PAHO Epidemiological Alert 19 December 2025

The PAHO Epidemiological Alert of 19 December 2025 was a formal Epidemiological Alert issued by the Pan American Health Organization on rising hantavirus cases across the Americas, specifically noting elevated caseload in the Southern Cone region (Argentina, Chile, Paraguay, Uruguay) and increased lethality in some countries. Epidemiological Alerts are PAHO's second-tier public health notification, below a full outbreak declaration but above routine surveillance reporting. They are distributed to member-state ministries of health and are publicly accessible on the PAHO website. The December 2025 alert noted that Argentina's hantavirus caseload through the second half of 2025 ran at approximately twice the prior year's rate.

The PAHO alert of 19 December 2025 is the key institutional document establishing that elevated Andes-virus risk in the Southern Cone was formally flagged five months before the MV Hondius sailed. No wire service or travel advisory picked up the alert; Antarctic cruise operators sailing from Ushuaia appear to have introduced no Andes-specific health briefings for passengers before the MV Hondius departure. The alert's existence is what makes the MV Hondius cluster a case of unacted-on early warning rather than a genuinely unforeseeable event. Its relationship to the cluster frames the surveillance gap: the advisory system functioned; the translation from institutional alert to operator-level biosecurity action did not.