Rapid response and surveillance for high-risk contacts during May 2026 Andes hantavirus outbreak: a Northern Italy experience

In May 2026, an outbreak of Andes hantavirus (ANDV) linked to the cruise ship MV Hondius prompted international contact tracing across multiple countries. Although population-level risk was low, the severity of hantavirus cardiopulmonary syndrome and limited evidence on person-to-person transmission supported precautionary management of selected contacts. Lombardy Region, Northern Italy, was notified of a contact-tracing chain involving four individuals: two direct flight-related contacts exposed to confirmed ANDV cases during international air travel and their two accompanying close contacts. A coordinated response was activated through regional, national, and international public health authorities. All four were referred to Luigi Sacco University Hospital and managed under precautionary measures proportionate to their exposure category. RT-PCR testing for ANDV was negative in all four. This experience illustrates how imported pathogens may generate complex regional demands even when population-level risk remains low, and underscores the value of predefined preparedness frameworks.