Abstract The number of known HPS cases in the United States is now more than 150, and the illness has occurred in all geographic areas of the country. Though the incidence of the disease is low, the mortality rate remains at 50%, owing to the difficulty in treating a simultaneous severe pulmonary capillary leak syndrome and cardiogenic shock. Adequate treatment of severe cases requires experienced critical care physicians and nurses, as well as advanced facilities. Although nosocomial transmission appears unlikely in North America, universal precautions must be used, and some consideration may be given to the use of respiratory isolation.