In 1993, a man and woman living on the Navajo Reservation in Muerto Canyon, New Mexico, suddenly experienced high fever, muscle pain, headache, and cough. Their lungs soon filled with fluid, and death from respiratory failure followed, first the woman and five days later the man. Public inquiries by the New Mexico Department of Health revealed twenty similar cases of acute respiratory distress in the region where the four states of New Mexico, Arizona, Utah, and Colorado join, the so-called "Four Corners" area. As with the initial two cases, all had been healthy young adults. Their mean age was thirty-four years. Of the twenty afflicted, half died.
Evaluation of these patients' medical histories and analysis of samples taken from their blood and tissues at autopsy by virologists at the Communlicable Disease Center in Atlanta, Georgia, indicated that a common infectious agent