In 1993 in the Four Corners region of the US Southwest a woman developed a cough and progressive shortness of breath and died shortly thereafter. A few days later, her fiancée, a young physically fit man developed similar symptoms was rushed to a hospital and also died. A series of laboratory tests failed to identify any known infectious agent. The Centers for Disease Control and Prevention (CDC) Special Pathogens Branch was notified. Further testing revealed a previously unknown strain of han...