RESUMO
We have determined the genomic sequence of an Andes virus (ANDV) strain isolated from an infected Oligoryzomys longicaudatus rodent trapped in Chile in 1997. This strain, for which we propose the designation Chile R123, reproduces essential attributes of hantavirus pulmonary syndrome (HPS) when injected intramuscularly into laboratory hamsters (Hooper et al., Virology 289 (2001) 6-14). The L, M, and S segment sequences of Chile R123 are 6562, 3671, and 1871 nt long, respectively, with an overall G+C content of 38.5%. These respective genome segments could encode a 247 kd RNA-dependent RNA polymerase (RdRP), 126 kd glycoprotein precursor (GPC), and 48 kd nucleocapsid (N) protein, in line with other Sigmodontine rodent-associated hantaviruses. Among hantaviruses for which complete genomic sequences are available, Chile R123 is most closely related to Sin Nombre virus (SNV) strain NM R11, with greater than 85% amino acid identity between translated L and S segments and 78% amino acid identity between translated M segments. Because Chile R123 shares essentially 100% amino acid identity in regions of overlap with partially sequenced Argentinian and Chilean ANDV strains, Syrian hamster pathogenicity and the potential for interhuman transmission are features likely common to all ANDV strains.
Assuntos
Sequência de Bases , Surtos de Doenças , Infecções por Hantavirus/veterinária , Orthohantavírus/química , Doenças dos Roedores/virologia , Animais , Chile , Cricetinae , Modelos Animais de Doenças , Genoma Viral , Orthohantavírus/classificação , Orthohantavírus/genética , Orthohantavírus/patogenicidade , Infecções por Hantavirus/epidemiologia , Infecções por Hantavirus/fisiopatologia , Infecções por Hantavirus/virologia , Humanos , Mesocricetus , Dados de Sequência Molecular , Muridae/virologia , Filogenia , Doenças dos Roedores/epidemiologia , Análise de Sequência de DNARESUMO
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.