus is extremely contagious for other dogs, but not at all for humans. Even though it could be transmitted to cats and possibly others species, they do not develop the associated symptoms. The dog must ingest the contaminated stool to be infected. Incubation period (the time it takes for the dog to become sick after contact with the virus) varies between three (3) to fourteen (14) days.

The dog will begin to shed the virus in its stools four (4) to five (5) days after being exposed, and continue shedding one (1) to ten (10) days thereafter. The virus can survive up to one (1) month in the environment and is very resistant to most disinfectants. Javel bleach (Chlorox) diluted at a ratio of 1/32 with water is effective in killing the virus.

How to diagnose the virus?

There exists a rapid test can be done here in the clinic that consists of rubbing a swab against the rectal membrane of the dog to collect fecal material and then exposing the sample to viral antibodies. If there is presence of the virus, then there will be a positive reaction. However, a false positive reaction can result in cases of recent vaccination (within two (2) weeks following the vaccination). You can also have a false negative result if the sample was taken outside the viral shedding period or in the presence of very hemorrhagic diarrhea.

A blood test showing a low level of white blood cells (cells from the immune systems) can also increase suspicion of the virus in the case where the parvovirus test is negative. Furthermore such leucopenia permits the veterinarian to determine how severely the immune system has been affected. Other anomalies concerning additional parameters in the blood test can also become evident. Sometimes dogs suffering from profuse diarrhea can develop what is called an intussusceptions the penetration of an intestinal segment into another intestinal segment leading to an obstruction; it is possible that additional tests such as abdominal x-rays be recommended by your veterinarian so as to exclude the possibility of such a complication which can, in many cases be fatal.


No treatment exists to eliminate the virus itself. The goal of the treatment is to provide support for the animal’s organism during the critical period of about five (5) during which there is almost complete absence of blood cells as well as thining of the intestinal lining. If he survives this period, there will be regeneration of the white blood cells by the immune system as well as of the intestinal lining. To correct dehydration and the electrolyte unbalance as well as normalizing blood pressure, intravenous solutions will be administered. To treat or prevent infection, antibiotics will be used. We will also inhibit vomiting with antiemetics and control pain with analgesics. We try to start feeding by mouth as soon as possible which is of primordial importance to the proper function of the immune system and the digestive tube. In certain cases, it may become necessary to proceed with one or more blood transfusions. Since there is frequently a secondary infection caused by intestinal parasites, it would be important to deworm the animal as soon as the critical period is over. With such treatments, the prognosis in survival of generally good; however, the mortality rate is very high without treatment. Puppies that survive acquire in most part, immunity for life against re-infection. Specific additional treatments to correct possible complications may be administered as needed. As well as an intussusception, rectal prolapse (exteriorization of the rectal membrane through the anus), infection of the joints or heart valves, respiratory distress syndrome and pneumonia are possible.


The best way to prevent the viral infection is vaccination. General vaccination starts between the ages of 6-8 weeks, with monthly booster shots up until the age of four (4) months. There is controversy concerning yearly vaccination of adult dogs since it has been shown that the antibody levels against the virus remain high for more than one (1) year. At the Hôpital Vétérinaire de l’Est, we continue to recommend yearly vaccination for adults for as long as the debate has not been resolved. Considering the long survival of the virus in the environment, introducing puppies in the immediate environment of another dog should be avoided, unless the dog has received the complete series of vaccination.