Canine Parvovirus Infection in Dogs
The canine parvovirus (CPV) infection is a highly contagious viral illness that affects dogs. The virus manifests itself in two different forms.
The more common form is the intestinal form, which is characterized by vomiting, diarrhea, weight loss and lack of appetite (anorexia). The less common form is the cardiac form, which attacks the heart muscles of fetuses and very young puppies, often leading to death.
The majority of cases are seen in puppies that are between six weeks and six months old. The incidence of canine parvovirus infections has been reduced radically by early vaccination in young puppies.
Signs & Symptoms of Parvo in Dogs
The major symptoms associated with the intestinal form of a canine parvovirus infection include:
The intestinal form of CPV affects the body's ability to absorb nutrients, and an affected animal will quickly become dehydrated and weak from lack of protein and fluid absorption. The wet tissue of the mouth and eyes may become noticeably red, and the heart may beat too rapidly.
When your veterinarian examines your dog’s abdominal area, your dog may respond due to pain or discomfort. Dogs who have contracted CPV may also have a low body temperature (hypothermia), rather than a fever.
How is Parvo Spread?
Most cases of CPV infections are caused by a genetic alteration of the original canine parvovirus: the canine parvovirus type 2b. There are a variety of risk factors that can increase a dog’s susceptibility to the disease, but mainly, parvovirus is spread either by direct contact with an infected dog, or indirectly, by the fecal-oral route.
Heavy concentrations of the virus are found in an infected dog’s stool, so when a healthy dog sniffs an infected dog’s stool (or anus), that dog can contract the disease. The virus can also be brought into a dog's environment by way of shoes that have come into contact with infected feces.
There is evidence that the virus can live in ground soil for up to a year. It is resistant to most cleaning products, or even to weather changes. If you need to clean up a parvovirus-contaminated area, first pick up and safely dispose of all organic material (vomit, feces, etc.), and then thoroughly wash the area with a concentrated household bleach solution, one of the few disinfectants known to kill the virus. If a dog has had parvovirus in a home, it is best not to have a puppy in that home for several years.
Due to the density of dogs, breeding kennels and dog shelters that hold a large number of unvaccinated puppies are particularly hazardous places. This is why your veterinarian will want to re-vaccinate your puppy even if records from the breeder indicate it has had a vaccination. Shelters and rescue groups will often place puppies into foster homes until they are ready for adoption to minimize risk of spreading parvovirus.
For unknown reasons, certain dog breeds, such as Rottweilers, Pit Bulls, Labrador Retrievers, Doberman Pinschers, German Shepherds, English Springer Spaniels and Alaskan sled dogs, are particularly vulnerable to the disease. Your veterinarian may recommend an extended vaccination protocol in these breeds.
Diagnosis of Parvovirus in Dogs
CPV is diagnosed with a physical examination, biochemical tests, and a special test for the parvovirus in feces. A urine analysis, abdominal radiographs and abdominal ultrasounds may also be performed. Low white blood cell levels and significant dehydration are indicative of CPV infection, especially in association with bloody stools.
Biochemical and urine analysis may reveal elevated liver enzymes, lymphopenia, and electrolyte imbalances. Abdominal radiograph imaging may show intestinal obstruction, while an abdominal ultrasound may reveal enlarged lymph nodes in the groin, or throughout the body, and fluid-filled intestinal segments.
You will need to give your vet a thorough history of your pet's health, vaccination history, recent activities and onset of symptoms. It is important to retrace your dog’s steps for both possible exposure and potential contamination.
Is Parvovirus Treatable?
Since the disease is a viral infection, there is no real cure for it. Parvovirus treatment is focused on curing the symptoms and preventing secondary bacterial infections, preferably in a hospital environment. Intensive therapy and systemic support are the keys to recovery.
Intravenous fluid and nutrition therapy are crucial in maintaining a dog’s normal body fluid after severe diarrhea and dehydration, and protein and electrolyte levels will be monitored and regulated as necessary. Dog medications that may be used in the treatment include drugs to curb vomiting (antiemetics), antacids, gastroprotectants, prescription pet antibiotics, and anthelmintics (vet-recommended dewormers) to fight parasites. The survival rate in dogs is about 70 percent when treated in the hospital, but death may sometimes result from severe dehydration, a severe secondary bacterial infection, bacterial toxins in the blood or a severe intestinal hemorrhage.
Prognosis is lower for puppies, since they have a less developed immune system. It is common for a puppy who is infected with CPV to suffer shock and sudden death.
It is possible to treat parvovirus in your home under the direction of your veterinarian. It is a very labor-intensive process but can mean the difference between life and death when funds or circumstances do not permit in-hospital treatment. Your veterinarian will teach you to give fluids and to monitor vital signs.
Living and Management
Even after your dog has recovered from a CPV infection, they will still have a weakened immune system for some time, and will be susceptible to other illnesses. A high-quality, easily digestible diet is best for your dog during recovery.
Your dog will also continue to be a contagion risk to other dogs for at least two months after the initial recovery. You will need to isolate your dog from other dogs for a period of time, and you may want to tell neighbors who have dogs that they will need to have their own pets tested.
Wash all of the objects your dog uses (e.g., dishes, dog crate, dog kennel, dog toys). Machine washing is best—anything that can go into the dishwasher or washing machine and dryer should. Everything else should be deep-cleaned using a concentrated bleach solution as recommended by your veterinarian.
Recovery comes with long-term immunity against the parvovirus, but it is no guarantee that your pet will not be infected with the virus again.
Prevention of Parvo in Dogs
The best prevention you can take against CPV infection is to follow the correct protocol for vaccination. Young puppies should be vaccinated beginning at six weeks of age, with at least two vaccines after 10 weeks of age, and should not be socialized with unknown dogs until at least two weeks after their third vaccination.
High-risk breeds may require a longer initial vaccination period of up to 22 weeks. During this time, your puppy should only socialize in private areas with known dogs. Friends and family members with healthy, fully vaccinated dogs can bring those dogs to your home, or you can bring the puppy to their home. Avoid all public areas where dogs spend time, including the dog park, dog beach, pet stores and other dog-designated areas.
Always pick up feces immediately. This is a good habit to start immediately, as it reduces environmental contamination and reduces the spread of intestinal parasites.
Parvo virus is a disease with serious consequences. Fast action by you and your veterinarian gives your dog the best prognosis for a full recovery.