Parvo

What is it?

If you are a new dog owner, and don’t know about Canine Parvo Virus (Parvo or CPV) you should. The disease syndrome caused by this nasty virus, can kill, and kill fast. Parvo produces an intestinal disease. Beginning signs include a tired mopey dog that does not want to eat. Soon vomiting and diarrhea begin. The diarrhea is often reddish and foul smelling. The outcome of the disease is difficult to predict. Some dogs seem to have a mild case while others ‘crash’ and die fast. With proper and timely treatment, however, many dogs recover, but without treatment many don’t. Most dogs can be protected with well-timed immunizations. Please, vaccines need to be given at 3 to 4 week intervals starting at 6 to 8 weeks of age for most pups and continued until at lest 16 weeks old.

Why a series of puppy shots? What makes the difference? Why do some cases seem mild, while other pups go steadily downhill despite heroic efforts to save them?

Why a series of puppy shots?

Since CPV 1^st "hit the scene" back in 1978, much has been learned about the way it reacts inside your dog’s body and how to prevent it. There are many good, safe and effective vaccines on the market and they are getting better each year. We must understand the way these vaccines work.

Most pups born in the last two decades receive temporary immunity against CPV from their mothers. This protects the pup but also interferes with the vaccine. CPV is unlike some of the other viruses (distemper, hepatitis) in that this ‘maternal immunity’ can block protection from vaccines. This blocking can last until 16 weeks of age. Because there is no way to determine when maternal immunity goes down or when your pup will respond to the vaccine the puppy vaccine ‘series’ needs to be given.

What makes the difference?

Many cases of CPV are mild, with death rates fairly low. Yet, in some situations, younger pups, and certain breeds the figures are much worse. Reported outbreaks yield severe illness and death rates between 50% and 90%. What’s going on?

CPV produces severe gastroenteritis (vomiting and diarrhea). Gastroenteritis from any cause can be serious in any animal, and parvo is no exception. Young puppies, however, seem particularly vulnerable to CPV’s debilitating effects. Viruses rely on the cells of the infected animal to reproduce and spread through the body. CPV targets intestinal lining cells, which grow rapidly in younger pups. Thus, the virus gets a better chance to overwhelm a younger pup then it dose in an older dog. Also, your puppies’ immune system is still developing, and not quite achieving the functions of an adult. The pup’s protective mechanisms are slow to respond, often unable to suppress virus replication. The result is a massive viral attack and severe consequences.

Based on accumulated clinical observations, we know that some breeds of dog are much more vulnerable to severe parvo infections than others. Doberman pinschers, Rottweilers and the entire "pitbull" group are breeds with unusual sensitivity. All the reasons are not known, but we have some hints. In Dobermans, for example, over 60% suffer (to some degree) from a bleeding disorder (von Willebrads’s disease). It has been suggested that CPV may be more devastating in them due to increased bleeding from the intestinal lining. The sensitivity to parvo even varies between dogs in the same breed. It seems that some dogs appear to be genetically more susceptible than others.

Stress takes many forms. It is clear that stress of any type negatively impacts our ability to resist disease. It has been well documented that puppies undergoing surgery at a young age, especially when put back into contaminated environment, have higher death rates from parvo than do other pups. The list of ‘stresses’ and risk factors is long and confusing. It includes such things as worm infestations, insufficient nutrition, dirty environment, etc. All can contribute to severe CPV ramifications. It is far better to reduce risk factors well in advance of possible infection. To do this, schedule regular puppy visits with your veterinarian, follow currently recommended vaccine schedules, try to keep young puppies away from areas frequented by other dogs until older and provide the best food and living conditions you can. And if you have any questions please call your veterinarian.