2026 Cruise Ship-associated Andes Hantavirus Outbreak and Public Health Response

Andes virus (ANDV) is an exceptional hantavirus for which human-to-human transmission has been repeatedly reported, and it causes hantavirus cardiopulmonary syndrome with high lethality in South America. This review aims to summarize the epidemiological and clinical features of hantavirus infections and their transmission routes, and to examine transmission patterns within a confined, high-density environment and future public health response strategies, using the 2026 ANDV outbreak on the MV Hondius cruise ship as a case study.

Drawing on publicly available reports from the World Health Organization (WHO), the European Centre for Disease Prevention and Control, the Pan American Health Organization, and the Korea Disease Control and Prevention Agency, as well as relevant literature, we reviewed the characteristics of hantavirus infections and this outbreak.

The MV Hondius departed from Ushuaia, Argentina, on April 1, 2026. On May 2, the UK International Health Regulations (IHR) National Focal Point formally alerted the WHO to a cluster of severe acute respiratory illnesses. By May 27, 13 individuals (11 confirmed and 2 probable cases) had been infected, and 3 had died. Genomic analysis revealed no more than one single-nucleotide polymorphism difference among patients, indicating onboard human-to-human transmission following a single or a very small number of zoonotic spillover events; the effective reproduction number was estimated to be 0.7 on May 22. Major factors contributing to transmission included advanced age (mean, approximately 65 years), shared cabins, communal indoor spaces, and close caregiving or clinical contact.

This outbreak demonstrates that pathogens with limited human-to-human transmissibility can nevertheless be amplified in a closed, high-density environment. Prompt identification, international coordination under the IHR, and efficient risk communication were central to controlling the outbreak, and preparedness for potential importation requires routine assessment of travel history, surveillance for suspected cases, and access to rapid diagnostic testing.