Arenaviridae

VÍCTOR ROMANOWSKI

Virus taxonomy: classification and nomenclature of viruses: Ninth Report of the International Commit

Elsevier-Academic Press

Año: 2011; p. 715 - 723

Arenaviridae...Species demarcation criteria in the genusThe parameters used to define a species in the genus are:- an association with a specific host species or group of species- presence in a defined geographical area- etiological agent (or not) of disease in humans- significant differences in antigenic cross-reactivity, including lack of cross-neutralization activity where applicable- significant amino acid sequence difference from other species in the genus (i.e. showing a divergence between species of at least 12% in the nucleoprotein amino acid sequence).For example, although both Pirital virus and Guanarito virus circulate in the same region of Venezuela, they are distinguished by their isolation from different rodent hosts (Sigmodon alstoni and Zygodontomys brevicauda, respectively). In addition, in ELISA with hyperimmune mouse ascitic fluids, titers differ by at least 64-fold, and sequence analysis shows less than 55% aa identity between partial nucleocapsid protein sequences. In another example, both Lassa virus and Mopeia virus share a common rodent host (Mastomys) at the genus level. However, they are distinguished by their different geographical range, different profiles of reactivity with panels of monoclonal antibodies, and by N protein aa sequence divergences of about 26%. Also, Lassa virus is the cause of hemorrhagic fever in humans and other primates, while Mopeia virus is not associated with human disease and does not cause disease in experimentally infected primates.Phylogenetic relationships within the family ArenaviridaeNucleic acid sequences from the N genes of all the known arenaviruses have provided the basis for phylogenetic analysis that supports previously defined antigenic groupings and further defines virus relationships within them. Sequence data derived from other regions of the genome including the L gene are largely consistent with this analysis. Among the Old World viruses, Lassa virus, Mopeia virus and Mobala virus are monophyletic, while Ippy virus and lymphocytic choriomeningitis virus are more distantly related. One interesting virus, LuJo virus, found in South Africa, is most related to Old World viruses but contains elements of New World sequence in its glycoprotein. The New World viruses can be divided into three groups on the basis of the sequence data. In group A are Pirital virus, Pichinde virus, Paraná virus, Flexal virus, and Allpahuayo (Peru) virus from South America, together with Tamiami virus, Whitewater Arroyo virus and Bear Canyon virus from North America. Group B contains the human pathogenic viruses Machupo virus, Junín virus, Guanarito virus, Sabiá virus and Chapare virus as well as the non-pathogenic Tacaribe virus, Amapari virus, and Cupixi virus (from Brazil). Latino virus and Oliveros virus form a small separate group (group C). The division of the arenaviruses into Old World and New World groups, as well as the subdivision of New World arenaviruses into three groups, is strongly supported by bootstrap resampling analysis. It is important to note that the trait of human pathogenicity appears to have arisen on at least two independent occasions during arenavirus evolution.Recombination may have influenced the evolution of arenaviruses.The nucleocapsid and glycoprotein genes of Whitewater Arroyo virus, Tamiami virus, and the Bear Canyon virus have divergent phylogenetic histories. Separate analysis of full-length amino acid sequences using maximum parsimony or neighbor-joining methods show that the nucleocapsid protein genes of these three viruses are related to those of Pichinde virus and Pirital virus (New World lineage A), while the glycoprotein genes are more closely related to those of Junín virus, Tacaribe virus, and Sabia virus (New World lineage B).Similarity with other taxaThe Arenaviridae are unique amongst the negative strand viruses for their bisegmented genome with ambisense coding strategy. Arenaviruses are most similar to the Bunyaviridae, another segmented negative-strand RNA virus family, whose members have three genome segments, some of which also encode genes in both senses.