How Does Parvovirus Affect Platelets in Dogs?

First recognized in the 1970s, CPV is caused by a highly infectious virus. An infected dog will shed the virus in his stool. Dogs can contract the virus from having oral contact with contaminated feces, but the virus can contaminate anything that touches the infected feces, such as the dog's paws. Some breeds, including Rottweilers and Doberman pinschers, seem more prone to contracting CPV. Also, puppies between the ages of six and 20 weeks are more susceptible, probably because their immune systems are still developing. No cure for CPV exists, so veterinarians typically treat symptoms while attempting to boost the sick dog's immune system so he can fight off the infection.

Platelets can be found in the bloodstream. They are produced, along with red and white blood cells, by bone marrow. In humans and dogs, platelets are essential for clotting. If a blood vessel is damaged, the platelets begin to adhere together to stop the bleeding. Veterinarians look at platelet counts in the blood as part of the process for diagnosing CPV.

Thrombocytopenia is a condition in which the level of platelets in the blood is too low. In dogs, the condition can be caused by leukemia, severe blood loss, lymphoma or infectious illnesses such as CPV that interfere with platelet production. The CPV virus attacks the red bone marrow of younger dogs and prevents the production of new platelets, along with red and white blood cells. Additionally, the virus causes damage to the dog's gastrointestinal tract and allows bacteria move into the bloodstream. The bacteria release a chemical called lipopolysaccharide (LPSI), which also attacks platelets and other cells. Furthermore, the GI tract begins using more platelets in reaction to the virus, so healthy platelets are quickly consumed by the body without sufficient amounts of replacements being produced.

With appropriate treatment, 70 percent of dogs survive CPV, according to the Claws and Paws Veterinary Hospital website, which stipulates that Rottweilers and other breeds more susceptible to the virus have less than a 50 percent chance of surviving, even with treatment. To avoid these risks, puppies need to be vaccinated against CPV. Even after the first vaccination, puppies may still be vulnerable to the virus and need to be kept away from situations in which they may come in contact with contaminated feces or other infected dogs.