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 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:

Severe, bloody diarrhea
Lethargy
Anorexia
Fever
Vomiting
Severe weight loss

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 palpates (examine by touch) your dog’s abdominal area, your dog may respond with pain or discomfort. Dogs that 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, it will 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 household bleach solution, one of the few disinfectants known to kill the virus.

Improper vaccination protocol and vaccination failure can also lead to a CPV infection. Breeding kennels and dog shelters that hold a large number of inadequately vaccinated puppies are particularly hazardous places. For unknown reasons, certain dog breeds, such as Rottweilers, Doberman Pinschers, Pit Bulls, Labrador Retrievers, German Shepherds, English Springer Spaniels, and Alaskan sled dogs, are particularly vulnerable to the disease. Diseases or drug therapies that suppress the normal response of the immune system may also increase the likelihood of infection.

Diagnosis of Parvovirus in Dogs

CPV is diagnosed with a physical examination, biochemical tests, urine analysis, abdominal radiographs, and abdominal ultrasounds. A chemical blood profile and a complete blood cell count will also be performed. Low white blood cell levels 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 a thorough history of your pet’s health, recent activities, and onset of symptoms. If you can gather a sample of your dog’s stool, or vomit, your veterinarian will be able to use these samples for microscopic detection of the virus.