Hantavirus Pulmonary Syndrome (HPS) is an uncommon respiratory disease caused by hantaviruses, most often the Sin Nombre virus. Though rare, HPS can be fatal. Deer mice are the primary carriers for the virus though other rodents can carry the virus as well. The virus is shed in the droppings, urine, and saliva of rodents. Humans can become infected when they inhale the virus which can get into the air when rodent droppings, urine, or nesting materials are agitated. Humans cannot transmit the virus to one another (e.g. close contact with or providing healthcare to someone who is infected).