Following the epidemic in Colombia last year, with a total of 82 cases and 35 deaths as of 31 December 2003, the presence of a yellow fever epizootic was confirmed on that same day among monkeys in Los Besotes Ecological Park in the federal Department of Cesar.

On November 24, 2003 the Roraima State Health Department reported to the Secretariat of Health Surveillance (SVS/MS) the existence of an epizootic in the Rorainópolis municipality, in the south of the state.

The Ministry of Health of Venezuela received a report on 27 February 2004 (Epidemiological Week/EW 8) on the death of monkeys in the town of Caserío El Salto, along the Morichal Largo river near the city of Maturín, Monagas state.

In October of this year, the health authorities of Argentina and Brazil have confirmed the occurrence of yellow fever epizootics in the Misiones province, Argentina, and the state of Rio Grande do Sul, Brazil, respectively.