NOTE: A surveillance case definition is a set of uniform criteria used to define a disease for public health surveillance. Surveillance case definitions enable public health officials to classify and count cases consistently across reporting jurisdictions. Surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health needs.
Hantavirus pulmonary syndrome, commonly referred to as Hantavirus disease, is a febrile illness characterized by bilateral interstitial pulmonary infiltrates and respiratory compromise requiring supplemental oxygen and simulating adult respiratory distress syndrome (ARDS). The typical prodrome consists of fever, chills, myalgias, headaches, and gastrointestinal symptoms. Typical clinical laboratory findings include hemoconcentration, left shift in the white blood cell count, neutrophilic leucocytosis, thrombocytopenia, and circulating immunoblasts.
An illness characterized by one or more of the following clinical features:
- A febrile illness (i.e., temperature >101°F [38.30°C]) occurring in a previously healthy person characterized by a) unexplained ARDS or b) bilateral interstitial pulmonary infiltrates with respiratory compromise requiring supplemental oxygen, developing within 72 hours of hospitalization.
- An unexplained respiratory illness resulting in death, with an autopsy examination demonstrating non-cardiogenic pulmonary edema without an identifiable cause.
Laboratory Criteria for Diagnosis
- Detection of hantavirus-specific immunoglobulin M or rising titers of hantavirus-specific immunoglobulin G, OR
- Detection of hantavirus-specific ribonucleic acid sequence by polymerase chain reaction in clinical specimens, OR
- Detection of hantavirus antigen by immunohistochemistry
A clinically-compatible case with laboratory criteria for diagnosis
Laboratory testing must be performed or confirmed at a reference laboratory. Because the clinical illness is non-specific and ARDS is common, a screening case definition should 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 hantavirus, and patients who have these underlying conditions and ARDS should not be tested for hantavirus.