Criteria

World Health Organization (WHO): surveillance case definition[75]

Suspected case:

  • A person who presents with a febrile illness (fever >101.3°F [38.5°C] 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 exam demonstrating noncardiogenic pulmonary edema without an identifiable specific cause of death.

Confirmed case:

  • A suspected case laboratory confirmed with:

    • The presence of hantavirus-specific immunoglobulin M (IgM) antibodies or a four-fold or greater increase in IgG antibody titers or hantavirus-specific IgG seroconversion

    • A positive reverse transcriptase polymerase chain reaction (RT-PCR) result for hantavirus RNA

    • Positive immunohistochemical results for hantavirus antigens.

World Health Organization (WHO): Andes virus (ANDV) infection case definition in the context of cruise ship outbreak[64]

Suggested case definition in the context of the MV Hondius cruise ship outbreak (current as of 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 (100.4°F [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:

  • A person with signs and symptoms of a suspected case that has been evaluated by a health professional AND has a known epidemiologic 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:

  • 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 6 foot (2 m) 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.

Centers for Disease Control and Prevention (CDC): hantavirus pulmonary syndrome (HPS) - 2015 case definition[62]

Clinical description:

  • An acute febrile illness (i.e., temperature greater than 101°F [38.3°C]) with a prodrome consisting of fever, chills, myalgia, headache, and gastrointestinal symptoms, and one or more of the following clinical features:

    • Bilateral diffuse interstitial edema; or

    • Clinical diagnosis of acute respiratory distress syndrome; or

    • Radiographic evidence of noncardiogenic pulmonary edema; or

    • An unexplained respiratory illness resulting in death, which includes an autopsy exam that demonstrates noncardiogenic pulmonary edema without an identifiable cause; or

    • Healthcare record with a diagnosis of HPS; or

    • Death certificate that lists HPS as a cause of death or as a significant condition contributing to death.

Laboratory criteria:

  • Detection of hantavirus-specific IgM or rising titers of hantavirus-specific IgG; or

  • Detection of hantavirus-specific RNA in clinical specimens; or

  • Detection of hantavirus antigen by immunohistochemistry in lung biopsy or autopsy tissues.

Case classification:

  • Confirmed: a clinically compatible case of HPS with laboratory evidence.

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