[Present status of zoonotic hemorrhagic fevers of South America].

Since 1958, the geographical distribution of Argentine hemorrhagic fever (AHF) has especially extended non only into the province of Buenos Aires but also towards the provinces of Santa Fe and Cordoba, leading to an estimated population at risk of about 1.2 M inhabitants. Recent epidemiological field studies has confirmed the major role of Calomys musculinus and C. laucha rodents in both transmission to man and conservation of Junin virus in nature. However, the human infection may result essentially from contacts with infected C. musculinus. Clinical condition of patients with AHF was greatly improved using AHF convalescent plasma and additional administration of vidarabin may still improve the results of treatment. A live attenuated vaccine, Candid No 1, is presently under evaluation in endemic foci of AHF. On the contrary Bolivian hemorrhagic fever (BHV) appears at present quite silent. A new disease resembling both AHF and BHF, the Venezuelan hemorrhagic fever, appeared in 1989 in the rural areas of central Llanos of Venezuela. The mortality was very high, reaching 23% or more among severely ill patients. The wild small rodents responsible for the disease were identified as Sigmodon alstoni and Zygotontomys brevicauda. Recent extension of agricultural practices and massive immigration may probably explain the recent emergence of this new viral zoonosis.