Taxobox | color=violet
name = "Parvovirus"
virus_group = ii
familia = "
genus = "Parvovirus"
subdivision_ranks = Species
subdivision = "
Canine parvovirus" " Chicken parvovirus" "Feline panleukopenia virus" " Feline parvovirus" " HB virus" " H-1 virus" " Kilham rat virus" " Lapine parvovirus" " LUIII virus" " Mink enteritis virus" " Minute virus of mice" " Murine parvovirus 1" " Porcine parvovirus" " Raccoon parvovirus" " RT parvovirus" " Tumor virus X"
"Parvovirus", commonly abbreviated to parvo, is a
genusof the " Parvoviridae" family linear, non-segmented single stranded DNA viruses with an average genome size of 5 kbp. Parvoviruses are some of the smallest viruses found in nature (hence the name, from Latin"parvus" meaning "small"). Some have been found as small as 23nm.
Many types of mammalian
specieshave a strain of parvovirus associated with them. Parvoviruses tend to be specific about the taxonof animal they will infect, but this is a somewhat flexible characteristic. Thus, all strains of canine parvoviruswill affect dogs, wolves, and foxes, but only some of them will infect cats.
No members of the genus Parvovirus are currently known to infect humans, but humans can be infected by viruses from three other genera from the Family Parvoviridae. These are the
Dependoviruses(e.g. Adeno-Associated Virus), the Erythroviruses(e.g. Parvovirus B19) and the Bocaviruses.
The viral capsid of parvovirus is made up of 3
proteinsknown as VP1, VP2 and NS1 that form an icosahedral structure that is resistant to pH, solvents and temperature up to 50°C.
Inside the capsid is a single stranded DNA genome. At the 5’ and 3’ ends of this genome are palindromic sequences of approximately 115
nucleotidesthat form hairpins and are essential for viral genome replication.
In order to enter host cells parvoviruses bind to a cell surface receptor. Once in the host cell the virus' DNA
genomeis translocated to the nucleus where transcription of the genes encoding the non-structural proteins into mRNAoccurs. The mRNAs are transported out of the nucleus into the cytoplasmwhere the host ribosomes translate them into viral proteins. Next the CAP ( capsid) proteins are transcribed and translated in the same way as the non-structural proteins. The replication of the viral genome can then occur. The process by which the parvovirus genome is replicated is poorly understood, although host DNApolymerase is needed for replication. Once the genome has replicated it is packaged inside the viral capsidwithin the cytoplasm.
Parvoviruses do not have an envelope and so are only released when the cell undergoes
In order for viral
replicationto take place the infected cells must be non-quiescent cells (i.e. must be actively mitotic). This is because the virus relies heavily on the host cell's replication machinery and therefore require the cell to pass through S phase. Unlike polyomaviruses, parvoviruses are unable to turn on DNA synthesis in host cells.
Parvoviruses can cause
diseasein some animals. Because the viruses require actively dividing cells in order to replicate, the type of tissue infected varies with the age of the animal. The gastrointestinal tractand lymphatic systemcan be affected at any age, leading to vomiting, diarrhea and immunosuppression, but cerebellar hypoplasia is only seen in cats that were infected in the womb or at less than two weeks of age, and disease of the myocardiumis seen in puppies infected between the ages of three and eight weeks.cite book|author=Fenner, Frank J.; Gibbs, E. Paul J.; Murphy, Frederick A.; Rott, Rudolph; Studdert, Michael J.; White, David O.|title=Veterinary Virology (2nd ed.)|publisher=Academic Press, Inc|year=1993|id=ISBN 0-12-253056-X]
Canine parvovirus" is a particularly deadly disease among young puppies, about 80% fatal, causing gastrointestinal tractdamage and dehydrationas well as a cardiac syndrome in very young pups. It is spread by contact with an infected dog's feces. Symptoms include lethargy, severe diarrhea, fever, vomiting, loss of appetite, and dehydration. " Mouse parvovirus1", however, causes no symptoms but can contaminate immunology experiments in biological researchlaboratories. " Porcine parvovirus" causes a reproductive disease in swineknown as SMEDI, which stands for stillbirth, mummification, embryonic death, and infertility. Feline panleukopeniais common in kittens and causes fever, low white blood cellcount, diarrhea, and death. Infection of the cat fetus and kittens less than two weeks old causes cerebellar hypoplasia. " Mink enteritis virus" is similar in effect to feline panleukopenia, except that it does not cause cerebellar hypoplasia. A different parvovirus causes Aleutian diseasein minks and other mustelids, characterized by lymphadenopathy, splenomegaly, glomerulonephritis, anemia, and death. The most accurate diagnosisof parvovirus is by ELISA. Dogs, cats and swinecan be vaccinated against parvovirus.
Parvovirus B19", which causes fifth diseasein humans, is a member of the " Erythrovirus" genus of " Parvoviridae" rather than "Parvovirus".
[http://www.cats.org.uk/catcare/leaflets/665_fpv.pdf Feline Parvovirus by Cats Protection]
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