GENETIC-CHARACTERIZATION AND PHYLOGENY OF ANDES VIRUS AND VARIANTS FROM ARGENTINA AND CHILE

Andes virus, one of five hantaviruses known to cause hantavirus pulmon ary syndrome (HPS), emerged in 1995 in southwestern Argentina (Lopez e t al. (1996) Virology 220, 223-226). The complete nucleotide sequence of Andes virus S genome segment was determined and compared with seque nces of viral RNAs in autopsy tissues of more recently reported HPS ca ses from southwestern Argentina and south of Chile (cases ESQ H-1/96 a nd CH H-1/96). Andes virus S segment was found to be 1876 nucleotides in length and to encode the nucleocapsid protein (N), 428 amino acids in length. S segment analysis also revealed a long 5' non-coding regio n (547 nucleotides) which displays three copies of an octanucleotide s equence repeat. Comparisons of S segment sequences of ESQ H-1/96 and C H H-1/96 (82% of the entire genome sequence) with the corresponding se quences of Andes virus revealed identities of 97.2% and 98.5%, respect ively. Sequence motifs identical and in the same positions as exhibite d in Andes virus 5' non-coding region were found in both, ESQ H-1/96 a nd CH H-1/96 sequences. Three genome fragments of the M segment sequen ce of the viruses (representing approximately 34% of the entire sequen ce) were also analyzed. Comparisons of S and M segment sequences of An des virus with the corresponding sequences of ESQ H-1/96 showed S and M segment identities which differ by less than 1.4%. Andes virus and C H H-1/96 have S segments that differ by 1.5% from one another while th eir M segment fragments differ by 5.5-8.2%. Phylogenetic analysis show ed that Andes virus along with ESQ H-1/96 and CH H-1/96 form a distinc t lineage within the clade containing Bayou and Black Creek Canal viru ses. It also showed that Andes virus branch of trees derived from comp arisons of S or M sequences differed. It is concluded that Andes virus variants causing HPS circulate east and west of the Andes mountains. (C) 1997 Elsevier Science B.V.