CANINE PARVOVIRUS INFECTION

WHAT IS PARVOVIRUS INFECTION?
Since 1978 dogs of all ages and breeds have been victims of a highly contagious virus disease that attacks the intestinal tract, white blood cells, and in some cases, the heart muscle.  The canine parvovirus infection, (CPV) has now spread worldwide.

CPV infection is spread by contact with material (dried vomit and feces) from an infected dog and has been diagnosed wherever dogs congregate, including dog shows, obedience trials, breeding and boarding kennels, pet shops, humane shelters, parks, and playgrounds and even in dogs isolated in their own back yards!

A dog that is confined to a house or yard and is rarely in contact with other dogs is less likely to be exposed to the virus BUT we see house dogs catch the infection. CPV infection can only be transmitted to dogs and other canids, not to other types of animals or people, but other animals, birds, insects and people can carry the virus to your dog.

The source of infection is fecal waste (and dried vomit) from infected dogs.  Large amounts of the virus may be present in fecal material of infected dogs.  The virus is resistant to extremes in enviromental conditions and can survive for long periods, even OVER A YEAR.  It is readily transmitted from place to place on the hair or feet of infected dogs or by contaminated cages, shoes, or other objects.  RULE NUMBER 1…PARVO IS EVERYWHERE AND EASILY TRANSMITTED.

HOW CAN YOU TELL IF A DOG HAS CPV INFECTION?
The first signs of CPV infection are depression, loss of appetite, vomiting, and severe diarrhea.  Rectal temperatures may be raised unless the dog is dehydrated.  These signs will most often appear 3-5 days after the dog is exposed to the virus.  At the onset of illness, the feces will generally be light gray or yellow-gray.  Sometimes, the first sign will be fluid feces streaked with blood.

Dogs may dehydrate rapidly due to vomiting and diarrhea.  Some dogs may vomit repeatedly and have projectile bloody diarrhea until they die.  Others may have only loose feces and be very depressed.  Only about 1 in 10 of all dogs infected will recover without treatment.

Most deaths occur within 48-72 hours following the onset of clinical signs.  Pups suffer most with shock-like deaths, occurring as early as two days after the onset of illness.  In the past, a high percentage of pups less than five months old and 2-3% of older dogs caught from this disease.  Now, due to widespread vaccination, these percentages have decreased dramatically.

Another form of parvoviral infection is inflammation of the heart (myocarditis) in pups less than three months of age.  This syndrome occurs without concurrent diarrhea because the virus multiplies rapidly in muscle cells of the growing heart. Pups with parvoviral myocarditis may act depressed and stop suckling shortly before they collapse gasping for breath.  Death may follow within minutes.  Others may die at intervals over the next several days.  There is no specific treatment.  Pups that survive may have permanently damaged hearts.  Such dogs may die from heart failure weeks or months after the have apparently recovered from infection.

HOW IS CPV INFECTION DIAGNOSED?  TREATMENT?
A veterinarian will make an initial diagnosis based on clinical signs but only after considering other causes of vomiting and diarrhea.  Evidence of rapid spread in a group of dogs is strongly suggestive of CPV infection and may be confirmed by fecal testing and blood counts.

There are no specific drugs that kill the virus in infected dogs and it is not safe to vaccinate ill dogs.

Treatment of CPV infection, which should be started immediately, consists primarily of efforts to combat dehydration by replacing electrolyte and fluid losses, controlling vomiting and diarrhea, and preventing secondary infections with antibiotics. 

Sick dogs should be kept warm and be provided good nursing care.

WHAT ABOUT PREVENTION AND PROTECTION?
With few exceptions, dogs of any age should be vaccinated to prevent CPV infection.  Unless the actual immune status of a pup or litter is known, it is recommended that a series of vaccinations be given to provide adequate protection.  Some vaccines provide protection against parvovirus, canine distemper, infectious hepatitis, leptospirosis, parainfluenza, and others.  Annual booster vaccinations are necessary.  Ask your veterinarian about vaccinations, duration of immunity, and recommended schedule for inoculations.  Many people try to save a few dollars by buying vaccines at feed store or drug stores.  These vaccines are not what veterinarians use and we often diagnose ill dogs vaccinated by these means!

Proper cleaning and disinfecting of kennels and other areas where dogs are housed is essential to control spread of the virus.  Remember that the virus is capable of existing in the environment for many months unless the area is thoroughly cleaned.  Sodium hypochlorite solution, such as one part household bleach to 30 parts water, is an effective disinfectant.

An owner should not allow a dog to come in contact with the fecal waste of other dogs when walking in a park or playground or along city streets.  Prompt and proper disposal of waste material is always advisable.  Check lawns, sidewalks, and street gutters for fecal waste from neighborhood dogs, and urge friends to do the same.  It is not possible, however, to disinfect the whole world so proper vaccination with quality vaccines and annual boosters is your best preventative measure.

If you are unsure whether this disease is affecting dogs in your community, check with a veterinarian.  The risk of exposure can be reduced if you prevent your dog from contacting other dogs in areas where the incidence of CPV infection is alarmingly high.