Southern Cone

The Southern Cone is a geographic and geopolitical term for the southernmost nations of South America: Argentina, Chile, Uruguay, and southern portions of Brazil and Paraguay. The region is characterised by temperate to sub-Antarctic climates, high-income economies by Latin American standards, significant European-descended populations, and strong regional integration through MERCOSUR. The Southern Cone includes Patagonia, Tierra del Fuego, the Pampas grasslands, and the Andes mountain chain. It is the primary habitat of the long-tailed pygmy rice rat, the reservoir host for Andes hantavirus, and of Junin virus, the cause of Argentine haemorrhagic fever endemic to the Pampas grain belt.

PAHO's Epidemiological Alert of 19 December 2025 specifically identified the Southern Cone as the geographic focus of elevated hantavirus activity, with Argentina's 2025 caseload running at roughly twice the prior-year baseline. The alert predated the MV Hondius voyage from Ushuaia by five months. The Southern Cone's dual zoonotic burden, Andes hantavirus in Patagonia and Junin arenavirus in the Pampas, makes it one of the world's highest-density zoonotic-spillover environments and directly relevant to the WHO R&D Blueprint's Arenaviridae roadmap published in March 2026. The region's Antarctic tourism economy, channelled through Ushuaia, is the vector by which locally elevated disease risk reaches an international passenger population with no prior hantavirus exposure or immunity.