Thirteen people, including the ship's doctor, tested positive for Andes virus during an outbreak aboard the cruise ship MV Hondius.1 Clinicians diagnosed Andes virus after travel history, negative initial respiratory tests, and rapidly worsening symptoms prompted them to expand their evaluation. Transmission during this outbreak to a healthcare worker underscores the critical importance of coordinated detection and response systems for high-impact pathogens which are both resource-intensive and capable of significant impact for both public health and healthcare.2 A recent review of nosocomial transmission of Andes virus to healthcare personnel identified 8 reports describing 7 events in which healthcare-associated exposures or outbreaks involving Andes virus occurred in the past.3 Three events involved secondary infections to 8 healthcare personnel, of which 4 died. The Andes virus is the only known hantavirus to spread between humans, spreading through close, sustained contact. Transmission is typically via respiratory droplets with aerosolized respiratory particles playing a role in specific outbreaks .4 Early detection depends on seamless coordination and communication between healthcare providers and public health authorities, as Andes virus testing remains specialized and is largely limited to public health, reference, and select academic laboratories.5,6
High-impact pathogens are infectious agents that cause human illness, can be transmitted person-to-person and cause clinical disease severe enough to disrupt standard healthcare routines. High-consequence infectious diseases are included within the array of high impact pathogens.7 Although the number of people infected by the Andes virus remained relatively small, the MV Hondius cruise ship outbreak demonstrated how a high-impact pathogen can quickly lead to both healthcare and public health responding to monitor returning passengers for symptoms, place people in appropriate quarantine, and ensure suspected cases are quickly identified, tested and isolated to prevent further spread. Similar to the uncertainty experienced during the beginning of the COVID-19 pandemic, many were questioning whether the outbreak could expand beyond the passengers and crew of the cruise ship, who were from diverse areas across the globe.8 While hantavirus outbreaks are uncommon, the recent cruise ship events demonstrate why high-impact pathogens have significant implications for both healthcare and public health preparedness and response.
Healthcare facilities are often among the first organizations responsible for recognizing and managing patients infected with HIPs, yet infectious diseases can spread before healthcare and public health systems fully recognize and understand the scope of the situation. For example, during the MV Hondius outbreak, some passengers returned to their home countries before the outbreak had been identified. This resulted in individuals being monitored across multiple regions across the world.
Thus, the recent Hantavirus outbreak acts as a reminder that unfamiliar infectious diseases can appear unexpectedly and require rapid responses from both healthcare and public health organizations. Strengthening partnerships before the occurrence of outbreaks allows healthcare systems and public health to respond more effectively when future events arise. The ability to quickly and consistently share information and guidance on topics such as isolation and personal protective equipment (PPE), environmental cleaning and disinfection, testing, vaccines, treatment and post-exposure prophylaxis can reduce confusion while improving the efficiency of outbreak response efforts.
Lessons learned from this experience include improving and maintaining collaboration with key partners, bridging clinicians and public health, developing clear guidance, and standardizing responses and communication processes when responding to these pathogens. For example, during the response for Andes virus the Los Angeles County Department of Public health maintained routine check-in meetings with the Region IX Special Pathogens center and the California Department of Health to ensure relevant stakeholders were updated during a highly evolving situation and pre-emptively had discussions regarding transportation scenarios and PPE guidance with EMS colleagues. During the response to an Andes virus case in King County, Washington, Public Health – Seattle & King County (PHSKC) partnered with the Northwest Healthcare Response Network (NWHRN), Washington state's healthcare coalition, to convene local healthcare partners and the Region X Special Pathogens Center. Together, they coordinated communication regarding the evolving outbreak response and aligned healthcare assessment and care planning in the event that a returning traveler required evaluation or treatment. This early, proactive coordination made a real difference, and they were able to stay ahead of the situation rather than react to it, which is a testament to the strength of the relationships and communication channels already in place across King County.
Without shared resources, guidance, and coordination between public health and healthcare systems, providers risk misdiagnosing or delaying the detection of high-impact pathogens—whether rare like Andes virus or common like measles. This delay can lead to outbreaks in communities and healthcare facilities before anyone can implement isolation and control measures. CORHA offers free online tools and resources to help detect, investigate, and control outbreaks involving healthcare-associated infections with CORHA’s Principles and Practices providing the knowledge base and strategies needed for effective healthcare outbreak response.9 These resources may be helpful for equipping both hospital and public health teams to rapidly recognize unusual illness patterns, coordinate appropriate laboratory testing across clinical and public health capabilities, and implement timely outbreak control measures.
References
- Andes Virus Outbreak Working Group. Andes Hantavirus Outbreak on a Cruise Ship, 2026 New Engl J med 2026; 394:2477-2479. DOI: 10.1056/NEJMc2606496
- CORHA, Bridging Gaps in Responding to High-Impact Pathogens; September 5, 2025; https://corha.org/news/bridging-gaps-in-responding-to-high-impact-pathogens
- Kakoullis L, Carr E, Baissary J, et al Andes Virus Exposure and Nosocomial Transmission Events to Healthcare Personnel: A Systematic Review, Clin Infect Dis, 2026; ciag394, https://doi.org/10.1093/cid/ciag394
- Martinez VP, Paola ND, Alonso DO, et al. “Super-Spreaders” and Person-to-Person Transmission of Andes Virus in Argentina N Engl J Med 2020; 383:2230-2241.
- Harris GH, Sinchi A, Lawler J, Frank M. Andes Virus-A Clinical Review 2026; DOI: 10.1056/NEJMra2606651
- U.S. Centers for Disease Control and Prevention, Health Alert. 2026 Hantavirus Outbreak: Testing for Potential Infection, May 18, 2026. https://www.cdc.gov/han/php/notices/han00529.html
- NETEC, Strengthening the Response for High Consequence Infectious Disease Preparedness; August 5, 2025; https://netec.org/2025/08/05/strengthening-the-response-a-framework-for-high-consequence-infectious-disease-preparedness/
- Van den Heuvel M. Cruise Ship Outbreak Raises Andes Virus Spread Concerns. May 11, 2026. Medscape. https://www.medscape.com/viewarticle/cruise-ship-outbreak-raises-andes-virus-spread-concerns-2026a1000f0e
- Council for Outbreak Response: Healthcare-Associated Infections (HAIs) and Antimicrobial-Resistant (AR) pathogens (CORHA); https://corha.org/