hantavirus are associated with a single primary rodent host of the familiy muridae in three sub families, two of them murinae and arvicolinae distributed in the paleartic region (europa, asia, china) and the sub family sigmodontinae in north, central and south america besides an arvicolinae genus (microtus) in north america. studies on the host and virus phylogeny show close similarities when are compared which implies that hantavirus are very ancient infectious agents which have coevolved with the rodent host. the history of earth, tectonic movements and climatic changes which affected the continents in the past are relevant to understand the host reservoir and its micro parasites current geographic distribution. this review provides historical biogeography of the sigmodontine rodents, phylogentic analyses of hantavirus, its molecular epidemiology and its geographical distribution in south america in order to sustain the proposal that the virus- rodent interaction has coevolved in the neartic before the family muridae was detached in subfamilies and before the sigmodontines rodents spread into the south american continent. it is described the existence of a large number of hantavirus lineages with small differences which make difficult to establish so far, well define species of hantavirus. an analisis between similarities and differences in the ecology and pathogenesis of two virus which have produced an important number of human cases in north america (sin nombre) and in the southern cone of america (virus andes) is discussed.