Parvoviridae
The virus family Parvoviridae ( parvoviruses ) includes species which bear the only human pathogenic viruses, a single-stranded DNA genome. The virions Parvoviridae have a diameter 18-26 nm; since they are thus among the smallest viruses, their name derives from the Latin parvus (small). Parvoviruses are non-enveloped, which makes them very resistant to external influences.
The Parvoviridae family is divided into two subfamilies: the Parvovirinae and Densovirinae. The Parvovirinae which exclusively infect vertebrates, include the genera Amdovirus, Boca virus Dependovirus, Erythrovirus and parvovirus. Triggered by virus species of the genus Parvovirus disease is called Parvovirosen. The second subfamily of Densovirinae includes the genera Denso virus Iteravirus, Pefudensovirus and Brevidensovirus, the parvoviruses of insects and other arthropods.
Genus Dependovirus
The dependoviruses (eg Adenoassozierte viruses ) depend on helper viruses to replicate. When helper viruses are adenoviruses, herpesviruses and vaccinia viruses in question. If these helper viruses, adeno-associated virus can then enter a latent state by site-specifically incorporate their own genome relative to the cellular genome and live long remain in the organism. In a co-infection with the appropriate helper virus, the integrated viral genome can be reactivated. The adeno-associated virus, AAV -2, AAV- 3 and AAV -5 can infect humans by droplet infection. Probably about 90 % of adults are infected but no disease pictures are known.
Genus Erythrovirus
The erythroviruses have a strong tropism for dividing precursor cells of erythrocytes, erythroblasts. They are dependent on cellular polymerases present in the S phase to replicate their genome. To this genus belongs, among others, parvovirus B19, the causative agent of fifth disease.
Genus parvovirus
The viruses of the genus Parvovirus replicate also autonomous. Among them are exclusively animal pathogenic ( disease-causing animals only ) pathogens which can cause serious diseases in domestic animals and livestock.
The genus includes, among other canine, feline and porcine parvovirus. These viruses are very closely related to each other with a across the entire genome extending homology with a sequence identity of more than 98 %.
The canine parvovirus emerged in 1978 probably directly from the feline parvovirus ( causative agent of feline distemper ) and occurred suddenly. It spread around the world very quickly, what in this pandemic killed millions of dogs. Meanwhile, the Parvovirosen in dogs and cats with the help of live vaccines are well controlled.
Type parvovirus H-1
This type of virus usually infects rodents, but can also infect human cells but causes no disease symptoms in humans there.
Medical relevance to humans
A working group of the University Hospital and the German Cancer Research Center ( DKFZ) in Heidelberg has demonstrated that the H- 1 PV Parvovirenart in cultures of human brain tumor cells and neuroblastoma develop a destructive effect without harming healthy tissue. In treatment experiments in rats in which you previously implanted cells of a malignant glioblastoma, the effect has been confirmed. The parvovirus therapy is currently being tested in a clinical trial in humans.