Interim guidance: Public health management of contacts of Andes virus cases from MV Hondius cruise ship (May 26, 2026)

On this page

• Introduction
• Definitions
• Risk-based classification of contacts
• Management and follow-up of contacts
• Travel measures
• Diagnostic laboratory testing
• Case management
• Updates
• Appendix: Testing strategy for high-risk contacts of the Andes virus (ANDV): Decision tree for public health response
• Resources

Introduction

Federal, provincial and territorial public health governments and agencies in Canada are applying a risk-based approach to the identification, investigation, monitoring and management of contacts of probable or confirmed Andes virus (ANDV) cases related to the MV Hondius cruise ship (voyage between April 1 and May 10, 2026). Human-to-human transmission of ANDV has been reported (data is limited), generally related to close and prolonged contact with an infected person while they are symptomatic.

The purpose of this guidance is to support a coherent and common approach to public health management of case contacts across public health authorities in Canada, with an aim to minimize opportunities for human transmission. In the context of the cluster of ANDV related to the MV Hondius cruise ship, the Public Health Agency of Canada (PHAC) has assessed the risk to the general public as low; this may be updated based on changes in epidemiological conditions in Canada and other countries.

The recommendations in this guidance follow a precautionary approach given some uncertainty surrounding the associated public health risk and evolving nature of the ANDV outbreak. This guidance is adapted from the WHO Interim Guidance (issued May 8 and updated May 15, 2026). Set in the Canadian context, this guidance is subject to change as new information becomes available (e.g. on incubation period, infectious period, transmission risk, epidemiology on ship, original exposure source, etc.) and the situation in other countries and in Canada unfolds. This guidance should be interpreted and applied in conjunction with relevant provincial/territorial and municipal legislation and policies, and consider factors such as local context, epidemiology, and other jurisdiction-specific considerations.

Definitions

Suspected case

Anyone who shared or visited a conveyance where there has been a confirmed or probable ANDV case OR had contact with a probable or confirmed ANDV case AND with acute (or history of) symptoms compatible with ANDV infection, including fever (38°C or above), myalgia, chills, acute gastrointestinal (e.g. nausea, vomiting, diarrhea, abdominal pain) or acute respiratory (e.g. cough, shortness of breath, chest pain, difficulty breathing) symptoms.

Probable case ^{Footnote 1}

A person with signs and symptoms of a suspected case that has been evaluated by a health professional AND has a known epidemiological link with a confirmed or probable ANDV case AND for which laboratory results are not available.

Confirmed case

A person with laboratory confirmation of ANDV through RT-PCR testing of blood and/or paired hantavirus serology.

Non-case ^{Footnote 2}

Infection cannot be ruled out during the incubation period while a contact is asymptomatic. A suspected or probable symptomatic case who tests negative for ANDV by RT-PCR can be considered to be a non-case, particularly if supported by an alternative diagnosis. Serology may be helpful follow-up especially if there is a negative baseline and if the specimen is taken at an appropriate time after onset of symptoms.

Contact

A person who was exposed to a confirmed or probable case of ANDV while the case was infectious, through interactions consistent with exposure to respiratory secretions, saliva, blood, or other bodily fluids; including:

• Direct physical contact, including exposure to saliva or other bodily fluids (e.g. care giving, intimate contact, sharing a bed, etc.)
• Close proximity exposure, defined as being within 2 meters for a cumulative period of more than 15 minutes (e.g. face to face interactions, shared meals or other social gatherings)
• Exposure in enclosed or shared spaces (e.g. multiple days on same ship, aircraft/conveyance seating proximity, etc.)
• Unprotected exposure in healthcare settings, particularly during patient care, as well as laboratory exposure. Refer to Notice: Interim recommendations for infection prevention and control of Andes hantavirus in healthcare settings ( June 2026) for detailed information on unprotected exposure.

Infectious period

The period of infectiousness or transmissibility is not precisely defined but is generally from the onset of symptoms until the recovery or death of the case. Pre-symptomatic transmission (up to 2 days before febrile presentation) of ANDV has been suggested based on RT-PCR detection and as such cannot be ruled out. ^{Footnote 3} The highest period of infectiousness is from onset (starting with non-specific febrile presentation) and throughout the prodromal and symptomatic phase (estimated at approximately 1 week) based on available outbreak data. The precise duration of infectiousness beyond the acute phase is not fully characterised. Given this, as a precautionary measure, it is recommended that contacts be identified from 2 days prior to reported symptom onset and 5 days after symptom onset of a confirmed or probable case.

Date of last exposure

Date of last contact with a confirmed or probable case. For MV Hondius passengers and crew members who disembarked in the Canary Islands, this is the date of disembarkation, May 10, 2026. For passengers who disembarked earlier or who were only on flights with a confirmed, it is the date of disembarkation from either the ship or the plane.

Risk-based classification of contacts

A precautionary approach is being taken to identifying, listing, tracking and follow-up of contacts. Public health authorities are assessing contacts of ANDV cases, classifying and managing them as high- or low/minimal-risk categories based on the intensity and duration of exposure, proximity to the case, type of interaction (e.g. direct contact vs. enclosed or shared spaces) and use of personal protective equipment.

High-risk contacts (adapted WHO definition)

Individuals with 1 or more of the following exposures with a probable or confirmed ANDV case:

• All passengers and crew on the MV Hondius after 1 April 2026 and before complete disembarkation and disinfection of the ship who were not consistently and appropriately wearing personal protective equipment (PPE).
• Persons sharing the same household, cabin or room.
• Intimate partners or individuals with direct physical contact.
• Persons sharing a bathroom or sleeping space.
• Persons within approximately 2 meters for prolonged periods (more than 15 minutes cumulative) without appropriate personal protective equipment.
• Persons participating in shared meals, prolonged social interactions, or caregiving activities.
• Healthcare workers exposed without wearing appropriate PPE.
• Aircraft passengers seated in the same row and/or within 2 rows in all directions from a confirmed case.
• Persons handling linens, clothing, other personal items of the case, medical waste, or body fluids without appropriate PPE.

All high-risk contacts will be managed the same regardless of source of potential exposure (e.g. cruise or flight).

Low-risk contacts (adapted WHO definition)

Individuals who have attended an event, been in a conveyance with a probable or confirmed ANDV case but have no known direct or prolonged close interaction, with the case including:

• Aircraft passengers outside the defined seating proximity zone, on a flight where a confirmed case was infectious.
• Persons with brief (less than 15 minutes cumulatively) indoor contact without documented bodily fluids exposure.

Note: Following provincial/territorial or local public health's interview and assessment of an individual's risk based on additional information, the classification of contacts and their related implementation of measures may be changed over time by local public health. Individuals who do not meet the high- or low-risk contact definitions outlined above are not considered contacts for public health risk assessment and follow-up.

Management and follow-up of contacts^{Footnote 4}

High-risk contacts: Active monitoring and quarantine ("self-isolation")

Duration of quarantine: 42 days minimum from day of last exposure to a probable or confirmed ANDV case during the case infectious period.

Self-quarantine/self-isolation:

• Should self-isolate for 42 days minimum since last exposure to case.
• Avoid contact with other household members, where possible remain in a separate, well-ventilated room or area, do not share towels, linen, cutlery etc. Where separation within a household is not feasible, public health authorities should assess the suitability of alternative self-isolation accommodation.
• Wash any bedding and clothing with laundry detergent in hot water.
• Clean and disinfect the environment and objects/surfaces with common household disinfectants.
• Waste should be managed like normal.
• Refrain from returning to work for designated period (including healthcare workers), unless able to telework.

Follow-up: Public health authorities should conduct daily active monitoring and recording of symptoms for 42 days minimum after last known exposure as defined above, during which time the contact should be advised to avoid contact with other persons through remaining in a designated location or at home. Follow-up may be by telephone, messaging, telehealth, or in person (see Annex 1).

Protective measures: In case social interactions are unavoidable, including when interacting with other household members and/or visitors, high-risk contacts should wear a respirator (e.g. FFP2 or N95 respirator), practice physical distancing, and practice regular hand hygiene.

Symptom reporting: Any of these symptoms should be communicated as soon as possible to the responsible local public health authorities: temperature, fever, fatigue or malaise, muscle ache, headache, gastrointestinal symptoms, respiratory symptoms.

Information: Contacts should receive from public health:

• Written information on signs and symptoms to look out for.
• Direction to contact public health immediately at onset of any symptoms and to call ahead before attending any healthcare facility.
• Emergency contact numbers.
• Instructions regarding healthcare seeking and testing.

Low-risk contacts: Passive self-monitoring

Duration of self-monitoring: Self-monitor daily, and for 42 days minimum from last exposure, for fever (using a thermometer, recording daily temperature), malaise, muscle ache, headache, gastrointestinal symptoms, respiratory symptoms, using a contact follow-up form (see Annex 2). Local public health may follow-up to check-in with low-risk contacts periodically based on local risk assessment and capacity.

Daily activities: Generally, no restrictions of the contact's daily occupational or recreational activities are warranted. Local public health may determine if any potential restrictions are required based on local risk conditions and context.

Symptom reporting: temperature, fever, fatigue or malaise, muscle ache, headache, gastrointestinal symptoms, respiratory symptoms, should be promptly reported to local health authorities. Call ahead before going to health care provider/facility.

Information:

• Written information on symptoms to look out for.
• Emergency contact numbers.
• Instructions regarding healthcare seeking and testing. and healthcare seeking

Travel measures

High-risk contacts: Avoid all travel for 42 days.

• Exception may be made for foreign nationals whose country arranges repatriation and continuation of quarantine or self-isolation in home country; arrangements need to be made in coordination with Government of Canada, ensuring public health measures in place.
• Movement of the contact out of the jurisdiction of public health authorities in charge of their follow-up may be allowed for life-threatening or humanitarian reasons, provided it is approved by local public health in discussion with PHAC and that arrangements are made with the public health authorities in the jurisdiction at destination, including internationally through International Health Regulations (IHR) National Focal Point (PHAC).

Low-risk contacts: All non-essential travel should be strongly discouraged during the 42-day self-monitoring period and should be postponed until after the end of the self-monitoring period.

• There are significant uncertainties regarding how public health measures related to the Andes hantavirus outbreak are implemented in other countries, including individuals not being permitted to board a plane or enter a country, or facing quarantine requirements on arrival.
• Any essential travel of the contact out of the jurisdictions of public health authorities in charge of their follow-up must be arranged with the public health authorities in the jurisdiction at destination, including internationally through IHR National Focal Point (PHAC).

Government of Canada and province to take risk-based, case-by-case approach with local public health risk assessment to inform inclusion or extension of individual on no board list for domestic or international flights originating from Canada.

Government of Canada is not permitting entry of any foreign nationals to Canada that were on MV Hondius cruise ship from April 1 to May 10, 2026 to prevent further importation of Andes virus to Canada. This will be lifted at the end of the 42-day period following the last day of the cruise (May 10, 2026).

Diagnostic laboratory testing

• High- or low-risk contact individuals with compatible ANDV symptoms and relevant epidemiological risk factors (e.g. exposure linked to the MV Hondius cruise ship cluster) should be promptly isolated, managed according to recommended infection prevention and control practices Footnote5, clinically evaluated and should undergo ANDV testing for infection as soon as possible after symptom onset, alongside other investigations guided by the clinical presentation and differential diagnosis.
  • The optimal time for testing is as soon as possible after symptom onset.
  • If results are negative early on in symptom onset, retesting can be done after 72 hours.
• Testing of asymptomatic individuals, including low-risk contacts is at the discretion of provinces and territories.
• Testing of infection by viral detection should be done using RT-PCR on whole blood or serum/plasma.
• Testing for symptomatic and asymptomatic patients should be undertaken in conjunction with local or regional public health guidance and their respective laboratory notification pathways.
  • Prior to shipping specimens from suspected or confirmed Andes virus cases, laboratories must notify public health and the provincial public health laboratory to ensure appropriate testing indications, preparation, transport, and response.
• Molecular detection for the detection of Andes virus RNA via RT-PCR testing can be done by provincial public health labs or the National Microbiology Laboratory (NML) if a jurisdiction does not have RT-PCR capability for hantavirus.
• Samples that have undergone molecular testing at provincial public health labs should also be sent to NML for parallel confirmatory testing to satisfy IHR reporting requirement.
• If serological testing is offered, samples are to be submitted to NML in parallel with molecular testing for the detection of IgM/IgG antibodies. Acute and convalescent samples are needed for symptomatic contacts for the detection of IgM and IgG antibodies indicative of recent/past infection.
• For further details on lab testing and biosafety, please see NMLB Laboratory Testing for Andes Virus (ANDV) Guidance (PDF) for further details and Molecular Detection of Andes virus (CNPHI).

Case management

The scope of this guidance does not include advice on the public health or clinical management of confirmed cases of ANDV in Canada. Drawing from the Pan-American Health Organization's Infection prevention and control of hantavirus infection, including Andes virus disease (Interim regional guidance for suspected or confirmed cases), jurisdictions may wish to consider the following:

• Initial management should begin at the point of first clinical suspicion and should prioritize early monitoring, and timely clinical evaluation and referral according to clinical management protocols. Every patient with a well-founded suspicion of hantavirus infection should be managed as potentially severe, even if initially stable. The window for effective intervention is early.
• Because transport may be delayed in rural or remote settings, early referral at initial suspicion is recommended to ensure timely access to advanced care. Do not delay referral while waiting for confirmatory results. Do not delay transfer solely to complete stabilization if this exposes the patient to preventable deterioration. Early transfer to a higher level of care should be considered at the stage of initial suspicion, particularly in settings where clinical deterioration may limit the feasibility or safety of later transfer.

Updates

This guidance is subject to change based on changes to global or domestic epidemiology and risk conditions, ANDV properties (e.g. transmissibility, severity), and evolving science on testing and management of ANDV, in consultation with the federal, provincial and territorial public health governments.

Appendix: Testing strategy for high-risk contacts of the Andes virus (ANDV): Decision tree for public health response

Day 0 refers to the date of last known possible exposure to ANDV. For others, the last known date of possible exposure (Day 0) may differ between individuals depending on their specific exposure history.

Download the appendix in PDF format

Step 1: Identify contact

Ask the question: Is the individual a high-risk contact of a confirmed or probable ANDV case?

If the answer is no, the individual is a low/minimal-risk contact.

Start passive self-monitoring: self-monitor daily, and for 42 to 45 days from last exposure, for fever (using a thermometer, recording daily temperature), malaise, muscle ache, headache, gastrointestinal symptoms, respiratory symptoms). If symptoms develop, report to public health authorities.

If the answer is yes, go to step 2.

Step 2: Start monitoring

Public health authorities should conduct daily active monitoring and recording of symptoms for 42 to 45 days after last known exposure, during which time the contact should be advised to avoid contact with other persons through remaining in a designated location or at home.

Symptom reporting: Any of these symptoms should be communicated as soon as possible to the responsible local, national and international public health authorities: temperature, fever, fatigue or malaise, muscle ache, headache, gastrointestinal symptoms, respiratory symptoms.

Information: Contacts should receive from public health:

• Written information on symptoms to look out for.
• Emergency contact numbers.
• Instructions regarding healthcare seeking and testing.

Step 3: Assess symptoms

Ask the question: Has the contact developed symptoms compatible with ANDV infection?

If the answer is yes, go to Step 4.

If the answer is no, go to Step 5.

Continue active symptom monitoring at home during self-isolation for 42 to 45 days from last exposure or Day 0.

If any symptoms develop at any point, proceed to Step 4.

Step 4: Symptom triggered testing

Action

Perform immediate PCR testing; whole blood (EDTA preferred) or serum/plasma (EDTA) and nucleocapsid protein swab. NML has decentralized a Laboratory Developed Test to requesting Provincial Laboratories.^{Footnote 6}

Samples can also be submitted to NML directly. Samples that are tested at provincial public health labs should also be sent to NML for parallel testing to satisfy International Health Regulations (IHR) reporting requirements.

*Testing bodily fluid samples other than blood has generally lower diagnostic value^{Footnote 7}, blood will be prioritized, if other sample types are submitted in parallel (i.e. swabs) they will be tested if the blood is positive.

If the samples is positive, whole genome sequencing can be considered to support the epidemiological interpretation of the outbreak. It is not required for case management.

Serological testing (IgM and IgG) will be performed in parallel to PCR testing, paired samples (acute and convalescent are requested).

Interpretation of results in samples collected from patients immediately after symptom onset will assess IgM and IgM antibodies to Andes virus are present. They will require careful interpretation and are best supported with a follow-up sample to monitor for a diagnostic (4-fold or greater) rise in antibody titers.

Consider repeating serology (e.g. weekly) to assess antibody titre increase.

Interpretation

PCR or serology positive → manage as a confirmed case.

PCR/serology negative and symptoms persist:

• Provide clinical management as needed.
• Consider re-testing by PCR 2 to 3 times per week under the precautionary principle.
• Continue PCF testing until after symptom remission.
• Perform immediate PCR testing in case of any clinical deterioration.
• PCR should be conducted after symptom remission.
• Once symptoms have resolved, return to self-quarantine for the remainder of quarantine period.
• Conduct post-quarantine serology and PCR.
• If any of the PCR tests are positive → classify and manage as a confirmed case.

Step 5: Asymptomatic high-risk contact

High risk contacts entering quarantine can have a baseline sample collected for PCR and serological analysis if supported by local public health.

Following step 5, go to Step 6.

Step 6: Testing of asymptomatic high-risk contact

Perform PCR testing; whole blood (EDTA preferred) or serum/plasma (EDTA). Testing bodily fluid samples other than blood has generally lower diagnostic value.^{Footnote 6}

Serological testing (IgM and IgG) will be performed in parallel to PCR testing, paired samples (baseline and end of isolation samples are requested).

Interpretation

PCR positive

• Indicates infection with ANDV → isolate in a medical facility, monitor for symptoms and prepare to manage as a case.
• If PCR is positive, whole genome sequencing can be considered to support the epidemiological interpretation of the outbreak (not required for case management).

PCR negative

• Does not rule out infection.
• Continue active clinical monitoring during quarantine until the end of quarantine period.

Serology

• IgM positive: may suggest recent infection with ANDV → manage as a potential case, monitor for symptoms and conduct PCR testing 2 to 3 times a week for confirmation of ANDV infection. Perform repeated serology in paired sera ( 2 weeks later) for demonstration of IgG antibody titre increase.
• IgG-positive and IgM-negative: this may reflect past exposure. Continue active clinical monitoring during the quarantine period. Perform repeated serology in paired sera ( 2 weeks later) for demonstration of IgG antibody titre increase.
• IgM/IgG negative: continue active clinical monitoring during self-quarantine until the end of quarantine period.
• Hantaviruses are known to exhibit a high degree of serological cross-reactivity, particularly against the immunodominant nucleocapsid protein (NP). For this reason, serological assays like ELISAs using infected whole-cell lysates or recombinant NP antigens from related New World hantaviruses (i.e. Black Creek Canal or Sin Nombre viruses), are appropriate for the detection of IgM and IgG antibodies generated during Andes virus infection. Interpretation of results in samples collected from asymptomatic patients or immediately after symptom onset require careful interpretation and are best supported with a follow-up sample to monitor for a diagnostic (4-fold or greater) rise in antibody titers.

Continue active symptom monitoring at home during self-isolation for 42 to 45 days from last exposure or Day 0.

If any symptoms develop at any point, proceed to Step 4.

Resources

• Interim recommendations for infection prevention and control of Andes hantavirus in healthcare settings (June 2026)
• World Health Organization Hantavirus toolkit:
  • WHO Technical note for the disembarkation and onward management of passengers and crew in the context of an Andes virus-associated cluster MV Hondius cruise ship (May 8, 2026)
  • WHO Management of contacts of Andes virus (ANDV) cases from the MV Hondius cruise ship (May 15, 2026):
    • Annex 1. Initial exposure risk assessment checklist
    • Annex 2. WHO contact monitoring form
• Pan-American Health Organization: Infection prevention and control of hantavirus infection, including Andes virus disease (2026)
• Canadian Network for Public Health Intelligence: Molecular detection of Andes virus
• Rapid scientific advice on the management of passengers - In the context of the Andes virus outbreak on the cruise ship MV Hondius (ECDC, May 9, 2026)