Community-acquired pneumonia: new facets of an old disease--Hantavirus pulmonary syndrome.

It seems that with climatic and geoecologic changes, Hantaviruses have re-emerged as human pathogens related to increases in interaction between humans and rodent reservoirs. Infection with SNV in North America and the Andes virus in South America can produce infection manifest initially as a flu-like illness. In the setting of a history of possible exposure to rodents or their excreta, clinical symptoms and laboratory clues such as thrombocytopenia should raise the suspicion of HPS. Clinical deterioration can be rapid, so patients should be hospitalized and transported to tertiary care centers where mechanical ventilation is available if necessary. Presumptive treatment for other forms of sepsis should be considered before confirmation of diagnosis. Survival seems to be determined in part by viral and host factors. Canadian and South American data suggest that there may be species variations influencing clinical manifestations and course of disease. Because the pathogenesis seems to be based on immunologic injury, future treatments will likely focus on interventions other than antiviral medications. Prevention strategies should be emphasized, particularly when recognized climatic conditions favor rodent abundance. Physicians should remain alert to the possibility of such a diagnosis when evaluating a patient with CAP and should request appropriate serology while supporting the patient in a closely monitored setting. The declining mortality rates seen over the past decade may be a consequence of improved medical management or better recognition of cases, including those less severe than originally described.