As their name implies ('parvus' in Latin means 'small'), parvoviruses are amongst the smallest and simplest animal viruses that comprise only DNA and protein. They are the only organisms in the known biosphere that have single-stranded linear DNA genomes.3 Parvoviruses survive many inactivation procedures and remain viable in the environment for years; they persist in their hosts following infection and can reemerge under favorable circumstances. Some parvoviruses are significant pathogens of domestic animals. Canine parvovirus (CPV) is an example of an emergin nonhuman pathogen. It appeared suddenly in 1978 and spread around the globe in less than six months. CPV-2 is closely related to feline panleukopenia virus (FPV) and to parvoviruses that circulate in foxes and other wild canids 4.
In young dogs and puppies, canine parvovirus-2 (CPV-2) causes a highly contagious, often fatal diarrheal disease. The development of safe, effective vaccines brought the disease under control, although it is still a serious killer, rivaling only canine distemper. Dogs should be vaccinated for parvovirus every three to four weeks from six to twenty weeks of age, and re-vaccinated once every year. The Doberman Pinscher, Rottweiler, Pit Bull Terrier, and Labrador Retriever breeds are believed to be more susceptible than other breeds.1
There is a wide variation in clinical response of dogs to infection with CPV, ranging from mild or unapparent infections in dogs more than 6 months of age to acute fatal disease in puppies less than 6 months of age. The most common signs in puppies include sudden onset of depression, lethargy and fever, followed within 24 hours by vomiting and bloody diarrhea. The diagnosis of canine parvovirus enteritis is frequently made by age of pet, signs, and physical examination. Because other diseases can mimic the signs of parvovirus, X-rays and blood tests are sometimes run to help eliminate them as a cause. A complete blood count test might show a reduced white blood cell level, an indication that a virus is present in the body. A blood sample can be run looking for antibodies, but the results are open to interpretation as to whether the dog has an active infection or not.
The main cause of death in infected dogs is septicemia, bacterial toxins, dehydartion, hypoglycemia, and electrolyte imbalances vomiting and not eating. The immune system becomes overwhelmed and death ensues if treatment is not instituted early. Dogs treated in a timely fashion with proper therapy typically live, especially if they survive the first four days of clinical signs. Dogs that have recovered from CPV-2 enteritis develop long-term immunity that may be lifelong.2
- C. Greene. Infectious Diseases Of The Dog And Cat.
- Richard W. Nelson, C. Guillermo Couto. Small Animal Internal Medicine.
- W. Michael Scheld, Scott Hammer, James M. Hughes. Emerging Infections
- James H. Strauss, Ellen G. Strauss. Viruses and Human Disease