Welcome to the Hantavirus Outbreak toolbox

Key reference documents

Hantavirus Fact sheet (WHO, 2026)
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 (WHO, 2026)
Management of contacts of Andes virus (ANDV) cases from the MV Hondius cruise ship: Interim guidance (WHO, 2026)
Hantavirus in the Americas: guidelines for prevention, diagnosis, treatment, and control (PAHO, 1999) (EN, ES)
Hantavirus (United States Centers for Disease Control and Prevention, USCDC, 2024)
Hantavirus case definition and reporting (USCDC, 2025)

Case definitions

Suggested Hantavirus pulmonary syndrome surveillance case definition*

Suspected case

A person who presents with a febrile illness (Fever > 38.5 °C [103 °F] oral) with an acute respiratory distress syndrome requiring supplemental oxygen AND bilateral diffuse infiltrates developed within 72 hours of hospitalization in a previously healthy person
Unexplained illness resulting in death plus an autopsy examination demonstrating noncardiogenic pulmonary oedema without an identifiable specific cause of death

Confirmed case

A suspected case laboratory confirmed with:

The presence of hantavirus-specific IgM antibodies or a 4-fold or greater increase in IgG antibody titres or hantavirus-specific IgG seroconversion.
A positive reverse transcriptase-polymerase chain reaction (RT-PCR) results for hantavirus RNA.
Positive immunohistochemical results for hantavirus antigens.

*These definitions are suggested to be used for surveillance purposes in the Americas (Hantavirus in the Americas: guidelines for prevention, diagnosis, treatment, and control (PAHO, 1999)). Different case definitions may be used during outbreaks and in different contexts.

WHO suggested Andes virus (ANDV) infection case definition in the context of the MV Hondius cruise ship outbreak (11 May 2026)

Suspected case

Anyone who shared or visited a conveyance where there has been a confirmed or probable 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, diarrhoea, abdominal pain) or acute respiratory (e.g. cough, shortness of breath, chest pain, difficulty breathing) symptoms.

Probable case

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 or serology testing.

Contact person

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.