What is Parvovirus?
Parvovirus,
often called “parvo” is an extremely contagious virus that infects dogs and
causes severe gastrointestinal (GI) illness. Puppies under 4 months of age and
adult dogs who have not received vaccines are most at risk from
parvovirus. The virus is spread by
contact between a dog’s oral or nasal cavity and the feces of a dog infected by
the virus. Parvovirus can also be
contracted through contact with infected surfaces, such as bowls, bedding, and
even outdoor areas where infected dogs have been housed. The parvovirus is
tough, and can live for months in soil or on surfaces if not properly
disinfected.
What Does Parvovirus Look Like?
Once a
dog has come into contact with the virus, it takes three to seven days before
any signs or symptoms are seen. Not all dogs that come into contact with the
virus will be infected; puppies are the most vulnerable because their immune
systems are not yet fully functional.
The virus attacks the cells which line the length of the intestines,
causing the infected dog to have large amounts of vomiting and diarrhea, which
is often bloody. This leads to severe dehydration and shock. Parvovirus also
attacks white blood cells, which reduces the dog’s ability to fight further
infections. As the illness progresses,
the intestines’ ability to prevent bacteria from entering the blood stream
decreases, which can lead to infection of the blood stream, called sepsis. Many infected puppies die within 48 to 72
hours if untreated, so a puppy (or adult dog) showing signs of severe vomiting,
diarrhea, dehydration, lethargy and loss of appetite should be seen by a veterinarian
immediately.
How Does a Veterinarian Diagnose and Treat Parvovirus?
If a
dog is suspected of having parvovirus, the veterinarian will often order a
virus-specific ELISA test to look for antibodies to the virus. A small swab is
taken from the dog’s rectum, and is added to a color-changing test. A color change at the test site indicates a
positive result; the more pronounced the color change, the more antibodies are
present. Since false positives or
negatives are possible, veterinarians will often order a complete blood count
(CBC) for confirmation. This test takes a small amount of blood and looks at
the dog’s blood cells. A low white cell count is often seen with dogs that are
infected with the virus. This result,
along with a positive ELISA test, gives the veterinarian confidence in the
diagnosis of parvovirus.
Treatment
for the virus mainly consists of supporting the dog through the course of the
illness; there is no specific cure for parvovirus. Infected dogs must often be
hospitalized in an isolated area, to prevent the transmission of the virus to
other dogs. The fluids and electrolytes
lost from vomiting and diarrhea must be replaced, often with the use of an IV
(intravenous) drip. Medications to stop
or combat vomiting, nausea, and diarrhea are given, and the dog is kept warm
and clean. As soon as possible, intake of food is encouraged, as this helps to
minimize the loss of cells in the intestine.
Treatment should be started early, and should be aggressive to give the
infected dog the best possible chance of survival. Even if these guidelines are
followed, some dogs may die, but successful outcomes may approach 90% if proper
treatment is initiated.
How Can Parvovirus Be Prevented?
Proper vaccination of both
puppies and adult dogs is of the utmost importance in preventing parvovirus
infection. Starting at 6 weeks of age,
puppies should receive a combination shot (which vaccinates against parvovirus,
distemper, adenovirus, and parainfluenza) every 3 to 4 weeks until they are at
least 16 weeks of age. The vaccine
should be boostered 1 year later, then every 1 to 3 years for the life of the dog.
Puppies
should be kept away from areas where large groups of dogs can be found, such as
kennels, doggy day cares, dog parks, and pet-friendly stores, until they are
finished with their puppy vaccines at 16 weeks of age. Adult dogs should receive yearly exams and
vaccine boosters as often as recommended by a veterinarian. Dogs should not be
taken to homes or areas where ill dogs have been housed. Though there is a
slight chance puppies or dogs can still contract the virus in spite of these
efforts, following these guidelines will dramatically decrease the chance that
infection will occur.
Written by, Sarah
Pavlina-Whelehan, LVT, VTS (ECC)
Clinical Educator at
VSES
