Expedition cruises, island hopping, and zoonotic risk: governance and operational lessons from the MV Hondius Andes hantavirus outbreak

The Andes orthohantavirus outbreak linked to the MV Hondius expedition cruise illustrates how a probable land-based zoonotic exposure can become a multinational public health event when it intersects with enclosed shipboard environments, delayed clinical recognition, remote navigation, medical evacuation, and international passenger dispersal. Although hantavirus infection is classically associated with exposure to infected rodents or contaminated environments, Andes virus is exceptional among orthohantaviruses because limited person-to-person transmission has been documented, particularly after close and prolonged contact. This Perspective uses the MV Hondius outbreak as an analytical case study to identify governance and operational gaps in expedition-era travel medicine. Existing International Health Regulations, WHO ship-event guidance, and ECDC recommendations provide essential foundations for coordination, notification, isolation, and contact tracing; however, this outbreak exposed expedition-specific gaps in safe port access, medical evacuation, onboard recognition of nonspecific febrile illness, diagnostic escalation, passenger traceability, and post-disembarkation monitoring. We therefore propose an accountability-oriented One Health preparedness model that operationalizes existing guidance through route-level risk assessment, exposure-history assessment, onboard syndromic surveillance, isolation and telemedicine triggers, reference-laboratory pathways, port-of-call agreements, auditable passenger and excursion records, and cross-border post-travel monitoring. The central lesson is not that expedition cruises, birdwatching, or ecological tourism are inherently unsafe, but that their expanding geographic reach requires binding, auditable, and expedition-specific outbreak protocols before passengers embark.