Hantaviruses: a tale of two hemispheres.

Infectious febrile nephropathies, initially described as epidemics during military campaigns in Europe and Asia at the turn of the 20(th) century, were eventually all unified under the rubric of hemorrhagic fever with renal syndrome (HFRS) and ascribed to infection from rodent-borne hantaviruses. At the end of the century, hantavirus pulmonary syndrome (HPS) was described throughout the Americas as a consequence of infection with the New World hantaviruses. The epidemiology and clinical manifestations of these diseases are linked to the ecology of their associated rodent hosts. Murine rodents (Old World mice and rats) are associated with the severe forms of HFRS in Asia and the Balkans due to Hantaan, Dobrava, and Seoul viruses. Hantaan virus causes an estimated 50-100,000 infections a year in China alone. Arvicoline rodents (voles) are associated with a mild form of HFRS in Europe called nephropathia epidemica due to Puumala virus. Sigmodontine rodents (New World rats and mice) are associated with approximately 200 HPS cases per year throughout the Americas caused by over a dozen viruses. The viruses are mainly transmitted as small-particle aerosols of rodent excreta, and the subsequent infections share cardiovascular shock as a prominent feature, although HFRS causes predominantly renal disease, while HPS causes a predominantly non-cardiogenic pulmonary edema - hemorrhage involvement varies in the syndromes on the basis of virus subtypes. Efforts are underway to refine prevention strategies, understand the pathogenesis of the shock, and identify therapeutic modalities.