Chapter 32 : Parvoviruses

Abstract:

The parvoviruses are a large group of DNA viruses capable of infecting a wide variety of both invertebrate and vertebrate hosts, including humans and their companion animals. Depending on the virus and the immune status of the host, human infection can range from overt disease to persistent asymptomatic infection. Current parvovirus taxonomy dates from 2004; however, in the intervening 10 years, as new viruses have been identified and more taxonomic data have become available, the current taxonomy is now considered outdated. A new taxonomic classification of the family Parvoviridae has therefore been proposed and is currently under review and likely to be instituted in the near future (1). The proposed taxonomy, based on the amino acid sequence of the NS1 and viral capsid proteins, maintains the family Parvoviridae and subfamily Parvovirinae for the vertebrate parvoviruses, but adds three new genera and a nomenclature change that impact the taxonomy of the human parvoviruses. A member of a proposed genus must now have >30% amino acid sequence identity to other members of the same genus but <30% identity to members of other genera (1). Criteria for inclusion in a viral species have also changed under the proposed taxonomy, with members of the same species having >85% amino acid sequence identity to other members of the same species and >15% amino acid diversity from members of other species (1). The proposed genera and the human viruses they contain are Bocaparvovirus: human bocaviruses 1–4 (HBoV1-4); Dependoparvovirus: human adeno-associated viruses (AAVs); Erythroparvovirus: human parvovirus B19-related viruses; Protoparvovirus: human bufaviruses; and Tetraparvovirus: human parvovirus 4–related viruses (Par4) (1).