MICE AND HUMANS - THE STORY OF AN UNANNOU NCED OUTBREAK

In May 1993, a pulmonary disease syndrome with novel clinical and epid emiologic features was identified in the southwestern United States. H ealthy young adults developed a febrile prodrome followed by the rapid onset of often lethal acute respiratory distress. Although an infecti ous disease was suspected, intensive investigations initially failed t o identify the causative agent. Multiple specialized microbiology labo ratories in a national reference center applied classic serologic and culture methods as well as recently developed molecular biological tec hniques to samples collected from field investigations of the patients . Serologic tests detected the presence of an active immune response t o a hantavirus. Reverse transcription and polymerase chain reaction am plification of RNA extracted from human tissues used primers designed from sequences of known hantaviruses to demonstrate genomic sequences of a novel hantavirus. Immunohistochemistry showed the presence of han tavirus antigens in the endothelium of lung tissues from patients and provided a final pathogenetic link to this group of viruses. These met hods were concordantly positive in virtually all samples available fro m 18 patients with compatible clinical histories identified between Ja nuary and July 1993. Tests of control subjects and searches for other agents in identified cases were negative. A newly recognized hantaviru s causes a novel syndrome of acute pulmonary edema and shock; the path ogenesis is related to the presence of virus antigens in the pulmonary capillaries. This virus may be an important cause of severe and fatal disease presenting as adult respiratory distress syndrome in otherwis e healthy persons. The Centers for Disease Control in collaboration wi th state and local health departments has begun a national surveillanc e program to determine the incidence of this newly described disease a nd is coordinating longitudinal and wider geographic studies of the na tural history virus-rodent relationship.