Submitted to: Berliner Muchener Tierarztliche Wochenschrift
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 18, 2013
Publication Date: November 1, 2013
Citation: Ridpath, J.F. 2013. A need to define characteristics to be used in the taxonomy of the expanding pestivirus genus. Berliner Muchener Tierarztliche Wochenschrift. 126(11-12):462-467. Interpretive Summary: The pestivirus genus includes viruses that cause disease in domestic animals such as cattle, pigs, goats and sheep. Originally there were just three members of this genus, bovine viral diarrhea virus of cattle, hog cholera virus of pigs (later renamed classical swine fever virus) and border disease virus of sheep. The diseases associated with these viruses have been recognized by veterinary medicine by more than half a century. Recently new member viruses have been proposed based on observation of different diseases or because if new techniques used to characterize viruses. This is leading to problems because there is no consensus on the criteria required to declare a new subgroups and there is little information regarding the practical significance of subgroups reported thus far. The division of the pestivirus genus into subgroups is important from a regulatory standpoint because some members of the genus have been or are in the process of being eradicated from some regions. From a trade standpoint it is important to have criteria that differentiate an eradicated subgroup of the genus from a subgroup that is still circulating in a region. This manuscript reviews the criteria that could be used to differentiate subgroups within the pestivirus genus and discusses need for a more organized method of determining divisions within this genus.
Technical Abstract: The relatively high rate of genetic drift observed with pestiviruses results not only in the emergence of new species but also in heterogeneity within recognized species. The grouping of pestiviruses into species was first based on host and to a lesser extent clinical presentation, then later by antigenic comparisons and more recently genetic comparisons. Subgrouping within species is a more recent taxonomic development and has been based primarily on genetic comparisons. While there are a number of publications proposing new species within the pestivirus genus or new subgroups within recognized pestivirus species, there is no consensus on the criteria required to declare a new species and subgroup. Defining the criteria used for segregation of species and subgroups within a species is not just an academic exercise because differentiating viral species and determining the regions in which they are endemic has profound implications for eradication efforts and for regulation of trade in livestock and animal derived products, such as fetal bovine serum. This review outlines criteria used for differentiating species within the different genera of the Flaviviridae, compares criteria previously used for differentiating pestiviruses and discusses the need for the development of a unified system for defining species and subgroups within the Pestivirus genus.