Transmission electron micrograph (TEM) revealed the ultrastructural appearance of a number of virus particles, or "virions", of the hantavirus known also, as the Sin Nombre virus (SNV). Infection with hantavirus can progress to Hantavirus Pulmonary Syndrome (HPS), which can be fatal. People become infected through contact with hantavirus-infected rodents or their urine and droppings. The Sin Nombre hantavirus, first recognized in 1993, is one of several New World hantaviruses circulating in the US. Old World hantaviruses, found in Asia, can cause Hemorrhagic Fever with Renal Syndrome (HFRS). Rodent control in and around the home remains the primary strategy for preventing hantavirus infection. All cases of Hantavirus infection are reported to and researched by the Viral Special Pathogens Branch (VSPB) of the CDC. Magnification: unknown.