Clinical Case Definition
An illness characterized by one or more of the following clinical features:
- A febrile illness (i.e., temperature greater than 101.0° F (greater than 38.3° C) characterized by bilateral diffuse interstitial edema that may radiographically resemble ARDS, with respiratory compromise requiring supplemental oxygen, developing within 72 hours of hospitalization, and occurring in a previously healthy person.
- An unexplained respiratory illness resulting in death, with an autopsy examination demonstrating noncardiogenic pulmonary edema without an identifiable cause.
Laboratory Criteria for Diagnosis
- Detection of hantavirus-specific immunoglobulin M or rising titers of hantavirus-specific immunoglobulin G.
- Detection of hantavirus-specific ribonucleic acid sequence by polymerase chain reaction in clinical specimens.
- Detection of hantavirus antigen by immunohistochemistry.
Case Classification
Confirmed: a clinically compatible case that is laboratory confirmed.
Comment
Laboratory testing should be performed or confirmed at a reference laboratory. Because the clinical illness is nonspecific and ARDS is common, a screening case definition can be used to determine which patients to test. In general, a predisposing medical condition (e.g., chronic pulmonary disease, malignancy, trauma, burn, and surgery) is a more likely cause of ARDS than HPS, and patients who have these underlying conditions and ARDS need not be tested for hantavirus.