Parvovirus is one of several viruses that cause diarrhea in dogs  

Puppies become infected with the virus when contaminated feces are ingested or inhaled  

Treatment of the disease is primarily supportive, while the immune system clears the viral infection  

Treatment in a hospital is essential in most cases, as this infection can be fatal

Affected animals that survive the first few days of a parvovirus infection usually recover completely

Our emergency team is available 24 hours daily, every day, to treat any type of emergency situation, including Parvo.

What is it?

• Parvovirus is one of several viruses that infects the intestines.
• It is a highly contagious and potentially fatal virus that can affect dogs of any age but most commonly causes clinical disease in animals less than six months of age.  
• Certain breeds tend to be affected more than others; these include Rottweilers, Doberman Pinschers, Pit Bull Terriers, and German Shepherds.      

Pertinent Anatomy

• See pertinent anatomy to the right; the intestines are affected by this viral infection

Clinical Signs

• Puppies become infected with the virus when contaminated feces are ingested or inhaled.  
• The virus reproduces in lymph nodes and travels via the bloodstream to certain cells in the intestinal lining.  
• Infection of these intestinal cells damages them so that they cannot perform their normal function which is to absorb water and nutrients.   This lack of proper absorption leads to diarrhea.  
• The virus also affects immature white blood cells interfering with their ability to mature into functional white blood cells which fight infection.  
• A less common manifestation of parvovirus infection occurs when the heart muscle is infected.   This clinical syndrome usually affects puppies less than eight weeks of age so it is rarely seen in animals that have been taken into homes as pets.     
• The most common clinical sign observed by a pet owner is diarrhea which may or may not be preceded by a period of poor appetite, lethargy, fever, and vomiting.  
• The diarrhea is usually watery, profuse, and foul-smelling, and may appear bloody.  
• Affected animals quickly become dehydrated.  

Diagnosis

• Parvovirus can be diagnosed by testing the feces for presence of the virus.  
• Your veterinarian will also run blood tests to check for electrolyte disturbances and evidence of systemic bacterial infection known as sepsis.    

Treatment

• Because this disease is caused by a virus, specific treatment options are limited.  
• There are no drugs that directly kill the virus.  
• Treatment of the disease is mainly supportive while the immune system clears the viral infection.  
• Hospitalization for several days is usually necessary. 
• Infected puppies must be treated with intravenous fluids to combat dehydration.  
• Medication to stop vomiting is often used.  
• Antibiotics are used to prevent or treat secondary bacterial infections.
• Some animals are so severely affected by the disease that they require plasma transfusions or supplemental intravenous nutrition.   

Care at Home

• During the recovery phase, animals are often sent home with a special highly-digestible diet that is gentle on the healing intestinal tract.  
• A course of oral antibiotics is usually recommended as well.  
• An important aspect of the recovery phase is the prevention of contamination of the home and environment with the virus.   Because infected puppies shed massive amounts of parvovirus in their feces, it is very important to keep them strictly isolated from other animals.   They should not be allowed to eliminate in public areas (parks, for example).   The virus can be killed with a diluted bleach solution but is very stable out of doors and cannot be eliminated from a yard.  

Complications

• In some cases, puppies with severe diarrhea from parvovirus develop a condition called intestinal intussusception.   This refers to a telescoping of a segment of intestines into an adjacent segment which results in disruption of the blood supply and death of the tissues.   Unfortunately, this is a complication which requires surgery since the intussusception must be manually corrected or removed.   The prognosis for puppies which develop an intussusception is worse than for those that do not.         

Prognosis

• Affected animals that survive the first few days of a parvovirus infection usually go on to make a complete recovery.
• Extended periods of hospitalization may be required in especially sick puppies and those who develop complications.  
• After recovery, most animals are immune to reinfection for at least a year and possibly even for life.  

Prevention

• Vaccination has been found to be very effective in preventing parvovirus infection if timed correctly.  
• Puppies are born with natural immunity from their mother which lasts until they are four to six weeks old or longer.  
• This natural immunity interferes with the ability of the vaccine to work so the vaccine must be given after this immunity is gone but before exposure occurs.  
• Therefore, a series of vaccinations given every three to four weeks from six weeks of age to 16 weeks of age is recommended.   During this period of transition from natural immunity to fully vaccinated status, puppies should be kept away from other puppies and exposure to public places should be avoided.   They should not be taken to parks or boarding facilities until their puppy vaccination series is complete.   Parvovirus boosters should be given every one to three years depending on the product used.     

References

• For more information on this topic, please visit the Parvovirus Information Center at www.veterinarypartner.com or contact your pet’s primary care provider or MVS clinician.  
• Greene.   Infectious Diseases of the Dog and Cat 2 nd Edition.   W.B. Saunders 1998.
• Ettinger and Feldman.   Textbook of Veterinary Internal Medicine 5th Edition.   W.B. Saunders 2000.