posted 07-29-2003 02:24 AM            

Canine parvovirus (CPV) is the most dangerous and contagious virus that affects unprotected dogs. When it was first discovered in 1978, most of the puppies under five months old and 2% to 3% of older dogs died from CPV. But subsequently a parvo vaccine has helped control its spread, and CPV infection is now considered most threatening to puppies between the time of weaning and six months of age. Adult dogs can also contract the virus, although it's relatively uncommon. All breeds of dog can be infected, but Rottweilers and Doberman Pinschers are more susceptible and have less chance of recovering.

CPV affects only dogs, and cannot be transmitted to humans or other species. However, other animals and humans can carry it to dogs. Dogs who become infected have a 50-50 chance of survival. If they survive the first four days, they will usually recover rapidly, and become immune to the virus for life. Most puppies will die without medical treatment.

The source of CPV infection is fecal waste from infected dogs. It has been diagnosed anywhere groups of dogs are found: dog shows, obedience trials, breeding and boarding kennels, pet shops, animal shelters, parks, and playgrounds. Dogs that spend their time confined to a house or yard and are not in contact with other dogs have much less chance of exposure to CPV. It's easily transmitted via the hair or feet of infected dogs, and also by contaminated objects such as cages or shoes. CPV is hardy and can remain in feces-contaminated ground for five months or more if conditions are favorable. Although most disinfectants cannot kill it, chlorine bleach is quite effective. There may be other means of transmission of CPV, but they are not known at this time.

Two forms of CPV have been identified: diarrhea syndrome and cardiac syndrome.

Diarrhea syndrome, or enteritis, has an incubation period of five to fourteen days. Dogs with enteritis act like they are in extreme pain. Early symptoms are depression, loss of appetite, vomiting, high fever, and severe diarrhea. Feces can be either grayish or fluid and bloody. Rapid dehydration is a danger, and dogs may continue to vomit and have diarrhea until they die, usually three days after onset of symptoms. Others may recover without complications and have no long-term problems. Puppies can die suddenly of shock as early as two days into the illness.

The second form of CPV is cardiac syndrome, or myocarditis, which can affect puppies under three months old. There is no diarrhea because the virus multiplies rapidly in muscle cells of the immature heart. Puppies may stop suckling and then collapse and die within minutes or days. No effective treatment is available for cardiac syndrome, and surviving puppies may have permanently damaged hearts.

The initial diagnosis of CPV can usually be made by a veterinarian after observing the dog’s symptoms; however, vomiting and diarrhea can be caused by a number of diseases. The rapid spread of illness in a group of dogs is another indication that CPV may be the culprit. A more definitive diagnosis of CPV can be made by testing feces for the virus, either at the veterinarian's office or through an outside laboratory.

Treatment for CPV should be started immediately. Hospitalization is necessary, except in relatively mild cases. Dogs must be kept warm. Dehydration is treated by replacing electrolytes and fluids and controlling vomiting and diarrhea. Antibiotics are used to prevent secondary infections. No drug is yet available that will kill the virus.

The easiest way to prevent CPV in adult dogs has been through annual vaccinations, although increasingly, veterinarians are recommending that vaccinations be administered every three years. Puppies need a series of booster shots, because of uncertainty about when maternal immunity wanes and the time the vaccine can provide puppies with their own immunity. This may be as early as six weeks of age or as late as fourteen weeks of age. If there is still a high level of maternal antibody present in the puppy, it will interfere with a vaccination. Veterinarians recommend that puppies get boosters every three weeks until they are sixteen weeks old, and they should be kept separate from unvaccinated dogs. Vaccinations given to puppies as well as adults also protect against other serious canine diseases like distemper, infectious hepatitis, leptospirosis, parainfluenza, and coronavirus.

Parvo vaccinations are usually required for participation in puppy obedience classes and for boarding your dog at kennels. A vaccination does not guarantee that your puppy will be safe from the virus, but it's good protective insurance.

A parvo-infected dog can shed the virus in his feces, which makes him extremely contagious to other dogs. The following precautions will help prevent the spread of this disease.

· Keep the dog isolated from all other dogs for at least a month after recovery.

· Pick up all the dog's stools in your yard.

· Use chlorine bleach and water to clean food and water bowls. Wash the dog's bedding in bleach and hot water. Disinfect all areas that the dog has been in, including linoleum floors, crates, etc.

· If you have any other dogs who are two years old or younger, or who have not had parvo vaccinations, take them to your veterinarian immediately for a booster shot.

· Feed your dog a bland diet until he recovers. Reintroduce regular food slowly.

A healthy puppy or adult dog should never be allowed contact with the feces of other dogs when walking or playing in public. Dispose of waste material properly and try to keep lawns, sidewalks, and street gutters clear of feces from neighborhood dogs.