Hantavirus

Hantaviruses are enveloped, segmented negative-sense single-stranded RNA viruses. Transmission is primarily through inhalation of aerosolized rodent excreta rather than person-to-person spread. In the Americas, Sin Nombre virus (carried by deer mice) causes Hantavirus Pulmonary Syndrome (HPS), presenting with a prodrome of fever, myalgias, and GI symptoms followed by rapid progression to noncardiogenic pulmonary edema and respiratory failure due to increased capillary permeability from cytokine-mediated endothelial dysfunction. In Europe and Asia, hantaviruses (e.g., Hantaan virus) cause Hemorrhagic Fever with Renal Syndrome (HFRS), characterized by fever, hemorrhage, and acute kidney injury progressing through five phases: febrile, hypotensive, oliguric, diuretic, and convalescent. Pathophysiology involves infection of endothelial cells and activation of immune-mediated capillary leak syndrome rather than direct cytopathic effect. Risk factors include exposure to rodent-infested areas (e.g., cleaning barns, cabins in endemic regions like the Four Corners area of the US). Diagnosis is via serology (IgM/IgG) or RT-PCR; treatment is supportive with ICU care, though ribavirin has been used for HFRS. There is no vaccine available in the US. High-yield board associations: deer mouse exposure, Four Corners region, noncardiogenic pulmonary edema, thrombocytopenia, and hemoconcentration.