Canine Parvovirus in Dogs

Canine parvovirus (CPV) is a highly contagious viral disease which has the potential to cause life-threatening complications. While any dog can be susceptible, parvovirus most often affects unvaccinated puppies between six and twenty weeks of age. Also known simply as parvo, this virus mainly affects the gastrointestinal system, and can cause cardiac damage.

While young dogs and puppies are the most susceptible to the virus, CPV can infect any dog who has not been vaccinated against it, regardless of age or gender. Canine parvovirus causes intense gastrointestinal distress, and is a common cause of acute, infectious illness in young puppies.

Dogs affected by parvovirus can exhibit symptoms such as:

• Lethargy
• Severe vomiting
• Severe or bloody diarrhea 
• Loss of appetite 
• Abdominal pain
• Bloating
• Fever or low body temperature
• Dehydration
• Myocarditis 
  
• Shock

The virus attacks each cell it comes into contact with, and can cause permanent damage to the cardiac system of the canine. If your unvaccinated dog begins to display any of the above symptoms, it is vital that you seek immediate veterinary care. 

Types  
There are two types of canine parvovirus in dogs caused by two different strains of the virus. 

• Canine parvovirus type 1 - CPV-1
• Canine parvovirus type 2 - CPV-2  

A canine parvovirus infection in dogs is caused by contact with the CPV-1 or CPV-2 virus. While the exact origin of the virus is not known, it is speculated to be a mutation of the feline panleukopenia virus.

These viruses are highly communicable, and are shed in the feces of the diseased host which can easily be transferred to objects and surfaces, including on people. The potency of the virus is maintained in the feces for weeks to years, allowing the virus to spread at alarming rates. Dogs can become infected with parvovirus through:

• Direct contact with an infected dog
• Exposure to infected feces
• Contact with infected surfaces, such as food and water bowls, collars, leashes, or bedding
• Contact with an infected environment
• Contact with people who care for infected animals

Not every dog can become infected through contact, but those who are immune-compromised are most at risk, most notably young, unvaccinated puppies. Older dogs and those suffering from health conditions can also be at risk. 

You can reduce your dog's chances of coming into contact with canine parvovirus by: 

• Vaccinating your dog against parvovirus
• Avoid taking your dog to public dog areas, such as dog parks, kennels and daycares, pet stores, classes, shows or groomers
• Prevent your dog from coming into contact with feces outside while playing or walking
• Thoroughly clean and disinfect all clothing, shoes, and items that have been in contact with an infected animal or environment

Diagnosis of a canine parvovirus infection begins with noting the symptoms the virus produces in an infected dog, such as severe vomiting and bloody stool. A physical examination by your veterinarian can give them more clues as to what is wrong with your dog. Your veterinarian will take into account the age of your dog, as well as their vaccination record and immune status. Be sure to relay if your dog has possibly come into contact with any infected animals or environments.

Confirmation of a canine parvovirus infection can be confirmed through an ELISA fecal test. This quick test can sometimes give false results, so a PCR fecal test may also be conducted. A blood sample may be taken to look for white blood cell counts. If the counts are low, this can be taken with other factors to confidently confirm a diagnose of parvovirus infection. 

There is no specific medication to treat either strain of canine parvovirus in dogs, rather treatment is supportive to help the dog's own immune system fight off the infection. Even with aggressive treatment, the virus can be lethal, so it is important to begin treatment as soon as possible. 

Treatment can include administering fluids through an intravenous drip to replace those lost through vomiting, diarrhea and fever. Antibiotics can be given to help fight secondary infections caused by a release of gut bacteria into the bloodstream. If needed, medications to help control diarrhea and nausea can also be administered.

If white blood cell counts are too low due to CPV infecting the bone marrow, a blood transfusion may be given to boost cell counts. 

Dogs being treated for canine parvovirus will generally be required to stay in a veterinary hospital so they can be monitored and given appropriate treatment as necessary. Once recovered, most dogs will retain a lifelong immunity to canine parvovirus.

Recovery statistics for dogs who survive the first 3 to 4 days are very good, as most deaths from canine parvovirus infection occur within 48 to 72 hours of the beginning of symptoms. With the right treatment, survival rates can be as high as 90%. 

Once a dog is allowed to return home, they may be sent with antibiotics, or medications for diarrhea or nausea. The virus can damage the intestinal tract, which may result in loose or no stool for the first few days. Normal stools should return within 3 to 5 days, though if diarrhea persists, contact your veterinarian. Food should be fed in several, smaller amounts throughout the day, and a restricted or easily digestable diet may be recommended by your veterinarian.

The most important thing to remember is that a recovering dog will be shedding canine parvovirus in their feces for about a month, which can be transferred to other dogs. The CPV-2 strain of the virus, the most common one affecting dogs, can also be transferred to cats. Humans can carry and transfer the virus to other animals and surfaces, but cannot become infected. Be sure to keep your recovering dog away from any public dog areas, and any young puppies or unvaccinated dogs.