Canine parvovirus
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- This article refers to canine parvovirus type 2. Canine parvovirus can also refer to canine parvovirus type 1, known as canine minute virus.
Canine parvovirus (CPV) is a contagious virus affecting dogs. The disease is highly infectious and is spread from dog to dog by physical contact and contact with feces.
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[edit] History
CPV is a relatively new disease that appeared in the mid 1970s. Before 1976, CPV did not exist anywhere; within two years, CPV had invaded every part of the world. The virus is very similar to feline distemper; in fact, they are almost identical, except for two amino acids in the capsid protein VP2.[1] The early belief was that the feline distemper mutated into CPV; however, this has never been proven. The current prevalent theory is that CPV mutated from an unidentified parvovirus of some wild carnivore.
Two additional strains of canine parvovirus CPV2a and CPV2b were identified in 1979 and 1984 respectively. Most cases of canine parvovirus is believed to be of these two strains; however, they are indistinguishable by most routine tests.
[edit] Varieties
There are two forms of CPV: intestinal and cardiac. Cardiac form is less common and affects puppies infected in utero or shortly after birth. Symptoms of heart failure usually emerge in puppies less than eight weeks old.[2] It attacks the heart muscle and the dog dies suddenly of heart failure.
Certain breeds, such as Rottweilers, Doberman Pinschers, Labrador Retrievers, and Pit bull terriers as well as other black and tan colored dogs may be more susceptible to CPV [3]
[edit] Infection
Dogs become infected through contact with CPV in feces or infected soil. Most dogs (more than 80 percent) that are infected will show no symptoms.[2] Dogs that develop the disease show symptoms of the illness within 5 to 10 days. The symptoms are lethargy, vomiting, and diarrhea (usually bloody). After a dog is infected, there is no cure, but dogs usually recover from the viral infection and associated symptoms within five days with aggressive treatment.[2] However, diarrhea and vomiting result in dehydration and secondary infections can set in, causing death even in treated dogs. Risk factors for severe disease include young age, a stressful environment, and concurrent infections with bacteria, parasites, and canine coronavirus.[2]
The virus attacks rapidly dividing cells, notably those in the lymph nodes, intestines, and the bone marrow. Bacteria that normally live in the intestines then cross into the bloodstream and cause septicemia. Due to dehydration, the dog's electrolyte balance is destroyed. Because of destruction of the normal intestinal lining, blood and protein leak into the intestines leading to anemia and loss of protein. The white blood cell level drops, further weakening the dog Any or all of these factors can lead to shock and death.
Myocarditis can occur when puppies younger than 8 weeks are infected.
Survival rate depends on how quickly it is diagnosed and how aggressive the treatment is. Diagnosis is made through detection of CPV in the feces, although the presence of bloody diarrhea and a low white blood cell count in an unvaccinated dog are strong indications of infection. Treatment usually involves extensive hospitalization, including IV fluids, antinausea injections, and antibiotic injections. Even with hospitalization, there is no guarantee that the dog will survive.
[edit] Prevention and contamination
Direct contact with infected feces is not necessary for the disease to spread: viral particles on shoes, clothing, hair, and so on are all that is needed for the transmission. The disease is extremely hardy and has been found to be present in feces or other organic material (eg. soil) even after a year including extremely cold and hot temperatures. The only household disinfectant that kills the virus is a mixture of bleach and water, 1 part bleach and 30 parts of water.[2]
Prevention is the only way to ensure that a puppy or dog remains healthy. This disease is extremely virulent and contagious. With severe disease, dogs can die in as little as 6 to 8 hours despite treatment. In the more common, less severe form, mortality is about 10 percent.[1]
It is extremely important to vaccinate puppies and adult dogs against CPV. Weaning puppies should receive initial vaccination at 6 weeks of age, then every 3 to 4 weeks until 15 or 16 weeks of age with a modified live virus low passage high titer vaccine. Older puppies (16 weeks or older) should receive 2 vaccinations 3 to 4 weeks apart. [3]
According to vaccine manufacturers' labels, CPV vaccination should be done yearly. However, most United States veterinary schools recommend vaccinating every three years after the puppy series and the first annual booster, because of the long-term immune system stresses placed on the dog. Vaccines labeled for three year CPV immunity are now available.
A dog that successfully recovers from CPV is still contagious for up to 2 months, so the dog must be kept away from other dogs and puppies. Neighbours and family members with dogs should be notified of infected animals so that they can ensure that their dogs are vaccinated and tested.
Canine parvovirus affects dogs, wolves and foxes. CPV2a and CPV2b have been isolated from a small percentage of symptomatic cats and is more common than feline panleukopenia in big cats. [4] It does not transmit to birds, or humans; although each species has its own parvovirus. Canine parvovirus cannot be spread to species outside of the canid family and other carnivores, but it can be spread by them. (ex. a bird comes in contact with feces and then the dog's environment, or a cat goes to the groomers and returns with an exposed petcarrier.)
[edit] See also
[edit] References
- ^ a b Carter, G.R.; Wise, D.J. (2006). Parvoviridae. A Concise Review of Veterinary Virology. Retrieved on 2006-06-11.
- ^ a b c d e Ettinger, Stephen J.;Feldman, Edward C. (1995). Textbook of Veterinary Internal Medicine, 4th ed., W.B. Saunders Company. ISBN 0-7216-6795-3.
- ^ a b Nelson, Richard W.;Couto, C. Guillermo (1998). Small Animal Internal Medicine, 2nd ed., Mosby. ISBN 0-8151-6351-7.
- ^ Recent Advances in Canine Infectious Diseases, Carmichael L. (Ed.) International Veterinary Information Service, Ithaca NY (www.ivis.org), 2000; A0106.0100
[edit] External links
- Canine Parvovirus Information-The Evolution of the Canine Parvovirus
- Parvovirus Information Center from The Pet Health Library
