Archived: Rapid risk assessment: Hantavirus (Andes virus) linked to international cruise ship outbreak

Assessment completed: May 29, 2026 (based on information available up to May 26, 2026)

On this page

• Reason for reassessment
• Risk question
• Risk statement
• Event summary (current situation as of May 26, 2026)
• Considerations for pathogens with pandemic potential
• Risk assessment details
• Limitations, knowledge gaps, and uncertainties
• Proposed actions
• Reassessment
• Methods
• Footnotes
• References

Reason for reassessment

Given that the individuals aboard the cruise ship MV Hondius (between April 1 and May 10, 2026) have all been identified as high risk for contracting the hantavirus (Andes virus (ANDV), identification of cases among this cohort is expected; one such case has been confirmed in Canada.^{Footnote 1} This assessment focuses on the risk of onward transmission outside of this cohort, which has not been observed to date globally, highlighting what is known and not known in relation to ANDV transmission dynamics. For further information on the situation see Event summary.

Risk question

What is the likelihood and impact of at least one individual confirmed with ANDV among the contacts^{Footnote a} of the MV Hondius cruise ship passengers and crew being identified in Canada within the next 4 weeks?

Risk statement

The overall risk of acquiring ANDV for the general population in connection with the ongoing cruise ship outbreak continues to be low (high uncertainty), as onward spread within Canada is not expected given ongoing public health measures.

The likelihood of at least one individual confirmed with ANDV among contacts^{Footnote a} of the MV Hondius cruise ship passengers and crew being identified in the next four weeks is low (high uncertainty), due to both the nature of their exposures and that all of these contacts are nearing the end of their potential incubation and self-monitoring period. The anticipated impact on those infected continues to be major (low uncertainty) as ANDV illness often requires hospitalization and can result in death. If at least one individual were to become positive, the impact of ANDV on the general population in Canada would be minor (high uncertainty). Although close contact is typically required for the limited person-to-person transmission of ANDV that has been documented, current evidence does not rule out potential for transmission from casual contact.

Event summary (current situation as of May 26, 2026)

This hantavirus (ANDV) outbreak is evolving. Please visit the most recent situation updates from the World Health Organization (WHO) and the Public Health Agency of Canada for the latest information on the event and Canada's response.

Six Canadians were identified as having been aboard the MV Hondius cruise ship, all of whom have returned to Canada. Of these, one confirmed case is hospitalized and isolated, and the other five are in quarantine (self-isolation) with monitoring. In addition to the six passengers, there are 30 contacts in Canada being monitored: three high-risk contacts and 27 low-risk contacts (all of which are linked to flight exposures); one additional contact is being monitored abroad. A WHO risk assessment completed May 15, 2026, assessed the global risk as low related to this outbreak.^{Footnote 2}

Considerations for pathogens with pandemic potential

At this time, ANDV is not considered to be a pathogen with pandemic potential. While limited person-to-person transmission of ANDV has been reported in the past, to date it has mainly been associated with close and prolonged contact and has not demonstrated the capacity for widespread prolonged transmission.^{Footnote 3} Additionally, there is evidence from in vivo passage studies that ANDV has high genomic stability and does not mutate easily.^{Footnote 4}

Risk assessment details

Limitations, knowledge gaps, and uncertainties

The overall uncertainty in this assessment is high, due to the following:

• There are significant knowledge gaps characterising the nature and extent of person-to-person transmission of ANDV. Observational studies currently indicate that ANDV spreads via exposure to infectious body fluids.^{Footnote 7Footnote 8Footnote 15} The possibility of ANDV aerosolization and transmission to transient contacts cannot be ruled out, however, strong epidemiological evidence remains limited at this time.^{Footnote 16} Evidence supporting the possibility of airborne transmission is provided via animal models,^{Footnote 17} biological plausibility, noncomparative outbreak investigations,^{Footnote 3} and molecular research.^{Footnote 18} Investigations of outbreaks of ANDV human-to-human transmission are very limited in number and size of affected populations.
• Poorly characterized incubation period and unknowns surrounding the possibility that ANDV can be spread while an individual is pre-symptomatic or asymptomatic.
• Limited information about the length of time an individual remains infectious post symptom onset.

Factors that would increase the risk include identification of cases from contacts not currently identified by public health, evidence of transmission before an individual is symptomatic, or infectivity during convalescence.

Proposed actions

• Continue utilizing the precautionary principle given the risk of ANDV person-to-person transmission. ANDV should be treated as a communicable disease as noted in the Quarantine Act.
• Continue case and contact management in a precautionary manner with quarantine (self-isolation) and self-monitoring as currently led by provinces and territories, and follow established Infection Prevention and Control Protocols as per federal or provincial and territorial guidance.
• Consider using existing clinical management guidelines from endemic countries, and where needed consider developing mechanisms to support clinicians with interim guidance, embed ethical research frameworks like the WHO MEURI framework for emergency use of unproven clinical interventions outside of clinical trials during public health emergencies.
• Continue targeted communications to public health and healthcare professionals for awareness and readiness to support early detection, diagnosis/testing, management, and notifying public health authorities as per their protocols.
• Consider supporting data collection, science and research activities (especially to explore transmission dynamics) to address knowledge gaps and contribute to emerging evidence for public health decision making.
• Consider research activities to test broad-spectrum antivirals and vaccine candidates for Andes virus, appropriate to their current stage of development.
• Continue timely coordinated risk communications informing people in Canada of the ANDV outbreak, any changes to domestic epidemiology, the level of risk, actions taken by public health authorities, and provide concrete actions individuals can take to protect themselves from hantavirus in general ( e.g., Sin Nombre).

Reassessment

The risk assessment team will reconvene to review new evidence and evaluate the need for reassessment if there is new evidence changing our understanding of person-to-person transmission of ANDV or if the situation escalates.

Methods

This assessment was completed by the Public Health Agency of Canada. The rapid risk assessment (RRA) methodology is based on the World Health Organization (WHO) Member State RRA tool.^{Footnote 19} Likelihood, impact, and overall risk were estimated using previously described scales and risk matrix (see risk assessment methods page), and capacity to respond was estimated using the WHO tool.^{Footnote 19}