Analysis of Hantavirus Genetic Diversity in Argentina: S Segment-Derived Phylogeny

Abstract

Nucleotide sequences were determined for the complete S genome segments of the six distinct hantavirus genotypes from Argentina and for two cell culture-isolated Andes virus strains from Chile. Phylogenetic analysis indicates that, although divergent from each other, all Argentinian hantavirus genotypes group together and form a novel phylogenetic clade with the Andes virus. The previously characterized South American hantaviruses Laguna Negra virus and Rio Mamore virus make up another clade that originates from the same ancestral node as the Argentinian/Chilean viruses. Within the clade of Argentinian/Chilean viruses, three subclades can be defined, although the branching order is somewhat obscure. These are made of (i) "Lechiguanas-like" virus genotypes, (ii) Maciel virus and Pergamino virus genotypes, and (iii) strains of the Andes virus. Two hantavirus genotypes from Brazil, Araraquara and Castello dos Sonhos, were found to group with Maciel virus and Andes virus, respectively. The nucleocapsid protein amino acid sequence variability among the members of the Argentinian/Chilean clade does not exceed 5.8%. It is especially low (3.5%) among oryzomyine species-associated virus genotypes, suggesting recent divergence from the common ancestor. Interestingly, the Maciel and Pergamino viruses fit well with the rest of the clade although their hosts are akodontine rodents. Taken together, these data suggest that under conditions in which potential hosts display a high level of genetic diversity and are sympatric, host switching may play a prominent role in establishing hantavirus genetic diversity. However, cospeciation still remains the dominant factor in the evolution of hantaviruses.Hantaviruses, members of the Bunyaviridae family, are enveloped, single-stranded, negative-sense RNA viruses (10). The virus genome consists of three segments, designated large (L), medium (M), and small (S), that are packed into helical nucleocapsids. These segments encode the RNA polymerase (20, 42), a glycoprotein precursor that is cotranslationally processed to yield two envelope glycoproteins (G1 and G2) and a nucleocapsid (N) protein, respectively (38, 42).Each hantavirus is typically predominantly associated with a specific rodent host indigenous to the geographic area from which the hantavirus was characterized (15,21,30,32,33), although there appear to be occasional occurrences of spillover infections in related rodent species (3,5,15,27,28,41). According to most studies, the rodent host appears to be an asymptomatic carrier with a persistent lifetime infection (21, 51). However, recent data indicate that North American SinNombre-like viruses cause some pathology within their reservoir hosts (25, 31). The genus Hantavirus includes approximately 30 distinct virus serotypes/genotypes (20, 38, 39). As only a small percentage of known rodent species has been examined for the presence of hantavirus genetic material, this number is likely to increase. In North America, hantaviruses are the cause of hantavirus pulmonary syndrome (HP...

Catacamas Virus, a Hantaviral Species Naturally Associated With Oryzomys Couesi (Coues’ Oryzomys) in Honduras

“…Also note that ANDV, CHOV, and MAPV are principally associated with Oligoryzomys species, BCCV, MULV, and CADV are principally associated with Sigmodon species, and-as indicated previously-BAYV is principally associated with Oryzomys palustris. 7,8,10,14,16,17,28,[41][42][43] The results of the NJ analysis of uncorrected p model distances generated from the alignment of N protein amino acid sequences, the MP analysis of the alignment of N protein gene sequences, and the MP analysis of the alignment of N protein amino acid sequences were essentially the same as the results of the NJ analysis of uncorrected p model distances generated from the alignment of N protein gene sequences.…”

“…Evidence for this ancient virus-host relationship includes the association of phylogenetically closely related hantaviral species with phylogenetically closely related rodent species, for example-SNV with P. maniculatus and NYV with P. leucopus, [49][50][51] and ANDV, CHOV and MAPV, and RIOMV with Oligoryzomys longicaudatus (long-tailed colilargo), 10,42,43 Oligoryzomys fulvescens (fulvous colilargo), 7,17 and Oligoryzomys microtis (small-eared colilargo), 18 respectively. The results of analyses of cytochrome b gene sequences in an earlier study indicated that Oryzomys species are phylogenetically more closely related to Oligoryzomys species than to Sigmodon species.…”

Molecular Clocks and the Puzzle of RNA Virus Origins

“…Two mechanisms seem most likely. First, if phylogenetically related host species tend to live sympatrically, then viruses will tend to jump between closely related host species, which appears to be the case for the hantaviruses (2). If this process occurs at sufficient frequency, then the host and virus trees may often match, giving a false impression of cospeciation.…”

“…A similar situation is apparent with the New World hantaviruses (family Bunyaviridae) and the arenaviruses, for which host and virus trees have been compared in detail. In most cases, it seems that these viruses have undergone cospeciation with their murid rodent hosts over several million years, although there is also evidence for occasional cross-species transfers (2,3,26,31). Moreover, a history of cospeciation is not restricted to animal viruses and has also been proposed for the plant tobamoviruses (17).…”

Ecology, Genetic Diversity, and Phylogeographic Structure of Andes Virus in Humans and Rodents in Chile

“…Diverse hantavirus genotypes have been reported to occur throughout a vast geographical range in southern South America (8,35); these include five different lineages of ANDV that have been proposed and named according to their geographic origin in Argentina and Chile (43). These viral genotypes include the following: ANDV Central Plata (ANDV Cent Plata) found on both sides of the Rio de la Plata (in Uruguay and Argentina) and central Buenos Aires province in Argentina; ANDV Central Buenos Aires (ANDV Cent Bs.As.)…”